Article

Factors affecting gestation length in the bitch

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Abstract

A retrospective analysis was performed to determine the effects of age, breed, parity, and litter size on the duration of gestation in the bitch. Bitches at two locations were monitored from breeding to whelping. A total of 764 litters whelped from 308 bitches (36 large hounds, 34 Golden Retrievers, 23 German Shepherd Dogs (GSD), and 215 Labrador Retrievers). By breed, the number of whelpings was 152, 72, 58, and 482 for the hounds, Golden Retrievers, German Shepherd Dogs, and Labrador Retrievers, respectively. Whelping was predicted to be 57 d from the first day of cytologic diestrus in the hounds or 65 d from the initial progesterone rise in the other breeds. The average gestation duration (calculated as 8 d prior to Day 1 of cytologic diestrus in hounds or measured from the initial progesterone rise in other breeds) by breed (days +/- S.D.) was 66.0 +/- 2.8, 64.7 +/- 1.5, 63.6 +/- 2.1, and 62.9 +/- 1.3 for the hounds, Golden Retrievers, German Shepherd Dogs, and Labrador Retrievers, respectively. The relationship of age, breed, parity, and litter size with the difference in gestation duration was evaluated using log linear modeling. Age or parity had no effect on gestation duration. Compared to Labrador Retrievers, the German Shepherd Dogs, Golden Retrievers and hounds were more likely to have a longer gestation duration; three, four and nearly eight times as likely, respectively. Bitches whelping four or fewer pups were significantly more likely to have a longer gestation duration than those whelping five or more pups; the prolongation averaging 1 d.

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... The interval is highly variable (2-10 months) among the breeds (3,4). Various factors that affect the interestrous period and pregnancy duration, such as breed, age, parity, and litter size have been described in previous studies (3,5,6). ...
... Furthermore, each puppy was associated with a 0.24 days decrease in pregnancy duration. The negative correlation between litter size and pregnancy duration is known from previous work (6,8,22). Eilts et al. (2005) reported that bitches that whelped up to 5 puppies had a 1-day shorter pregnancy duration than bitches that whelped up to 4 puppies. ...
... The negative correlation between litter size and pregnancy duration is known from previous work (6,8,22). Eilts et al. (2005) reported that bitches that whelped up to 5 puppies had a 1-day shorter pregnancy duration than bitches that whelped up to 4 puppies. A shorter pregnancy and a larger litter could be the result of a better planned mating time in relation to ovulation. ...
Article
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The aim of this retrospective study was to evaluate the effects of breed, parity, and season on the reproductive parameters in bitches reared under a temperate climate. Breeding and pregnancy statuses, proestrus, estrus, and pregnancy durations, litter size, and cycle interval were recorded from German shepherds (GS, n = 34), Labrador retrievers (LA, n = 23), Belgian Malinois dogs (BM, n = 13), and Pointers (PO, n = 9) up to 10th parities. The mean age at first breeding (464.8 ± 26.2 days, mean ± SD) and the pregnancy rate (74.6%) were not different among breeds. The pregnancy duration was shortened as the number of puppies born increased in each whelping (P < 0.008). The cycle interval varied by breed (208.2, 215.1, 208.6, and 237.0 days for GS, LA, BM, and PO, respectively, P < 0.01) and decreased linearly from 241.1 to 202.0 days as parity increased from 1 to 10 (P < 0.04). The season did not affect the cycle interval, proestrus, and estrus length (P > 0.05). Reproductive parameters varied among the GS, LA, BM, and PO bitches reared in Turkey. The effect of seasonal variation was negligible.
... Moreover, this study also showed that the duration of pregnancy in West Highland White Terrier was significantly longer than in German Shepherd Dog, Labrador Retriever and Dobermann. Pregnancy length and its variation factors were also evaluated by Eilts et al. (2005) from LH peak, estimated to occur 8 days prior to Day 1 of cytological dioestrus in large hounds or measured from the initial P4 rise (estimated as the first day of serum P4 reached 2 ng/ml), in a colony of Labradors Retrievers, Golden Retrievers and German Shepherd Dogs. They concluded that pregnancy length was 66.0 ± 2.8, 64.7 ± 1.5, 63.6 ± 2.1 and 62.9 ± 1.3 for large breeds (hounds, Golden Retrievers, German Shepherd Dogs and Labrador Retrievers, respectively). ...
... Our results are in accordance with previous studies that concluded that the size of the litter had a clear influence in pregnancy length (Bobic Gavrilovic et al. 2008;Eilts et al. 2005;Okkens et al. 1993 and. Litters with less than three puppies were significantly longer than bigger litters. ...
... Litters with less than three puppies were significantly longer than bigger litters. These results are similar to those of Eilts et al. 2005, which analysed 764 pregnancies from bitches in the same breed and showed that there was a negative correlation in litters from 1 to 4 puppies. The relation between EPL and litter size may therefore be the most important one to consider within certain breeds, especially large breeds. ...
Article
An accurate timing of parturition is very useful for managing canine parturition. It is generally accepted that parturition in bitches occurs between 64 and 66 days after the luteinizing hormone peak. In this retrospective study, we determined pregnancy length in different breeds and its influencing factors dating it from the estimated day of ovulation (EDO), defined as the day when peripheral plasma level of progesterone (P4) reaches 6 ng/ml. From January 2001 to December 2006, 162 pregnancies in 151 bitches of 53 different breeds were followed. Different parameters concerning the bitch, the litter, the type of semen and the type of reproduction were studied. The mean estimated pregnancy length in the bitch from EDO to parturition was 63.1±2.1 days. The main influencing factors for the pregnancies studied were the breed, the size of the bitch and the number of puppies within the litter.
... Factors influencing litter size are for example season of the year, number of previous litters (Gavrilovic et al. 2008), age of parents (Borge et al. 2011), and breed (Okkens et al. 2001;Borge et al. 2011). However, results published in various studies are inconsistent (Gavrilovic et al. 2008;Borge et al. 2011), possibly because they are based on reproductive efficiency data sets of bitches pertaining to various breeds (Bouchard et al. 1991;Okkens et al. 2001;Eilts et al. 2005;Chatdarong et al. 2007;Ortega-Pacheeo et al. 2007;Borge et al. 2011) and only very few studies deal with reproductive efficiency of only one dog breed, more specifically Drever (Gavrilovic et al. 2008), Irish hounds (Urfer 2009), German Shepherds (Mutembei et al. 2002), Beagles (Shimatsu et al. 2007), Boxers (Forsberg and Persson 2007), and English bulldog breed (Wydooghe et al. 2013). Moreover, results of some studies are only based on data from a questionnaire (Mutembei et al. 2002;Forsberg and Persson 2007;Wydooghe et al. 2013) and there is no information (or no rigorous information) about reproductive management of the breeders concerned. ...
... Hare and Leighton (2006) also reported a significant influence of the season (GBS), contrarily Mutembei et al. (2002) did not note any variations during the year in GSB bred in Africa. The reason for such conflicting results (non-seasonality) could be the effect of the comparison of reproductive data enrolling several breeds instead of evaluating sufficient records from each breed separately (Eilts et al. 2005). Another reason could be different housing conditions of animals which are kept as a colony. ...
... The results of our study are in line with Eilts et al. (2005), Mir et al. (2011), andPolat et al. (2015) who found a negative relationship between litter size and pregnancy length in large breeds as well. Our study documented for the first time the negative effect of gestation length on the number of live puppies born. ...
Article
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The present study on German Shepherd bitches bred in the same environment of a private kennel and producing offspring for working purposes aimed to ascertain if any of the parameters: litter size, number of live puppies, stillbirth and mortality of puppies is determined by the month of whelping, parity, number of whelpings for one bitch over the course of one year, pregnancy length or bitch age at the time of whelping. Reproductive records of 73 bitches of German Shepherd breed (GSB) documented since 2001 till 2013 were processed. A total of 298 whelpings resulted in 2075 puppies; mortality of puppies was evaluated within the first 3 weeks of life. A significant seasonal influence on litter size and number of live born puppies, but not on stillbirth or mortality, was found. The parity of GSB significantly influenced litter size, live born puppies, and the incidence of stillbirths. The number of whelpings in one bitch over the course of one year significantly influenced litter size, while puppy losses were the same when bitches were bred once or twice a year. Litter size and number of live born puppies had a significant negative effect on pregnancy length. Furthermore, the number of stillbirths significantly increased when pregnancy was prolonged. Bitch age did not influence litter size, number of live born puppies and stillbirths, however it significantly affected mortality.
... Its length, usually calculated as a interval from mating till delivery, ranges from 57 to 72 days Correspondence to: P. Socha, e-mail: piotr.socha@uwm.edu.pl, tel.: +48 89 523 34 97 (Concannon et al. 1983, 1989, Luvoni and Grioni 2000, Kutzler et al. 2003a, Eilts et al. 2005, Johnson 2008, Socha et al. 2008, which is related to the specificity of fertilization in this species (Concannon et al. 1975, Concannon et al. 1983, Concannon et al. 1989, Hoffmann et al. 1996. ...
... This phenomenon is also correlated with an increase in progesterone concentration (P4) to about 2 ng/ml (Concannon et al. 1975, Concannon et al. 1989, Luvoni and Grioni 2000, Root Kustritz 2001, Rota et al. 2007). It has been proven that ovulation, which lasts on average 12 hours, occurs after about 2 days of the described hormonal changes, while the delivery usually starts after 63 ± 1 days as of this process (Concannon et al. 1975, Concannon et al. 1989, England 1996, Kutzler et al. 2003a, Eilts et al. 2005. However, it seems that hormonal fluctuations in individual animals, as well as the breed, can affect the length of pregnancy (Okkens et al. 2001, Son et al. 2001, Eilts et al. 2005. ...
... It has been proven that ovulation, which lasts on average 12 hours, occurs after about 2 days of the described hormonal changes, while the delivery usually starts after 63 ± 1 days as of this process (Concannon et al. 1975, Concannon et al. 1989, England 1996, Kutzler et al. 2003a, Eilts et al. 2005. However, it seems that hormonal fluctuations in individual animals, as well as the breed, can affect the length of pregnancy (Okkens et al. 2001, Son et al. 2001, Eilts et al. 2005. ...
