Article

Association of conception rate with pattern and level of somatic cell count elevation relative to time of insemination in dairy cows

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

The aim was to evaluate the effects of mastitis, determined by the pattern and level of somatic cell count (SCC) around first artificial insemination (AI), on conception rate (CR). Data from 287,192 first AI and milk records covering a 7-yr period were obtained from the Israeli Herd Book. Analyses examined the association of probability of conception with SCC elevation relative to timing of AI, using generalized linear mixed models. A SCC threshold of 150,000 cells/mL of milk was set to distinguish between uninfected cows and cows with mastitis. Accordingly, cows with high SCC before and low SCC after AI were designated cured, those with low SCC before and high SCC after AI were designated newly infected, and cows with high SCC before and after AI were designated chronic (likely subclinical) mastitic cows. Compared with uninfected cows, the cured, newly infected, and chronic subgroups showed reduced CR (39.4±0.1, 36.6±0.2, 32.9±0.3, and 31.5±0.2, respectively). In the chronic, subclinical group, probability of conception was lowered by 14.5% in the mild and moderately elevated SCC subgroups and by 20.5% in cows with high SCC elevation compared with the uninfected group (CR of 29.7 vs. 39.4%, respectively). A single high elevation of SCC (>10(6) cells/mL on only 1 milk test day) lowered the probability of conception by 23.6% when it occurred during the 10 d immediately before AI, but not when it occurred earlier. For 30 d after AI, probability of conception was lowered by about 23%, as reflected in a CR of about 27% compared with the uninfected group. Probability of conception was lowered in cows with uterine and foot health problems (33.9%), in multiparous cows (34.1%), and in cows in the summer (29.1%), but no interactions with mastitis were detected. Results indicate that SCC elevation around AI, typical for subclinical mastitis, was associated with a significant reduction in probability of conception, and that even mild SCC elevation reduced CR. Severe elevation of SCC before AI, typical for clinical intramammary infection, reduced the probability of conception.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... The increase of SCC in milk is a good indicator of intramammary infection (Ruegg and Erskine, 2014). Previous studies have estimated the effect of SCC on different indicators of reproductive performance, such as longer days to first service (Barker et al., 1998;Schrick et al., 2001;Pinedo et al., 2009), lower conception risk (Lavon et al., 2011a;Hudson et al., 2012;Hertl et al., 2014;Fuenzalida et al., 2015), and higher risk of pregnancy loss (Chebel et al., 2004;Pinedo et al., 2009). Even if the size of the association estimated among those studies are not directly comparable due to differences in study designs and indicators of udder health status used (clinical mastitis records, periodic SCC records, or a combination of both), the most deleterious effect occurred when mastitis events took place after insemination, and when the severity of the cases increased (Lavon et al., 2011a;Hudson et al., 2012;Hertl et al., 2014;Fuenzalida et al., 2015). ...
... Previous studies have estimated the effect of SCC on different indicators of reproductive performance, such as longer days to first service (Barker et al., 1998;Schrick et al., 2001;Pinedo et al., 2009), lower conception risk (Lavon et al., 2011a;Hudson et al., 2012;Hertl et al., 2014;Fuenzalida et al., 2015), and higher risk of pregnancy loss (Chebel et al., 2004;Pinedo et al., 2009). Even if the size of the association estimated among those studies are not directly comparable due to differences in study designs and indicators of udder health status used (clinical mastitis records, periodic SCC records, or a combination of both), the most deleterious effect occurred when mastitis events took place after insemination, and when the severity of the cases increased (Lavon et al., 2011a;Hudson et al., 2012;Hertl et al., 2014;Fuenzalida et al., 2015). These field observations agree with other experimental studies showing that mastitis events could alter the hormonal profile leading to pregnancy failure (Herath et al., 2007;Lavon et al., 2011b). ...
... In our study, the conception risk in cows having high SCC before service (such as cured and new case groups) were less affected than in a previous report (Lavon et al., 2011a), but the negative effect detected in severe cases of mastitis (chronic group) were almost the same. Lavon et al. (2011a) showed that cured, new case, and chronic groups had 7, 16, and 20% [proportion of pregnant cows among those inseminated (CR) = 39.4, ...
Article
Poor udder health status can have a detrimental effect on milk yield and reproductive performance, leading to reductions in the dairy farm profit. The objective of this retrospective longitudinal study was to assess the associations of somatic cell count (SCC) with daily milk yield and reproductive performance. A database with 1,930,376 lactations from 867 Argentinean grazing dairy herds records collected for 14 years was used. The association of the evolution of SCC (healthy vs. new case vs. cured vs. chronic; with 150,000 SCC/mL as threshold) and of the severity of SCC [mild (150,000­–400,000 SCC/mL) vs. moderate (400,000–1,000,000 SCC/mL) vs. severe (>1,000,000 SCC/mL)] with the odds for conception were estimated. Finally, the associations of the linear score of SCC (LS-SCC) with daily milk yield were estimated depending on parity and milk production quartile. The odds ratios (CI 95%) for conception at first service were 0.921 (0.902–0.941), 0.866 (0.848–0.884), and 0.842 (0.826–0.859) for the new case, cured, and chronic cows compared with healthy cows, respectively. Also, the odds ratios (CI 95%) for conception were 0.902 (0.881–0.925), 0.837 (0.808–0.866) and 0.709 (0.683–0.736) for mild, moderate and severe cases compared with healthy cows, respectively. An increase of one point of LS-SCC was associated with decreases of 0.349, 0.539, and 0.676 kg in daily milk yield for first-, second-, and third-lactation cows, respectively. In conclusion, SCC is negatively associated with the risk for conception and with daily milk yield in grazing dairy cows. This negative relationship with conception is higher when SCC increase occurs after the service date and it is influenced by severity of mastitis, and in the case of milk yield, the negative association is influenced by parity, milk production quartile, and severity of mastitis.
... Previous studies have reported associations with detrimental effects of subclinical (Schrick et al., 2001;Lavon et al., 2011a) and clinical (Lavon et al., 2011a;Dalanezi et al., 2020) mastitis on the reproductive performance of dairy cows. Cows with subclinical or clinical mastitis inseminated after detection of estrus had increased intervals between calving and first service (Schrick et al., 2001). ...
... Previous studies have reported associations with detrimental effects of subclinical (Schrick et al., 2001;Lavon et al., 2011a) and clinical (Lavon et al., 2011a;Dalanezi et al., 2020) mastitis on the reproductive performance of dairy cows. Cows with subclinical or clinical mastitis inseminated after detection of estrus had increased intervals between calving and first service (Schrick et al., 2001). ...
... Previous studies have reported the negative association between subclinical mastitis or SCC and the interval between calving and first service by detection of estrus, days open (Schrick et al., 2001), or pregnancy per AI (Lavon et al., 2011a). In contrast, no previous study has evaluated the association between SCS and diameter of the largest follicle present on the ovaries in anovular cows. ...
Article
The objective of the current study was to evaluate the relationship of body condition score (BCS) at 35 d in milk (DIM), milk production, diseases, and duration of the dry period with prevalence of anovulation at 49 DIM and then, specifically, with the prevalence of each anovular phenotype. We hypothesized that anovular follicular phenotypes, classified based on maximal size of the anovular follicle, have different etiologies. A total of 942 lactating Holstein cows (357 primiparous and 585 multiparous) from 1 herd had ovaries evaluated by ultrasonography at 35 ± 3 and 49 ± 3 DIM to detect the absence of a corpus luteum (CL), and to measure the diameter of the largest follicle. Cows were classified as cyclic at 49 DIM if a CL was observed in at least 1 of the 2 examinations, or anovular if no CL was observed at either examination. Cows considered anovular were divided into 3 groups based on the largest diameter of the largest follicle as follows: ranging from 8 to 13 mm, 14 to 17 mm, or ≥18 mm. Cows were evaluated for the following diseases: retained placenta, metritis, hyperketonemia, mastitis, lameness, respiratory problem, and digestive problem. At 35 DIM, BCS was determined, and milk yield for individual cows was recorded. A total of 28.5% (268/942) of cows were classified as anovular. Anovular cows had longer dry periods (90 vs. 71 d) and smaller BCS than cyclic cows (2.83 vs. 2.99). Cows with a single disease or multiple diseases had 2 and 3-fold increase in odds of being anovular, respectively. Anovular cows had follicles that ranged from 4 to 50 mm. The prevalence of anovular phenotype, among anovular cows, that had the diameter of the largest follicle ranging from 8 to 13 mm, 14 to 17 mm, and ≥18 mm was 29.9 (79/264), 37.5 (99/264), and 32.6% (86/264), respectively. Anovular cows with follicles of 8 to 13 mm had longer dry periods than those with follicles ≥18 mm (104 vs. 74 d), whereas anovular cows with medium size follicles had intermediate days dry (99 d). Cows with small and medium anovular follicles had smaller BCS and greater prevalence of multiple diseases than cyclic cows. For almost all risk factors, the cows with large anovular follicles (≥18 mm) were similar to cyclic cows and different from cows with smaller anovular follicles (8–13 mm). Thus, longer dry periods, less BCS at 35 DIM, and diseases were risk factors for anovulation. Moreover, the risk factors for the 3 distinct anovular follicle phenotypes differed.
... The milk somatic cell count, which is often considered as an indicator of udder health [13], proved to be significantly correlated to the number of services per conception. The increase in milk somatic cell count, being indicative of the advanced stage of mastitis, caused the number of services per conception to increase from 2. 15 Values differing significantly within a factor are marked with the same letters as A,B at P ≤ 0.01, a,b at P ≤ 0.05 ...
... Similarly, for highly productive Montbeliard cows, Januś and Borkowska [6] achieved better results in secundiparous (SPC of 1.81) compared to primiparous cows (1.98). Lavon et al. [15] observed that primiparous cows conceive more easily than multiparous cows. Muller et al. [16] found the number of services per conception to increase linearly with an increasing number of lactations. ...
... Increasing attention has recently been given to udder inflammation in the context of reproductive disorders [13]. Results show that mastitis diagnosed in the period preceding insemination has a negative effect on reproductive efficiency in Holstein-Friesian cows [15]. According to Ahmadzadeh et al. [18] and Pinedo et al. [33], udder inflammation is conducive to the presence of estrous cycle disturbances. ...
... During the last decade, however, an association between decreased fertility and clinical and subclinical mastitis has been recognized (Schrick et al., 2001;Santos et al., 2004;Hertl et al., 2010), causing significant disruption of reproductive performance associated with additional loss to dairy farms. In a large epidemiological study of 287,000 AI cows, we showed a significant decrease in the probability of conception in likely subclinical mastitic cows exhibiting chronic elevation of SCC >150,000 cells/mL of milk (Lavon et al., 2011a). Similar findings showing an association between subclinical mastitis and poor conception were then also reported by Hudson et al. (2012). ...
... Composite milk samples were obtained by technicians, preserved by the addition of Bronopol (Advanced Instruments, Norwood, MA) and analyzed in a Milkoscan with Fossomatic Analyzer (Foss Electric, Hillerød, Denmark) for SCC. A SCC threshold of 150,000 cells/ mL of milk was set to distinguish between uninfected and infected cows, as previously described (Lavon et al., 2011a). This cutoff was based on a meta-analysis of 21 published studies conducted in different countries (Djabri et al., 2002). ...
... This cutoff was based on a meta-analysis of 21 published studies conducted in different countries (Djabri et al., 2002). Cows with 2 or 3 (depending on duration of calving to first AI interval) monthly milk tests before first AI (first postpartum milk test collected excluded) with SCC elevated above the cutoff line, in all samples collected, were considered to be subclinical mastitic cows (Lavon et al., 2011a). Cows with all samples below 150,000 cells/mL of milk were considered to be uninfected, and those with mixed values (above and below the cutoff) were not included in the study. ...
Article
Mastitis, particularly in its subclinical form, is a widely spread disease that reduces the fertility of lactating cows. A major cause of poor conception risk has been associated with delayed ovulation of a large subgroup of subclinical mastitic cows. This study examined 2 approaches to improve fertility in this subgroup. Subclinical mastitic cows were defined by somatic cell count elevated above a threshold of 150,000 cells/mL of milk determined in all monthly test day samples collected before AI. Uninfected (control) cows were defined by somatic cell count below threshold. In experiment 1, we examined a hormonal approach aimed to correct the timing of ovulation in mastitic cows in which it would otherwise be delayed. The probability of conception of mastitic and uninfected groups following Ovsynch (OVS) and timed AI versus AI following detected estrus (E) was examined (n = 1,553 AI) and analyzed by a multivariable, logistic model statement using the GLIMMIX procedure of SAS. The OVS protocol significantly elevated the probability of conception of mastitic cows to a level similar to that of their uninfected counterparts. Actual mean conception risks for uninfected-E, subclinical-E, uninfected-OVS, and subclinical-OVS groups were 41.8, 26.4, 39.3, and 40.5%, respectively. The OVS protocol did not improve probability of conception in cows diagnosed with uterine disease postpartum. In experiment 2, a management approach aimed to better synchronize timing of ovulation with timing of AI in subclinical mastitic cows was examined. A second AI was added 24 h after the first (routine) AI, following detection of natural estrus. Probability of conception did not differ between subclinical mastitic cows inseminated once or twice. Lack of improvement in conception risk might be related to low preovulatory LH surge in mastitic cows, which is likely to induce not only delayed ovulation but also disruption of oocyte maturation. Thus the OVS protocol can improve fertility of subclinical mastitic cows, probably due to “corrected” timing of ovulation in cows in which it would otherwise be delayed.
... Mastitis is a worldwide-spread issue that negatively affects the farms' economy by reducing milk production and increasing both the use of drugs and culling rates (Halasa et al., 2007;Pérez-Cabal et al., 2008). Moreover, according to the literature, the incidence of mastitis is also associated with a negative effect on reproductive performance such as conception rate (CR), days open (DO), and number of services per conception (Schrick et al., 2001;Santos et al., 2004;Lavon et al., 2011). Unlike clinical mastitis (CM), subclinical mastitis (SCM) is not characterized by visible symptoms of inflammation. ...
... Previous studies have demonstrated that an increased SCC before and after artificial insemination (AI) negatively affects CR and pregnancy loss (PL) (Schrick et al., 2001;Pinedo et al., 2009;Lavon et al., 2011), although the timing regarding before or after AI is still controversial. Lavon et al. (2011) reported a considerable reduction in CR in SCM-affected cows when SCC rose 10 days before to 30 days after AI; moreover, these researchers observed that such reduction was related to the degree of SCC elevation, considering the CR plummeted as SCC soared. ...
... Previous studies have demonstrated that an increased SCC before and after artificial insemination (AI) negatively affects CR and pregnancy loss (PL) (Schrick et al., 2001;Pinedo et al., 2009;Lavon et al., 2011), although the timing regarding before or after AI is still controversial. Lavon et al. (2011) reported a considerable reduction in CR in SCM-affected cows when SCC rose 10 days before to 30 days after AI; moreover, these researchers observed that such reduction was related to the degree of SCC elevation, considering the CR plummeted as SCC soared. However, some studies claim that there is no effect on CR and DO (Klaas et al., 2004), whereas others declare that a high SCC before AI has some effect on the nonreturn rate (Miller et al., 2001). ...
Article
Full-text available
Aim of study: To investigate the effect of subclinical mastitis (SCM) before and after first artificial insemination (AI), characterized by a somatic cell count (SCC) higher than 200×103 cell/mL, on reproductive performance including first service conception rate (FSCR) and pregnancy loss (PL) in Holstein dairy cows. Area of study: The central area of Lugo, Galicia, Spain. Material and methods: This retrospective study was conducted on herd database of a population of 80 commercial Holstein dairy cow farms. A total number of 2053 lactations were included in this study. A binary logistic regression was carried out to analyse all data. Main results: The results of this study indicated that cows that registered a SCC lower than 200×103 cell/mL within 30 days after first AI were more likely to conceive pregnancy than cows with a higher SCC (31.2% and 25.1% FSCR, respectively; OR=1.285, 95% CI=1.000-1.653). Additionally, an increased SCC neither 30 days before nor 30 days after first AI had a negative effect on prevalence of PL in dairy cows. Research highlights: These findings revealed that SCM within 30 days after first AI negatively affected FSCR, whilst 30 days before first AI did not affect it. Therefore, it could be suggested that preventing subclinical mastitis after first AI, during a critical period of 30 days, is important to maximize the reproductive performance of dairy cows.
