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Effects of a dietary supplement of β-carotene given during the dry period on milk production and circulating hormones and metabolites in dairy cows
Abstract
The objective of this study was to investigate whether a supplement of β-carotene given during the dry period is able to 1) improve milk production and milk composition and 2) modify hormone and metabolic status in dairy cows during the dry and postpartum periods. This study was conducted using 40 Holstein, primiparous and multiparous cows. On the day of drying-off, cows were allocated to one of two dietary treatments: control diet (n=20) or control diet plus 1g/cow/d β-carotene (n=20). The β-carotene supplement was given individually to the cows until calving. Blood samples were obtained regularly and the concentrations of β-carotene in blood and circulating metabolites and hormones in plasma were measured. Live weight and body condition score (BCS) were monitored once a month. Daily milk production was recorded starting 5 days after calving. Milk composition was measured every 15 days. The dietary supplement of β-carotene increased blood concentrations of β- carotene during the dry period (P<0.05) and although the difference decreased postpartum β-carotene concentrations remained higher compared to the control group until the end of experiment. Live weight, BCS, milk production and composition: milk protein, milk fat, milk urea and somatic cell count, were unaffected by treatment (P>0.05). Plasma concentrations of insulin, insulin- like growth factor-1, glucose, non-esterified fatty acids and urea were unaffected by dietary supplementation with β-carotene (P>0.05). In conclusion, supplementation with β-carotene during the dry period increased blood concentrations of β-carotene but had no effect on milk production and milk quality nor on hormone and metabolic status.
... However, blood β-carotene concentration was lowest immediately after calving in both experiments, although it was increased by the supplement in both experiments. The supplementation of β-carotene before calving did not affect milk yield in early lactation in this experiment, similarly to the observations of others (Kaewlamun et al., 2012). However, Aréchiga et al. (1998) reported an increase in milk yield when cows under heat stress were supplemented with β-carotene from 15 to 170 DIM. ...
... The trend for decreased proportion of primiparous cows with a milk fat to protein ratio greater than 1.5 when β-carotene was fed, suggests that the supplement had a beneficial effect on the incidence of ketosis in first lactation cows (Heuer et al., 1999). Although previous studies have not detected differences in plasma NEFA and glucose in response to β-carotene supplementation before calving (Kawashima et al., 2010;Kaewlamun et al., 2012), the large numerical difference in the frequency of high milk fat to protein ratio between supplemented and nonsupplemented primiparous cows (22.6% vs. 6.4%) suggests that this finding may be worthy of further study. ...
The prepartum supplementation of dairy cows with β-carotene was evaluated. Cows were blocked by parity and expected calving date and assigned to a treatment: β-carotene (1.2 g/cow per d) or control (no supplementation). The same total mixed ration batch was offered to all cows, and β-carotene was top dressed to individual cows once per day. The data set contained 283 Holsteins that received a treatment for >14 d (29.1 ± 6.9 d). Frequency distributions were analyzed with the GENMOD procedure of SAS using logistic regression for binomial data. Continuous variables were analyzed with the MIXED procedure of SAS. Within parity, nonparametric estimates of the survivor function for reproductive variables were computed using the product-limit method of the Kaplan-Meier method with the LIFETEST procedure of SAS. Plasma β-carotene concentration before supplementation was similar between supplemented and nonsupplemented cows (2.99 µg/mL) and peaked at 3.26 ± 0.175 µg/mL on d -15 ± 2.4 precalving for supplemented cows (2.62 ± 0.168 µg/mL for control). Colostrum density, milk yield, and milk composition were similar between treatments. Beta-carotene tended to increase milk protein content from 2.90 to 2.96% and to decrease the proportion of primiparous cows with a milk fat to protein ratio >1.5 from 22.6 to 6.4%. The proportion of primiparous and multiparous cows with difficult calving, metritis, progesterone >1 ng/mL at 21 d and at 42 d in lactation, % conception at first service, and % pregnancy at 90 and 150 d in lactation were similar between treatments. A trend for decreased incidence of somatic cell count >200,000 cells/mL was present in multiparous cows supplemented with β-carotene (38.9% vs. 28.1%). Beta-carotene was associated with a reduction in the proportion of multiparous cows with retained placenta 12 h postpartum from 29.9 to 21.7%; time of placenta release was 392 min (340 to 440) for β-carotene and 490 min (395 to 540) for control (median and 95% confidence interval). For primiparous cows, placenta release was not affected by β-carotene (incidence was 15.4%). The intervals from calving to first estrus, to first service, and to conception were not affected by β-carotene supplementation in either parity. However, independent of treatment, cows with improved reproductive efficiency had increased postpartum β-carotene concentration in plasma. The prepartum supplementation of β-carotene increased plasma concentration around calving. No response in milk yield or reproductive performance was detected. Beta-carotene supplementation was associated with a lower incidence of retained placenta in multiparous cows.
Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
... rit and highly productive cows had a low BC in postpartum. The effects of diet and BC change may occur at the biochemical level by changes in concentrations of blood metabolites. In the present study, blood glucose was relatively stable at around 60mg/dl according to observation of Melendez et al. (2007) in cattle and Pulina et al. (2012) in sheep. Kaewlamun et al. (2012) noted that glucose concentrations remained stable and increased slightly at calving reflecting an increase in gluconeogenesis in response to calving stress. However, other researchers reported that glucose concentrations were higher in dry cows (Singh et al., 2009) and increased with food (Marongiu et al., 2002). Cows in negative energy ...