Article
In clinical practice, the parturition date in bitches is calculated on the basis of the established ovulation date, using determination of the level of LH and P4. Additionally cytological examination of vaginal smears makes it possible to establish the onset of diestrus, from which the delivery occurs after about 57 days. The latest method used in bitches for this purpose is foetal biometry. Measurements of the inner chorionic cavity diameter (ICC) and biparietal diameter (BP) with formulas published by Luvoni and Grioni have been popularized and the most practically useful. In a group of six bitches the effectiveness obtained with the use of ICC was 66.67% with an accuracy of 1 day and 100% with an accuracy of 2 days. BP measurements gave better results, as the accuracy was respectively 83.33% and 100%. The effectiveness of predicting the delivery date on the base of method consisting in determining the LH surge was 66.67% with an accuracy of 1 day and 100% with an accuracy of 2 days. The best effectiveness was obtained while using the method based on P4 level determination (100% both with an accuracy of 1 day, as well as of 2 days). The lowest accuracy was obtained while using the cytological method. Generally, a comparison of the methods used for predicting the date of delivery in bitches confirms practical usefulness of fetometry. Its effectiveness was not lower than traditional methods used so far, while its advantage lies in the ease of performance and the long term of application during gestation. However, full confirmation of the practical usefulness of this method requires further research on a larger number of animals.
... Gestation length in the bitch is well-documented to be 63 ± 2 days from ovulation, although breed differences also seem to play a role (11)(12)(13)(14)(15)(16). Consequently, determination of ovulation date through serum P4 measurements during breeding allows veterinarians to calculate the expected parturition date and prepare for the whelping, manage a small litter or highrisk pregnancies. ...
... Additionally, "reverse P4 timing" at the end of gestation, i.e., daily or every other day serum P4 measurements starting 5-7 days before the expected day of parturition, can be used together with ultrasonographic evaluation of fetal maturation (13,25,26) to determine when a Cesarean section (C-section) can be safely performed. Puppies delivered prematurely may not be sufficiently developed for survival, and puppies delivered too late could outlive their placental nutrient supply and die in utero (12,13). Accurate timing of C-section is critical when the date of ovulation is unknown, especially in breeds that have difficulty whelping naturally, such as brachycephalic dogs, or in bitches carrying small litters (singleton or two-pup pregnancies) where placental prostaglandin F2α release may be insufficient to cause timely prepartal drop of P4. ...
... The remaining 89 were estrual, which were further categorized by their day of estrus with day one defined as the first day of serosanguineous vulvar discharge. Twenty-seven samples were collected during the first week of estrus (days 1-7), 48 were collected during the second week (days [8][9][10][11][12][13][14], and 14 samples were collected during the third week (days [15][16][17][18][19][20][21]. Only samples with sufficient serum volume to be analyzed on the three analyzers were included in the study. ...
Article
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Accurate serum progesterone measurements for timing bitches during breeding management is critical for reproductive practice, especially as artificial insemination has become routine to facilitate breeding of animals that are geographically or temporally separated. To measure serum progesterone, chemiluminescent immunoassay (CLIA) has replaced radioimmunoassay as the current standard in the bitch due to its high correlation and increased practicality. In January 2019, a colorimetric point-of-care (POC) immunoassay for quantitative in-clinic canine serum progesterone measurements in <30 min was released. This study provides an independent comparison of the POC (Catalyst One, IDEXX) to the current industry standard, CLIA (Immulite-2000, Siemens). To assess inter-assay imprecision of POC and agreement of the POC and CLIA results, 100 canine serum samples were analyzed on three analyzers (POC-1, POC-2, and CLIA), of which, 74 (POC-1) and 75 (POC-2) results were within POCs' reportable range of 0.2–20 ng/mL and included in the study. To assess intra-assay imprecision, pooled canine serum samples at low (L1), intermediate (L2), and high (L3) progesterone concentrations were analyzed ten times each on POC-1 and CLIA. Relative to CLIA, POC values showed good correlation (POC-1, r ² = 0.9366; POC-2, r ² = 0.9438, P < 0.0001) and significant positive proportional bias at values >2 ng/mL. The POC inter-assay coefficients of variation (CVs) were 13.2% (0.2–2.9 ng/mL, 0.6–9.2 nmol/L, L1), 10.0% (3.0–9.9 ng/mL, 9.5–31.5 nmol/L, L2), 7.1% (10.0–20.0 ng/mL, 31.8–63.6 nmol/L, L3), and 11.2% (all samples). The intra-assay CVs for POC (L1, 15.3%; L2, 7.0%; L3, 4.7%) were higher than those for CLIA (L1, 5.89%; L2, 4.89%; L3, 3.44%). Based on the more rapid increase in serial serum progesterone concentrations in ovulating bitches and the greater imprecision of the POC, the clinical interpretations of serum progesterone measurements as they relate to canine breeding management should be made with caution.
... Pregnancy length from ovulation to parturition seems not to be affected by sex ratio of puppies, age of the bitch, regularity of interestrous intervals, parity, type of mating (assisted or natural) and type of semen used [20]. Litter size, breed and maternal size seems to affect gestational length [20,21], although this was not evidenced by all authors [6,12,22,23]. ...
... Singleton or two-puppy pregnancies are reported to be longer than those with more than three puppies (65.2 ± 2.6 days for ≤2 puppies, 62.8 ± 1.9 for 3-9 puppies, 62.2 ± 1.3 days for >10 puppies, respectively) [20]. In large-size bitches, pregnancies are reported to be on average one day longer when carrying four or fewer puppies, compared to those with five or more puppies (65.2 ± 2.9 days and 63.5 ± 1.9 days, respectively) [21]. In a retrospective study on Drever bitches, an increase or a decrease of 0.25 days in length was observed in pregnancies with a litter size lower or greater than the mean number of pups (6-8 puppies/litter), respectively [24]. ...
... The results available in the literature about the relationship between pregnancy length and maternal size and breed are controversial [20,21,25,26]. In a retrospective study taking into account 162 pregnancies, small-size bitches (<10 kg) had a gestational length shorter than large and giant size bitches (25-40 kg and >40 kg, respectively) [20]. ...
Article
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An accurate parturition timing is of key importance for breeders and veterinarians in order to give professional assistance to parturition in dogs. However, pregnancy length calculated from the breeding date has a wide variability. Different parameters and formulas have been described and calculated, as well as their accuracy which is affected by various factors: stage of pregnancy, litter and maternal size. Therefore, the selection of the most appropriate parameter panel poses the challenge of weighing their influences and impact on the overall accuracy. The aim of this review is to analyze the parameters useful for parturition timing, especially their accuracy, and to propose the addition of fetal maturity and criteria for its evaluation to detect readiness for parturition. Parameters, as described in literature, are classified as: (i) maternal parameters, (ii) fetal parameters, (iii) ultrasonographic assessment of maternal and fetal heart rate and blood flow, (iv) parameters indicating fetal maturity. A focus on recently described parameters—such as fetal gastrointestinal motility and fetal lung development detected by quantitative ultrasound—is reported. Currently, the most accurate way to predict parturition day is represented by a prepartum progesterone drop, but the identification of a panel of ultrasonographic parameters combining their significance and their accuracy throughout pregnancy is still needed.
... Further, accuracy of these prediction formulas was verified in 22 other pregnant bitches (Group B). Which factors could affect pregnancy length in dog is still a controversial issue (Kutzler et al., 2003a;Eilts et al., 2005;Michel et al., 2011;Mir et al., 2011). We hypothesized that, in dogs from the same breed, gestational duration and, as a consequence, fetal biometric measurements and accuracy of related equations were not influenced by maternal weight and age, while being inversely proportional to the litter size. ...
... However, when calculated by BP measurement, accuracy was significantly higher in medium (4-8 pups) compared to small (≤3 pups) sized litters. In agreement with literature (Eilts et al., 2005;Mir et al., 2011), this aspect reflects the longer duration of pregnancy in dogs with less than three pups. It is reported that fetal ultrasonographic measurement is not as accurate as plasma progesterone concentration in predicting the parturition date in dogs (Kutzler et al., 2003a,b;Lopate, 2008;Michel et al., 2011). ...
... A difference that may depend on several factors, such as prediction equations of parturition derived from bitches of differing breed conformation (Saunders, 1992). Indeed, many parameters involved in gestational age estimation are breed-dependent, such as litter size (Sokolowski, 1977;Johnston et al., 2001;Kutzler et al., 2003a,b), maternal body weight (Kutzler et al., 2003a,b) and duration of pregnancy (Okkens et al., 2001;Eilts et al., 2005;Lopate, 2008). We obtained excellent accuracy, comparable to that deriving from plasma progesterone concentration, based on ICC measurement. ...
... The duration of pregnancy of the bitch is relatively short which leads to a short time frame prior to parturition in that fetuses need to become fully mature to be able to survive [14]. In addition, gestation duration may be affected by influencing factors such as breed and litter size [15], with gestation being shorter for large litters and longer for small litters [16]. Accurate prediction of delivery date allows a better management of parturition and helps reducing the loss of neonates [17]. ...
... Duration of pregnancy in bitches is most commonly cited being 65.1 ± 0.1 days from the LH peak [15] or 63 days from ovulation [19]. Accuracy to predict time of parturition within a time frame of ± 24 h by using the LH surge and rise of progesterone concentrations was 80% [20]. ...
... Also the identification of cytological onset of diestrus allows prediction of the day of parturition which is expected 57 days later [15,17]. Some authors suggest that prediction by vaginal cytology is more precise compared to ovulation timing via clinical examination, vaginal cytology and progesterone measurement [20]. ...
Article
Around parturition, a bitch has to cope with various challenges such as hormonal changes, whelping, nursing, milk production, and uterine involution. Monitoring the health of bitches in this period is essential to detect potential illnesses and dystocia early. In that regard, it is elementary to know the normal progress and parameters during pregnancy, parturition and in the puerperium. Some research has been published in the past 50 years giving insights into hormonal and functional changes and findings including definitions of normal parturition and dystocia or puerperal conditions. However, taking a closer look into the literature reveals that for some issues heterogeneous data and varying conclusion were presented, indicating that further research is required. This paper gives an overview on endocrinology and methods to predict the time of parturition in the dog. Furthermore, the stages and mechanisms of parturition and signs of dystocia and puerperal health monitoring are discussed. Fields in which contradictory data have been published include for example the decline of hematocrit in the second half of pregnancy, the body temperature immediately before and after parturition, the interpretation of ultrasound findings, and the length of the canine puerperium. Even if thresholds are not clear for each parameter, examinations such as regular temperature measurement or ultrasound are important to monitor the bitches’ health status. Nevertheless, for the practitioner it is important to know that research findings for some parameters used in daily practice are controversial.