... uberis is considered to be an environmental pathogen (Abureema et al., 2014). Several studies have reported lower conception rates in mastitic cows; increased number of AI per conception (Schrick et al., 2001;Santos et al., 2004;Lavon et al., 2011a); disorders associated with the estrous cycle (Huszenicza et al., 2005), follicle development (Lavon et al., 2010), and hormone secretion (Lavon et al., 2011b); and impaired oocyte competence (Soto et al., 2003;Asaf et al., 2013) and embryo development (Hansen et al., 2004). An association has been noted between the increasing number of AI per conception and the increased incidence of mastitis caused by Strep. ...
... Experiments 1 and 2 were analyzed independently. A multivariable model was designed with a logistic model statement using the GLIMMIX procedure of SAS (version 9.2, SAS Institute, Cary, NC), with first insemination outcome P/1stAI and PREG 300, as previously described (Lavon et al., 2011a(Lavon et al., , 2016. In addition, we used PROC MIXED procedure of SAS with continuous variables: rest days (calving to first AI), days open, resumption of cyclicity, and number of AI/P as the dependent variable. ...
... These additional analyses enabled comparing not only each of the mastitis groups to the uninfected control group, but also the 2 mastitis groups to one another before or after resumption of cyclicity, separately. Probability of conception for the level of a specific variable included in the models was based on least squares means values, and P-values were adjusted by the Bonferroni correction for multiple comparisons, as described previously (Lavon et al., 2011a(Lavon et al., , 2016. ...
Article
In 2 epidemiological studies, we evaluated the effect of mastitis induced by gram-positive Streptococcus and gram-negative Escherichia coli on impaired reproductive performance in lactating Holstein cows. In the first study, 52,202 cows from 178 dairy farms throughout Israel were divided into groups based on infection before first artificial insemination (AI) with Streptococcus or E. coli, 3 groups with elevated somatic cell count (SCC) without infection by those pathogens [low SCC (200–400) × 10³ cell/mL; medium SCC (401–1,000) × 10³ cell/mL; high SCC, >1,000 × 10³ cell/mL], and uninfected controls. Pregnancy per first AI (P/1stAI) and pregnancy rate at 300 d in milk (PREG 300) were analyzed by the GLIMMIX procedure (SAS); number of AI per pregnancy (AI/P), days open, and rest days (calving to first AI) were analyzed by the MIXED procedure (SAS Institute Inc., Cary, NC). Values of P/1stAI were similarly low for Streptococcus and E. coli (27–28%) versus 42% in controls; PREG 300 was lower for Streptococcus (76%) than for E. coli (79%) versus 88% for uninfected controls and a mean 83% for the elevated SCC groups. Days open and number of AI/P were higher than in controls and similar in Streptococcus and E. coli groups. The second study included 778 cows on 6 dairy farms; the cows were infected before first AI by Streptococcus or E. coli or uninfected. Resumption of cyclicity was determined by an automated activity-monitoring system, and data were sorted by time of infection before or after cyclicity resumed. The Streptococcus group had lower P/1stAI before and after cyclicity (26 and 27%, respectively) than the E. coli group (31 and 34%, respectively) and uninfected controls (42%). Notably, PREG 300 in the Streptococcus group before (73%) and after (67%) cyclicity was much lower than for the E. coli group (85 and 93%, respectively) and the controls (95%). A marked rise in day of cyclicity resumption (∼80 d) was observed in cows that were infected early on. Number of AI/P was higher in the mastitic groups than in uninfected controls. Uterine disease postpartum, although more prevalent among Streptococcus cows, did not substantially alter the larger reduction in P/1stAI and PREG 300 in Streptococcus versus E. coli cows. Thus, long-term Streptococcus-induced mastitis disrupted fertility more than short-term acute E. coli–induced mastitis, resulting in a much higher percentage of Streptococcus cows in late lactation that did not conceive due to reproduction failure.
... Subclinical (SC) infections result in decreased milk yield, reduction in fertility, deterioration of milk quality and increased risk of culling (3,15,16), especially owing to its wide prevalence, which may reach about 20 to 40% of the udders in some herds (1,17). Many of the cows with chronic SC infection are not diagnosed because there are no recognizable symptoms and the milk appears normal. ...
... On the farm level, in most instances SC mastitis cases are chronic and can persist through the entire lactation period until the dry-off period between lactations, which might result in lowered milk yield (47) and with negative effects on reproduction (15). Thus, the decisions for non-intervention, to treat infected udders with antibiotics or to dry-off infected quarters in SC-infected cows have economic implications. ...
... Thus, the decisions for non-intervention, to treat infected udders with antibiotics or to dry-off infected quarters in SC-infected cows have economic implications. In the case of no treatment, the economic loss which relates to SC cases consists of a decrease in milk yield of ~5% through a lactation (11,000 -550 = 10,450 kg/milk, 305 days), increase in the number of inseminations (~20%) and increase in extra open days (~15%) (15). Additionally, SC IMI could result in lower milk prices due to increased SCC, especially in countries with penalties for high SCC. ...
Article
Full-text available
The decision on whether to treat cows’ subclinical udder infections or to ignore it is not straightforward as antibiotic treatment of animals that are not at risk should be justified with respect to the cost of treatment and milk loss. Data regarding 152 dairy cows was used to evaluate the economics of mastitis-control according to five categories: a) No intervention; b) Antibiotic treatment; c) Drying off quarter/s; d) Drying-off the whole udder and e) Culling. The data was analyzed according to parity, bacteria, time in lactation at infection recording, treatment, time elapsed between infection and treatment and somatic cell count at treatment. Cure of first lactation cows was significantly higher than that of cows at their 2nd and 3rd onward lactations and depended on the bacteria causing the infection. It was higher in cows infected with coagulase negative staphylococci than with various types of Streptococci, and lowest in cows previously infected with Escherichia coli. The effect of day of treatment after onset of the infection was significant. It was also demonstrated that use of casein hydrolysate (a drug in development that can dry-off the inflamed quarter with modest reduction in overall milk yield by avoiding the problem of withholding milk), eliminates the need to use antibiotics and the cost of treatment becomes highly economical. In conclusion, antibiotic treatment is unavoidably associated with milk waste; thus, when the alternative is no intervention it is the preferable option. In cases where the infected gland produces low quality milk with somatic cell count ~1,000×10³cells/mL milk, drying-off the gland by using a drug such as casein hydrolysate is the preferable option. © 2017, Israel Veterinary Medical Association. All rights reserved.
... Subclinical mastitis is recorded in about 20-40% of cows postpartum [15]. We recently found that one-third of subclinical mastitic cows exhibit delayed ovulation, low follicular estradiol and delayed preovulatory LH surge, leading to lower P/AI in subclinical mastitic cows relative to uninfected controls [16][17][18]. ...
... Cows were held in open shaded structures in both herds. Postpartum uterine disease, mastitis and metabolic diseases, mainly ketosis, were diagnosed and recorded, as previously detailed [17,26]. Cows were treated by the veterinarian according to routine protocols. ...
... Data from the fertility experiment were analyzed by a multivariable model that was designed with a logistic model statement using the GLIMMIX procedure of SAS (version 9.2, SAS Institute Inc., Cary, NC, USA); insemination outcome was the dependent variable, as previously described [17,26]. Pregnancy per first, second and third service and P/AI for all services were calculated as number of pregnancies divided by number of AI. ...
Article
Full-text available
We examined gonadotropin-releasing hormone (GnRH) administration at onset of estrus (OE), determined by automatic activity monitoring (AAM), to improve fertility of dairy cows during the summer and autumn. The study was performed on two dairy farms in Israel. The OE was determined by AAM recorded every 2 h, and a single im dose of GnRH analogue was administered shortly after OE. Pregnancy was determined by transrectal palpation, 40 to 45 d after artificial insemination (AI). Conception risk was analyzed by the GLIMMIX procedure of SAS. Brief visual observation of behavioral estrus indicated that about three-quarters of the events (n = 40) of visually detected OE occurred within 6 h of AAM-detected OE. Accordingly, the GnRH analogue was administered within 5 h of AAM-detected OE, to overlap with the expected endogenous preovulatory LH surge. Overall, pregnancy per AI (P/AI) was monitored over the entire experimental period (summer and autumn) in 233 first, second or third AI (116 and 117 AI for treated and control groups, respectively). Least square means of P/AI for treated (45.8%) and control (39.4%) groups did not differ, but group-by-season interaction tended to differ (p = 0.07), indicating no effect of treatment in the summer and a marked effect of GnRH treatment (n = 58 AI) compared to controls (n = 59 AI) on P/AI in the autumn (56.6% vs. 28.5%, p < 0.03). During the autumn, GnRH-treated mature cows (second or more lactations), and postpartum cows exhibiting metabolic and uterine diseases, tended to have much larger P/AI than their control counterparts (p = 0.07–0.08). No effect of treatment was recorded in the autumn in first parity cows or in uninfected, healthy cows. In conclusion, administration of GnRH within 5 h of AAM-determined OE improved conception risk in cows during the autumn, particularly in those exhibiting uterine or metabolic diseases postpartum and in mature cows. Incorporation of the proposed GnRH treatment shortly after AAM-detected OE into a synchronization program is suggested, to improve fertility of positively responding subpopulations of cows.
... Cows diagnosed with CM after 62 days postpartum (i.e., after voluntary waiting period) but before first artificial insemination (AI), had worse reproductive performance than cows that had CM during the early postpartum period [9]. Hertl et al. [10] and Lavon et al. [11] reported lower probability of conception in dairy cows diagnosed with CM at any time between 14 days before and 35 days after AI and this effect was less pronounced if the CM event occurred earlier than Available at www.veterinaryworld.org/Vol.10/May-2017/3.pdf that while Hudson et al. [12] reported a prolonged risk period (28 days before and 70 days after AI) for the negative effect of CM on conception. ...
... Ahmadzadeh et al. [21] also reported that cows experienced mastitis before end of the voluntary waiting period had greater SC and DO, suggesting that occurrence of CM before first AI can have a carryover effect on the reproductive performance. Lavon et al. [11] also stated clearly that a CM event diagnosed during the first 10 days before first AI depresses fertility, and that this effect is less pronounced if the event occurs earlier than that. Hudson et al. [12] also found that mastitis before AI was generally associated with lesser effects on fertility. ...
Article
Full-text available
Aim: Evaluation of the effect of clinical mastitis (CM) and its treatment outcome on the reproductive performance in crossbred cows retrospectively. Materials and Methods: Datasets of 835 lactating cows affected with CM during a period of 12 years (2001-2012) were considered for this study. Mastitis treatment related data and reproductive parameters such as days to first detected heat (DTFDH), days to first insemination (DTFI), days open (DO), and number of services per conception (SC) were collected from mastitis treatment and artificial insemination registers, respectively. Data were analyzed by ANOVA using SPSS 20 software. The means were compared with the Duncan's multiple comparison post-hoc test. Results: CM affected cows had significantly (p
... Occurrence of clinical or subclinical mastitis can negatively affect reproduction (Lavon et al., 2011;Hudson et al., 2012). Cows with clinical mastitis require more AI events because they have a decreased conception rate (Barker et al., 1998;Santos et al., 2004). ...
... Furthermore, cows diagnosed with clinical mastitis have shown longer intervals between calving and first AI, greater pregnancy losses, more days open, decreased milk production, and decreased milk fat percentage compared with healthy cows (Boujenane et al., 2015;Kumar et al., 2017). Similarly, subclinical mastitis after AI has been associated with a decreased conception rate (Lavon et al., 2011;Hudson et al., 2012). Cows with SCC greater than 200 × 10 3 cells/mL had a 10% decrease in pregnancies per AI compared with nonmastitic cows (Bijker et al., 2015). ...
Article
In dairy cattle, mastitis is a disease of the mammary gland caused by pathogens such as bacteria, viruses, fungi, and algae. Mastitis causes economic losses to dairy farms as well as public health concerns. The reproductive efficiency of commercial dairy herds has important implications for the economic success of dairy operations and is strongly associated with the health status of cows. Mastitis has previously been linked with decreased fertility of dairy cows, but the effect of specific pathogens on the severity of fertility reduction is still unclear. In this study, cows diagnosed with mastitis caused by major pathogens (Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli, Klebsiella spp., Mycoplasma spp., and environmental Streptococcus) needed more artificial inseminations (AI) than did cows with mastitis caused by minor pathogens (coagulase-negative Staphylococcus and Corynebacterium spp.) and healthy cows. Cows diagnosed with mastitis, independent of what pathogen was causing mastitis, had more days open compared with nonmastitic cows. The percentage of cows that successfully established pregnancy at first AI was greater for the control group than for the major pathogens group but not significantly different from the minor pathogens group. Pregnancy loss was lower in the control group than in the major pathogens group; however, there was no difference compared with the minor pathogen group. Mastitis caused by gram-negative bacteria decreased the percentage of pregnancy per first AI and increased days open and pregnancy loss compared with the control group. Cows with mastitis caused by gram-positive bacteria also had increased days open compared with control cows. This study shows that different mastitis-causing bacteria can affect the fertility of cows differently. Mastitis events caused by major pathogens and gram-negative bacteria were associated with the greatest decrease in reproductive efficiency.
... Also, results indicate that mastitis incidence at Day À15 (before) and Day þ15 (after) AI was associated with a significant reduction in probability of pregnancy rates in buffalo cows. Similar findings were demonstrated in dairy cows [35][36][37][38][39]. Cows with clinical or subclinical mastitis at the time of service exhibited a significant reduction in pregnancy rate [39]. ...
... Also, presence of subclinical mastitis between Days 1 and 30 after service was associated with a large decrease in pregnancy rate [39]. Reduction in pregnancy rate could be related to the release of inflammatory mediators such as PGF2a, which can alter the interestrus interval by causing premature luteolysis [38]. Furthermore, observations of cows with mastitis suggest that an activation of inflammatory or immune responses external to the reproductive tract can lead to embryonic mortality [22]. ...
Article
Full-text available
The aim of this study was to investigate the effects of mastitis on CL development and function and pregnancy rate in buffaloes. Sixty-six buffaloes (Bubalus bubalus) reared in a commercial farm at El-Beheira governorate, north of Egypt were used in this study. According to the visual observation of milk, physical examination of the udder and actual somatic cell count in milk, buffalo cows were divided into three groups: without mastitis (W), n ¼ 23; subclinical mastitis (SC), n ¼ 18; and clinical mastitis (C), n ¼ 25. All buffalo cows were synchronized by double dose of PGF2a (11-day interval) and inseminated by frozen-thawed semen of fertile bull. Mean CL diameter was ultrasonically examined on Days 5, 9, 12, 16, 21, and 25 after artificial insemination (AI). Blood samples were taken on the days of ultrasonography for progesterone (P4) assay. Results indicated that pregnancy rates were lower (P < 0.05) in C (28.00%) and SC (55.56%) compared with W (69.57%) on Day 25 after first AI. Pregnancy rates reduced to 60.87%, 44.45%, and 16.00% inW, SC, and C, respectively, at Day 45 after insemination. Thus, the embryonic loss was 8.7%, 11.11%, and 12.00 % in W, SC, and C cows, respectively. Pregnancy rates decreased between 44.32% and 50.51% when mastitis occurred during Day �15 before to Day þ30 after AI, compared with 59.22% in the uninfected cows. The diameter of CL was greater (P < 0.05) inWthan SC and C cows starting at Day 9 postbreeding onward. Likewise, P4 concentrations on Days 9 through 25 after AI were greater (P < 0.05) in W cows as compared to SC and C cows. Positive correlations (P < 0.01) were found on Days 5, 9, 12, 16, 21, and 25 after AI between CL diameter and P4 concentrations. Similar trend was found among CL diameter, P4 concentrations, and pregnancy rate. Accordingly, incidence of mastitis revealed suppression to both CL diameter and function leading to significant reduction in pregnancy outcome of buffalo cows.
... Le nombre d'inséminations nécessaires pour obtenir la gestation augmente (Barker et al, 1998 ;Schrick et al, 2001 ;Santos et al, 2004 ;Huszenica et al, 2005 ;Ahmadzadeh et al, 2009 ;Pinedo et al, 2009 ; tableau 1). En ce qui concerne la réussite d'une insémination donnée, la mammite agit dans une fenêtre de sensibilité : la phase la plus « à risque » d'apparition d'une mammite en termes de conséquences sur les performances de reproduction se situe dans une fenêtre de 3 semaines avant l'insémination jusqu'à 30 jours après celle-ci Perrin et al, 2007 ;Herlt et al, 2010 ;Lavon et al, 2011b ;Hudson et al, 2012). Un taux cellulaire supérieur à 400 000 cellules par ml 2 mois avant l'IA ou au cours des 30 jours qui suivent l'insémination diminue signifi cativement les performances de reproduction (Hudson et al, 2012). ...
... Cependant l'association entre mammite et infection utérine mériterait d'être précisée. Au sein d'une même lactation ou même sur une plus courte période d'observation, aucune corrélation entre la survenue d'une infection utérine et celle d'une mammite n'a pu être mise en évidence par plusieurs auteurs (Curtis et al, 1985 ;Lavon et al, 2011b ;Parker Gaddis et al, 2012). ...