... In the present study, blood glucose was relatively stable at around 60mg/dl according to observation of Melendez et al. (2007) in cattle andPulina et al. (2012) in sheep. Kaewlamun et al. (2012) noted that glucose concentrations remained stable and increased slightly at calving reflecting an increase in gluconeogenesis in response to calving stress. However, other researchers reported that glucose concentrations were higher in dry cows (Singh et al., 2009) and increased with food (Marongiu et al., 2002). ...
This study aimed to investigate the correlation between body condition score (BCS), blood biochemical metabolites, milk yield (MY) and quality (Mfat) in Montbéliarde cattle (31 cows) reared in 5 farms of Algerian semi arid area. The BCS was measured in dry and peak of lactation (6 weeks after calving). Blood samples were taken at the time of body condition (BC) measurement for determination of energy (Glucose, cholesterol, triglycerides and B-Hydroxybutyrate), nitrogen (urea and albumin) and mineral (calcium) metabolites. Milk yield was recorded in the 6th week of lactation (peak). A sample of milk for each cow was used to determinate milk fat, density and acidity. The results showed a significant decrease in postpartum BCS accompanied by an increase in cholesterol and B-Hydroxybutyrate (BHB) concentration. The correlation analysis showed that BHB concentration in pre calving was negatively correlated with BCS (r=-0.321; P<0.05) and cholesterol (r=-0.308; P<0.05). In postpartum, BCS was negatively correlated with cholesterol (r=-0.416; P<0.05), urea (r=-0.366; P<0.05) and BHB (r=-0.487; P<0.05). However, the level of milk production decreased significantly with high glucose (r=-0.449; P<0.05) and BHB (r=-0.514; P<0.05). The fat content increased significantly with blood triglycerides (r=0.681; P<0.05) and BHB (r=0.522; P<0.05) concentration, indicating a high mobilization of body reserves used for the synthesis of milk fat. In conclusion, it can be assumed that the rate of BHB seems to be the best indicator of the nutritional status of dairy cows that determines their production level and quality.
Key words: Body condition, Blood metabolites, Milk fat, Milk yield, Montbéliarde cattle
... rit and highly productive cows had a low BC in postpartum. The effects of diet and BC change may occur at the biochemical level by changes in concentrations of blood metabolites. In the present study, blood glucose was relatively stable at around 60mg/dl according to observation of Melendez et al. (2007) in cattle and Pulina et al. (2012) in sheep. Kaewlamun et al. (2012) noted that glucose concentrations remained stable and increased slightly at calving reflecting an increase in gluconeogenesis in response to calving stress. However, other researchers reported that glucose concentrations were higher in dry cows (Singh et al., 2009) and increased with food (Marongiu et al., 2002). Cows in negative energy ...
This study aimed to investigate the correlation between body condition score (BCS), blood biochemical metabolites, milk yield (MY) and quality (Mfat) in Montbéliarde cattle (31 cows) reared in 5 farms of Algerian semi arid area. The BCS was measured in dry and peak of lactation (6 weeks after calving). Blood samples were taken at the time of body condition (BC) measurement for determination of energy (Glucose, cholesterol, triglycerides and B-Hydroxybutyrate), nitrogen (urea and albumin) and mineral (calcium) metabolites. Milk yield was recorded in the 6 th week of lactation (peak). A sample of milk for each cow was used to determinate milk fat, density and acidity. The results showed a significant decrease in postpartum BCS accompanied by an increase in cholesterol and B-Hydroxybutyrate (BHB) concentration. The correlation analysis showed that BHB concentration in pre calving was negatively correlated with BCS (r=-0.321; P<0.05) and cholesterol (r=-0.308; P<0.05). In postpartum, BCS was negatively correlated with cholesterol (r=-0.416; P<0.05), urea (r=-0.366; P<0.05) and BHB (r=-0.487; P<0.05). However, the level of milk production decreased significantly with high glucose (r=-0.449; P<0.05) and BHB (r=-0.514; P<0.05). The fat content increased significantly with blood triglycerides (r=0.681; P<0.05) and BHB (r=0.522; P<0.05) concentration, indicating a high mobilization of body reserves used for the synthesis of milk fat. In conclusion, it can be assumed that the rate of BHB seems to be the best indicator of the nutritional status of dairy cows that determines their production level and quality.
... In the present study, blood glucose was relatively stable at around 60mg/dl according to observation of Melendez et al. (2007) in cattle andPulina et al. (2012) in sheep. Kaewlamun et al. (2012) noted that glucose concentrations remained stable and increased slightly at calving reflecting an increase in gluconeogenesis in response to calving stress. However, other researchers reported that glucose concentrations were higher in dry cows (Singh et al., 2009) and increased with food (Marongiu et al., 2002). ...