... respectively in German Shepherd, Belgainmalnois, Pointer, Golden Retriever, Rottweiler, Labrador Retriever and Dalmatian. This result was agreed with those recorded by (Eilts et al., 2005). Gestation length varied significantly between breeds (Okkens et al., 1993;Okkens et al., 2001;Eilts et al., 2005) the relationship of breed, parity, and the litter number with the difference in the gestation duration. ...
... This result was agreed with those recorded by (Eilts et al., 2005). Gestation length varied significantly between breeds (Okkens et al., 1993;Okkens et al., 2001;Eilts et al., 2005) the relationship of breed, parity, and the litter number with the difference in the gestation duration. Concerning the age and parity as shown in table 5 and 6 revealed that there was a no significant difference between bitch ages. ...
... and multiparous bitches (60.23 ±0.18). This result was agreed with those recorded by (Eilts et al.,2005) found that age or parity had no effect on the gestation duration (Okkens et al., 1993) illustrated that primiparous and multiparous status of the bitch did not influence the length of gestation. ...
... A determinação da duração da gestação torna-se mais rigorosa quando calculada a partir do pico de LH (65 ± 1 dia), da data de ovulação (63 ± 1 dia) e do primeiro dia de diestro citológico (57 ± 3 dias) (Feldman & Nelson, 2004;Johnson, 2008;Linde-Forsberg, 2005). Além disso, nas cadelas, o tempo de gestação parece variar com a raça e tamanho da ninhada (Eilts, Davidson, Hosgood, Paccamonti & Baker, 2005;Johnson, 2008), sendo que ninhadas grandes tentem a ter um tempo de gestação menor (Feldman & Nelson, 2004), enquanto que ninhadas de 4 ou menos cachorros tendem a ter um tempo de gestação mais prolongado (Eilts et al., 2005). ...
... A determinação da duração da gestação torna-se mais rigorosa quando calculada a partir do pico de LH (65 ± 1 dia), da data de ovulação (63 ± 1 dia) e do primeiro dia de diestro citológico (57 ± 3 dias) (Feldman & Nelson, 2004;Johnson, 2008;Linde-Forsberg, 2005). Além disso, nas cadelas, o tempo de gestação parece variar com a raça e tamanho da ninhada (Eilts, Davidson, Hosgood, Paccamonti & Baker, 2005;Johnson, 2008), sendo que ninhadas grandes tentem a ter um tempo de gestação menor (Feldman & Nelson, 2004), enquanto que ninhadas de 4 ou menos cachorros tendem a ter um tempo de gestação mais prolongado (Eilts et al., 2005). ...
... Nas gatas, pelo facto da ovulação ser maioritariamente induzida pela cópula, a variabilidade na duração da gestação é menor, sendo de 63 a 65 dias (Jutkowitz, 2005;Kutzler, 2009). A previsão rigorosa da data do parto é importante para o planeamento de partos normais e de cesarianas electivas e também para o reconhecimento de situações de distócia (Eilts et al., 2005;Feldman & Nelson, 2004;Johnson, 2008). ...
... Each time, at least two fetuses from two opposite uterine horns were evaluated [6]. The technique of measuring was described precisely in earlier report [17,18]. Examinations were conducted using the MyLab Gold Vet scanner with a microconvex probe of Table 1 The list of breeds and number of examined dogs included in the study. ...
... In our study, only bitches with normal litter size according to giant weight were included. In previous publications, it has been suggested that small or large litters can affect the pregnancy length [1,17]. Beccaglia and Luvoni [1] reported that the higher accuracy was obtained in pregnancies with normal litter size when compared with small and large litters, especially considering BP measurement. ...
... We believe that a main weakness of many fetometric studies is a relatively small number of dogs used for the development of specific formulas. It has been suggested that the growth rate of the particular fetal and extra-fetal structures in different animals and across breeds strongly depends on numerous physiological and pathologic factors that affect the pregnancy [13,17,18,20]. ...
... A low birthweight may be caused by a short gestation time and/or intrauterine growth retardation as reported in humans and other mammalian species including the dog [8,9]. Possible influences on gestation length in dogs including breed, litter size, parental age and size or parity have been investigated in different breeds [2,[10][11][12][13], but were not conclusive. This could be due to differences in the assessment and/or the classification of the data. ...
... The final data set comprised 7827 puppies in 1013 litters by 386 dams and 193 sires, born from September 2001 to February 2018 (Additional file 4). Potential predictors were chosen based on literature [4,11,26,29,36,37]. Breed, a well-known factor influencing PBW [6] was not relevant for the present study because all animals were LR. ...
Article
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Background: Weight at birth is an important predictor of neonatal mortality and morbidity in dogs. In addition, the birthweight of the puppies in a litter influences the decision to perform a cesarean section. The goal of the present study was to estimate heritabilities for the puppy birth weight in Labrador retrievers. Results: Of the 1138 Labrador retriever litters whelped at the Guiding Eye for the Blind between September 2001 and February 2018, 1013 were included in the analyses after data editing. Puppy weight at birth was the target trait, measured on a continuous scale in pounds, and converted to grams. Linear mixed models were used to identify factors influencing puppy weight at birth. The analyses showed that the sex of the puppy, litter size, length of gestation, adult weight of the dam, parity, year of birth and inbreeding coefficient of the puppies and dams contributed to the variance of the puppy birth weight. Dam and litter effects were included as random effects. A multiple trait derivative free restricted maximum likelihood approach was used to estimate variance components and genetic parameters with two animal models, one without covariates (Model 1) and one with covariates (Model 2). Sex of the puppy and litter size had moderate effects, whereas gestation length, adult weight of the dam, parity, year of birth and inbreeding coefficients of the dam and the puppies had minor effects. Estimates for Model 1 and Model 2 were 0.21 and 0.17 for the direct heritabilities, 0.22 and 0.22 for the maternal additive genetic heritabilities, 0.07 and 0.07 for the maternal permanent environmental proportions, and 0.14 and 0.08 for the environmental proportion of the litter. Conclusions: In order to estimate reliable breeding values for puppy weight at birth, sex of puppy, litter size, length of gestation and the adult weight of the dam should be included. Estimates could benefit from weighing the dams prior to each mating.
... Wie in den eigenen Untersuchungen konnten auch Munday und Davidson (1993) bei der Katze und Eilts et al. (2005) bei der Hündin keinen Zusammenhang zwischen der Gestationsdauer und dem Alter des Muttertiers nachweisen. Bei den in die Studie eingegangenen Kat- Originalarbeit zen entsprach das Alter der Anzahl der Würfe, da die in der Universität gehaltenen Van-Katzen einmal pro Jahr bedeckt werden und werfen. ...
... Ähnliche Beobachtungen beschrieben Munday und Davidson (1993) bei der Katze und Tsutsui et al. (2006) bei der Hündin. Andere Autoren berichten dagegen bei Hund (Okkens et al., 1993;Eilts et al., 2005;Seefeldt et al., 2007) und Schwein (Dziuk, 1991;Sasaki und Koketsu, 2007) von einer signifikanten negativen Korrelation zwischen Gestationsdauer und Anzahl an Früchten. So stellte Dziuk (1991) in seiner Untersuchung beim Schwein einen Zusammenhang zwischen kürzerer Gestationsdauer und höheren Östrogenkonzentrationen bzw. ...
Article
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The gestation period in Van cats is between 54 and 68 days, with high individual differences. Because of this variability, the date of birth cannot be predicted precisely, while the factors influencing the gestation period in Van cats have not been examined previously. The aim of this first study was to evaluate the influence of age, body weight of the dams and the litter size on the gestation period in Van cats. 28 Van cats aged one to nine years were used for this study. The body weight of the cats in the oestrus at the beginning of the study varied between 2.1-4.1 kg (3.1 ± 0.6 Kg). The time from first mating until birth was regarded as being the gestation period. Correlations were determined between the duration of pregnancy and the age and body weight of the females as well as litter size. The mean duration of pregnancy in all 28 Van cats was 63.6 ± 3.6 days (min. 54 days, max. 68 days) with a mean litter size of 3.4 ± 1.3 kittens (min. 1, max. 6). No correlations could be found between the factors examined meaning that the duration of pregnancy does not depend on the age or body weight of the dams or on the litter size. It must be concluded that other factors may cause this high variability of pregnancy duration in Van cats and these still need to be investigated.
... Essa variação pode em parte ser explicada devido ao fato de os espermatozóides caninos poderem sobreviver por até seis a sete dias no interior do sistema reprodutivo da cadela (Doak et al., 1967). Além disso, embora ainda seja um assunto controvertido entre pesquisadores, pode existir, mesmo que pequena, uma variação na duração da gestação em cadelas por influência racial, tamanho da ninhada ou quantidade de fetos (Concannon, 2000; Eilts et al., 2005). Segundo Okkens et al. (2001), em estudo com cadelas de raças grandes, ocorre uma variação de quatro a sete dias na duração da gestação, mesmo tendo sido o período de ovulação considerado como referência para o cálculo da duração. ...
... Segundo Okkens et al. (2001), em estudo com cadelas de raças grandes, ocorre uma variação de quatro a sete dias na duração da gestação, mesmo tendo sido o período de ovulação considerado como referência para o cálculo da duração. De acordo com Eilts et al. (2005), cadelas com quatro ou menos fetos possuem gestação mais prolongada do que cadelas com cinco ou mais fetos, sendo o prolongamento de um dia. ...