... Also, results indicate that mastitis incidence at Day À15 (before) and Day þ15 (after) AI was associated with a significant reduction in probability of pregnancy rates in buffalo cows. Similar findings were demonstrated in dairy cows [35][36][37][38][39]. Cows with clinical or subclinical mastitis at the time of service exhibited a significant reduction in pregnancy rate [39]. ...
... Also, presence of subclinical mastitis between Days 1 and 30 after service was associated with a large decrease in pregnancy rate [39]. Reduction in pregnancy rate could be related to the release of inflammatory mediators such as PGF2a, which can alter the interestrus interval by causing premature luteolysis [38]. Furthermore, observations of cows with mastitis suggest that an activation of inflammatory or immune responses external to the reproductive tract can lead to embryonic mortality [22]. ...
Article
The aim of this study was to investigate the effects of mastitis on CL development and function and pregnancy rate in buffaloes. Sixty-six buffaloes (Bubalus bubalus) reared in a commercial farm at El-Beheira governorate, north of Egypt were used in this study. According to the visual observation of milk, physical examination of the udder and actual somatic cell count in milk, buffalo cows were divided into three groups: without mastitis (W), n = 23; subclinical mastitis (SC), n = 18; and clinical mastitis (C), n = 25. All buffalo cows were synchronized by double dose of PGF2α (11-day interval) and inseminated by frozen-thawed semen of fertile bull. Mean CL diameter was ultrasonically examined on Days 5, 9, 12, 16, 21, and 25 after artificial insemination (AI). Blood samples were taken on the days of ultrasonography for progesterone (P4) assay. Results indicated that pregnancy rates were lower (P < 0.05) in C (28.00%) and SC (55.56%) compared with W (69.57%) on Day 25 after first AI. Pregnancy rates reduced to 60.87%, 44.45%, and 16.00% in W, SC, and C, respectively, at Day 45 after insemination. Thus, the embryonic loss was 8.7%, 11.11%, and 12.00 % in W, SC, and C cows, respectively. Pregnancy rates decreased between 44.32% and 50.51% when mastitis occurred during Day -15 before to Day +30 after AI, compared with 59.22% in the uninfected cows. The diameter of CL was greater (P < 0.05) in W than SC and C cows starting at Day 9 postbreeding onward. Likewise, P4 concentrations on Days 9 through 25 after AI were greater (P < 0.05) in W cows as compared to SC and C cows. Positive correlations (P < 0.01) were found on Days 5, 9, 12, 16, 21, and 25 after AI between CL diameter and P4 concentrations. Similar trend was found among CL diameter, P4 concentrations, and pregnancy rate. Accordingly, incidence of mastitis revealed suppression to both CL diameter and function leading to significant reduction in pregnancy outcome of buffalo cows.
... We categorize mastitis as acute short-term clinical or chronic, long-term subclinical. Such a distinction between clinical and subclinical mastitis is common in several studies dealing with mastitis effects on reproduction and fertility [6,11,[16][17][18]. In particular, we focus on the impact of clinical and subclinical mastitis on ovarian responses. ...
... In the first study in which mastitis occurrence was related to a 75 reduction in fertility, gram-negative bacteria in cows with clinical mastitis 76 were linked to greater estrous intervals and shorter diestrus [7]. Ensuing 77 studies confirmed a negative correlation between mastitis and fertility in 78 dairy cows [8,10,11] by lengthening of the periods of return to estrus and to 79 the first post-partum artificial insemination and by increasing the number of 80 services per conception [12,13]. Additionally, conception [11,14] and 81 pregnancy [15] rates were lower in cows with mammary infection, indicating 82 a possible effect of oocyte and embryo development. ...
Article
The objective was to evaluate the effect of mastitis by somatic cell count (SCC) on follicular growth, ovulation, oocytes and cumulus cells quality and on the concentration and size of exosomes in follicular fluid of dairy cows. In the study, crossbred cows (Bos taurus - Holstein x Bos indicus - Gir) were classified for analysis as Control (SCC<200.000 cells/mL) and Mastitis (SCC>400.000 cells/mL) groups. In experiment 1 (follicular dynamics), cows (n = 57) were submitted to ultrasound evaluations every 24 h, from progesterone-releasing-intravaginal-device (PRID) removal (D8) until 48 h later (D10). Thereafter, evaluations were performed every 12 h, until ovulation or up to 96 h after PRID removal. In experiment 2 (oocyte, cumulus complexes, and follicular fluid evaluation), cows (n = 26) were submitted to follicular aspiration (OPU) for oocyte quality and cumulus cells transcript evaluation. The amount of cumulus complexes transcripts (BCL2, BAX, PI3K, PTEN, FOXO3) was determined by Real-Time Polymerase Chain Reaction. Moreover, seven days after the OPU session, the dominant follicle was aspirated. Exosomes were isolated from the follicular fluid for evaluation of particle size and concentration. Ovulation rate [Control 77.4% (24/31) and Mastitis 57.7% (15/26); P = 0.09] and viable oocytes rate [Control 59.1% (130/220) and Mastitis 41.9% (125/298); P = 0.01] were higher in Control animals. Additionally, there was a greater number of degenerate oocytes [Control 6.7 ± 1.2 and Mastitis 13.3 ± 5.5; (P = 0.001)] in subclinical mastitis cows. There was greater abundance (P = 0.003) of BAX cumulus cell transcripts and exosome mean (P = 0.03) and mode (P = 0.02) was smaller in subclinical mastitis cows. In conclusion, ovulation rate, oocyte quality, and exosome diameter were smaller in cows with SCC>400.000 cells/mL.
... They also found that the probability of pregnancy decreased by 44% and the risk of abortion increased (1.22) during the first 90 days of gestation if a high linear SCC occurred before breeding. Lavon et al. (2011c) evaluated the association of CR with the pattern and level of SCC elevation relative to time of insemination and found significantly reduced CR even in mild SCC elevation before AI. Recently, Filho et al. (2012) reported that those cows diagnosed as affected with CM up to 60 days postpartum had significantly the shortest calving to conception intervals (132.4 ± 7.2 days), followed by those diagnosed during 60-120 days postpartum (153.9 ± 8.0 days) and by those diagnosed after 120 days postpartum (231.3 ± 9.9 days). ...
Article
Full-text available
The reproductive performance of dairy animals is influenced by several factors, and accumulating lines of evidence indicate that mastitis is one of the determinants. Most of the published information relating mastitis with reproduction has evolved based on retrospective approach rather than controlled clinical studies. The complex nature of both mastitis and reproduction could be a limiting factor for understanding their relationship in detail. In this review, we analyzed the available retrospective studies on the effects of clinical mastitis on reproductive function and explained the possible mechanisms by which mastitis affects reproduction in dairy animals.
... The discrete traits; including culling rate, conception rate of nulliparous calves; first parity dystocia and stillbirth and rates of abortion, metritis, ketosis, milk fever and displaced abomasum were analyzed by Proc Glimmix of SAS (SAS, 2008). Differences between the purebred and F-1 cows, computed on the logit scale were transformed back to the trait scale as proposed by Lavon et al. (2011). (The same procedure could not be used to transform standard errors of the difference (SED), and therefore the SED are not presented for the Proc Glimmix analyses.) ...
Article
Full-text available
A total of 1922 first generation crossbred cows born between 2005 and 2012 produced by inseminating purebred Israeli Holstein cows with Norwegian Red semen, and 7487 purebred Israeli Holstein cows of the same age in the same 50 herds were analyzed for production, calving traits, fertility, calving diseases, body condition score, abortion rate and survival under intensive commercial management conditions. Holstein cows were higher than crossbreds for 305-day milk, fat and protein production. Differences were 764, 1244, 1231 for kg milk; 23.4, 37.4, 35.6 for kg fat, and 16.7, 29.8, 29.8 for kg protein; for parities 1 through 3. Differences for fat concentration were not significant; while crossbred cows were higher for protein concentration by 0.06% to 0.08%. Differences for somatic cells counts were not significant. Milk production persistency was higher for Holstein cows by 5, 8.3 and 8% in parities 1 through 3. Crossbred cows were higher for conception status by 3.1, 3.6 and 4.7% in parities 1 through 3. Rates of metritis for Holsteins were higher than the crossbred cows by 7.8, 4.6 and 3.4% in parities 1 to 3. Differences for incidence of abortion, dystocia, ketosis and milk fever were not significant. Holstein cows were lower than crossbred cows for body condition score for all three parities, with differences of 0.2 to 0.4 units. Contrary to comparisons in other countries, herd-life was higher for Holsteins by 79 days. A total of 6321 Holstein cows born between 2007 and 2011 were higher than 765 progeny of crossbred cows backcrossed to Israeli Holsteins of the same ages for milk, fat and protein production. Differences were 279, 537, 542 kg milk; 10.5, 17.7, 17.0 kg fat and 6.2, 12.9, 13.2 kg protein for parities 1 through 3. Differences for fat concentration were not significant, while backcross cows were higher for protein percentage by 0.02% to 0.04%. The differences for somatic cell score, conception rate, and calving diseases other than metritis, were not significant. Holstein cows were lower than backcross cows by 1.5% to 2.5% for conception status in parities 1 to 3 and lower for body condition score for parities 1 and 2, with differences in the range of 0.06 to 0.09 units. Culling rates were higher, and herd-life lower for the crossbred cows. The gains obtained in secondary traits for crossbred cows did not compensate for the major reduction in production.
... Apart from local inflammation of the mammary tissue, mastitis exerts varied systemic effects (Bannerman et al., 2004). Moreover, deterioration of reproductive performance is observed in cows with clinical as well as subclinical mastitis (Pinedo et al., 2009;Lavon et al., 2011a;Roth et al., 2013). ...
Article
Data from various studies indicate that the ovarian function in dairy cows can be compromised during intramammary infections. Therefore, in this study, we investigated if an experimentally induced mastitis has an effect on corpus luteum (CL) function in 14 lactating cows. On d 9 of the estrous cycle (d 1 = ovulation), cows received a single dose of 200 μg of Escherichia coli lipopolysaccharide (LPS; dissolved in 10 mL of NaCL; n = 8) or 10 mL of saline (control; n = 6) into one quarter of the mammary gland. Measurements included plasma cortisol, haptoglobin, and progesterone (P4) concentrations, as well as luteal size (LTA) and relative luteal blood flow (rLBF). Sampling was performed on d 1, 4, and 8. On d 9, the main examination day, sampling was performed immediately before (0 h), every 1 h (or at 3-h intervals for LTA and rLBF) until 9 h, as well as 12 and 24 h after treatment. Thereafter, measurements were taken on d 12, 15, 18, and then every 2 d until ovulation. Luteal tissue was collected for biopsy 24 h before and 6 h after treatment. Quantitative real-time PCR was applied to assess mRNA expression of steroidogenic factors (STAR, HSD3B), caspase 3, toll-like receptors (TLR2, -4), tumor necrosis factor α (TNFA), and prostaglandin-related factors (PGES, PGFS, PTGFR). Intramammary LPS infusion caused considerable inflammatory responses in the treated udder quarters. No decrease in plasma P4 concentrations was noted after LPS-challenge, and P4 levels did not differ between LPS-treated and control cows. Furthermore, LTA and rLBF values were not decreased after LPS challenge compared with the values obtained immediately before treatment. However, LPS infusion increased plasma levels of cortisol and haptoglobin compared with the control group. In the CL, mRNA abundance of TLR2 and TNFA was increased in cows after LPS-challenge (but not in control cows), whereas TLR4, steroidogenic, and prostaglandin-related factors remained similar to the mRNA abundance before treatment. In conclusion, intramammary LPS challenge induces systemic inflammatory reactions which alter the luteal mRNA abundance of TLR2 and TNFA but does not induce lysis of the CL.
... Infection of the mammary gland causes mastitis in a comparable proportion of animals, and these infections reduce conception rates. Metritis or mastitis also retard follicular growth, reduce circulating and intrafollicular estradiol concentrations, extend luteal phases, and disrupt ovarian cyclic activity (5)(6)(7). The Gram-negative bacte-rium Escherichia coli is a main pathogen causing metritis and mastitis, and these infected animals have reduced fecundity even after resolution of clinical disease (8,9). ...
Conference Paper
Full-text available
Precursor to: FULL PAPER AVAILABLE OPEN ACCESS AS: Lipopolysaccharide initiates inflammation in bovine granulosa cells via the TLR4 pathway and perturbs oocyte meiotic progression in vitro John J. Bromfield and I. Martin Sheldon Endocrinology. 2011 Dec; 152(12): 5029–5040. Published online 2011 Oct 11. doi: 10.1210/en.2011-1124 PMCID: PMC3428914 EMSID: UKMS49352 PMID: 21990308
... Mastitis also has deleterious effects on reproductive performance. For instance, the time from parturition to first insemination is longer and the number of services for conception is larger in mastitic cows (Schrick et al. 2001, Maizon et al. 2004, Lavon et al. 2011a. Other epidemiological studies have demonstrated that conception rates (Loeffler et al. 1999, Santos et al. 2004) and pregnancy rates (Harman et al. 1996) are lower in mastitic vs healthy cows. ...
... Embora a MS seja caracterizada por ausência de sinais clínicos e de o leite ainda poder ser comercializado, isso resulta em vários efeitos prejudiciais para a produção leiteira, tais como redução na produção e qualidade do leite e de produtos lácteos (Barbano et al., 2006), redução da fertilidade (Lavon et al., 2011), e problemas com o bem-estar animal (Peters et al., 2015). ...
Thesis
Full-text available
Subclinical mastitis (SM) is the most prevalent disease in dairy herds and can be identified by individual somatic cell counts (SCC) of cows. From this, indicators can be calculated as, for example, prevalence and incidence. Prevalence refers to the number of infected cows in a herd at a given time, while the incidence estimates the rate of new intramammary infections over time. High prevalence and incidence values result in high bulk tank SCC (BTSCC), which consequently leads to penalties from payment programs based on milk quality (PPBMQ). In this way, estimating current values of prevalence and incidence of SM related to future values of BTSCC and financial losses from PPBMQs becomes important to stimulate the improvement of the quality of milk produced in Brazil. Therefore, the objective of this study is to estimate the epidemiological indicators of SM in Brazilian dairy herds, besides to predicting the BTSCC and relating it to the financial losses due to the PPBMQ. For this, two databases were used, the first one with individual SCC data from cows to estimate the prevalence and incidence of SM, and the second with BTSCC data for prediction and calculation of financial losses due to PPBMQ. For statistical analysis, the mixed generalized linear model was used to compare the prevalence and incidence of SM between years, regions, herd size and number of test-day categories sent during the studied period, as well as time series models for prediction of BTSCC and multiple linear regressions to predict the probability of changing the current payment class for milk quality. The results indicate that both prevalence and incidence of SM remained high and with a slight tendency to increase over the years studied, and there were no differences between regions and herd sizes. On the other hand, herds that performed more test-day during the studied period presented a lower prevalence, showing the importance of the routine analysis of individual SCC. For BTSCC, values have remained high in recent years and no trend for improvement. The probability of class change was strongly affected by the mean and standard deviation of BTSCC for classes 1 and 2 (1,000 to 200,000 and 201,000 to 400,000 cells/mL, respectively). Time series models indicated that at some point of the year, farms could not remain in their current class and accumulated financial losses due to PPBMQ. Finally, this study allows to conclude that the prevalence and incidence of SM are high and do not improve over the years, and this ends up increasing the BTSCC values. In addition, there are financial losses in all classes of PPBMQ, showing that producers have not been efficient in capturing the maximum PPBMQs bonus. Therefore, the development of milk quality programs should be a priority in order to improve the quality of milk from Brazilian herds.
... Elevated SCC is considered a useful indicator of subclinical mastitis (Hudson et al., 2012). Lavon et al. (2011) have reported that high SCC levels during artificial insemination may be related to reduce pregnancy rates and that pregnancy rates increase with decreased levels of SCC, an indicator of subclinical mastitis. McDougall and Voermans (2002) attributed the decrease in milk yield during estrus to an increased SCC level in goats when using two different estrus synchronization methods. ...
Article
Effect of various estrus synchronization methods on bulk tank milk somatic cell count (BTMSCC) was investigated. One-hundred Simmental cows within a single dairy farm were randomized into four equal groups: no treatment (Group 1, control group); application of a progesterone-releasing intravaginal device (Group 2); administration of double-dose prostaglandin F2 alpha (PGF2-alpha) with an 11-day interval (Group 3); and subjected to the Ovsynch protocol (Group 4). Bulk tank milk (BTM) samples were collected daily for one month and BTMSCCs calculated. Progesterone and estradiol concentrations were also measured at 3-day intervals. BTMSCC of the Ovsynch protocol group was not significantly different from that of the control group, suggestive of good udder health. Based on this finding, we propose that spontaneous estrus and the Ovsynch protocol are preferable methods for estrus synchronization than progesterone-releasing intravaginal device (PRID) and PGF2-alpha approaches.