A well-managed, high-producing com-mercial dairy herd was used to test the impact of supplementing β-carotene (425 mg/d per cow) to lactating multiparous Holstein cows with normally low serum β-carotene (<3 µg/mL). Milk production was not affected by treatment (43.83 and 43.65 kg/d for the β-carotene and control diets). There was no difference because of treatment in overall 3.5% FCM (43.23 vs. 42.24 kg/d for the β-carotene and control diets) but early-lactation cows (0 to 100 DIM) and mature cows (3+ lacta-tion) tended to produce more 3.5% FCM when supplemented with β-carotene (P < 0.10). Milk fat percentage was higher (P < 0.05) with supplemental β-carotene (3.28 and 3.18% for β-carotene and con-trol cows), especially in early-lactation cows and mature cows. Overall milk fat yield (kg/d) was unaffected by treatment but early-lactation and mature cows supplemented with β-carotene tended to produce more milk fat than control cows. Milk true protein percentage and yield were not affected by treatment. Milk urea N levels were higher for cows supple-mented with β-carotene (16.06 vs. 15.72 mg/dL for β-carotene-supplemented and control cows; P < 0.05). Somatic cell count was not affected by treatment. Overall pregnancy rate was unaffected by treatment, but after 105 d of β-carotene supplementation, pregnancy rate was 22% for β-carotene-supplemented cows compared with 11% for control cows. β-Carotene supplementation increased percentage of milk fat and tended to increase 3.5% FCM and milk fat yield in early-lactation and mature cows.
Conjugated linoleic acid (CLA) is a group of polyunsaturated fatty acids found in beef, lamb, and dairy products that exist as positional and stereo-isomers of octadecadienoate (18:2). Over the past two decades numerous health benefits have been attributed to CLA in experimental animal models including actions to reduce carcinogenesis, atherosclerosis, onset of diabetes, and body fat mass. The accumulation of CLA isomers and several elongated/desaturated and beta-oxidation metabolites have been found in tissues of animals fed diets with CLA. Molecular mechanisms of action appear to include modulation of eicosanoid formation as well as regulation of the expression of genes coding for enzymes known to modulate macronutrient metabolism. This review focuses on health benefits, metabolism, and potential mechanisms of action of CLA and postulates the implications regarding dietary CLA for human health.
The main aim of this work was to assess the effect of lactation period on the secretion of carotenoids in cow's milk. Our objective was to determine the variations in carotenoids in the plasma and milk of dairy cows from drying off to wk 12 of lactation, and to specify whether these variations depend on body stores of these micronutrients at calving. We also investigated the relationship between beta-carotene (BC) and color in plasma and milk to evaluate the methods based on direct or indirect characterization of these micronutrients for traceability of feeding management. The experiment was carried out on 18 dairy cows, which were dried off 8 wk before their expected date of parturition. They were then divided into 2 homogeneous groups and fed diets contrasting in carotenoid content, high (grass silage) vs. low (corn silage), from wk -7 until parturition. From parturition through wk 12 of lactation, both groups received a grass silage-based diet. Variations in concentrations of carotenoids and the color index (CI) in plasma and milk were monitored from drying off to wk 12 of lactation. Other components of nutritional interest (i.e., vitamins A and E) were also measured. Lutein, all-trans BC and cis-13 BC were the carotenoids found in plasma and milk. Plasma concentrations of carotenoids, vitamin A, and vitamin E decreased throughout the dry period and in the first week of lactation, then increased through the first 3 mo of lactation, parallel to grass silage intake. For both groups, carotenoid and vitamin concentrations in milk drastically decreased during the first week of lactation, then did not vary significantly throughout the remainder to the experiment (wk 12). Plasma concentrations of carotenoids and vitamins were higher in the high-carotenoid group than in the low-carotenoid group during the dry period. Those differences were also observed in colostrum and disappeared in both plasma and milk during the first 10 d of the lactation period. This work allowed us to conclude that, unlike in plasma, variations in carotenoids, vitamin A, and vitamin E in milk were only slight in early lactation. In both plasma and milk, the concentrations were only transitorily affected by the nature of forage fed during the dry period, showing that they depended mainly on the dietary supply, even during the lipid mobilization period. The relationship between concentrations of BC and the CI was linear in plasma (R2 = 0.51) and milk (R2 = 0.37) and reached a plateau in the milk + colostrum data set (R2 = 0.77). The changes in CI during the first 3 mo of lactation were not negligible compared with variations related to the nature of forage reported in previous studies. This implies that methods being developed for the traceability of feeding management of dairy cows based on direct or indirect characterization of these micronutrients in milk, plasma, or both will need to account for changes in relation to lactation stage, which requires further investigation.
The objective of this review was to explore the relationship between lactational performance and health. We focused on lactational incidence rates (LIR) of the production diseases that are of economic importance to the dairy industry. Based on a review of 11 epidemiological and 14 genetic studies we found little evidence that high yielding cows have increased risk of dystocia, retained placenta, metritis and left-displaced abomasum. Results for periparturient paresis were inconsistent. Whilst we found no phenotypical relationship between milk yield and the risk of ketosis and lameness, selection for higher milk yields will probably increase LIR for these diseases. Mastitis was the only disease where there was a clear relationship between milk yield and risk of infection. Continued selection for higher milk yields will worsen this situation. However, our overall conclusion is that reviewing existing literature, even with a structured literature selection, is inadequate to the task of elucidating the relationship between lactational performance and risk of production diseases. There are substantial problems with confounding effects and unaccounted for biological correlations. In the second part of the review we argue towards a common basis for addressing production diseases. We propose abnormal body mobilisation and immune competence as common currencies for metabolic and immune status and argue for the development of indicators of metabolic imbalance and the early development of diseases. Furthermore, we suggest the use of indicators of ‘imbalance’ to guide feeding according to the needs of individual cows with their specific genotype and management history. We believe that this approach has the potential to provide new diagnostic and decision support tools to improve animal health and reproduction, whilst simultaneously maintaining optimal production and efficiency. Further research is needed to identify and validate new indicators and individual feeding strategies.