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The present study aimed at describing ovarian arterial venous complex (OVAC) obliteration technique consisting in tying a knot over its own axis. It also aimed at evaluating the efficacy of this hemostatic technique in queens ovariosalpingohisterectomy, as well as checking partial OVAC obliteration time and total procedure time. After previous training – based on alternative methods – for the demanded surgical skills acquisition, in vivo surgical procedures were conducted. Once gathered the necessary skills, an experimental study was carried in order to compare this technique with the linking technique in which three hemostatic clamps are used. In vivo training, firstly applied in healthy queens, and later in uterine affection carriers, helped consolidating the dexterity previously acquired through alternative practice methods, and also contributed to the feasibility verification of the described technique, which showed to be effective. Comparative study did not reveal any significant statistic difference between both groups on total surgical elapsed time (p=0.2848) and time spent for the right OVAC obliteration (p=0.1036), however significant difference was observed on the left OVAC obliteration (p=0.0001). The results obtained during transoperatory observation led to the conclusion that the described technique is feasible and provides appropriate OVAC hemostasis.
... La determinación de P 4 constituye, en la actualidad, el método más utilizado para estimar la ovulación en la perra, debido a su estrecha relación con los cambios preovulatorios de LH. Existen diversas técnicas de laboratorio para determinar P 4 canina, sérica o plasmática; entre ellas, el enzimoinmunoensayo (ELISA), el radioinmunoanálisis (RIA) y el inmunoensayo quimioluminiscente (CLIA), además de disponerse de kits comerciales, basados en un procedimiento semi-cuantitativo que aplica la técnica de ELISA en membrana (Eilts et al., 2005). ...
... Variables tales como edad de la madre, paridad, tamaño de camada y raza han sido analizados, observándose que la edad y la paridad no tienen efecto. El tamaño de la camada en perras con 4 o menos cachorros tiende a prolongar la gestación en alrededor de 24 horas comparado con perras con 5 o más cachorros; y en cuanto a la raza, comparado con Labrador retrievers, las hembras Ovejero alemán, Golden retrievers y Hound tiene una mayor probabilidad de gestar por mayor tiempo (Eilts et al., 2005). ...
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La gestación en la perra transcurre entre la fecundación y el parto, y su duración tiene importancia clínica. La compleja biología de los gametos y embriones influye en la duración de la gestación, cuyo lapso fisiológico fluctúa entre los 57 y 70 días. Este amplio rango puede estar influenciado por los métodos referenciales para la estimación del inicio de la gestación. El realizar montas o inseminaciones en base a detección de la ovulación permite estrechar el rango a 62 a 64 días. Una condición de alto impacto obstétrico es la gestación de un solo cachorro, la cual es más prolongada y representa alto riesgo de distocia. Dada la importancia clínica de una adecuada proyección de la duración de la gestación y de la predicción de la fecha de parto, se han desarrollado fórmulas matemáticas para el cálculo de la edad fetal y tiempo al parto a través de la sistematización de la ultrasonografía gestacional.
... Ovulation occurs when a bitch in cytological oestrus reaches 4–8 ng/ml of P4, and best breeding days for natural mating are considered those in the range from 1 to 4 days post-ovulation, while for frozen semen, the window is narrower and closer to day 4 (Badinand et al. 1993; Steckler et al. 2013). Pregnancy length from the day of ovulation has been described to range 62–64 days (Concannon et al. 2001; Tsutsui et al. 2006; Fontbonne 2008), 61–65 days (Okkens et al. 2001; Elits et al. 2005) or even 58–67 (Mir et al. 2011). Progesterone levels decrease significantly (<1–2 ng/ml) 24 h before parturition (Concannon et al. 1978; Chakraborty 1987; Hoffmann et al. 1994; England and Verstegen 1996; Veronesi et al. 2002). ...
Article
The evaluation of progesterone (P4) concentration is a valuable tool in assessing physiological reproductive events and reproductive disorders in bitches. A reliable and rapid (preferable, point of care) determination of P4 is advisable in most cases. Aims of this study were to evaluate a fluorescence enzyme immunoassay (FEIA) for canine serum P4 concentration by (i) the agreement with liquid chromatography-tandem mass spectrometry (LC/MS/MS), (ii) the association with vaginal cytology and (iii) the accuracy in the prediction of the parturition date calculated from the estimated day of ovulation. Serum samples were collected from client-owned bitches presented between 2011 and 2014 for the evaluation of their oestrous cycle, pregnancy or reproductive disorders. The agreement between FEIA and LC/MS/MS, evaluated on 19 samples, was statistically significant (R(2) = 95.7%, p < 0.001), although FEIA showed significantly higher values than LC/MS/MS (p < 0.05). In the different phases of oestrous cycle, as determined by vaginal cytology, P4 concentrations (by FEIA) were statistically different (p < 0.05): anoestrus (n = 7) 0.38 ± 0.14 ng/ml, proestrus (n = 14) 1.04 ± 0.67 ng/ml and oestrus (n = 72) 6.8 ± 7.26 ng/ml. Mean pregnancy length from the estimated day of ovulation was 62.9 ± 1.8 days. In 13 of 22 (59.1%), 19 of 22 (86.3%) and 21 of 22 (95.5%) bitches pregnancy lasted 63 ± 1, 63 ± 2 and 63 ± 3 days, respectively. Three pregnancies were outside the 61-65 days range (60, 60 and 67 days). In conclusion, the FEIA method employed can be considered reliable and, in association with vaginal cytology, effective in evaluating the canine oestrous cycle.
... For example medium sized, broadly and compactly built breeds might weigh the same as large, slim breeds. Previous studies on larger dog breeds report a mean litter size of 6.9 [18] and 7.6 [4], which is similar to the results found for the large and giant dog breed groups. Unfortunately, the database contained no information about the body weight of the individual bitch. ...
Article
Despite the long history of purebred dogs and the large number of existing breeds, few studies of canine litter size based upon a large number of breeds exist. Previous studies are either old or include only one or a few selected breeds. The aim of this large-scale retrospective study was to estimate the mean litter size in a large population of purebred dogs and to describe some factors that might influence the litter size. A total of 10,810 litters of 224 breeds registered in the Norwegian Kennel Club from 2006 to 2007 were included in the study. The overall mean litter size at birth was 5.4 (± 0.025). A generalized linear mixed model with a random intercept for breed revealed that the litter size was significantly influenced by the size of the breed, the method of mating and the age of the bitch. A significant interaction between breed size and age was detected, in that the expected number of puppies born decreased more for older bitches of large breeds. Mean litter size increased with breed size, from 3.5 (± 0.04) puppies in miniature breeds to 7.1 (± 0.13) puppies in giant breeds. No effect on litter size was found for the season of birth or the parity of the bitch. The large number of breeds and the detail of the registered information on the litters in this study are unique. In conclusion, the size of the breed, the age of the bitch and the method of mating were found to influence litter size in purebred dogs when controlling for breed, with the size of the breed as the strongest determinant.
... When a distinction is made between altricial and precocial mammals, the scaling relationships of precocial and altricial mammals become distinct, but retain similar scaling exponents [48,50] (Fig. 2). Additionally, offspring in altricial mammals are typically born in litters; increased litter sizes have been shown to reduce gestation lengths in cats [52] and dogs [53]. Similarly, multiple births in humans show reduced gestation lengths, with 50% of twin and 90% of triplets pregnancies born preterm [54]. ...
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Human preterm birth (PTB), a multifactorial syndrome affecting offspring born before 37 completed weeks of gestation, is the leading cause of newborn death worldwide. Remarkably, the degree to which early parturition contributes to mortality in other placental mammals remains unclear. To gain insights on whether PTB is a human-specific syndrome, we examined within- and between-species variation in gestation length across placental mammals and the impact of early parturition on offspring fitness. Within species, gestation length is normally distributed, and all species appear to occasionally give birth before the "optimal" time. Furthermore, human gestation length, like that of many mammalian species, scales proportionally to body mass, suggesting that this trait, like many others, is constrained by body size. Premature humans suffer from numerous cognitive impairments, but little is known of cognitive impairments in other placental mammals. Human gestation differs in the timing of the "brain growth spurt", where unlike many mammals, including closely related primates, the trajectory of human brain growth directly overlaps with the parturition time window. Thus, although all mammals experience early parturition, the fitness costs imposed by the cognitive impairments may be unique to our species. Describing PTB broadly in mammals opens avenues for comparative studies on the physiological and genetic regulators of birth timing as well as the development of new mammalian models of the disease. © The Author(s) 2015. Published by Oxford University Press on behalf of the Foundation for Evolution, Medicine, and Public Health.
... Deze grote variatie in drachtduur heeft verschillende redenen. De lange overleving van hondensperma in de vrouwelijke geslachtstractus, het vrijkomen van onrijpe eicellen bij ovulatie, de langdurige maturatieperiode van de eicellen, de lange overleving van mature eicellen en het feit dat vaak meerdere dekkingen tijdens dezelfde oestrus plaatsvinden (Eilts et al., 2005;Luvoni en Beccaglia, 2006). Hierdoor kan er een grote variatie zijn tussen de dekdatum en de eigenlijke bevruchtingsdatum. ...
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Vaginale cytologie bij de teef is gemakkelijk uit te voeren in de praktijk, de staalname is vrij eenvoudig en het is een relatief goedkope techniek met vele toepassingsmogelijkheden. Doordat de resultaten bovendien snel beschikbaar zijn, kan het praktijkdierenartsen helpen bij het beoordelen en het opvolgen van het cyclusstadium van een teef. Vaginale cytologie kan ook voor andere doeleinden gebruikt worden, zoals het voorspellen van het exacte partustijdstip, het bevestigen van een (ongewenste) dekking en het vaststellen van vaginitis, verlengde loopsheid, ovarieel restsyndroom, problemen post partum of vaginale neoplasie. Het optimale moment van dekking of inseminatie kan niet met vaginale cytologie bepaald worden en dient te worden uitgevoerd door middel van vaginoscopie en/of progesteronbepaling.
... This parameter changes according to the breed and litter size: the duration of pregnancy is 0.25 days longer for each puppy less than the average for the breed [9]. Also, litters of four or fewer tend to have longer gestation duration [16]. ...