... Our group performed a large epidemiological study on the effects of mastitis, determined by the pattern and level of the SCC around first AI, on probability of conception (Lavon et al., 2011a). Data from 287,000 AI were obtained from the Israeli Herd Book. ...
Article
Mastitis (intramammary infection) causes the deterioration of ovarian follicular responses in cows, resulting in low fertility. The shortterm, acute clinical form of mastitis has a time-dependent disruptive effect on conception rate. It effectively lowers conception rate if events occur mainly 10 days before to 30 days after artificial insemination. Long-term subclinical mastitis is widely spread in commercial herds. Although it is less severe than clinical mastitis, its long-term nature causes a more pronounced decrease in conception rate. Even mild elevation of somatic cell count in subclinical cows significantly lowers conception rate. Disrupted follicular responses include depression of steroid production in the preovulatory follicle associated with low and delayed preovulatory luteinizing hormone surge, resulting in delayed ovulation in onethird of subclinical cows. Mastitis, clinical and subclinical, also impairs oocyte competence, reflected in low production of blastocysts. The corpus luteum seems to be insensitive to mastitis, possible due to the use of non-steroidal anti-inflammatory drugs when mastitis is first diagnosed.
... In the present study, CM before the time of insemination was associated with a reduction in P/AI, an increase in the number of inseminations required to establish a pregnancy and a longer interval between calving and pregnancy compared with uninfected cows prior to breeding. Similar findings have been obtained using a small or large data set of dairy cows in temperate zones regardless of types of mastitis (Lavon et al 2011, Hertl et al 2014. The subfertility associated with mastitis does not appear to be related to the ovulation process (Morris et al 2009), but the activation of inflammatory or immune responses in the udder can lead to abnormal estrous cycle lengths (Huszenicza et al 2005, Pinzón-Sánchez andRuegg 2011), anovulation at estrus, fertilization failure, or embryonic mortality (Moore et al 2005). ...
Article
Full-text available
The aim of this study was to determine the association among periparturient events such as mastitis, lameness (infectious and non-infectious) and ketosis and the reproductive performance of high producing Holstein cows in a hot environment. The health status and reproductive data variables were recorded from 6,566 completed lactations in a large dairy operation. A logistic regression model with the stepwise procedure was used, considering the occurrence of the health problems during the pre-breeding period as fixed effect risk factors and reproductive variables as dependent variables. Pregnancy rate of cows contracting clinical mastitis (CM) around the period of first inseminations was five percentage points lower than cows without this disease. Cows with CM shortly before or after the first service had twice the risk of requiring more than three services per pregnancy than cows with healthy udders. Cows experiencing abortion, laminitis or metritis were two times more likely to require >3 services per pregnancy than cows not experiencing these reproductive disorders. Cows experiencing lameness, mastitis and metritis presented a significantly longer interval between calving and pregnancy compared to healthy cows. Ketosis and lameness increased the odds of a cow of being inseminated for the first time after 70 days in milk. In conclusion, these results suggest that abortion, ketosis, CM, retained placenta (RP), metritis, and lameness are associated with decreased reproductive performance in high producing Holstein cows subjected to thermal stress.
... The reproductive failures associated with mastitis in dairy cows have become important in the last decade (Lavon et al., 2011). There is a negative association between clinical and subclinical mastitis and reproductive performance in the beginning of lactation in high yielding cows (Schrick et al., 2001). ...
... Besides compromised cow welfare, it incurs economic losses through cost of treatment, production loss, and withdrawal of milk (Hogeveen et al., 2011). In addition, CM impairs reproductive performance, including a longer interval from calving to conception, more services per conception (Barker et al., 1998;Schrick et al., 2001), lower conception rates Lavon et al., 2011), and a higher risk of embryo loss (Chebel et al., 2004;McDougall et al., 2005). ...
Article
Full-text available
Recently, it has been shown that the addition of meloxicam to standard antimicrobial therapy for clinical mastitis (CM) improves the conception rate of dairy cows contracting CM in the first 120 d in milk. The objective of our study was to assess whether this improved reproduction through additional treatment with meloxicam would result in a positive net economic benefit for the farmer. We developed a stochastic bio-economic simulation model, in which a dairy cow with CM in the first 120 d in milk was simulated. Two scenarios were simulated in which CM cases were treated with meloxicam in conjunction with antimicrobial therapy or with antimicrobial therapy alone. The scenarios differed for conception rates (31% with meloxicam or 21% without meloxicam) and for the cost of CM treatment. Sensitivity analyses were undertaken for the biological and economic components of the model to assess the effects of a wide range of inputs on inferences about the cost effectiveness of meloxicam treatment. Model results showed an average net economic benefit of €42 per CM case per year in favor of the meloxicam scenario. Cows in the no-meloxicam treatment scenario had higher returns on milk production, lower costs upon calving, and reduced costs of treatment. However, these did not outweigh the savings associated with lower feed intake, reduced number of inseminations, and the reduced culling rate. The net economic benefit favoring meloxicam therapy was a consequence of the better reproductive performance in the meloxicam scenario in which cows had a shorter calving to conception interval (132 vs. 143 d), a shorter intercalving interval (405 vs. 416 d), and fewer inseminations per conception (2.9 vs. 3.7) compared with cows in the no-meloxicam treatment scenario. This resulted in a shorter lactation, hence a lower lactational milk production (8,441 vs. 8,517 kg per lactation) with lower feeding costs in the meloxicam group. A lower culling rate (12 vs. 25%) resulted in lower replacement costs in the meloxicam treatment scenario. All of the scenarios evaluated in the sensitivity analyses favored meloxicam treatment over no meloxicam. This study demonstrated that improvements in conception rate achieved by the use of meloxicam, as additional therapy for mild to moderate CM in the first 120 d in milk, have positive economic benefits. This inference remained true over a wide range of technical and economic inputs, demonstrating that use of meloxicam is likely to be cost effective across many production systems.
... Estos factores pueden explicar las variaciones de costos totales de la enfermedad e influir drásticamente en la conveniencia o no del control de la misma a nivel predial (McInnerney y col 1992). Las pérdidas por producción atribuidas a la mastitis están relacionadas a sus formas de presentación, clínica y subclínica, las que afectan en diferente grado el nivel de producción (Seegers y col 2003), el riesgo de descarte (Seegers y col 2003) o muerte de la vaca (Miller y col 1993 a ) y las chances de fallas reproductivas (Lavon y col 2011). Una parte importante de las pérdidas asociadas a la mastitis podrían deberse a la forma subclínica de la enfermedad, como fue documentado en los trabajos de Yalcin (2000) y Huijps y col (2008). ...
Article
Full-text available
The aim was estimate the daily direct cost and the expenditures due to mastitis control and prevention, evaluating their magnitude and variation among dairy farms. A random sample of dairy farms was the study population. Forty eight farms were visited once. The visit included a clinical mastitis check-up of lactating cows, a visual inspection of milking routine, and the analysis of a questionnaire. Milk composite samples (n = 1955) were randomly collected for somatic cell count (SCC). Productive and economic daily losses were characterised and quantified according to the composite sample SCC and valuing discarded milk as result of the clinical onset. Dairy farm control and prevention expenditures were also determined. The losses for subclinical mastitis showed a median of 2.8 liters/milking cow/day (percentile 25% = 2.0; percentile 75% = 2.9) for all cows studied, that represents US$ 0.99/milking cow/day. Losses due to milk discarded for clinical mastitis, showed a dairy farms median 0.12 liters/milking cow/day (percentile 25% = 0; percentile 75% = 0.31), that represents a cost of US$ 0.04/milking cow/day. The control and prevention expenditures dairy farm median was about US$ 0.06/milking cow/day (percentile 25% = 0.034; percentile 75% = 0.095). The total cost of mastitis, including the loss caused by the disease and the cost of its control and prevention measures were ≥ US$ 1.0/milking cow/day (percentile 25% = 0.8; percentile 75% = 1.2) in at least 50% of the dairy farms. Daily total cost for mastitis represented 16% of the dairy farm daily gross income in at least 50% of the dairies. No difference of cost across distinct farm production strata was found, except by the ratio of total mastitis cost over daily gross income. That ratio was higher among low producing farms. This is the first report about mastitis costs variation among small and medium dairy farms in Argentina.
... A potential mechanism and link between inflammation and infertility in cattle has been proposed by Hansen et al. 32 involving inflammation caused by bacterial infection leading to increased proinflammatory cytokine production effecting levels of reproductive hormones, increasing body temperature, and destabilizing the corpus luteum 32 . In fact, mastitis has been shown to decrease reproductive parameters including conception rate 33 . Using metabolomics, a recent study compared the plasma metabolomic profiles between dairy cows with subclinical mastitis and healthy control cows 34 . ...
Article
Full-text available
Infertility remains the most prevalent reason for cattle being removed from production environments. We utilized metabolomic profiling to identify metabolites in the blood plasma that may be useful in identifying infertile heifers at the time of artificial insemination (AI). Prior to AI, phenotypic parameters including body condition, weight, and reproductive organ measurements were collected. These were determined not effective at differentiating between fertile and infertile heifers. Analysis of the resulting metabolomic profiles revealed 15 metabolites at significantly different levels (T-test P ≤ 0.05), with seven metabolites having a greater than 2-fold difference (T-test P ≤ 0.05, fold change ≥2, ROC-AUC ≥ 0.80) between infertile and fertile heifers. We further characterized the utility of using the levels of these metabolites in the blood plasma to discriminate between fertile and infertile heifers. Finally, we investigated the potential role inflammation may play by comparing the expression of inflammatory cytokines in the white blood cells of infertile heifers to that of fertile heifers. We found significantly higher expression in infertile heifers of the proinflammatory markers tumor necrosis factor alpha (TNFα), interleukin 6 (IL6), and the C-X-C motif chemokine 5 (CXCL5). Our work offers potentially valuable information regarding the diagnosis of fertility problems in heifers undergoing AI.
... Mastitis causes a 26 to 28% reduction in conception rates when it occurs within 10 days before or 30 days after artificial insemination (Lavon et al., 2011). The reduced pregnancy rate after mammary gland infection can be explained by alterations in ovarian steroid production and gonadotropin secretion . ...
Article
Oxidative stress is the result of an imbalance between free radicals and antioxidants. Under normal physiological conditions, free radicals are involved in reproductive events such as cell cycle activation, ovulation and luteolysis. However, when an overproduction of free radicals surpasses antioxidant capacity, oxidative damage, reproductive anomalies and diminished fertility occur. Supplementation with antioxidants prevents oxidative damage and can be incorporated into reproductive management to improve fertility in females. Selection of the preovulatory follicle, ovulation, fertilization, embryo development and formation of the corpus luteum occur during the periconceptional period. This is a dynamic period and the events are susceptible to oxidative stress damage. Therefore, the objective of this review is to discuss the effect of oxidative stress on reproductive events during the periconceptional period, as well as to address antioxidant supplementation during this period.
... A negative correlation was found between the reproduction and incidence of clinical mastitis in cows leading to alteration in inter-estrus interval and decreasing the luteal phase (Moore et al., 1991), and poor pregnancy rate (Hertl et al., 2010). Also, the high incidence of mastitis was associated with increased postpartum first service interval, the number of services per conception, days from calving to conception, embryonic loss, abortion, and failure to become pregnant to the first service and decreased pregnancy rate (Moore et al., 2005;Pinedo et al., 2009;Lavon et al., 2011;Hudson et al., 2012). ...
Article
Full-text available
Abstract | This study aimed to determine the influence of early postpartum clinical mastitis on the reproductive performance, antioxidant, hormonal profile and trace elements in Egyptian buffaloes. A total of 90 multiparous lactating Egyptian buffaloes (500-600 kg live body weight, 5-7 years old, 3-5 parities, and 10.75 ± 2.66 kg/day milk yield were used in this study. The buffaloes were managed and feed at similar traditional conditions. Mastitis diagnosis was performed 21 days after calving, then animals (n=90) were grouped to normal (n= 75), and clinical mastitis (n=15) groups. Results show that interval from calving to first estrus (31.60±0.86 vs. 33.10±0.98 d) or first service (55.20±0.97 vs. 61.00±1.96) was not affected (P≥0.05). Mastitis decreased (P<0.05) estrus/mating (93.3 vs. 80.0%) and pregnancy rates (86.66 vs. 53.33%), prolonged (P<0.001) days open (63.45±3.25 vs. 104.10±3.92 d), and increased services number required for conception (1.35±0.11 vs. 2.800±0.25 services). Mastitis decreased (P<0.0001) reduced glutathione (5.66±0.182 vs. 4.71±0.302 mmol/l) and total antioxidant capacity (1.64±0.046 vs. 0.76±0.049 mmol/l), and increased (P<0.0001) in malondialdehyde (0.80±0.043 vs. 1.68±0.064 mmol/ml). Mastitis significantly decreased serum concentration of progesterone (P4), estrogen (E2), thyroxin (T4), zinc (Zn), and selenium (Se) by about 24.05, 13.80, 5.36, 2.50, and 3.44%, respectively, while triiodothyronine (T3) concentration showed non-significant decrease by about 3.77%. Mastitis incidence at early postpartum in lactating Egyptian buffaloes delayed the resumption of estrous and ovarian activity and decreased pregnancy rate, antioxidant status, thyroid and reproductive hormones and trace elements such as Zn and Se. Keywords | Mastitis, Buffaloes, Pregnancy rate, Antioxidant, Trace elements.
... A negative correlation was found between the reproduction and incidence of clinical mastitis in cows leading to alteration in inter-estrus interval and decreasing the luteal phase (Moore et al., 1991), and poor pregnancy rate (Hertl et al., 2010). Also, the high incidence of mastitis was associated with increased postpartum first service interval, the number of services per conception, days from calving to conception, embryonic loss, abortion, and failure to become pregnant to the first service and decreased pregnancy rate (Moore et al., 2005;Pinedo et al., 2009;Lavon et al., 2011;Hudson et al., 2012). ...
Article
Full-text available
This study aimed to determine the influence of early postpartum clinical mastitis on the reproductive performance, antioxidant, hormonal profile and trace elements in Egyptian buffaloes. A total of 90 multiparous lactating Egyptian buffaloes (500-600 kg live body weight, 5-7 years old, 3-5 parities, and 10.75 ± 2.66 kg/day milk yield were used in this study. The buffaloes were managed and feed at similar traditional conditions. Mastitis diagnosis was performed 21 days after calving, then animals (n=90) were grouped to normal (n= 75), and clinical mastitis (n=15) groups. Results show that interval from calving to first estrus (31.60±0.86 vs. 33.10±0.98 d) or first service (55.20±0.97 vs. 61.00±1.96) was not affected (P≥0.05). Mastitis decreased (P<0.05) estrus/mating (93.3 vs. 80.0%) and pregnancy rates (86.66 vs. 53.33%), prolonged (P<0.001) days open (63.45±3.25 vs. 104.10±3.92 d), and increased services number required for conception (1.35±0.11 vs. 2.800±0.25 services). Mastitis decreased (P<0.0001) reduced glutathione (5.66±0.182 vs. 4.71±0.302 mmol/l) and total antioxidant capacity (1.64±0.046 vs. 0.76±0.049 mmol/l), and increased (P<0.0001) in malondialdehyde (0.80±0.043 vs. 1.68±0.064 mmol/ml). Mastitis significantly decreased serum concentration of progesterone (P4), estrogen (E2), thyroxin (T4), zinc (Zn), and selenium (Se) by about 24.05, 13.80, 5.36, 2.50, and 3.44%, respectively, while triiodothyronine (T3) concentration showed non-significant decrease by about 3.77%. Mastitis incidence at early postpartum in lactating Egyptian buffaloes delayed the resumption of estrous and ovarian activity and decreased pregnancy rate, antioxidant status, thyroid and reproductive hormones and trace elements such as Zn and Se.
... However, we decided to present the result at two cutoff levels, CL2 and CL5. Multivariable models were designed with a logistic model statement using the GLIMMIX procedure of SAS, with recovery or culling rate (until 90 days from SCC elevation) as the dependent variable, as previously described [20]. The first model tested the probability of recovery to level R2 and culling at the cutoff level CL2. ...