Eighteen crossbred cows in their advance pregnancy were distributed into three equal groups. Group I was kept as control, whereas, groups II and III were supplemented with 1000IU dl-α-tocopheryl acetate (Vitamin E) and 1000IU dl-α-tocopheryl acetate + 300mg β-carotene per cow per day, respectively, from 30 days prepartum to 2 weeks postpartum. Blood samples were collected at 30, 20, 10 and 5 days prepartum, at calving and 3, 7 and 12 days postpartum. Vitamin E and β-carotene contents of feeds offered and blood samples were estimated using HPLC. Total Vitamin E and β-carotene intake in the three respective groups was 185, 1185, 1185IU per day and 397, 397, 697mg per day. Plasma α-tocopherol concentration at 30 days prepartum was 3.62, 2.74 and 4.10μg/ml which decreased by 56.6, 17.8 and 33.6% on the day of parturition in the three respective groups. Higher plasma α-tocopherol in groups II and III at calving helped to regain normal plasma Vitamin E status of 3.0μg/ml for better immune function, within 2 weeks, whereas, unsupplemented cows could not reach this level during this period. Decrease in plasma retinol and β-carotene concentrations was observed in cows of all the groups on the day of parturition which continued to decrease further up to 7 days post-calving in unsupplemented cows (groups I and II), whereas, these levels were maintained in group III cows. Plasma retinol and β-carotene levels were higher in group III cows. Total antioxidant activity of plasma did not differ among groups. The data indicated that the extent of decrease in the levels of α-tocopherol, retinol and β-carotene at parturition can be reduced by supplementing these vitamins during dry period in order to improve their immunity status.
The objective of this review was to address the basis for and prevention of selected diseases (fatty liver, ketosis, rumen acidosis and displaced abomasums) that are feeding-and management-related and frequent in periparturient cows. The focus has been to discuss (1) the general physiological regulation and adaptations that are believed to be important for a successful transition to lactation, (2) for each disease the disease incidence rate, risk factors, aetiology and pathophysiology and (3) feeding and management strategies to prevent diseases. Unfortunately, few studies have documented prevention strategies and they consequently need to be developed based on risk factors and knowl-edge of the aetiology of the diseases. Strategies to prevent these diseases are therefore based on major factors directly or indirectly increasing the risk of fatty liver, ketosis, acidosis and displaced abomasum—factors such as over-conditioning at calving, excessive mobilisation of body fat, low nutrient intake, nutrient or diet specific factors and management and environmental stress. Finally, thoughts are presented on how prevention potentially could be improved in the future. It is suggested that there should be greater focus on individual animals in order to identify "risk animals". Status-oriented strategies for optimising dairy cow health, reproduction and production are suggested that aims at securing a desirable status of epithelia, metabolism and immune function in different cells, tissues or organs through surveillance and health and production management based on indicators.
The objective of this study was to evaluate the effect of diets differing in energy density (ED) in the last 4 weeks of the dry period and in the first 8 weeks of lactation on energy balance (EB), blood metabolites and reproductive performance. Three diets (grass silage:straw 75:25 on a dry matter basis (SS), grass silage (S) and grass silage+3 kg/day of concentrates (C)) pre-calving and two diets (4 kg (LC) or 8 kg/day of concentrates (HC)+grass silage ad libitum) post-calving were combined in a 3×2 factorial design. Sixty second-lactation Holstein–Friesian cows were blocked according to expected calving date and body condition score into groups of six and were then allocated at random to the treatments. Individual feeding started on average 34 days prior to parturition and measurements were made until the end of the 8th week of lactation. Net energy (NE) intake increased (5.6, 6.5 and 9.0 UFL/cow per day; (standard error of the difference (S.E.D.)=0.22) and EB improved pre-calving as the ED of the diet increased. Post-calving, milk energy output was significantly different between pre-calving treatments at 10.5, 11.6 and 12.7 UFL/day (S.E.D.=0.48) for SS, S and C respectively. Cows on the highest ED diet pre-calving (C) had a greater degree of negative energy balance (NEB) than cows on the lowest ED diet pre-calving (SS) for 7 of the first 8 weeks of lactation. At calving, cows on C had a lower plasma urea concentration than those on S and cows on SS had a lower plasma bile acid concentration than those on S. At week 2 post-calving, C had a higher plasma β-hydroxybutyrate concentration than SS and a higher plasma protein concentration than SS or S. Post-calving, cows receiving HC had higher NE intakes averaged over the first 8 weeks of lactation and lower NEB in each of the first 8 weeks of lactation than those on LC. Plasma glucose and bile acid concentrations were higher on HC compared to LC at week 2 post-calving. Plasma urea concentrations were lower (P<0.05) on HC compared to LC.