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The Dogo Argentino (DA) is the first and only breed from Argentina recognized worldwide. Although its morphologic features have been well established, its normal reproductive parameters are not clearly known. The aim of this study was to determine the main DA bitch reproductive parameters. One hundred and forty-nine surveys were obtained from breeders from Córdoba province, Argentina: one for each intact DA bitch from 1 to 14 years old. The DA bitch reached puberty at an average of 8.93 months. The mean duration of vulval bleeding found in this study was 11.11 days. The clinical signs characteristic for proestrous-estrous were vulval edema (89.93%), bleeding during the time of mating (32.21%), holding the tail to the side (95.30%), and docility during mating (85.91%). DA bitches had a whelping rate of 84%. Out of 299 pregnancies, 89.30% exhibited a normal parturition, 6.69% presented dystocia, 2.68% needed Cesarean section, and 1.34% aborted. In conclusion, the reproductive parameters of the DA bitch are similar to those identified for other large breeds. DA often showed a prolonged vulval bleeding longer than proestrus. Its high whelping rate, its low incidence of dystocia, and its good maternal ability define the DA as a good reproductive breed with normal reproductive functions.
... Door de grote variatie in de schijnbare draagtijd is het moeilijk om de exacte partusdatum van de hond te voorspellen. Deze variatie heeft verschillende redenen: de lange overleving van hondensperma in de genitaaltractus van de teef, de uitgestelde eicelmaturatie, de lange overleving van mature eicellen, het variabele interval tussen het begin van de oestrus en de ovulatie, meerdere dekkingen tijdens dezelfde oestrus, de worpgrootte , het ras en de pariteit van de teef (Doak et al., 1967; Okkens et al., 1993; Naaktgeboren, 1995; Concannon, 2000; Okkens et al., 2001; Eilts et al., 2005; Luvoni en Beccaglia, 2006). Er zijn verschillende technieken beschreven om de partusdatum bij de hond te voorspellen, zoals de berekening vanaf het dektijdstip, het moment van de ovulatie , het tijdstip van de LH-piek of de progesteronstijging , radiografisch onderzoek van de foeti, de temperatuursdaling vlak vóór de partus en echografisch onderzoek. ...
... days (n=29) while in multiparous it was 59.90±0.5 days (n=60). No significant difference was observed in gestational length in relation to parity (Table 1), which was correlated with the findings of Okkens et al. (1993) and Eilts et al. (2005) who found no influence of parity on gestational length. In recent study Mir et al. (2011) found no influence of parity on gestational length in nulliparous (63.1 ± 2.2 days) and multiparous (63.3 ± 2 days) bitches. ...
... La gestación en la perra tiene un tiempo variable de 57 a 72 días después de la monta, 65 días desde la subida inicial de progesterona o pico de LH, 63 días a partir de la ovulación o 57 días desde el inicio del diestro (Galina y Valencia, 2009 ). La duración de la gestación se prolonga en camadas de 4 o menos crías (Eilts et al., 2005; Groppetti et al., 2015). La distocia ocurre cuando el parto no sucede en la forma y tiempo normal, necesitando asistencia veterinaria. ...
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El presente estudio tuvo por objetivo la determinación de la medición ecográfica cuantitativa del diámetro biparietal de fetos a término en perras. Se trabajó con 181 informes ecográficos de varias razas de perras en gestación cuyos fetos tenían menos de 210 latidos por minuto, y que fueron examinados en el consultorio de ecografía de la Clínica de Animales Menores de la Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Perú, entre los años 2000-2014.
... Comparison of preovulatory P 4 rise among Golden retrievers, German shepherd dogs, and Labrador retrievers revealed that German shepherd dogs were 3 times more likely, and Golden retrievers 4 times more likely, to have a Clinical Theriogenology • Volume 12 Number 4 • December 2020 longer duration of pregnancy compared to Labrador retrievers. 15 This study also compared duration of pregnancy as determined by cytologic diestrus in hounds to that of Labrador retrievers, and reported that hounds were 8 times more likely to have a longer pregnancy. In another study, duration of pregnancy, defined as the period from mating to parturition, was determined in 113 dogs of 6 breeds (31 Dobermans, 31 Labrador retrievers, 14 German shepherd dogs, 13 Bernese mountain dogs,12 golden retrievers, and 12 West Highland white terriers). ...
Article
Duration of pregnancy was evaluated in 17 Cavalier King Charles spaniel bitches, based on timing of LH surge (progesterone concentrations between 2.0 and 3.0 ng/ml, with continued rise in subsequent 48 hours) and compared to 17 bitches of other breeds. Duration of pregnancy was shorter (p < 0.05) in Cavalier King Charles spaniel bitches compared to others (mean ± SD, 62.8 ± 2.0 days [range; 60 - 66 days] versus 64.5 ± 1.4 days [range; 62 - 68 days]). This observation has clinical implications for pregnancy management of this breed, including recommendations for scheduling a timed caesarean section and approaches to managing late-term complications.
... Owners usually present their bitches for pregnancy diagnosis around 23-25 days corresponding to 40-38 days before parturition; our data confirms ICC as the most reliable parameter in estimating parturition date in this interval of pregnancy in GSD bitches. Pregnancy may be slightly prolonged with 1-3 fetuses (Eilts et al., 2005;Mir et al., 2011). We only saw 2 pregnancies with ≤3 puppies. ...
... days (n=29) while in multiparous it was 59.90±0.5 days (n=60). No significant difference was observed in gestational length in relation to parity (Table 1), which was correlated with the findings of Okkens et al. (1993) and Eilts et al. (2005) who found no influence of parity on gestational length. In recent study Mir et al. (2011) found no influence of parity on gestational length in nulliparous (63.1 ± 2.2 days) and multiparous (63.3 ± 2 days) bitches. ...
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A large variation in the gestation length can be expected when the gestation is calculated from the day of mating to birth. The present study was designed to assess the influence of different factors like litter size, breed, parity and age on gestation length in bitches. A total of 89 small sized bitches of different breeds having different age, parity and body weight, were selected for the study. The mean age, body weight and parity of the animals included in the present study were 3.00 ± 0.15 years (1 to 8 years), 9.9 ± 0.25 Kg (6 to 15kg) and 1.14 ± 0.10 (0-4 th parity) respectively. The mean gestation lengths observed in different small sized breeds were 60.68 ± 0.55, 59.82 ± 0.54, 60.78 ± 1.74, 58.83 ± 1.35 and 58.17 ± 0.74 in the Pug, Beagle, Dachshund, French Bulldog and the Spitz, respectively. The mean litter size in the study was 4.34 ± 0.13 with a range of 2-8. The mean gestational length in animals having ≤ 3 litter size was 60.83 ± 0.64 days and 59.90 ± 0.43 days in animals having >3 litter size. Age limit of the animals ranged from 1 to 8 years with a mean of 3 ± 0.15 years. The mean gestation length in bitches aged ≤3 years was 60.21 ± 0.23 days (n=63) and this was 60.15 ± 0.3 (n=26) days in bitches in the >3 years group. Mean gestational length observed in nulliparous bitches was 60.86 ± 0.4 days (n=29), while in multiparous bitches it was 59.90 ± 0.5 days (n=60). From the present investigation it could be concluded that no significant difference exists in gestational length between different breeds, litter size, age group and parity.
... days (n=29) while in multiparous it was 59.90±0.5 days (n=60). No significant difference was observed in gestational length in relation to parity (Table 1), which was correlated with the findings of Okkens et al. (1993) and Eilts et al. (2005) who found no influence of parity on gestational length. In recent study Mir et al. (2011) found no influence of parity on gestational length in nulliparous (63.1 ± 2.2 days) and multiparous (63.3 ± 2 days) bitches. ...
Article
Full-text available
A large variation in the gestation length can be expected when the gestation is calculated from the day of mating to birth. The present study was designed to assess the influence of different factors like litter size, breed, parity and age on gestation length in bitches. A total of 89 small sized bitches of different breeds having different age, parity and body weight, were selected for the study. The mean age, body weight and parity of the animals included in the present study were 3.00 ± 0.15 years (1 to 8 years), 9.9 ± 0.25 Kg (6 to 15kg) and 1.14 ± 0.10 (0-4th parity) respectively. The mean gestation lengths observed in different small sized breeds were 60.68 ± 0.55, 59.82 ± 0.54, 60.78 ± 1.74, 58.83 ± 1.35 and 58.17 ± 0.74 in the Pug, Beagle, Dachshund, French Bulldog and the Spitz, respectively. The mean litter size in the study was 4.34 ± 0.13 with a range of 2-8. The mean gestational length in animals having ≤ 3 litter size was 60.83 ± 0.64 days and 59.90 ± 0.43 days in animals having >3 litter size. Age limit of the animals ranged from 1 to 8 years with a mean of 3 ± 0.15 years. The mean gestation length in bitches aged ≤3 years was 60.21 ± 0.23 days (n=63) and this was 60.15 ± 0.3 (n=26) days in bitches in the >3 years group. Mean gestational length observed in nulliparous bitches was 60.86 ± 0.4 days (n=29), while in multiparous bitches it was 59.90 ± 0.5 days (n=60). From the present investigation it could be concluded that no significant difference exists in gestational length between different breeds, litter size, age group and parity
... In the present study, larger litter size was associated with a shorter gestation length, and small litter size was associated with longer gestation (P < 0.05) ( Table 2). A negative correlation between litter size and pregnancy duration was also found in previous studies (Eilts et al. 2005;Gavrilovic et al. 2008). Recently, Polat et al. (2015) reported that each additional puppy was associated with a 0.24day decrease in pregnancy duration. ...
Article
The Kunming dog is the first and only working dog breed from China to be recognized worldwide. As a domestic working dog, its excellent working performance has been well established; however, its normal reproductive parameters are not well understood. Therefore, this study was conducted to document the main reproductive parameters of this purebred working dog in field breeding conditions. Data on 1004 heats (753 with mating) from 203 bitches between 2008 to 2014, were collected and analyzed. The pregnancy rate and whelping rate was 79.42% and 75.30%, respectively. Finally, for 567 litters (4298 puppies), the mean litter size was 7.19 ± 0.12 puppies (range 1–15). The mean gestation period and birth weight were approximately 61.64 ± 0.10 days and 407.25 ± 1.21 g. The mean sex ratio was 1.03 males to 1.00 female. Estrus occurred throughout the year with no significant differences between seasons and months (P > 0.05), which confirms that Kunming dogs are non-seasonal breeders; births occurred in every month of the year. Pregnant bitches exhibited significantly longer inter-estrus intervals than non-pregnant bitches (220.85 ± 2.05 vs. 180.19 ± 2.94 days, P < 0.05). Bitch parity influenced litter size, and the gestation length and birth weight of the puppies were negatively affected by litter size. This study helps elucidate the reproductive potential of this breed and provides reference values for reproductive performance in the Kunming dog.