Article
Full-text available
The term “spontaneous recovery” refers to a return to a previous condition without any external treatment. In cow mastitis, it refers to cases exhibiting visual symptoms (clinical) or an increase in somatic cell count (SCC) with no visual symptoms (subclinical), with or without identification of a pathogen, from which the animal recovers. A large retrospective analysis of data compiled from the Israeli Dairy Herd Book was performed to evaluate the occurrence of: (i) actual “spontaneous recovery” from the inflammation; (ii) recovery from the inflammation due to antibiotic treatment. In 2018, 123,958 cows from 650 herds with first elevation of SCC at monthly test-day milk yield were clustered into five SCC-cutoff levels (CL) (×103 cells/mL): CL1 (200–299), CL2 (300–399), CL3 (400–499), CL4 (500–999), CL5 (≥1000). Each cutoff level was analyzed separately, and each cow appeared only once in the same lactation and cutoff level, thus resulting in five independent analyses. Recovery was defined as decreased SCC on all three monthly test days, or on the second and third test days, set to: R1 (
... Such variations among herds were an ultimate result of combined effects of factors such as breed and milking method in addition to the other differences among herds such as hygienic milking practices, health management, and other environmental and management conditions. Decreased reproductive performance due to SCM has been recorded in many regions of the world (Klaas et al., 2004;Pinedo et al., 2009;Lavon et al., 2011a). The studies that have investigated the effects of SCM on reproductive performance of dairy cows are rare in Sri Lanka (Rahularaj et al., 2019). ...
Article
Full-text available
Compared with clinical mastitis, the subclinical form of mastitis (SCM) is more common and thought to cause more economic losses to the dairy industry. The current study aimed to investigate the prevalence, risk factors of SCM, and effects on reproduction of dairy cows in major milk-producing areas of Sri Lanka. A total of 1,357 cows of selected farms in 3 regions were examined in the study. California Mastitis Test was conducted for individual cows, and a score of 2 or more for any quarter without any clinical symptoms and abnormalities in milk was considered as positive for SCM. Samples from infected animals were collected and subjected to bacteriological analysis. A pretested questionnaire was used to collect data on individual cows and herds. Risk factors associated with SCM were analyzed using binary logistic regression in generalized linear mixed models. The effect of SCM on calving to conception interval and days from calving to artificial insemination were analyzed by survival analysis using Cox's proportional hazards regression and Kaplan-Meier survival function estimates, respectively. A Poisson regression model was run to determine the effect of SCM on number of artificial inseminations per conception. The prevalence of SCM was 57.5, 11.8, and 45.5% in the regions A, B, and C, respectively. The most common pathogen was Staphylococcus aureus, with 87.1, 56.5, and 92.3% in the regions A, B, and C, respectively. Logistic regression analysis showed that parity, farming system, milking area, region, and herd significantly affect the prevalence of SCM. Subclinical mastitis during the pre-breeding period was associated with 14% increase in the chance of having a greater number of artificial inseminations per conception. Likewise, median days from calving to artificial insemination was longer in cows with SCM compared with normal cows (79 and 64 d, respectively). Therefore, SCM affected the inseminated proportion of studied cows. However, SCM was not associated with the calving to conception interval. The results revealed that the cow factors and milk hygiene play a significant role in the prevalence of SCM.
... Differences between effect of treatments-APT or no treatment of cows with subclinical mastitis-on recovery: A multivariable model was designed with a logistic model statement using the GLIMMIX procedure of SAS (version 9.2, SAS Institute, Cary, NC, USA, 2009), with recovery as the dependent variable, as previously described [14]. The model was analyzed with the general form: Recovery rates = intercept + Herd + Group + Lactation number + DIM + error, where: Recovery rate = ln P/(1-P), P = probability of recovery; Herd = six different dairy farms; Group = cows treated with APT vs. untreated cows; Lactation number = first, second, third and more lactations days in milk. ...
Article
Full-text available
A cow with mastitis has a high somatic cell count (SCC) in its milk. Cow-share-contribution of somatic cells to the bulk milk tank (BMTSCC) refers to the relative addition made by each cow’s milk to the bulk tank’s SCC. Since bulk milk is graded and priced according to the BMTSCC, high-yielding cows with mastitis are the main contributors to penalizations in milk price. The benefits of acoustic pulse technology (APT) application to tissues are well documented, including its anti-inflammatory effect and restoration of tissue function by triggering natural healing processes. An APT-based device was developed specifically for treating mastitis in dairy cows. It enables rapid and deep penetration of the acoustic pulses over a large area of the udder in a single session. A study was performed on six farms with a total of 3,900 cows. One unit of cow-share-contribution equaled the addition of 1,000 cells to each mL of the bulk milk volume above the mean BMTSCC. A total of 206 cows were selected: 103 were treated with APT and 103 served as controls. All of the cows contributed over 1.5 units to the BMTSCC at the time of treatment. Seventy-five days after APT treatment, 2 of the 103 treated cows (1.9%) were culled, compared to 19 (18.5%) of the 103 control cows, as well as infected quarter dry-off in 5 others (4.85%). Overall success was defined as a decrease of >75% in cow-share-contribution from treatment time in two of the three monthly milk recordings following treatment. Results indicated 57.3% success for the APT-treated cows vs. 14.6% for the untreated control groups. Highest share-contribution provide an additional tool for the farmer’s decision of how to control BMTSCC. Because the cow-share-contribution value is relative to herd size and BMTSCC, this study included a similar number of cows, with similar SCC and milk yield from each of the six herds.
... The association between elevated SCC and P/ AI seems to be more consistent in the literature, as numerous studies reported reduced fertility for cows with both subclinical (Schrick et al., 2001;Lavon et al., 2011) and clinical (König et al., 2006;Hudson et al., 2012;Fuenzalida et al., 2015) mastitis. Comparison among studies remains difficult, however, because of their inconsistency on thresholds for defining elevated SCC and the breeding risk periods (SCC data from before and/or after DHIA test date). ...
Article
The objective of this observational study was to identify factors associated with estrous duration (DU) and intensity measured as the peak of activity (PA) change and subsequent fertility in lactating Holstein cows using a neck-mounted automated activity monitor (Heatime Pro, SCR Engineers Ltd., Netanya, Israel). Ambient temperature and relative humidity were recorded hourly to calculate the temperature-humidity index (THI). A total of 5,933 estrus events from 3,132 cows located on 8 commercial dairy farms in Germany were used for this study. Farms participated in monthly DHIA testing. Pregnancy diagnosis was performed either by transrectal palpation [farm 1: 42 ± 3 d; farm 3: 40 ± 3 d; farms 4 and 8: 38 ± 3 d; farm 5: 43 ± 3 d after artificial insemination (AI)] or transrectal ultrasonography (farms 2, 6, and 7: 30 ± 3 d after AI). Estrous intensity was categorized based on peak activity of estrus into low (35-89 index value), and high (90-100 index value) PA. Overall, 73.5% of estrus events were of high PA. The mean (± standard error of the mean) DU was 14.94 ± 0.06 h. There was a strong correlation between DU and PA (r = 0.67). In the final statistical model, only PA was associated with pregnancy per artificial insemination (P/AI), with 1.35 greater odds of pregnancy for cows with high PA compared with cows with low PA. Increased THI 1 wk before AI was associated with shorter DU, lower PA, and decreased P/AI. A small percentage of cows (4.7%) showed short interestrus intervals (i.e., more than 1 activity peak within 7 d close to the event of estrus), resulting in reduced DU, PA, and P/AI. The change of weighted rumination was associated with DU and PA, as a lower nadir was associated with a greater risk for high PA and long DU. There was no association, however, between the nadir of change of weighted rumination and P/AI. Whereas milk yield and somatic cell count from the DHIA test date before AI were negatively associated with estrous expression, neither milk yield nor somatic cell count was associated with P/AI. Surprisingly, multiparous cows expressed estrus with longer DU (13.15 ± 0.31 h) compared with primiparous cows (12.52 ± 0.32 h), whereas PA did not differ among parities. Pregnancy per AI was greater for primiparous (29.4%) than for multiparous (22.1%) cows. An estrus event with long DU or high PA was more likely later in lactation. Milk fat, milk protein, milk urea nitrogen, and lactose from the DHIA test date closest to AI had no association with estrous expression or P/AI. In conclusion, DU and PA were highly correlated, and cows with high PA were particularly associated with greater odds for pregnancy. A negative association between estrous expression and P/AI was identified for increased THI 1 wk before AI and cows with short interestrus intervals using automated activity monitor.
... If animal welfare and milk safety are not compromised and treatment is not economically justified, then the inflammation could be accepted for the time being. This is, in fact, the common practice, and most subclinical mastitis cases are routinely ignored, even though they may negatively affect milk yield and reproduction efficiency at the animal level [23,24] and decrease milk quality for dairy industrial processing [20,21]. New regulations for antibiotic use in dairy farms restrict the ability to treat IMI during lactation and subclinical mastitis during the dry-off period. ...
Article
Full-text available
The aim of the current study was to verify the existence of a significant correlation between bacterial isolation (or not) and mammary gland inflammation, using traditional bacterial culturing and PCR, milk leucocytes distributions, and tissue histology. Twenty-two cows were tested at the level of the individual gland for bacteriological culture and real-time PCR (RT-PCR), milk composition, somatic cells count (SCC), and cell differentiation. Post-slaughter samples of teat-ends and mammary tissues were tested for histology and bacteriology by RT-PCR. The 88 glands were assigned to either outcome: 1. Healthy—no inflammation and no bacterial finding (NBF) (n = 33); 2. Inflammation and NBF (n = 26); 3. Inflammation and intra-mammary infection (n = 22) with different bacteria. Bacteriology of milk samples and that of the RT-PCR showed 91.4% agreement. In the lobule’s tissues of healthy glands, ~50% were milk producers and the other glands had dry areas with increased fat globules with a low number of leukocytes. In contrast, ~75% of the infected glands were identified as inflamed, but with no isolation of bacteria. Infiltration of mononuclear cells and neutrophils into the connective tissue was observed but not in the lobule’s lumen. In summary, the study confirms that not every mastitis/inflammation is also an infection.
... The occurrence of infectious diseases has a negative impact on fertility (Sheldon et al. 2004). Cows with uterine or mammary infections have decreased follicular growth and steroid hormone concentrations, prolonged luteal phase, and interruption of ovarian activity (Sheldon et al. 2002, Lavon et al. 2011a, b, Krause et al. 2014. ...
Article
The aim of this study was to evaluate the effect of exposing bovine oocytes to lipopolysaccharides (LPS) in vivo and in vitro on early embryo development. In experiment 1, cumulus oocytes complexes (COCs, n=700/group) were challenged with 0, 0.1, 1.0 or 5.0 μg mL-1 of LPS during in vitro maturation (IVM). After, in vitro fertilization (IVF) and in vitro culture (IVC) was performed. In experiment 2, COCs (n=200/group) matured and in vitro fertilized without LPS were subjected to IVC with the same doses of LPS from experiment 1. In experiment 3, heifers received two injections of saline solution (n=8) or 0.5 μg Kg-1 of LPS (n=8) 24 hours apart and three days later COCs were recovered and submitted to IVM, IVF, and IVC. In experiments 1 and 3, the expression of TLR4, TNF, AREG and EREG genes in cumulus cells was evaluated. Exposure to 1 and 5 μg mL-1 of LPS during IVM decreased nuclear maturation (39.4 and 39.6%, respectively) compared to control (63.6%, P < 0.05). Despite that, no effect in cleavage and blastocyst rate were observed. Exposure to LPS during IVC did not affect embryonic development. In vivo exposure to LPS decreased the in vitro cleavage rate (54.3% vs 70.2%, P = 0.032), but cleaved embryos developed normally. Number of cells per embryo and gene expression were not affected by the LPS challenge in any experiment. In conclusion, although in vitro exposure to LPS did not affect early embryo development, in vivo LPS exposure reduced cleavage rate.
... Clinical mastitis was defined when nonsevere signs of inflammation were detected at least 14 d after a previous case. Subclinical mastitis (SCM) was defined when monthly DHIA SCC was greater than 150,000 cells/mL (Lavon et al., 2011). Clinical mastitis history was the occurrence of CM in the cow (any quarter) within the preceding 55 d before detection of the enrolled case. ...
Article
Full-text available
The objective of this negatively controlled, randomized clinical trial was to examine clinical outcomes of 2-d or 8-d treatment using an approved intramammary (IMM) product containing ceftiofur hydrochloride compared with no antimicrobial treatment of nonsevere, gram-negative cases of clinical mastitis (CM). Additionally, we contrasted clinical outcomes of cases caused by Escherichia coli (n = 56) or Klebsiella pneumoniae (n = 54). Cases (n = 168) of nonsevere (abnormal milk or abnormal milk and udder) CM were randomly assigned to receive 2 d (n = 56) or 8 d (n = 56) of IMM ceftiofur or assigned to a negative control group (n = 56). At enrollment, quarter milk samples were collected and used for on-farm culture, somatic cell count (SCC), and confirmatory microbiological analysis. Quarter milk samples were collected weekly from 7 to 28 d after enrollment for microbiological and SCC analysis. Clinical outcomes were followed for 90 d or until the end of lactation (follow-up period, FUP). Overall, no significant differences in quarter-level recurrence of CM (32% for negative control, 34% for the 2-d treatment, and 32% for the 8-d treatment), culling (18% for negative control, 12% for 2-d treatment, and 11% for 8-d treatment), voluntary dry-off of affected quarters (20% for negative control, 30% for 2-d treatment, and 27% for 8-d treatment), days until return to normal milk (4.2 days for negative control, 4.8 days for 2-d treatment, 4.5 days for 8-d treatment), weekly quarter-SCC during the FUP (6.1, 6.3, and 6.0 log 10 SCC for the negative control, 2-d, and 8-d treatments, respectively), or daily milk yield during the FUP (37.1, 36.3, and 37.6 kg/cow per day for the negative control, 2-d, and 8-d treatments, respectively) were observed among experimental groups. Days of discarded milk were greater for cows assigned to 8-d IMM ceftiofur (11.1 d) than for cows assigned to 2-d (6.9 d) or cows assigned to negative control (5.6 d). Bacteriological cure (BC) at 14 and 21 d after enrollment was greater in cows assigned to 8-d (89%) and 2-d (84%) treatment than in cows assigned to negative control (67%), but this outcome was confounded by pathogen. For CM caused by Kleb. pneumoniae, BC was greater for quarters assigned to receive treatment (combined 2-d and 8-d groups; 74% BC) than for quarters assigned to negative control (18%). In contrast, no differences in BC were observed for CM caused by E. coli (97–98%). Culling and voluntary dry-off of affected quarters were significantly greater for cows with quarters affected by Kleb. pneumoniae (22% culled, 39% voluntary dry-off of quarters) than for cows with quarters affected with E. coli (7% culled, 11% voluntary dry-off of quarters). Overall, use of IMM ceftiofur did not result in improvement of most clinical outcomes, but differences between E. coli and Kleb. pneumoniae were evident. In contrast to E. coli, Kleb. pneumoniae caused chronic intramammary infection and induced worse clinical outcomes. Intramammary antibiotic treatment of most mild and moderate cases of CM caused by E. coli is not necessary, but more research is needed to identify which quarters affected by Kleb. pneumoniae may benefit from antimicrobial therapy.
... 16 A similar reduction in conception rate has been demonstrated in cows with elevated SCCs. 17 18 Mastitis also has the potential to impact on the apparent (measured) oestrus detection efficiency by leading to embryonic death and irregular returns 19 or by direct effects on ovarian function. 20 21 This includes potential impact on the apparent interovulatory interval of the cow. ...
Article
Oestrus detection is an important part of maintaining efficient reproductive performance in dairy herds. Both lameness and mastitis are common diseases of dairy cows that may impact oestrus detection. A set of data from 28 herds identified as having good recording of clinical mastitis and lameness incidents was used for the study. Logistic regression was used to identify associations between disease episodes within 100 days of insemination and changes in the probability of reinsemination at either 18–24 or 19–26 days after an unsuccessful insemination. Population attributable risk was calculated to understand the impact these diseases may have at a herd level. Lameness 0–28 days after the first insemination of the interval decreased the odds of a reinsemination at an appropriate time by approximately 20 per cent. Clinical mastitis 1–28 days prior to the first insemination of the interval increased the odds of reinsemination at the expected time by approximately 20 per cent. The associations were similar for either interservice interval outcome. Population attributable risk suggested that the effect of these diseases on the probability of reinsemination at the expected time at a population level would likely be extremely small.
... Cases of CM that occurred at least 14 d after a previous case were considered new cases. Subclinical mastitis (SCM) was defined when monthly DHIA SCC exceeded 150,000 cells/mL (Lavon et al., 2011). ...