Diet-induced low-fat milk syndrome, milk fat depression (MFD), was first described over a century ago. It continues to be an active research area and we reviewed theories that have been proposed to explain diet-induced MFD. Many theories were based on the concept that reduced milk fat was a consequence of a limited supply of lipid precursors, e.g. the insulin-glucogenic theory; experimental data provide little support for this concept as the basis for diet-induced MFD. Other theories attributed MFD to a direct inhibition of lipid synthesis in the mammary gland. Davis and Brown (In: Phillipson, A.T. (Ed.), Physiology of Digestion and Metabolism in the Ruminant. Oriel Press, Newcastle upon Tyne, UK, 1970, pp. 545–565) noted increased trans-C18:1 fatty acids in milk fat during MFD, and proposed these fatty acids inhibited fat synthesis. We recently established the increase was specific for trans-10 C18:1 and its rumen precursor, trans-10, cis-12 conjugated linoleic acid (CLA). Across a range of diets there was a curvilinear relationship between the reduction in milk fat yield and the increase in milk fat content of trans-10, cis-12 CLA. Furthermore, postruminal infusion of trans-10, cis-12 CLA resulted in a marked inhibition of milk fat synthesis and a shift in fatty acid pattern similar to dietary-induced MFD. Therefore, diets that cause MFD alter rumen biohydrogenation resulting in the production of trans-10, cis-12 CLA, and perhaps other unique fatty acids, that are potent inhibitors of milk fat synthesis. We refer to this as the biohydrogenation theory of MFD and discuss the possibility that it may represent a unifying concept to explain diet-induced MFD.
In three experiments, we tested the efficacy of timed artificial insemination (AI) and beta-carotene supplementation for improvement of reproduction and milk yield. Experiments 1 and 2 were conducted during hot months, and Experiment 3 was conducted during cooler months. Cows were fed rations supplemented with beta-carotene at 0 or 400 mg/d per cow for > or = 15 d before the first AI. Cows were inseminated at each observed estrus after 70 d (Experiment 1) or at 50 d postpartum (Experiments 2 and 3) or were included in a timed AI program [d 0 (i.e., approximately 40 or 60 d postpartum), 8 micrograms of GnRH agonist; d 7, 25 mg of PGF2 alpha; d 9, 8 micrograms of GnRH agonist; d 10, AI] for first breeding. Pregnancy rate at first AI was similar among groups, but the percentage of cows that were pregnant by 90 d postpartum was greater for cows in the timed AI group in Experiments 1 (16.6% vs. 9.8%) and 2 (34.3% vs. 14.3%) but not in Experiment 3 (24.1% vs. 28.7%). Overall, beta-carotene had no effect on reproductive function. For cows fed supplemental beta-carotene for > or = 90 d, however, pregnancy rate at 120 d postpartum was increased in Experiment 1 (35.4% vs. 21.1%). In all experiments, beta-carotene increased cumulative milk yield on the last test day by 6 to 11%. In conclusion, timed AI can improve pregnancy rates during periods of heat stress. Supplemental beta-carotene may increase pregnancy rates for cows in the summer and can increase milk yield.
Oxidation and the production of free radicals are an integral part of aerobic metabolism. A variety of reactive oxygen species (ROS) are produced by normal metabolic processes and by certain leukocyte populations during defense against disease. Accumulated scientific evidence supports the concept that oxidative damage of tissues and cellular components are either a primary or secondary cause of many human diseases. Unfortunately, considerably less is known about how oxidative stress can affect veterinary health and well-being, particularly during times of high metabolic activity. The performance of high producing dairy cattle can be optimized to a certain extent by supplementing diets with optimal levels of micronutrients with antioxidant capabilities. However, oxidative stress continues to be a problem in transition cows. Innovative approaches are needed to enhance the antioxidant defense mechanisms of dairy cattle during times of increased metabolic demands.
Effects of vitamin A or beta-carotene supplementation during the dry period and early lactation on the frequency of new intramammary infection and clinical mastitis and on SCC and milk yield were examined. Eighty-two Holstein cows were randomly assigned to one of three groups: 1) 50,000 IU/d of vitamin A per cow (approximately equivalent to 1978 NRC recommended daily intake for dairy cows); 2) 170,000 IU/d of vitamin A per cow; or 3) 50,000 IU/d of vitamin A plus 300 mg of beta-carotene per cow. Cows were supplemented during the 2 wk before drying off, throughout the dry period, and for the first 6 wk of lactation. Concentrations of serum vitamin A did not differ among treatment groups but tended to decrease for all treatment groups from 14 d before drying off to calving. After calving, serum vitamin A tended to increase in all groups through wk 6 of lactation. Serum beta-carotene tended to be higher in beta-carotene-supplemented cows at dry-off, in the early dry period, and again during lactation. Serum beta-carotene decreased sharply in all groups during the prepartum period. The frequency of clinical mastitis and of new intramammary infection during the dry period, near parturition, and for the first 6 wk of lactation did not differ among treatment groups. The percentage of quarters newly infected over the entire trial was 26.8 in the control, 25.0 in the high vitamin A, and 30.6 in the beta-carotene group. Pathogens isolated most frequently were coagulase-negative staphylococci, streptococci other than Streptococcus agalactiae, and coliforms.(ABSTRACT TRUNCATED AT 250 WORDS)
The effects of in vitro supplementation of beta-carotene, retinol, and retinoic acid on phagocyte function during the peripartum period were assessed. Blood was collected at wk -4, -1, 0 (calving), 1, and 4; mammary secretions were collected at wk -1, 0, 1, and 4 from 14 Holstein cows for the isolation of phagocytic cells. Blood polymorphonuclear leukocytes and mammary macrophages and polymorphonuclear leukocytes (phagocytic cells) were assayed for phagocytic and intracellular kill abilities of Staphylococcus aureus in the presence of beta-carotene and retinol at 10(-8) and 10(-7) M and retinoic acid at 10(-9) and 10(-8) M. Phagocytosis by blood or milk phagocytic cells was not influenced by beta-carotene. However, beta-carotene enhanced kill by blood and milk phagocytic cells during certain prepartum and post-partum periods. In contrast to beta-carotene, retinol and retinoic acid either had no effect or suppressed phagocytosis and kill. These results are interpreted to suggest a mechanism by which beta-carotene affords the mammary gland protection against infection, i.e., through enhanced intracellular kill by phagocytes.