... In these cases we used the sample size (n) and the SE to calculate the SD [ √ n*SE]. To compare the different species, we calculated the coef- Akkayan and Ada (1975), Brakel et al. (1952), Burris and Blunn (1952), DeFries et al. (1959), Dessouky and Rakha (1961), Fitch et al. (1924), Knott (1932), Piedrafita et al. (2000), Rendel (1959), Sabatini (1908), Stallcup et al. (1956), Tessier (1817), Ward and Castle (1947) Dog Chakraborty (1987), Concannon et al. (1983), Eilts et al. (2005), Krzyzanowski et al. (1975), Kutzler et al. (2003), Okkens et al. (1993), Shimatsu et al. (2007), Tsutsui et al. (2006) Goat Amoah et al. (1996), Asdell (1929), Greyling (2000), Mellado et al. (2000), Talukder (1817), Thompson et al. (1995), West (1996), Zarkawi (1997) ficient of variance [(SD*100)/Mean], which is an informative value independent of the differences in average gestation length. We evaluated differences in gestation length among species using a non-parametric Kruskal-Wallis test followed by a Tukey post-hoc test. ...
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The variability of life history traits is affected by domestication. As gestation length is an important life history trait for production management, its variability is hypothesized to be lower in highly controlled production animals. Furthermore, some authors claim that horses have a particularly variable gestation length compared to other domesticated mammalian species. To test this, we compared 192 gestation lengths from the literature for eight different mammalian species. In this sample, gestation length does not contain a phylogenetic signal. Instead, production animals display lower variation than non-production animals. Horses fall well within the range of variation of gestation length in other domesticated companion animals.
... This hypothesis was not confirmed by the results in this study: in bitches with a body weight of less than 10 kg (n = 24), gestation lasted 62.3 ± 1.2 days, while in bitches weighing 10 to 25 kg (n = 40), 25 to 40 kg (n = 26) or more than 40 kg (n = 8), gestation duration was 63.1 ± 1.3, 63.1 ± 1.6 and 63.0 ± 1.5 days, respectively. As in previously published work, age had no effect on the duration of gestation [47]. ...
Article
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Pregnancy and lactation are amongst the most challenging times of a bitch’s life. Most studies focusing on the endocrinological aspect of pregnancy consider only a small number of animals. The aim of this study was to evaluate progesterone (P4) concentrations in a large number of bitches during early, mid and late pregnancy. In total, 126 bitches of various breeds were recruited following a thorough clinical and gynecological examination during estrus. Blood samples were collected three times (T1–T3) during pregnancy or from non-pregnant dogs in diestrus, and P4 was measured via chemiluminescence. At T1 (11–19 days post-ovulation (dpo)), serum P4 concentrations were 30.23 ± 6.65 ng/mL and 28.45 ± 6.26 ng/mL, at T2 (23–32 dpo) they were 22.73 ± 6.27 ng/mL and 22.59 ± 5.77 ng/mL and at T3 (52–60 dpo) they were 6.68 ± 2.18 ng/mL and 3.17 ± 2.26 ng/mL, in pregnant (n = 98) and non-pregnant (n = 23) dogs respectively. The P4 concentrations differed significantly between pregnant and non-pregnant animals at the last examination (p ≤ 0.001). In the context of hypoluteoidism, the gathered data yielded interesting results. Overall, 28 out of 98 pregnant bitches showed a greater decline (>15 ng/mL) in P4 concentrations from early to mid-pregnancy, and 56 bitches showed P4 concentrations lower than deemed adequate (>20 ng/mL at T1 and T2, >5 ng/mL at T3) according to existing recommendations. Despite not being supplemented with P4, none of those animals suffered from abortion or preterm delivery. Considering that supplementation of P4 can entail considerable risks for the bitch and the puppies, more research on P4 concentration patterns, diagnosis of hypoluteoidism and treatment indications and options is indicated.
... Similar results were obtained in the present study, although without statistically significant correlations. Similarly, Eilts et al. (2005) found that the litter size was an important factor determining gestation length. They showed that pregnancies with four or fewer pups per litter were significantly longer than pregnancies with five or more pups. ...
Article
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The aim of this study was to determine the basic reproductive parameters, i.e., litter size, gestation length, neonatal mortality rate and the type of delivery in Yorkshire terrier dogs, one of the most popular breeds in Poland. We have verified a hypothesis put forward by breeders that larger females have fewer whelping difficulties and produce larger litters and that pregnancies of females having one or two pups last longer. The focus of investigation was reproductive data from 66 Yorkshire terrier females registered in the Lublin Branch of the Polish Kennel Club, an FCI (Federation Cynologique Internationale) member, which whelped 124 litters comprising in total 508 pups from 37 fathers. The data were collected between August 2009 and December 2014. The significance of differences was verified using Mann-Whitney U and Kruskal-Wallis H-tests. The relationships between the recorded dogs’ reproduction traits were estimated by calculation of Spearman’s correlation coefficients with the use of the statistical programmes Statistica and SPSS 20. The investigations have confirmed the hypothesis concerning the larger litter size produced by larger females and the lower incidence of postpartum dystocia; however, the hypothesis of the impact of body weight on the length of pregnancy was rejected. The differences between the body weights of stud females and males reached 125%. The Yorkshire terrier appears to be a good reproductive breed with normal reproductive functions and good reproductive parameters.
... Bitches had a mean ± SD body weight 32 ± 2.5 kg with an average age of 49.52 months ± 22.50 with a minimum of 20 and a maximum of 110 months. We considered day of conception to be 62-64 d before the day of parturition according to the determination of the ovulation peak and to the gestation length reported for large-sized bitches (Eilts et al. 2005). Ovulation was determined by measurements of progesterone concentration in blood (ovulation peak concentration: 5-8 ng/ ml), determined by MINI VIDAS® (Biomerieux, France), a compact automated immunoassay system based on the Enzyme-Linked Fluorescent Assay (ELFA) principles. ...
Article
The effect of seasonal variation and lunar cycles on reproductive parameters in dogs is unknown. Lunar cycles have important effects on several biological events. Controversy exists about the influence of lunar cycles on offspring sex ratio. This study examined the sex offspring distribution of 973 puppies (48% females and 52% males) from 150 bitches in Italy between 2015 and 2020. A two-way ANOVA followed by post-hoc t-test (Bonferroni correction) was used to analyze the influence of season and lunar phase on offspring sex ratio at conception. Sex offspring distribution was not affected by season, whereas lunar phase had a significant effect (p< .05). During the new moon, the proportion of male puppies born was significantly lower than during the full moon phase (p < .05). We conclude that season had no effect on sex offspring distribution. The new moon phase at conception appeared to be related to a lower male sex ratio at birth. Further studies assessing additional factors will help provide a better understanding of the lunar cycle differences observed in the sex ratio distribution of dogs.
... Phenotypic reproductive trait data for litter size (number of pups), cesarean rate, stillbirth rate and gestation length across 128 breeds were collected from a variety of breeder's handbook and primary journal articles [31,[37][38][39][40][41][42][43][44][45][46][47] (see also Supplementary File S1). We also included body mass as a control trait. ...
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Background and objectives: The diversity of eutherian reproductive strategies has led to variation in many traits, such as number of offspring, age of reproductive maturity and gestation length. While reproductive trait variation has been extensively investigated and is well established in mammals, the genetic loci contributing to this variation remain largely unknown. The domestic dog, Canis lupus familiaris is a powerful model for studies of the genetics of inherited disease due to its unique history of domestication. To gain insight into the genetic basis of reproductive traits across domestic dog breeds, we collected phenotypic data for four traits, cesarean section rate, litter size, stillbirth rate and gestation length, from primary literature and breeders' handbooks. Methodology: By matching our phenotypic data to genomic data from the Cornell Veterinary Biobank, we performed genome-wide association analyses for these four reproductive traits, using body mass and kinship among breeds as covariates. Results: We identified 12 genome-wide significant associations between these traits and genetic loci, including variants near CACNA2D3 with gestation length, MSRB3 and MSANTD1 with litter size, SMOC2 with cesarean section rate and UFM1 with stillbirth rate. A few of these loci, such as CACNA2D3 and MSRB3, have been previously implicated in human reproductive pathologies, whereas others have been associated with domestication-related traits, including brachycephaly (SMOC2) and coat curl (KRT71). Conclusions and implications: We hypothesize that the artificial selection that gave rise to dog breeds also influenced the observed variation in their reproductive traits. Overall, our work establishes the domestic dog as a system for studying the genetics of reproductive biology and disease. Lay summary: The genetic contributors to variation in mammalian reproductive traits remain largely unknown. We took advantage of the domestic dog, a powerful model system, to test for associations between genome-wide variants and four reproductive traits (cesarean section rate, litter size, stillbirth rate and gestation length) that vary extensively across breeds. We identified associations at a dozen loci, including ones previously associated with domestication-related traits, suggesting that selection on dog breeds also influenced their reproductive traits.
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Precise prediction of the date of onset of parturition in the bitch is clinically important. The study compared the precision with which four peri-oestrous predictors predict the date of onset of parturition. The predictors evaluated in 24 bitches were: the date of the first or only day of the LH surge, the date on which the concentration of progesterone in the blood plasma first exceeded 6 nmol/L, the date on which the concentration of progesterone in the blood plasma first exceeded 16 nmol/L and the date of onset of cytological dioestrus. Among the 24 bitches, the date of onset of cytological dioestrus predicted the date of onset of parturition with greater precision than the other three predictors. Following the evaluation of another 218 intervals between the onset of cytological dioestrus and the date of onset of parturition, it was shown that the onset of cytological dioestrus predicted the date of onset parturition with a precision of ±1 d, ± 2 d and ±3 d in 88%, 99% and 100% of the 242 pregnancies. This study concludes that the first day of cytological dioestrus is a useful predictor of the date of onset of parturition.
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Uterine inertia is a common cause of dystocia in the bitch and is designated as primary (i.e., uterine contractions fail to ever be initiated) or secondary (i.e., uterine contractions cease after a period of time but before labor is completed). The etiology of primary uterine inertia is not well understood. The accurate diagnosis of primary uterine inertia requires the use of tocodynamometry (uterine monitoring). Primary uterine inertia has been postulated to result from a failure of luteolysis resulting in persistently elevated progesterone concentrations. In this study, primary uterine inertia was diagnosed in a series of four bitches in which luteolysis was documented suggesting some other etiopathogenesis for primary uterine inertia.