Article
Full-text available
The objective of this negatively controlled randomized clinical trial was to compare clinical outcomes of 5-d intramammary treatment using ceftiofur hydrochloride and no antimicrobial treatment of nonsevere culture-negative cases of clinical mastitis (CM). A total of 121 cases of nonsevere (abnormal milk or abnormal milk and udder) culture-negative CM were randomly assigned to either treatment (n = 62) or negative control (n = 59) groups. Quarters assigned to treatment received 1 daily intramammary infusion with an approved commercially available product containing ceftiofur hydrochloride for 5 d. Quarters assigned to the negative control group did not receive any interventions. Enrolled cows were followed for 90 d or until the end of lactation. At enrollment, milk samples from the affected quarter were used for on-farm culture, somatic cell count (SCC) analysis, and further microbiological analysis. During the follow-up period, milk samples were collected for microbiological analysis and SCC analysis. No significant differences between treatment and negative control groups were identified for treatment failure (5% for treatment vs. 10% for negative control, n = 121), quarter-level CM recurrence (8 vs. 5%, n = 91), intramammary infection at 14 or 28 d after enrollment (13 vs. 26%, n = 86), days until clinical cure (4.2 vs. 4.0 d), days to culling (48.3 vs. 36.8 d), daily milk production (43.3 vs. 43.6 kg/cow per day), or weekly quarter SCC (5.5 vs. 5.4 log10 SCC). Days of milk discard were greater for cows assigned to the treatment group (8.5 d) compared with cows assigned to the negative control group (5.6 d). During the follow-up period, cases in the treatment group had a 50% risk reduction in IMI compared with cases in the negative control group. Irrespective of group, negative outcomes such as quarter-level CM recurrence (12%), treatment failure (12%), and culling (5%) occurred infrequently in nonsevere culture-negative cases of CM. Use of intramammary ceftiofur for treatment of nonsevere culture-negative cases of CM did not improve any economically relevant clinical outcome such as culling, milk production, or SCC.
Article
Mastitis has deleterious effects on ovarian function and reproductive performance. We studied the association between plasma or follicular fluid (FF) obtained from endotoxin-induced mastitic cows, and oocyte developmental competence. Lactating Holstein cows were synchronized using the Ovsynch protocol. On Day 6 of the synchronized cycle, an additional PGF2α dose was administered, and either Escherichia coli endotoxin (LPS, 10 μg; n = 3 cows) or saline (n = 3 cows) was administered to one udder quarter per cow, 36 h later. Milk samples were collected and rectal temperatures recorded. Cows treated with LPS showed a typical transient increase in body temperature (40.3 °C ± 0.4), whereas cows treated with saline maintained normal body temperature (38.9 °C ± 0.04). A higher (P < 0.05) somatic cell count was recorded for cows treated with LPS. Plasma samples were collected and FF was aspirated from the preovulatory follicles by transvaginal ultrasound probe, 6 h after LPS administration. Radioimmunoassay was performed on plasma samples to determine estradiol and cortisol concentrations. Either FF or plasma was further used as maturation medium. In the first experiment, oocytes were matured in TCM-199 (Control) or in FF aspirated from cows treated with saline (FF-Saline) or LPS (FF-LPS). Cleavage rate to the 2- to 4-cell stage embryo did not differ among groups. However, the proportion of developed blastocysts on Day 7 postfertilization in the FF-LPS group tended to be lower for that in FF-Saline and was lower (P < 0.05) than that in the Control groups (10.6 vs. 22.4 and 24.4%, respectively). In the second experiment, oocytes were matured in TCM-199 (Control), or in plasma obtained from cows treated with saline (Plasma-Saline) or LPS (Plasma-LPS). Similar to the FF findings, cleavage rate did not differ among groups; however, the proportion of developing blastocysts tended to be lower in the Plasma-LPS group than in the Plasma-Saline group and was lower (P < 0.05) from that in the Control group (11.0 vs. 25.5 and 34.7%, respectively). The proportion of apoptotic cells per blastocyst, determined by TUNEL assay, did not differ among the experimental groups. The findings shed light on the mechanism by which mastitis induces a disruption in oocyte developmental competence. Further studies are required to clarify whether the negative effect on oocyte developmental competence is a result of LPS, by itself, or due to elevation of secondary inflammatory agents.
Article
Full-text available
Inflammation is not only the first line of defense of the organism but is also required in many reproductive processes such as ovulation, corpus luteum development, luteolysis, uterine clearance after insemination and post partum. Nevertheless, if excessive or persistent, inflammation can switch from a positive mechanism to a deleterious process, impairing oocyte quality and embryo development. Not only uterine but also non genital inflammatory sites can depreciate reproductive performances, with a carry over effect of 2 to 4 months. Since the metabolic challenges of the peripartum transition period make difficult for the cow to control inflammation, dairy cows are frequently in a pro-inflammatory stage, suggesting that inflammation, rather than infection, is a limiting factor of fertility in modern dairy cows. Within the first week after calving, cows have to mount an intense inflammatory response to the bacterial invasion of the uterine cavity with the challenge of being able to switch it off in no more than 5-6 weeks. The absence of neutrophils on endometrial smear is associated with the highest success rate at insemination. Since a fine tuning – rather than an absence - of inflammation is required along the reproductive cycle, anti-inflammatory drugs do not allow any improvement of pregnancy rate, except in the specific case of embryo transfer. Appropriate management of the transition period (especially nutritional) and in a long term perspective, genetic selection contribute to improve the aptitude of cows to controls the intensity of inflammatory process.
Article
Mastitis is the inflammation of the mammary gland and is a common disease that affects dairy cattle health and wellbeing. Economic losses attributed to mastitis include lower milk production, increase in the amount of discarded milk, labor and medical costs, and premature culling (Fetrow, 2000). In addition to these costs, over the past two decades there has been mounting evidence that both clinical and subclinical mastitis reduce reproductive efficiency in dairy cattle (Kumar et al., 2017; Dahl et al., 2017). This paper discusses the effect of mastitis on dairy cattle reproduction from an inflammatory response basis of the mammary gland to infection.
Article
The objective of this study was to conduct a meta-analysis to quantitatively characterize the effects of mastitis on the reproductive performance of dairy cows as well as to identify factors that interact with this relationship. A total of 29 publications were identified that contributed 24, 41, 27, 38, and 13 trial results to the meta-analysis of how mastitis is related to time to first service (TFS), days open (DO), services per conception (SPC), pregnancies per insemination at first service (FSP/AI) and pregnancy loss (PL), respectively. The meta-analyses were conducted using multilevel linear mixed-effects models. Overall, high levels of heterogeneity were present and meta-regression models only explained a small amount of heterogeneity. Results suggest that cows with mastitis pre-first insemination experience, on average, an additional 13.29 d to first service [95% confidence interval (CI): 6.64, 19.95] when compared with cows with no mastitis in the same time period. Moreover, in relation to cows with no mastitis in the same time period, 22.34 additional DO (95% CI: 12.89, 31.79) were estimated, on average, for cows with clinical mastitis at pre-insemination leading to conception. Additionally, 32.41 added DO (95% CI: 20.58, 44.25) were estimated, on average, for cows with clinical mastitis at pre- or post-insemination leading to conception compared with cows with no mastitis in the same time period. Finally, 20.03 additional DO (95% CI: 3.11, 36.95) were estimated, on average, for cows with subclinical mastitis pre- or post-insemination leading to conception compared with cows with no mastitis in the same time period. Effect size estimates from the meta-regression models for SPC, in relation to cows with no mastitis in the same time period, suggest that, on average, SPC increases by 0.46 inseminations (95% CI: 0.30, 0.62) for a cow experiencing mastitis pre-insemination leading to conception. When mastitis occurs either pre- or post-insemination leading to conception, SPC is expected to increase, on average, by 0.72 inseminations (95% CI: 0.48, 0.95) compared with cows with no mastitis in the same time period. The estimated effect sizes for FSP/AI suggest a risk ratio of conceiving at first insemination of 0.90 (95% CI: 0.82, 0.99) for cows with mastitis diagnosed pre-first insemination with respect to cows with no mastitis in the same time period, and a risk ratio of 0.79 (95% CI: 0.72, 0.86) for cows diagnosed with mastitis either pre- or post-first insemination with respect to cows with no mastitis in the same time period. Publication bias was identified in 4 of the meta-analysis models (TFS, DO, SPC, and FSCR), but no influential trials were identified in any models; the reliability of the meta-analysis results should be interpreted carefully keeping these limitations in mind. Further meta-regression analysis would be valuable as additional studies are published that report other potential sources of heterogeneity.
Article
Reproductive performance is a key factor in determining the profitability of dairy farm, which is affected by many factors such as environment and diseases. Mastitis is a common and important disease, which has caused huge economic losses to the dairy industries worldwide. Mammary gland infection causes immune responses, resulting in the abnormal secretion of cytokines and hormones and abnormal function of the reproductive system such as the ovary, corpus luteum, uterus, and embryo. Cows with mastitis have delayed estrus, decreased pregnancy rate, and increased risk of abortion. The adverse effects of mastitis on reproductive performance are affected by many factors, such as occurrence time, pathogen, and cow factors. This paper primarily reviews the progress in the effects and mechanisms of mastitis on reproductive performance, with emphasis on maternal transcriptome, genomic analysis, epigenetic modification, microbiota, inflammatory regulation, and immune evasion mechanism of mastitis, aiming to provide directions for the prevention and control of mastitis in the future.
Article
The objective of this study was to assess the impact of mastitis-causing bacteria and somatic cell count (SCC) on pregnancy per embryo transfer (P/ET) in Holstein-Gir crossbred (Girolando) lactating dairy cows. Cows (n = 1397) were subjected to a timed-embryo transfer protocol. Milk samples were collected two days before embryo transfer for SCC and bacteriological culture analyses. Pregnancy diagnosis was performed on days 31 and 66 after timed-embryo transfer. The animals were grouped according to the National Mastitis Council recommendations: Gram-positive environmental (EV+), Gram-negative environmental (EV-), Gram-positive contagious (C+), coagulase-negative staphylococci (CNS) and control (no bacterial growth). Additional analysis was made by categorizing bacteria based on degree of pathogenicity (Major or Minor). Bacterial growth reduced P/ET (P < .01) at both 31 and 66 days of gestation. The P/ET was lower (P < .05) at 31 days in EV- (30.1%) and EV+ (29.9%) groups and tended (P = .09) to be lower in the C+ group (36.6%) than the control group (44.0%). The P/ET from the Major group at 31 days of gestation was lower (P = .03) compared with the Minor and control groups (32.1 vs 41.1 vs 43.2%, respectively). Cows with SCC > 400,000 cells/mL had lower P/ET (P < .01) than animals with SCC < 200,000 cells/mL at both 31 (30.4% vs 40.8%) and 66 days (24.7% vs 32.2%) of gestation. Pregnancy loss was not different between bacterial isolates and SCC categories. Elevated SCC significantly reduced P/ET, whereas environmental agents and those with Major pathogenicity yielded the greatest reduction in P/ET.
Article
Full-text available
The study was conducted to detect the presence of bacterial and fungal contamination in imported semen straws used for Artificial Insemination (AI) in cows and antibiotic sensitivity test for those isolates. For this purpose, a total of 118 imported semen straws from local markets in Baghdad and some veterinarian clinics from December 2011 to February 2012 transported directly to the laboratories of Unit of Zoonotic Diseases (College of Veterinary Medicine / Baghdad University) frozen in liquid nitrogen (-196 ºC), the cultured on brain and heart broth and Sabouraud dextrose broth with routine biochemical tests, as well as antibiotic sensitivity test was done using 11 antibiotics. The results revealed isolation of Bacillus subtilis 34 isolates (28.81%), Staphylococcus aureus 27 (22.88%), and E. coli 13 (11.07%), also mixed infection was registered B. subtilis + S. aureus found in 9 straws (7.63%) and B. subtilis + E. coli in 3 straws (2.54%). The results of antibiotic sensitivity showed resistant strains of S. aureus against most antibiotics used, while B. subtilis and E. coli showed intermediate sensitivity to many antibiotics. In general, all isolates were sensitive to Azithromycin and Ceftriaxone. Fungal isolation showed Penicillium 16 isolates (13.65%), Aspergillus 7 isolates (5.93%), Alternaria 4 (3.39%), and Cladosporium only 2 isolates (1.69%). It could be concluded that there was a need to use a dose of Azithromycin to get rid of contamination and using of hygienic precautions in artificial insemination and using of disinfectants for sterilization of instruments and tools to avoid contamination.
Article
Full-text available
RESUMEN. La leche proporciona nutrientes esenciales y es una fuente importante de energía alimentaria, proteínas de alta calidad y grasas. Contribuye considerablemente a la ingestión necesaria de nutrientes como el calcio, magnesio, selenio, riboflavina, vitamina B12 y ácido pantoténico. El consumo de este alimento puede representar diferencias en la calidad de las dietas de las personas sin acceso a una nutrición adecuada, especialmente entre los niños. La composición de la leche varía de acuerdo a la incidencia de múltiples factores como la raza, tiempo de lactancia, alimentación, genética, condición climática, estado de salud y estrés de los animales, etc. La calidad y seguridad de la leche cruda de vaca puede verse perjudicada por diferentes razones, microorganismos, residuos químicos y otros contaminantes, lo que incide significativamente sobre la salud pública. El incremento de microorganismos en la leche causa importantes pérdidas. Actualmente, existe muy poca o ninguna publicación o referencia a nivel nacional que indique una caracterización de calidad de la leche cruda de vaca según su condición fisicoquímica, ni microbiológica. No obstante, los escasos trabajos existentes evidencian condiciones que requieren un mayor estudio y seguimiento para considerar el estado general de los hatos lecheros del país. De lo anterior, se desprende la necesidad de realizar estudios de Investigación, Desarrollo e innovación (I+D+i), que permitan establecer las condiciones de calidad de la leche que se produce en el país y correlacionar esta condición a los parámetros de calidad establecidos internacionalmente. Palabras clave. Leche cruda de vaca, calidad de leche, parámetros físico-químicos, composición, microbiología. ABSTRACT. Milk provides essential nutrients and is an important source of dietary energy, high-quality protein, and fat. It contributes considerably to the necessary intake of nutrients such as calcium, magnesium, selenium, riboflavin, vitamin B12 and pantothenic acid. The consumption of this food can represent differences in the quality of the diets of people without access to adequate nutrition, especially among children. The composition of milk varies according to the incidence of multiple factors such as breed, lactation time, feeding, genetics, climatic condition, health status and stress of the animals, etc. The quality and safety of raw cow's milk can be affected by different reasons, microorganisms, chemical residues and other contaminants, which significantly affects public health. The increase of microorganisms in milk causes significant losses. Currently, there is very little or no publication or reference at the national level that indicates a quality characterization of raw cow's milk according to its physicochemical, or microbiological condition. However, the few existing studies show conditions that require further study and monitoring to consider the general state of the country's dairy herds. From the above, it is clear the need to carry out research, development and innovation (R & D & i) studies, which make it possible to establish the quality conditions of the milk produced in the country and correlate this condition with the internationally established quality parameters. Keywords. Raw cow's milk, milk quality, physico-chemical parameters, composition, microbiology.
Article
Full-text available
The purpose of this project was to study the impact of the somatic cell count measured at different test days on pregnancy rates of Holstein cows located in Eastern Frisland applying logistic models. Test days observations for somatic cell count were defined as follows: the last test day before the insemination, the first test day after the insemination and the geometrical average from the whole lactation. In statistical models, somatic cell count was considered in classes of fixed effects, whereas the impact of protein yield and service interval on pregnancy rates was tested as regression coefficients of different polynomial structure. Somatic cell counts above 400 000 indicate mastitis whereof 10% of cows were affected. Especially chronic diseased cows over the whole lactation and cows with a somatic cell count above 400 000 in their first test day after the insemination showed about 4% lower pregnancy rates compared with cows in somatic cell count classes below 150 000. In conclusion, our study revealed a strong impact of udder health on success of first insemination after calving. The somatic cell count should be considered in selection decisions. An adequate measure in this context seemed to be the relative breeding value for somatic cell count, recently available for the selection on the cow dam path. High protein yield next to the date of insemination decreased the pregnancy rate of cows. A longer service interval is recommended for dairy producers to circumvent the phase of metabolic stress in the first stadium of lactation. Heifers producing in the first lactation and actually in a period of growth have distinct problems to reach a balanced stadium of energy. The success of first insemination in heifers was lower than it was in adult cows. The results from the present study indicated that information collected at different test days, especially the somatic cell count, are informative to characterize the status of fertility from individual cows. Detailed physiological relationships concerning mastitis and fertility should be investigated in further studies.