The effects of beta-carotene, retinol, and retinoic acid on function of mononuclear cells during the peripartum period was assessed in vitro. Blood was collected from 14 Holstein cows on wk -4, -1, 0, 1, and 4 postpartum, and mononuclear cells were obtained by gradient centrifugation. Mononuclear cell proliferation induced by concanavalin A was measured in the presence of beta-carotene, retinol (1 x 10(-9) and 1 x 10(-8) M), and retinoic acid (1 x 10(-10) and 1 x 10(-9) M). Retinol and beta-carotene had no effect on spontaneous cell proliferation, whereas retinoic acid was suppressive. However, 1 x 10(-9) M beta-carotene enhanced concanavalin A-induced proliferation at wk -1, whereas 1 x 10(-8) M beta-carotene was suppressive at wk -4. Retinoic acid suppressed concanavalin A-induced proliferation at wk 0, but retinol had no effect. These results suggest a mechanism by which beta-carotene affords the mammary gland protection against infection immediately prepartum.
Vitamin A and beta-carotene improved mammary health in dairy cows around dry off. To define possible mechanisms, cows were fed 1) 53,000 IU vitamin A, 2) 213,000 IU vitamin A, or 3) 53,000 IU vitamin A plus 400 mg beta-carotene/cow per d (n = 10/treatment) from 6 wk before to 2 wk after dry off. Blood polymorphonuclear neutrophil function (phagocytosis, kill, and chemotaxis) and lymphocyte proliferation were measured at wk -6, 0 (dry off), and 2. Concentrations of vitamin A in serum did not differ across vitamin treatments. beta-Carotene in serum was elevated in cows fed beta-carotene. Treatment did not influence phagocytosis or kill. Kill ability increased after dry off in all treatment groups, but phagocytosis tended to decrease after dry off in cows fed vitamin A only. Lymphocyte blastogenesis stimulated by concanavalin A on wk 2 for cows fed 53,000 IU vitamin A but did not vary in the other two groups. Lipopolysaccharide-stimulated blastogenesis peaked at wk 0 and then decreased to pretreatment values by wk 2 in cows fed 213,000 IU vitamin A. These data indicate lymphocyte function is influenced by vitamin A supplementation and that beta-carotene supplementation seems to exert a stabilizing effect on neutrophil and lymphocyte function during the period around dry off.
Dietary vitamin A and beta-carotene were assessed on their interaction with lactational status to influence neutrophil function in vitro. Cows were fed 1) 53,000 IU or 2) 213,000 IU vitamin A, or 3) 53,000 IU vitamin A plus 400 mg beta-carotene/cow per d from 6 wk before to 2 wk after dry off. Blood neutrophils were isolated the day of dry off and 2 wk after dry off and incubated with retinol, retinoic acid, or beta-carotene. Phagocytosis and kill of Staphylococcus aureus were measured. Across all treatments, kill was higher after dry off than before dry off. Phagocytosis tended to be lower after dry off than before in cows fed vitamin A only. In vitro, 10(-6) M beta-carotene stimulated phagocytosis after dry off and kill before dry off in cows fed vitamin A only. In general, retinol and retinoic acid suppressed phagocytosis but did not affect kill. Neutrophils from cows fed high amounts of vitamin A were more susceptible to in vitro suppression than those from cows fed adequate amounts of vitamin A. Therefore, vitamin A and beta-carotene supplementation interacts with lactational status to influence the responsiveness of bovine neutrophils to vitamin challenge in vitro.
Fifty-four lactating Holstein cows were assigned by parity and calving date to a 2 X 3 factorial arrangement of a randomized block design to determine effects of beta-carotene supplementation and ration fiber content on reproduction. Because ration fiber treatments did not differ in their effects on reproductive performance, data for beta-carotene analyses were pooled over the three rations. From 3 to 98 d postpartum, cows were individually fed either 0 or 300 mg supplemental beta-carotene daily by adding it on top of their complete mixed ration. By wk 3 postpartum, concentrations of beta-carotene in blood serum were higher in cows fed supplemental beta-carotene and remained higher throughout the experimental period. Feeding supplemental beta-carotene had no effect on the interval from the time of parturition to uterine involution, ovulation, first observed estrus, or conception. Feeding beta-carotene did not influence incidence of cystic follicles based on palpation, ovarian cyclicity based on blood progesterone patterns, peak progesterone concentrations, or first service conception rate. Cows fed supplemental beta-carotene required fewer treatments for clinical mastitis. Reproductive performance in lactating Holstein cows was not improved by feeding supplemental beta-carotene.