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It has been suggested that co-transferring parthenogenetic embryos could improve the pregnancy success rate with cloned embryos in mammals. As an alternative to co-transferring parthenotes, in dogs we employed recipient females that possessed in vivo-fertilised embryos as a result of mating to determine whether mated bitches could be suitable recipients for cloned embryos. The effect of using mated recipients on implantation and pregnancy rates of canine somatic cell nuclear transfer embryos was also determined. Cloned embryos were transferred into the oviducts of naturally synchronous females that had mated with male dogs before ovulation. The pregnancy rate appeared to be similar between mated recipients (50%) and non-mated recipients (28.57%; P>0.05). However, the delivery rate of cloned pups was significantly higher in mated recipients than non-mated recipients (10.53 vs 2.38%; P<0.05). A decrease in progesterone levels in the mated recipients before the due date induced natural delivery. However, cloned pups in non-mated recipients were delivered by Caesarean section because the fall in progesterone concentration in these females did not occur until the due date. The present study demonstrated for the first time that mated female dogs can be used as recipients for cloned embryos.
Article
The aim of this study was to investigate gestation duration and the physiologic characteristics of pregnant dogs bearing cloned fetuses, especially in the prepartum period. A retrospective study was performed to compare gestation duration in females pregnant with cloned (somatic cell nuclear transfer) fetuses (cloned group) with those bearing noncloned fetuses (control group), and effects of litter size, birth weight, and breed of somatic cell donors on gestation duration in the cloned group were evaluated. Clinical delivery onset signs associated with serum progesterone concentration and rectal temperature were also compared in both groups. The gestation duration calculated from day of ovulation was significantly longer in the cloned (62.8 ± 0.3 days) versus the control group (60.9 ± 0.5 days; P < 0.001). There was a negative correlation between litter size and gestation duration including both groups (r = -0.59; P < 0.01), but there were no differences between birth weights or breed of cell donors and gestation duration in the cloned group. Even though the basal rectal temperature in the prepartum period was not different between control and cloned groups (36.9 ± 0.1 °C and 37.2 ± 0.1 °C, respectively), serum progesterone concentration on delivery day was significantly higher in the cloned group (2.2 ± 0.4 ng/ml) compared with the control group (0.5 ± 0.1 ng/ml; P < 0.05). The longer gestation duration of pregnant dogs bearing cloned fetuses might be because of the smaller litter size in this group. Also, the weaker drop in serum progesterone levels in the prepartum period in cloned dog pregnancies indicates that the parturition signaling process might be altered resulting in longer gestation periods.
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Wczesne rozpoznanie ci¹¿y jest niezwykle istotnym i po¿¹danym elementem planowanego rozrodu uwszystkich gatunków zwierz¹t. W przypadku zwie-rz¹t gospodarskich ma to znaczenie ze wzglêdu na pro-ces produkcyjny, jak równie¿ ze wzglêdu na koszty wynikaj¹ce z przed³u¿aj¹cego siê okresu miêdzyci¹-¿owego. U suk, które s¹ samicami sezonowo mono-estralnymi, ci¹¿a lub jej brak nie wp³ywa na okres wy-st¹pienia kolejnego cyklu (10). Niemniej równie¿ u tego gatunku zwierz¹t informacja o tym, czy suka jest ciê¿arna, czy te¿ nie, mo¿e mieae istotne znaczenie dla hodowcy. Wiedza na temat obecnoœci ci¹¿y lub jej braku jest niezbêdna do prawid³owej opieki nad suk¹ w okresie metoestrus (21). Zwi¹zane jest to, miêdzy innymi, z ró¿nymi potrzebami ¿ywieniowymi (17). Obecnoœae ci¹¿y mo¿e równie¿ wp³ywaae na sposób u¿ytkowania suki w przypadku psów pracuj¹cych, a ponadto wyklucza lub ogranicza mo¿liwoœae stoso-wania okreœlonych leków (np. glikokortykosterydy) oraz mo¿e mieae równie¿ wp³yw na program szczepie-nia i odrobaczania samicy. Kolejnym, niezwykle istotnym elementem zwi¹za-nym z rozpoznawaniem ci¹¿y u suk jest diagnostyka ci¹¿y u samic pokrytych przypadkowo lub jedynie podejrzewanych o to, ¿e takie zdarzenie mog³o mieae miejsce. W tym przypadku istotne wydaje siê jak naj-szybsze postawienie diagnozy, tak aby mieae czas na podjêcie odpowiednich kroków w celu bezpiecznego dla suki usuniêcia k³opotliwej ci¹¿y (14, 21). Ci¹¿a u samic z gatunku Canis familiaris trwa œred-nio 62-65 dni (57-72 dni) (3, 6, 7, 9, 10, 22, 24, 27). Do zap³odnienie dochodzi w górnej czêœci jajowodu, po czym zarodki w stadium moruli schodz¹ do maci-cy, co ma miejsce ok. 9 dni po owulacji. Do zagnie¿d¿e-nia zarodków dochodzi pomiêdzy 17. a 21. dniem od owulacji (6, 13). Przed tym okresem p³ywaj¹ one swo-bodnie, przemieszczaj¹c siê w obrêbie obu rogów macicy (13, 24). Rutynowo pierwsze badanie w kierunku ci¹¿y prze-prowadza siê ok. 28.-30. dnia ci¹¿y (15, 25, 26). Wba-daniu klinicznym, podczas omacywania wyczuwalne powinny byae wtedy ampu³owato rozszerzone rogi macicy. Miêdzy 30.-35. dniem ampu³y te zbli¿aj¹ siê do siebie, powoduj¹c zmianê kszta³tu macicy na ruro-waty. Badanie palpacyjne w tym okresie niesie ze sob¹ niebezpieczeñstwo pomylenia ci¹¿y z ropomaciczem i z tego wzglêdu w tym czasie nie jest zalecane (1, 13). U suk nie stwierdzono produkcji specyficznej go-nadotropiny ci¹¿owej, takiej, jak hCG u kobiet lub eCG u klaczy. Ze wzglêdu na podobny profil hormonalny, niemo¿liwe jest równie¿ wykorzystanie pomiaru pro-Porównanie skutecznoœci wybranych metod wczesnego rozpoznawania ci¹¿y u suk
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Bu çalışma, 2016-2017 yılları arasında Iğdır ili Çalpala Köyü’ndeki yonca tarlalarında önemli derecede ekonomik zarara yol açan yonca hortumlu böceği (Hypera postica (Gyllenhal, 1813) (Coleoptera: Curculionidae))'nın erginlerine karşı, Satureja hortensis L., S. montana L., S. spicigera L. ve S. thymbra L. (Lamiaceae) bitkilerinden elde edilen uçucu yağların insektisidal etkilerini belirlemek amacıyla laboratuvar şartlarında (25±1 °C, %60±5 orantılı nem ve 14:10 aydınlık:karanlık) yürütülmüştür. Bu uçucu yağların toksisitelerini test etmek için her bir petriye (9 × 1,5 cm) 15’er adet ergin birey konulmuş ve üzerlerine her bir dozda (5, 10 ve 20 μL/petri) uçucu yağlar püskürtülmüştür. Daha sonra, her petri kabına erginlerin beslenmesi için yeterli miktarda taze yonca (Medicago sativa L.) yaprağı ilave edilmiştir. Petrilerin kapağı kapatılarak etrafı parafilm ile sarılmıştır. Kontrol olarak steril su+etanol ve pozitif kontrol olarak ise ticari insektisit olan Malathion kullanılmıştır. Tüm testler 3’er kez tekrarlanmıştır. Uygulamanın 24, 48, 72 ve 96 saatler sonrasında ergin ölümleri kaydedilmiştir. Ölüm oranları %4.44 ile 100 arasında farklı oranlarda saptanmıştır. En yüksek ölüm oranları (%48.8’den %100’e kadar) S. hortensis’in uçucu yağının 20 μL/petri dozunda, en düşük ölüm oranları ise (%4.44’den %62.20’e kadar) S. spicera’nın 5 μL/petri dozunda tespit edilmiştir. Bu sonuçlara göre, S. hortensis ve S. thymbra uçucu yağlarının H. postica’nın erginlerine karşı daha etkili oldukları, S. montana ve S. spicigera’nın uçucu yağlarının ise daha düşük etki gösterdiği belirlenmiştir. Test edilen uçucu yağların, yonca hortumlu böceği erginleri üzerinde insektisidal etkiye sahip oldukları ve bu zararlının mücadelesinde kullanılabilecekleri tespit edilmiştir.
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The objective of this study was to identify and quantify factors presenting simultaneous moderate or strong influence on gestation length and perinatal mortality (until 4 days postpartum) in Holstein-Frisian dams. The overall gestation length least square mean was 278.2 ± 0.2 days (n = 962). According to the multivariate model (p < 0.001), a shorter gestation length was observed in Holstein-Friesian (–2.0 days) and Red Holstein-Friesian (–3.9 days) breed sires whereas Brown Swiss (2.0 days) and Aberdeen-Angus (2.3 days) breed sires showed a longer gestation length. Primiparous cows and twin pregnancies, as well calving in June and July, shortened gestation length in –1.4, –4.0, –1.9 and –1.8 days, respectively. The perinatal mortality incidence was 7.4% (n = 72) and was more likely to occur in twin pregnancies (p < 0.01) than in pregnancies carrying female (odds ratio = 8.1) or male (odds ratio = 7.9) singletons, as well in primiparous (odds ratio = 2.6) than multiparous dams (p < 0.05). In conclusion, parity and twinning were the major factors which influenced simultaneously gestation length of dams and perinatal mortality incidence. Nevertheless, all studied factors had a significant impact on gestation length and should be considered for reproductive management programs of dairy herds.