Article
Full-text available
The objective of this study was to estimate the effects of different types of clinical mastitis (CM) on the probability of conception in New York State Holstein cows. Data were available on 55,372 artificial inseminations (AI) in 23,695 lactations from 14,148 cows in 7 herds. We used generalized linear mixed models to model whether or not a cow conceived after a particular AI. Independent variables included AI number (first, second, third, fourth), parity, season when AI occurred, farm, type of CM (due to gram-positive bacteria, gram-negative bacteria, or other organisms) in the 6 wk before and after an AI, and occurrence of other diseases. Older cows were less likely to conceive. Inseminations occurring in the summer were least likely to be successful. Retained placenta decreased the probability of conception. Conception was also less likely with each successive AI. The probability of conception associated with the first AI was 0.29. The probability of conception decreased to 0.26, 0.25, and 0.24 for the second, third, and fourth AI, respectively. Clinical mastitis occurring any time between 14 d before until 35 d after an AI was associated with a lower probability of conception; the greatest effect was an 80% reduction associated with gram-negative CM occurring in the week after AI. In general, CM due to gram-negative bacteria had a more detrimental effect on probability of conception than did CM caused by gram-positive bacteria or other organisms. Furthermore, CM had more effect on probability of conception immediately around the time of AI. Additional information about CM (i.e., its timing with respect to AI, and whether the causative agent is gram-positive or gram-negative bacteria, or other organisms) is valuable to dairy personnel in determining why some cows are unable to conceive in a timely manner. These findings are also beneficial for the management of mastitic cows (especially those with gram-negative CM) when mastitis occurs close to AI.
Article
Full-text available
The objectives were to evaluate the effect of high linear somatic cell counts (LNSCC > or =4.5) during early lactation on reproductive performance and to estimate their association with the risk of abortion in a population of central-southern Chilean dairy cattle. The analysis included records from a population of 157 farms and considered 1,127,405 test-day records including 101,944 lactations that began between 1997 and 2006. After data edits, the analyses of calving to first service and calving to conception intervals consisted of 88,633 and 70,877 lactations, respectively. Once controlling for significant variables, time to first breeding was 21.8 d longer in cows with at least 1 high LNSCC before the first breeding compared with controls. Cows with at least 1 high LNSCC before the fertile breeding had an increment in time to conception of 48.7 d and required, on average, 0.49 more services to conceive. The odds of conception at first service in cows with a high LNSCC within 30 d before [after] breeding were 0.85 (0.81 to 0.89; 95% confidence interval ) [0.82 (0.78 to 0.87; 95% confidence interval)] times the odds of conception for cows without a high LNSCC during that period. The Cox proportional hazard model indicated that after correction by calving year, lactation number, and milk yield standardized to 305 d, the risk of pregnancy decreased by 44% if a high LNSCC occurred before breeding. Cows registering a high LNSCC during the first 90 d of gestation had an increased risk of abortion, being 1.22 (1.07 to 1.35; 95% confidence interval) times more likely to abort than nonaffected cows. It is concluded that subclinical mastitis, measured as LNSCC >/=4.5, had a significant effect on reproductive performance in Chilean dairy cattle.
Article
Full-text available
Dairy Herd Improvement data from 284,450 cows in 37 states were used to examine the relationship of test-day somatic cell score, herd, calving year, parity, lactation stage, and calving ease score with fertility measures (rate of nonreturn to estrus by 70 d after first service, days to first service, and days open) for US Holsteins and Jerseys. Factors other than somatic cell score were examined to ensure that the estimation of the effect of somatic cell score was independent of other effects. Nonreturn rates were highest during April and May and lowest during June. Parity had a large effect on nonreturn rate, which was 6 to 7% higher for first parity than for sixth parity and later. Effect of lactation stage at first service on nonreturn rate was large; nonreturn rate increased by 8 to 13% from early to late lactation. Effect of calving ease score on nonreturn rate also was large: a 7% decline in nonreturn rate from score 1 to 5. For Holsteins, a small linear regression was found for nonreturn rate on preceding test-day somatic cell score, but this relationship was not significant for Jerseys. The magnitude of the effect of somatic cell score on fertility traits does not warrant postponing first service when somatic cell score is high.
Article
Full-text available
The aim of this paper was to evaluate the effects associated with intramammary infection (IMI) by a bacterium or a group of bacteria (Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, coliforms, Staphylococci other than S. aureus, and Corynebacterium bovis) on the somatic cell count (SCC) in quarter milk of dairy cows. Papers selected for analysis had to provide SCC values associated with the natural infection in quarters by different bacteria. Sampling for measurement of SCC and determination of the infection had to be done on the same day. Only papers published in English or in French after 1971 were considered. Twenty-one papers fulfilled the selection criteria. The animals sampled, the measurement techniques for SCC and the bacteriological identification, as well as the definition of the infection, all differed widely among the selected studies. The meta-analysis method was used to estimate both the mean SCC (arithmetic and geometric) value and the average increase on SCC of each type of infection. The geometric mean SCC in bacteriologically negative quarters was 68 000 c/mL. In case of IMI, the retained SCC was 357 000, 857 000, 547 000, 1 024 000, 1 151 000, 138 000 and 105 000 c/mL in quarters infected by Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, coliforms, staphylococci other than S. aureus and Corynebacterium bovis, respectively. The variation factors that could influence these SCC values and the bacteriological results are discussed.
Article
Full-text available
In this article the use of somatic cell counts for monitoring udder health and milk quality is discussed. Somatic cell count dynamics at quarter, cow, herd and population level are discussed and illustrated with examples. Quarter and cow somatic cell counts directly represent the inflammatory status of the mammary gland. Herd and population somatic cell count are related to the inflammatory process in individual cows but much more reflect the udder health status of the herd and the quality of the raw milk in the herd and the population. Application of monitoring tools in herd health management are illustrated using a case study. Understanding infection dynamics requires precise longitudinal data. Monitoring tools are required to find the areas of risk in the herd. It is inevitable that more complete udder health programs and monitoring systems are to be developed and implemented. These programs are necessarily dynamic and complex. Implementation of complete udder health programs should be accompanied by research efforts to further fine-tune these complete udder health control and monitoring programs.
Article
Full-text available
Staphylococcus aureus and Escherichia coli are among the most prevalent species of gram-positive and gram-negative bacteria, respectively, that induce clinical mastitis. The innate immune system comprises the immediate host defense mechanisms to protect against infection and contributes to the initial detection of and proinflammatory response to infectious pathogens. The objective of the present study was to characterize the different innate immune responses to experimental intramammary infection with E. coli and S. aureus during clinical mastitis. The cytokine response and changes in the levels of soluble CD14 (sCD14) and lipopolysaccharide-binding protein (LBP), two proteins that contribute to host recognition of bacterial cell wall products, were studied. Intramammary infection with either E. coli or S. aureus elicited systemic changes, including decreased milk output, a febrile response, and induction of the acute-phase synthesis of LBP. Infection with either bacterium resulted in increased levels of interleukin 1beta (IL-1beta), gamma interferon, IL-12, sCD14, and LBP in milk. High levels of the complement cleavage product C5a and the anti-inflammatory cytokine IL-10 were detected at several time points following E. coli infection, whereas S. aureus infection elicited a slight but detectable increase in these mediators at a single time point. Increases in IL-8 and tumor necrosis factor alpha were observed only in quarters infected with E. coli. Together, these data demonstrate the variability of the host innate immune response to E. coli and S. aureus and suggest that the limited cytokine response to S. aureus may contribute to the well-known ability of the bacterium to establish chronic intramammary infection.
Article
Full-text available
This study investigated the effect in heifers of infusion of a bismuth subnitrate teat-canal sealant and bacterial intramammary infection (IMI) precalving on prevalence of postcalving IMI and incidence of clinical mastitis in the first 2 wk postcalving. Glands (n = 1,020) from heifers (n = 255) in 5 seasonally calving, pasture-fed dairy herds were randomly assigned within heifer to 1 of 4 treatment groups (no treatment; mammary gland secretion collection; infusion of a teat sealant; or sample collection with infusion of teat sealant). Heifers within a herd were enrolled on one calendar day, 31 d on average before the planned start of the seasonal calving period. Duplicate milk samples were collected from each gland within 4 d after calving for bacterial culture. Herd owners collected duplicate milk samples, before treatment, for bacterial culture from glands they defined as having clinical mastitis. The gland prevalence of IMI precalving was 15.5% and did not differ between herds. Bacteria isolated precalving included coagulase-negative staphylococci (76.9% of all bacteriologically positive samples), Streptococcus uberis (14.1%), Staphylococcus aureus (5.1%), Corynebacterium spp. (3.8%), and others (0.1%). The presence of an IMI precalving increased the risk of an IMI postcalving 3.6-fold and the risk of clinical mastitis 4-fold, relative to no IMI precalving. Infusion of the teat sealant reduced the risk of postcalving IMI due to Strep. uberis by 84%, and of clinical mastitis by 68%. Sampling the glands precalving had no effect on postcalving IMI or on clinical mastitis incidence. Use of an internal teat canal sealant in heifers precalving may be a useful tool for reducing the risk of subclinical and clinical mastitis in heifers.
Article
Problem: Mastitis and immunization against constituents of organisms causing mastitis can reduce fertility of cattle and sheep, respectively. For the current experiments, it was hypothesized that these effects are mediated via actions of lipopolysaccharide (LPS), prostaglandin F2α (PGF2), and nitric oxide on oocyte maturation and embryonic development. Method of study: To evaluate effects on oocyte maturation, oocytes were matured with various concentrations of LPS, PGF2α, or the nitric oxide (NO) generator, sodium nitroprusside (SNP). Following maturation, oocytes were fertilized and cultured until day 8 after fertilization. To test effects on embryo growth, oocytes were matured and fertilized and cultured after fertilization with LPS, PGF2α, or SNP. Results: Addition of 100 and 1000 ng/mL LPS and 50 and 100 ng/mL PGF2α to oocyte maturation medium reduced the proportion of oocytes that became blastocysts at day 8 after fertilization. When added after fertilization, in contrast, neither LPS nor PGF2α reduced development to the blastocyst stage. Unlike for LPS and PGF2α, addition of SNP during oocyte maturation was without effect on the proportion of oocytes that became blastocysts at day 8 after fertilization. However, addition of 10 μm SNP to culture medium after fertilization completely prevented development to the blastocyst stage while 0.1 and 1 μm SNP did not affect development. Conclusions: Results indicate that increased local concentrations of LPS, PGF2α, and NO can have deleterious consequences on oocyte function (LPS, PGF2α) and embryonic development (NO). Thus, these molecules are putative mediators of effects of infectious disease or inflammation, including mastitis, on fertility of cattle.
Article
Chronic, subclinical intramammary infection depresses fertility. We previously found that 30% of subclinical mastitic cows exhibit delayed ovulation, low circulating estradiol levels, and delayed luteinizing hormone surge. We examined the function of preovulatory follicles of cows experiencing subclinical mastitis or a past event of acute clinical mastitis. Cows were diagnosed for mastitis by somatic cell count and bacteriological examination. All clinical infections were caused by Escherichia coli, and most subclinical infections were caused by Streptococcus dysgalactiae and coagulase-negative staphylococci. On day 6 of the cycle, cows received PGF2α; 42 h later, follicular fluids and granulosa cells or theca cells were aspirated from preovulatory follicles in vivo or following slaughter, respectively. Overall, follicular estradiol and androstenedione concentrations in the subclinical group (n = 28) were 40% lower (P < 0.05) than those in uninfected cows (n = 24) and lower than in past clinical mastitic cows (n = 9). Distribution analysis revealed a clear divergence among subclinical cows: one-third (9/28) exhibited low follicular estradiol; the other two-thirds had normal levels similar to all uninfected (P < 0.01) and most clinical cows (P < 0.08) that had normal follicular estradiol levels. Subclinical normal-estradiol cows had twofold higher (P < 0.05) circulating estradiol concentrations and sevenfold and fourfold higher (P < 0.05) follicular androstenedione levels and estradiol-to-progesterone ratio, respectively, than subclinical low-estradiol cows. Follicular progesterone level was not affected. Reduced expression (P < 0.05) of LHCGR in theca and granulosa cells, CYP11A1 (mRNA and protein) and CYP17A1 in theca cells, and CYP19A1 in granulosa cells may have contributed to the lower follicular steroid production in the subclinical low-estradiol subgroup. StAR and HSD3B1 in theca cells and FSHR in granulosa cells were not affected. Mastitis did not alter follicular growth dynamics, and no carryover effect of past clinical mastitis on follicular function was detected. These data indicate that a considerable proportion (one-third) of subclinical mastitic cows have abnormal follicular steroidogenesis, which can explain the reproductive failure associated with this disease.
Article
The effects of naturally occurring subclinical chronic or clinical short-term mastitis on time of ovulation, plasma steroid and gonadotropin concentrations, and follicular and luteal dynamics were examined in 73 lactating Holstein cows. Cows were sorted by milk somatic cell count and bacteriological examination into an uninfected group (n=22), a clinical mastitis group (n=9; events occurring 20+/-7 d before the study), and a subclinical chronic mastitis group (n=42). In addition, uninfected and mastitic cows were further sorted by their estrus to ovulation (E-O) interval. About 30% of mastitic cows (mainly subclinical) manifested an extended E-O interval of 56+/-9.2h compared with 28+/-0.8h in uninfected cows and 29+/-0.5h in the other 70% of mastitic cows. In mastitic cows with extended E-O interval, the concentration of plasma estradiol at onset of estrus was lower than that of uninfected cows or mastitic cows that exhibited normal E-O intervals (3.1+/-0.4, 5.8+/-0.5, and 5.5+/-0.5 pg/mL, respectively). The disruptive effect of mastitis on follicular estradiol probably does not involve alterations in gonadotropin secretion because any depressive effects of mastitis on pulsatile LH concentrations were not detected. Cortisol concentrations did not differ among groups. The preovulatory LH surge in mastitic cows with delayed ovulation varied among individuals, being lower, delayed, or with no surge noted compared with the normal LH surge exhibited by uninfected cows or mastitic cows with normal E-O interval (6.8+/-0.7 ng/mL). The diameter of the second-wave dominant follicle was larger and the number of medium follicles was smaller in uninfected and subclinical cows with normal intervals compared with subclinical cows with extended intervals (13.4+/-0.5 vs. 10.9+/-0.9mm, and 3.8+/-0.2 vs. 6.7+/-0.14 follicles, respectively). Mid-luteal progesterone concentrations were similar in uninfected and mastitic cows. These results indicate for the first time that around 30% of cows with subclinical chronic mastitis exhibit delayed ovulation that is associated with low plasma concentrations of estradiol and a low or delayed preovulatory LH surge.
Article
This study was conducted to characterize Staphylococcus simulans isolated from cases of bovine mastitis. A total of 134 isolates of S. simulans selected from 80 quarters from 61 cows or heifers in 37 different herds were characterized by EcoRI ribotyping. From 22 quarters two to seven consecutive isolates taken at weekly intervals were selected. Furthermore, three isolates from clinical infections in humans and two reference strains were included. A total of 16 different ribotypes were found, however, two types predominated. In most herds more than one type was found. From the 22 different quarters, where 76 paired or multiple isolates were at disposal, the same ribotype was constantly found in the same quarter. This study showed that S. simulans causing bovine mastitis could be divided into relatively large number of different types, but that two types predominated. More than one type could be found in the same herd and within different quarters of the same cow, but ribotyping confirmed that S. simulans could be the cause of persistent and stable infections.
Article
The associations between occurrence of diseases, milk yield, and body condition score on conception risk after first artificial insemination (AI) were analyzed in an observational study on a convenience sample of 43 farms participating in a herd health program. Data were taken from 9369 lactations, from 4382 cows inseminated between 20 and 180 d in milk from 1990 to 1996. Two logistic regression models, one containing data from all lactations and a subset containing data from 1762 lactations with body condition scoring, were used to determine pregnancy risk at first AI. The effects of herd deviation in test-day milk yield, body condition score loss, and milk fat to protein ratio changes in early lactation were significant predictors of pregnancy risk, independent of disease; days in milk; farm; and seasonal factors. Three different methods of disease parameterization (incidence rates, binomial classes dependent on the interval in days since last occurrence with respect to AI, and a linear variable weighted for this interval) produced similar results. Metritis, cystic ovarian disease, lameness, and mastitis gave odds ratios for pregnancy risk ranging from 0.35 to 1.15, largely dependent on the interval in days from final disease occurrence to first AI. Displaced abomasum, milk fever, and retained fetal membranes resulted in odds ratios for pregnancy risk of 0.25, 0.85, and 0.55, respectively. These diseases showed little relationship between fertility and the number of days since last occurrence. Results of this study confirm the negative effects of milk yield, body score condition loss, and disease on dairy cow fertility. The effects of some diseases on first service conception were strongly dependent on the interval since last disease occurrence. This was especially valid for clinical mastitis, which has an extremely weak effect on conception if occurring prior to AI and is associated with >50% reduction in pregnancy risk if occurring in the 3 wk directly after AI.