Fifty-six Holstein cows were used in a replicated study to determine whether supplemental beta-carotene improved reproductive performance. Each of two replicates was of completely randomized design with 2 X 2 factorial arrangement of two diets with or without beta-carotene supplementation. On a dry matter basis, diet 1 was 5% hay, 20% haylage, 25% corn silage, and 50% concentrate. Diet 2 was 7.5% hay, 42.5% corn silage, and 50% concentrate. The diets contained adequate amount of vitamins A, D, and E. From 10 d postpartum until pregnancy was confirmed by rectal palpation, half the cows on each diet received a supplement of 400 mg beta-carotene per head daily. The remaining cows on each diet received a supplement of 160,000 IU vitamin A per head daily. Supplemental beta-carotene increased plasma beta-carotene throughout the trials. Median days to first ovulation, first service, days open, and mean services per conception were: 22, 77, 97, and 1.6 for cows receiving beta-carotene supplement compared with 19.5, 73, 82, and 1.9 in controls. Supplementation did not affect first service conception rate, uterine involution, or milk yield. Incidence of follicular cysts, luteal cysts, pyometra, and endometritis in cows fed beta-carotene were 11, 7, 0, and 7% compared with 8, 21, 4, and 13% in control cows. Supplemental beta-carotene did not improve the fertility of Holstein cows.
Thirty-six Holstein cows fed a corn silage-based ration and 34 fed an alfalfa-grass silage-based ration were assigned according to calving date to receive either 300 mg/head per day of synthetic beta-carotene in a gelatin capsule or an empty gelatin capsule daily for the first 100 days postpartum. Supplemental vitamin A was provided at 3919 IU/kg of ration dry matter. Cervix diameters for cows supplemented with beta-carotene were smaller at 21 days and 28 days postpartum. Days from parturition to first observed estrus were less when beta-carotene was added and less when corn silage was fed. Means of other reproductive traits were more favorable for cows treated with beta-carotene (fewer services per conception and shorter intervals between parturition and conception). Milk progesterone at 21 and 28 days postpartum was not affected by either roughage or beta-carotene treatment. Milk from cows receiving alfalfa-grass silage contained lower somatic cell concentrations than that produced by cows fed corn silage. Milk somatic cell concentrations were lower in both roughage treatment groups for cows supplemented with beta-carotene. No effects of roughage or beta-carotene on milk production or milk fat percentages were significant.
Seventy-eight Holstein cows alternately were assigned at calving to receive beta-carotene supplementation or act as controls to determine effects of beta-carotene on reproduction and carotene, luteinizing hormone, progesterone, insulin, glucose, and glucagon concentrations in blood plasma. Cows were fed a corn silage-based complete ration. Biweekly jugular blood samples were collected beginning the week after parturition through 90 days. At day 30, supplemented cows received 600 mg synthetic beta-carotene daily for 60 days. Plasma carotene reached a peak of 2.45 micrograms/ml compared to 1.50 micrograms/ml in controls. Supplementation significantly increased plasma carotene but had no effect on luteinizing hormone, progesterone, insulin, glucose, glucagon, or reproductive measures. Days to first heat, days to first breeding, days open, and services per conception averaged 74, 74, 95, and 1.7 for supplemented cows and 64, 76, 102, and 1.9 for control cows. Progesterone increased as lactation progressed. Somatic cells were not different between supplemented and control cows. Supplementation of beta-carotene did not improve reproductive efficiency or alter luteinizing hormone, progesterone, insulin, glucose, or glucagon in blood plasma or affect somatic cells in milk.
Beginning 4 wk prior to predicted calving, 14 Holstein cows per treatment were fed diets 1) unsupplemented (control) or supplemented daily with 2) 300 mg of beta-carotene, 3) 600 mg of beta-carotene, or 4) 120,000 IU of vitamin A. Blood was collected around calving on wk -4, -2, -1, 0 (within 24 h postcalving), 1, 2, and 4 for isolation of lymphocytes and neutrophils and for the analysis of plasma vitamins. Lacteal secretions were collected on wk 0, 1, 2, and 4 for the isolation of phagocytes. Cows supplemented with 600 mg of beta-carotene had higher concentrations of plasma beta-carotene and retinol than did unsupplemented cows. Supplemental vitamin A increased plasma retinol on wk 4 and decreased plasma beta-carotene on wk -1 and 0. Treatment did not affect concentrations of plasma alpha-tocopherol. Blood lymphocyte proliferation in response to concanavalin A, phytohemagglutinin, and pokeweed mitogen during the peripartum period was higher in cows supplemented with beta-carotene than in unsupplemented controls. Phagocytic activity of blood neutrophils was enhanced on wk 1 in cows fed 300 mg of beta-carotene. Intracellular killing by blood neutrophils was enhanced in cows supplemented with beta-carotene (wk 0) and vitamin A (wk 0 and 1). Iodine uptake and nitroblue tetrazolium reduction by blood neutrophils was stimulated in cows supplemented with beta-carotene. Phagocytic activity, iodine uptake, and nitroblue tetrazolium reduction by mammary phagocytes from all cows generally were lower postpartum than on the day of calving. The incidence of retained placenta and metritis was higher for unsupplemented cows than for cows supplemented with beta-carotene. Therefore, dietary beta-carotene can elevate peripartum concentrations of blood beta-carotene, enhance host defense mechanisms by potentiating lymphocyte and phagocyte function, and decrease the incidence of certain reproductive disorders.
Addition of safflower oil to a growth medium depressed the growth of mixed rumen bacteria above 200 mg/L and did not significantly increase bacteria, even at lower concentrations. However, when 10 mg/L of beta-carotene were added to 50 to 100 mg/L of safflower oil, bacterial growth was significantly increased. When more than 200 mg/L of safflower oil were present, beta-carotene markedly restored the growth capacity. alpha-Tocopherol was more effective than beta-carotene, although it inhibited growth at high concentrations. The combination of beta-carotene and alpha-tocopherol (each 5 mg/L) exerted partially additive effects. beta-Carotene plus alpha-tocopherol enhanced bacterial cell yield in the presence of safflower oil, caprate, stearate, or linoleate, suggesting that beta-carotene and alpha-tocopherol increase the utilization of fatty acids. beta-Carotene plus alpha-tocopherol also stimulated cellulose digestion in the presence of 100 mg/L of safflower oil, evidently through the increased growth of cellulolytic bacteria.
This study compared the effects of two levels of crude protein (CP) fed during late gestation on the performance, blood metabolites, and ovarian activity of Holstein cows. One-hundred and six cows (42 primigravid and 64 multiparous) 32 d before calving were divided into two groups and fed diets containing moderate (12.7% CP, 36% rumen undegradable protein, (RUP) or high (14.7% CP, 40% RUP) protein. Higher prepartum CP diet increased milk production during the first 120 d in milk (DIM), but most of that effect was detected for the primigravid cows. Primigravid cows fed the prepartum diet higher in protein produced 2.0 kg/d more milk and 3.1 kg/d more 3.5% fat-corrected milk (FCM) during early lactation. Yields of milk fat and protein in early lactation were also increased by the high prepartum CP diet fed to primigravid cows. During the complete lactation, the response to prepartum dietary protein differed between primigravid and multiparous cows. Yields of milk, 3.5% FCM, and milk fat and protein were not affected by the prepartum diet for primigravid cows, but decreased for multiparous cows fed the high protein diet. However, primigravid cows fed the high prepartum protein diet had a higher 305-d mature equivalent milk yield. Colostrum composition, blood metabolites, ovarian activity, and disease incidence were not influenced by prepartum protein. Data from this study suggest that the current prepartum protein recommendation seems to be adequate for multiparous cows, but late-gestation primigravid cows might benefit from diets with a CP content above 12.7%.
Six lactating Holstein cows were assigned to a replicated Latin square design to test the effect of dietary vitamin E on milk fat depression and on the increased production of milk trans-10 C18:1 classically observed when feeding high doses of unsaturated fatty acids with low-fiber diets. Two diets (linseed diet and linseed diet + 12,000 IU of vitamin E/d) were compared during 2 periods of 21 d. The linseed diet presented a forage-to-concentrate ratio of 50:50 and contained extruded linseed (1.86 kg/d) and linseed oil (190 g/d). It was conceived to favor the "trans-11 to trans-10 shift" (low structural value and high level of unsaturated fatty acids). Milk yield and protein content were not affected by the diets. Milk of cows fed the linseed diet presented the typical symptoms of milk fat depression associated with a shift in biohydrogenation pathways: low fat content and high level of trans-10 C18:1. However, the high dose of dietary vitamin E provided significantly increased milk fat content (by 17.93%) and yield (by 15.56%) and decreased trans-10 C18:1 content (by 47.06%). In addition, it managed to significantly increase the daily yields of vaccenic (by 102.56%) and rumenic acids (by 56.67%). However, the sequence of administration of vitamin E influenced its effect, as vitamin E seemed to be more active in limiting the "trans-11 to trans-10 shift" when it was incorporated in the diet simultaneously with the fat. Once the shift had occurred, the subsequent addition of vitamin E was no longer able to completely counteract this process.
During the early postpartum period dairy cows mobilize fat and muscle to support lactation. This is associated with alterations in blood metabolite and hormone profiles which in turn influence milk yield and fertility. This study developed models to determine how metabolic traits, milk yield and body condition score were inter-related at different times in the periparturient period and to compare these relationships in primiparous (PP, n=188) and multiparous (MP, n=312) cows. Data from four previous studies which included information on blood metabolic parameters, parity, milk yield, body condition score and diet were collated into a single dataset. Coefficients of polynomial equations were calculated for each trait between -1 week pre-calving and week +7 postpartum using residual maximum likelihood modelling. The completed dataset was used in a multiple correlation model to determine how the best fit curves were related to each other over time. PP cows had higher concentrations of insulin-like growth factor-I and lower beta-hydroxybutyrate concentrations throughout, higher leptin concentrations pre-partum and both the peak in non-esterified fatty acids and the nadir in urea concentration occurred earlier after calving. These differences were associated with significantly lower milk production. Leptin concentrations fell at calving and were related to body condition score. Insulin was negatively correlated with yield in MP cows only. In MP cows the relationship between insulin-like growth factor-I and yield switched from negative to positive between weeks +4 and +7. Both beta-hydroxybutyrate and urea were positively related to yield in PP cows. In contrast, in MP cows beta-hydroxybutyrate was negatively correlated with yield and urea was strongly related to body condition score but not yield. These results suggest that there are differences in the control of tissue mobilization between PP and MP cows which may promote nutrient partitioning into growth as well as milk during the first lactation.