Article
Coagulase-negative staphylococci (CNS) are the most frequently isolated bacteria from bovine mammary gland milk samples. The objective of this study was to determine the type of inflammation evoked by CNS in the mammary gland of cows during their first lactation. Twenty-four Israeli-Holstein heifers in their first lactation were tested for bacteriological status, somatic cell count (SCC) and differential leucocyte count in milk 60-120 days postparturition and every 50-60 days after until drying off. Following the first testing, the 96 quarters of the 24 heifers were classified as follows: 69.8% as no bacterial growth (NBG), 27.1% infected with CNS and 3.1% infected with Staphylococcus aureus. During lactation, 84.5% quarters had no change in their classification, 6.2% were newly infected with other pathogens, 3.1% were classified as self-cured and in 6.2% sporadic bacteria were isolated. Among the CNS, S. intermedius, S. chromogenes and S. haemolyticus were the most frequently isolated. Milk from CNS-infected quarters had significantly higher SCC than milk from NBG quarters. An analysis of the leucocyte pattern in milk from CNS vs. NBG quarters revealed a significant increase in polymorphonuclears and a significant decrease in the percentage of total lymphocytes and lymphocytes bearing CD4+ or CD8+. The high percentage of CNS-infected quarters that remained unchanged in their bacterial status during the first lactation, indicates that those CNS have the ability to elude the immune system and persist in the mammary gland for a long time. The persisting infection, resulting to some extent from an increase of SCC by some CNS strains, suggests that in the near future control steps will have to be taken into consideration, in order to enhance the improvement of milk quality.
Article
Concentrations of LH, cortisol, estradiol-17beta (E(2)), prolactin and 13,14-dihydro-15-keto-prostaglandin F(2alpha) (PGFM) were determined in cows with experimentally induced clinical mastitis during early lactation. Cows free of intramammary infection (IMI) and in the luteal phase of the estrous cycle were balanced by lactation number and days in milk and assigned to either control (n=5) or treatment (n=5) groups. Treated cows were infected experimentally (day 0), in two mammary quarters, with Streptococcus uberis and developed clinical mastitis within 60 h after inoculation as evidenced by increased mastitis scores, elevated rectal temperatures, mammary swelling and isolation of S. uberis pathogen. Four days following bacterial challenge, blood samples were collected every 20 min for 8 h for determination of PGFM and LH following administration of oxytocin and GnRH, respectively. Blood samples were also collected on days 0, 4 and 7 of the experiment to determine concentrations of E(2), prolactin and cortisol. Four days after bacterial challenge, concentrations of cortisol were higher (P=0.04) in experimentally infected cows than controls. Experimentally challenged cows had increased (P=0.02) concentrations of cortisol on days 4 and 7 compared with day 0. Control cows had no significant increase in blood cortisol during the experimental period. Baseline concentrations of PGFM did not differ between groups; however, peak concentrations of PGFM following oxytocin challenge were elevated (P=0.006) in cows with clinical mastitis compared with control animals. Prolactin, E(2) and LH did not differ between cows with clinical mastitis or controls. Experimentally induced mastitis during early lactation elevated concentrations of cortisol during the luteal phase of the estrous cycle. Furthermore, mastitic cows demonstrated an increased PGFM response following oxytocin administration. Altered reproductive efficiency in cows with clinical mastitis caused by Gram-positive pathogens may be the result of increased uterine sensitivity to prostaglandin F(2alpha) (PGF(2alpha)).
Article
In this study, the relationship between maternal hormone environment and early embryo development in mature non-lactating Holstein-Friesian cows was investigated. Animals were inseminated at either 72 or 96 h after prostaglandin injection (n = 23) or were left as uninseminated controls (n = 10). Plasma samples were collected once a day from the first day of insemination (day 1) until day 16, when the cows underwent an oxytocin challenge, and were then slaughtered and their reproductive tracts removed. The tracts were flushed to collect embryos and the flushes were measured for interferon tau (IFN-tau) activity. Inseminated cows without an embryo on day 16 (n = 5) underwent both delayed ovulation (indicated by delayed decrease in oestradiol concentrations) and a delayed increase in progesterone concentrations after ovulation compared with cows with an embryo on day 16 (n = 15). Within the group of cows with an embryo, those with poorly developed embryos producing undetectable concentrations of IFN-tau (n = 7) had similar oestradiol profiles but underwent a delayed progesterone increase after ovulation compared with cows with well developed embryos producing measurable quantities of IFN-tau (n = 8). In the cows with an embryo, the plasma concentration of 13,14-dihydro-15-keto PGF2a, the principal metabolite of PGF2a, after injection of oxytocin was lower than that of control cows and cows without an embryo. However, when the cows with an embryo were compared on the basis of production of embryonic IFN-tau, the PGF2a response to oxytocin was attenuated completely in cows that had measurable IFN-tau activity, whereas a response of similar magnitude to that in control cows and cows without an embryo was observed in those with undetectable IFN-tau activities. In conclusion, the successful maternal recognition of pregnancy in cows depends on the presence of a sufficiently well developed embryo producing sufficient quantities of IFN-tau, which is, in turn, dependent on an appropriate pattern of maternal progesterone secretion.
Article
Our objective was to determine the effects of mastitis during early lactation on the reproductive performance of Jersey cows. From 1986 to 1997, quarter foremilk samples were collected every 4 to 8 wk during lactation, at drying off, near calving, and when clinical mastitis was diagnosed and were evaluated microbiologically to identify causative bacteria. Services per conception, days open, and days to first service were obtained from DHIA records on 752 cows. Cows were separated by mastitis type (clinical, n = 186; subclinical, n = 240; control, uninfected or infected after confirmed pregnancy, n = 326). Cows were reclassified based on the time of clinical or subclinical mastitis as follows: period 1, before first service (n = 374); period 2, between first service and pregnancy (n = 52); and period 3, after confirmed pregnancy or uninfected (control; n = 326). Milk production did not differ for any group separations. Reproductive performance did not differ between gram-negative or gram-positive mastitis pathogens. Cows with clinical or subclinical mastitis before first service had increased days to first service (77.3+/-2.7 and 74.8+/-2.7 d), days open (110.0+/-6.9 and 107.7+/-6.9 d), and services per conception (2.1+/-0.2 and 2.1+/-0.2) compared with controls (67.8+/-2.2 d, 85.4+/-5.8 d, 1.6+/-0.2; P < 0.05). Days to first service were not increased in cows with clinical or subclinical mastitis during period 2 (70.6+/-3.3 and 61.2+/-7.8 d). However, days open (143.6+/-8.5 d) and services per conception (3.0+/-0.2) were increased (P < 0.05) in cows with clinical mastitis during period 2, but not in cows with subclinical mastitis (90.9+/-20.2 d and 2.1+/-0.5). Cows initially diagnosed subclinical that became clinical during period 2 exhibited increased days to first service (93.9+/-10.1 d), days open (196.0+/-26.2 d), and services per conception (4.3+/-0.7) compared with control animals (P < 0.05). In conclusion, subclinical mastitis reduced reproductive performance of lactating cows similar to clinical mastitis. Subclinical mastitis followed by clinical mastitis resulted in the most severe loss in reproductive performance.
Article
The effect of endotoxin on follicular growth and on secretion of LH, estradiol-17beta, progesterone and cortisol during the proestrous phase in cattle was investigated. Holstein heifers were treated with PGF2alpha at 11-13 d after ovulation to induce luteolysis. At 42 hr after PGF2alpha treatment, heifers were administered either lipopolysaccharide (LPS; Escherichia coli, O111:B4, 5 microg/kg, n = 6) or saline (control; n = 6) by i.v. bolus injection. Ovarian structures were monitored daily by transrectal ultrasonography, and blood samples were collected at various times for hormonal analysis. The duration from PGF2alpha treatment to ovulation was significantly longer in the LPS group (8.0 +/- 1.3 d) than in the control group (4.2 +/- 0.2 d). LPS significantly reduced the pulse frequency of LH for 6 hr after the administration, and increased the mean concentration and pulse amplitude of LH from 3 to 6 hr after the administration. The plasma concentrations of progesterone and cortisol were transiently increased after LPS administration. The plasma concentration of estradiol-17beta was significantly decreased at 24 hr after LPS administration compared to that in the controls. Five of six LPS-treated heifers exhibited no preovulatory LH surge until 120 hr after PGF2alpha treatment and the remaining heifer exhibited the surge at 108 hr after PGF2alpha treatment, while the LH surge was observed at 54-78 hr after PGF2alpha treatment in control heifers. These results suggest that endotoxin disrupts progression of the proestrous phase of cattle, interrupting the preovulatory estradiol rise and thus delaying the LH surge and the subsequent ovulation.
Article
Progesterone is unequivocally required for maternal support of conceptus (embryo/fetus and associated extraembryonic membranes) survival and development. In cyclic sheep, progesterone is paradoxically involved in suppressing and then initiating development of the endometrial luteolytic mechanism. In cyclic and pregnant sheep, progesterone negatively autoregulates progesterone receptor (PR) gene expression in the endometrial luminal (LE) and superficial glandular epithelium (GE). In cyclic sheep, PR loss is closely followed by increases in epithelial estrogen receptor (ERalpha) and then oxytocin receptor (OTR), allowing oxytocin to induce uterine release of luteolytic prostaglandin F2alpha pulses. In pregnant sheep, the conceptus produces interferon tau (IFNtau) that acts on the endometrium to inhibit transcription of the ERalpha gene and thus development of the endometrial luteolytic mechanism. After Day 13 of pregnancy, the endometrial epithelia do not express the PR, whereas the stroma and myometrium remain PR positive. The absence of PR in the endometrial GE is required for onset of differentiated function of the glands during pregnancy. The sequential, overlapping actions of progesterone, IFNtau, placental lactogen (PL), and growth hormone (GH) comprise a hormonal servomechanism that regulates endometrial gland morphogenesis and terminal differentiated function during gestation. In pigs, estrogen, the pregnancy-recognition signal, increases fibroblast growth factor 7 (FGF-7) expression in the endometrial LE that, in turn, stimulates proliferation and differentiated functions of the trophectoderm, which expresses the receptor for FGF-7. Strategic manipulation of these physiological mechanisms may offer therapeutic schemes to improve uterine capacity, conceptus survival, and reproductive health of domestic animals and humans.
Article
Objectives of this study were to determine the influence of timing of first clinical mastitis case occurrence on lactational and reproductive performance in high producing lactating dairy cows during the first 320 days in milk (DIM). Holstein cows, 1001, from two commercial dairy farms in California were retrospectively divided into four treatment groups according to timing of first clinical mastitis case caused by environmental pathogens: control with no recorded clinical cases of mastitis (C; n=501); first clinical mastitis prior to first postpartum AI (MG1; n=250); first clinical mastitis between first postpartum AI and pregnancy diagnosis (MG2; n=147); and first clinical mastitis after diagnosed pregnant (MG3; n=103). Clinical cases of mastitis were identified at every milking by the herd personnel based on abnormal milk or swelling of the mammary gland. A fore sample of milk was aseptically collected from every clinical case for microbiological culture. Mastitis decreased yields of milk, 3.5% fat-corrected milk, and milk components, but the effect was only observed for MG1 and MG2. Cows in the control group had lower linear somatic cell count (SCC) score throughout the lactation. Culling was increased by mastitis, and cows in the mastitis groups left the study earlier than controls. Conception rate at first postpartum AI and pregnancy rate at the end of the study were both decreased by mastitis prior to or after first AI, and MG1 and MG2 cows had extended days open. Furthermore, cows experiencing mastitis during lactation had a higher incidence of abortions. The negative effects of mastitis on reproduction were observed regardless of clinical case being caused by either Gram positive or negative bacteria. Mastitis either prior to or after first postpartum AI impairs lactation performance, increases culling, and decreases reproductive efficiency in high producing Holstein dairy cows.
Article
The coagulase-negative staphylococcal species causing mastitis in lactating cattle were identified and possible differences in the clinical characteristics or persistence of mastitis caused by different CNS were evaluated. The effect of antimicrobial treatment was also assessed. In addition, AFLP-typing of CNS was compared with the phenotypic identification. A total of 133 clinical or subclinical quarter cases of intramammary infection caused by CNS from the practice area of the Ambulatory Clinic of the University of Helsinki were studied. Bacteriological diagnosis was based on biochemical (API) testing. Staphylococcus simulans (43.6%) followed by S. chromogenes (23.3%) were the most common CNS species isolated from the milk samples. Ninety-nine isolates were genotyped using AFLP-analysis. Only 75.0% of S. chromogenes and S. simulans isolates identified with API test were clustered with the type strains of these species. Approximately half of the mastitis cases were clinical, and in the majority clinical signs were mild. The severity and persistence of intramammary infection were unaffected by CNS species. Fifty-nine percent of the quarter cases were treated with antimicrobials, and the rest were left without treatment. Mastitis due to beta-lactamase-negative CNS was treated with penicillin G and that due to beta-lactamase-positive CNS with cloxacillin. Nineteen percent of the isolates were beta-lactamase-positive. The bacterial cure rate for quarters treated with antimicrobials was high, 85.9%, as opposed to only 45.5% for untreated quarters. Bacterial cure rates for the most common CNS species or AFLP clusters were not statistically different. Further studies on identification of CNS species are needed.
Article
This study was undertaken to elucidate the possible role of endotcxin in mediating premature luteolysis in the well- documented phenomenon of short estrous cycles in postpartum dairy cows. Four groups of Holstein heifers (n = 4 to 6 each) received either intrauterine infusion of sterile culture medium (Group I); intrauterine infusion of Escherichia coli (E. coli ) endotoxin (5 mug/kg) in sterile culture medium (Group II); intrauterine administration of 10 ml of a 24-h culture of a strain of E. coli isolated from the uterus of a cow with metritis (approximately 10(9) colony forming units/ml; Group III); or intravenous administration of E. coli endotoxin (5 mug/kg; Group IV) on Day 7-9 of the estrous cycle. Blood samples were collected every 48 h during the pretreatment estrous cycle and up to the administration of the experimental treatment, thereafter 4-h samples were collected for 5 d. Sample collection was then performed every 48 h for the remainder of the treatment cycle and the post treatment cycle. Serum concentrations of progesterone and plasma concentrations of 15-keto-13, 14-dihydroprostaglandin F(2alpha) (PGFM) were determined by radionmmunoassay. Intrauterine infusion of endotoxin had no effect on the cycle length or on hormone concentrations, while infusion of viable E. coli organisms tended to shorten the estrous cycle. Intravenous administration of endotoxin produced a sharp increase in both progesterone and PGFM concentrations, followed by a transient decrease in progesterone concentrations. Cycle length remained unchanged. It was concluded that the intact endometrium prevents the uptake of endotoxin although pathogenic E. coli organisms may disrupt the endometrial integrity sufficiently to shorten the estrous cycle by premature luteolysis. It is postulated that intravenous administration of endotoxin influences luteal function by the activation of the arachidonic acid cascade, by a direct effect on the corpus luteum, or via other mediators.
Article
Several studies have been published since 1990 on the economics of mastitis and mastitis management. However, hardly any of these studies has discussed the consistency of results with other studies. In the present paper, the economic factors associated with mastitis are explained, providing a framework for economic analysis. As a second step calculations of the costs of mastitis and the costs in relation to the benefits of mastitis management published since 1990 in peer-reviewed journals are extensively reviewed and analysed. The result shows a large variation in the calculated costs and benefits of mastitis and mastitis management between the different studies. Moreover, it is clear that important factors were ignored in some of the studies. The framework provided in this paper can provide a basis for analysis for future studies on the economics of mastitis and mastitis management.
Coagulase-negative staphylococci and mammary gland infections in cows Quarter milk somatic cell count in infected dairy cows: A meta-analysis
  • A Ezra
  • Saran
  • B Djabri
  • N Bareille
  • F Beaudeau
  • H Seegers
Ezra, and A. Saran. 1999. Coagulase-negative staphylococci and mammary gland infections in cows. Zentralbl. Veterinarmed. B 46:707–712. Djabri, B., N. Bareille, F. Beaudeau, and H. Seegers. 2002. Quarter milk somatic cell count in infected dairy cows: A meta-analysis. Vet. Res. 33:335–357
Causes for failure of fertilization in domestic species. Pages 1–22 in Embryonic Mortality in Domestic Species
  • R H F Hunter
Hunter, R. H. F. 1994. Causes for failure of fertilization in domestic species. Pages 1–22 in Embryonic Mortality in Domestic Species. M. T. Zavy and R. D. Geisert, ed. CRC Press, Boca Raton, FL.