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The aim of this study was to evaluate the suitability of three different formulas to predict the parturition date in German Shepherds, using the ultrasonographic fetometry method involving inner chorionic cavity diameter (ICC) and biparietal diameter (BP) measurements in the same population of a single breed. Overall, 53 ICC and 42 BP measurements were taken on 34 bitches. The measured values were substituted into breed-specific formulas for the German Shepherd as well as non-specific formulas for medium-sized bitches. Comparisons of clinical accuracy and statistical analyses of regression lines were performed to test the compatibility of the formulas used. We confirmed the similarity of our clinical results to outcomes obtained using the one breed–specific (Groppetti et al. 2015) and non–specific fetometry models (Luvoni and Grioni 2000), whereas another breed–specific formula (Milani et al. 2013) showed rather low accuracy. Comparing the clinical accuracy of the three formulas, the authors demonstrated that the Luvoni and Grioni (2000) formula for ICC dedicated to medium-sized dogs can also be effectively used in the German Shepherd, even with better results than breed-specific formulas by Groppetti et al. (2015). By contrast, the evaluation of BP formulas proves the successful usage of the Groppetti et al. (2015) formula to determine the date of birth by measuring scull bone structures (p < 0.05). The statistical analysis of regression lines were in agreement with the clinical results and confirmed the higher predictability of Groppetti et al. (2015) and Luvoni and Grioni (2000) formulas, than those of Milani et al. (2013).
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Contents The aim of this study was to derive the growth curves of the inner chorionic cavity and the biparietal distance in miniature dog breeds by ultrasonographic fetometry and present new specific formulas for prediction of parturition date. In this study, foetal biometry parameters were obtained using serial ultrasonographic examinations in 24 pregnant bitches of six different miniature breeds (≤5 kg). The mating time was unknown. Overall, 25 inner chorionic cavity diameter (ICC) and 22 biparietal diameter (BP) measurements were taken. The relationship between ICC or BP growth and days to parturition was analysed by linear regression. The results showed a significant relationship between days before delivery and ICC or BP. The equations derived from the growth curves can be used in practical prediction of parturition date in miniature dog breeds.
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The aim of this study was to evaluate the suitability of the ultrasonographic fetometry involving inner chorionic cavity diameter (ICC) and biparietal diameter (BP) measurements for predicting the parturition date in two dog breeds: the Yorkshire Terrier and Golden Retriever. Additionally, the authors studied whether developing specific mathematical formulas for predicting parturition dates in the breeds was justified. In the group of Yorkshire Terrier bitches, 12 ICC measurements and 14 BP measurements were taken. In the Golden Retrievers the ICC was measured 8 times and BP - 10 times. The obtained values were substituted into Luvoni-Grioni formulas, taking into account the body mass before pregnancy. Due to the lack of earlier studies on dogs with a body mass over 25 kg, the parturition date for the Golden Retrievers was calculated using formulas for medium-sized dogs (body mass 10-25 kg). In the case of the Yorkshire Terriers, formulas for dogs smaller than 10 kg were used. The method proved to be highly useful in predicting the accuracy of the parturition date in both breeds. Prediction accuracy in the Golden Retrievers reached 80% to 100%, depending on the type of measurement used, and precision levels. In the Yorkshire Terriers, the accuracy reached 57%-93%. Comparing the effectiveness of the parturition date prediction in the two breeds, no statistically significant differences were found. Regression lines based on the authors' own fetometric measurements were highly convergent with the lines defined by the Luvoni-Grioni formulas. The only statistically significant difference was found in BP measurements in the Golden Retrievers; this suggests that the commonly used Luvoni-Grioni formula should be modified when applied to large dog breeds.
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Aims: The suitability of using indirect diagnostic procedures (vaginoscopy, vaginal cytology, progesterone analysis) for determination of ovulation in order to predictthe day of parturition and the factors that influence the gestation length were examined. Materials and methods: In 236 bitches the day of ovulation was characterised by semiquantitative or quantitative measurement of progesterone (5-8 ng/ml). Pregnancy was diagnosed the earliest 24 days after ovulation and the number of fetusses was estimated by ultrasonography. Whelping was predicted to occur 62 to 64 days after ovulation. After parturition the breeders were interviewed for the duration of gestation, the number and the sex ratio of puppies. Results: The average gestation length was 62.3±1.5 days. 66.1% of the bitches whelped 62 to 64days after ovulation. On average 6.8±2.6 puppies were born. The number of puppies was negatively correlated with the duration of gestation (p < 0.01) and positively correlated with the size of the bitch (p < 0.001). Gestation length was also influenced by the breed. The time of mating (before or after ovulation) had no effect on the sex ratio of the offspring. Conclusions: Prediction of the day of parturition in relation to ovulation (62 to 64 days after ovulation) is successful in two thirds of the bitches. The variation of gestation from 59 to 70 days is essentially caused by methodical inaccuracies in determination of the time of ovulation, an individual variability of the progesterone concentration at ovulation and the number of puppies. Clinical relevance: In case of sonographic diagnosis of a normal pregnancy the day of parturition should be predicted and documented in relation to the day of ovulation as determined in the preceding oestrus. By this, disorders in later pregnancy (suspected abortion, premature birth, delayed parturition) can be easily and precisely related to gestation stage, thus facilitating the choice of optimum diagnostic and therapeutic procedures in order to avoid loss of puppies and/or fertility.
Chapter
Veterinarians are commonly presented with bitches or queens for pregnancy diagnosis or assessment of disorders of pregnancy. This chapter describes the technology and methodology currently available to determine gestational age as well as to assess fetal well-being in the bitch and queen. Gestational age is most accurately determined by using either the luteinizing hormone (LH) surge or determination of ovulation date. All estimations and calculations of gestational age and fetal maturation are expressed in days after the LH surge unless otherwise noted. There are a number of methods to estimate gestational age in the bitch and queen including ovulation timing, radiography, and ultrasonography. Ultrasound can be used to monitor organ development, determine fetal viability, and to assess fetal stress, uterine compromise, or placental disease. Fetal stress can be assessed by examining the fetal fluids and fetoplacental units.
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Accurate prediction of delivery date in canine and feline allows a better management of parturition, reducing the loss of neonates. This review evaluates the most common methods adopted to accurately predict the day of delivery: determination of ovulation and hormonal assays, first appearance of embryonic/foetal structures using ultrasound or radiography, echographic measurement of extra-foetal and foetal structures, or evaluation of foetal flux and heart rate. Determination of ovulation and hormonal assays at the time of breeding and close to pregnancy term is widely used to predict parturition in dogs (Concannon et al. American Journal of Veterinary Research 44, 1983, 1819; Hayer et al. Journal of Reproduction and Fertility, Suppl. 47, 1993, 93; Hase et al. Journal of Veterinary Medical Science, 62, 2000, 243; Kutzler et al. Theriogenology, 60, 2003a, 1187). In cats, some studies have been carried out, but no hormonal parameters for accurate prediction of parturition have been described so far (Buff et al. Journal of Reproduction and Fertility, Suppl. 57, 2001, 187; De Haas van Dorsser et al. Biology of Reproduction, 74, 2006, 1090; DiGangi et al. Journal of the American Veterinary Medical Association, 237, 2010, 1267; Dehnhard et al. Theriogenology, 77, 2012, 1088). Many studies suggested that gestational timing can be obtained by observation using ultrasound or radiography of specific structures in relation to the time of appearance during gestation (Concannon and Rendano American Journal of Veterinary Research, 44, 1983, 1506; Rendano et al. Veterinary Radiology, 25, 1984, 132; Shille and Gontarek Journal of the American Veterinary Medical Association, 187, 1985, 1021; Davidson et al. Veterinary Radiology, 27, 1986, 109; England et al. Journal of Small Animal Practice, 31, 1990, 324; Yeager et al. American Journal of Veterinary Research, 53, 1992, 342; Zambelli et al. Theriogenology, 57, 2002a, 1981; Zambelli et al. Journal of Feline Medicine and Surgery, 4, 2002b, 95; Zambelli and Prati 2006; Lopate Theriogenology, 70, 2008, 397; Davidson and Baker Topics in Companion Animal Medicine, 24, 2009, 55). Ultrasonographic measurement of extra-foetal and foetal structures is a common and accurate method for the prediction of parturition day during pregnancy, when specific formulae are used depending on the ultrasonographic parameter, the species and, in canines, the size of the bitch (Shille and Gontarek Journal of the American Veterinary Medical Association, 187, 1985, 1021; England et al. Journal of Small Animal Practice, 31, 1990, 324; Luvoni and Grioni Journal of Small Animal Practice, 41, 2000, 292; Luvoni and Beccaglia Reproduction in Domestic Animals, 41, 2006, 27; Lopate Theriogenology, 70, 2008, 397; Michel et al. Reproduction in Domestic Animals, 46, 2011, 926; Beccaglia and Luvoni Reproduction in Domestic Animals, 47, 194, 2012). Recent studies demonstrated that in dogs, the imminence of parturition could be predicted by evaluating foetal flux and foetal heart rate by ultrasound (Gil et al. Theriogenology, 82, 2014, 933; Giannico et al., Animal Reproduction Science, 154, 2015, 105). For an accurate prediction of parturition date, the combination of different methods is desirable.
Article
The aim of this prospective cohort study was to utilize multivariable statistical methods to identify factors that significantly affected whelping rate, litter size and gestation length in a large population of bitches of many different breeds, presented for routine breeding management. In addition, we aimed to determine the incidence of dystocia and the proportion of bitches undergoing a caesarean section procedure. A total of 1146 individual bitches representing 84 different breeds contributed 1203 inseminations over the 9 year (2007–2015) study period. Bitches were inseminated with either frozen-thawed (n = 645), fresh (n = 543) or chilled (n = 15) semen from 1371 different males. The mean (SD) whelping rate was 74± 4% and the mean litter size was 5.8 ± 3.1 pups per litter for all bitches in the study. The whelping rate was significantly lower in bitches inseminated with frozen-thawed semen compared with bitches inseminated with fresh semen (71% vs 80% respectively; P < 0.001). Semen that was classified as having poor motility (<30% progressive) resulted in a significantly lower whelping rate (37%) than semen classified as good (30–65% progressive; whelping rate = 67%) or excellent (>65% progressive; whelping rate = 79%). There was a linear decline in whelping rate with advancing age. Greyhounds and Labradors demonstrated a significantly higher whelping rate (88% and 94% respectively) compared with all other breeds (71.3%, P < 0.001). Bitches inseminated with frozen-thawed semen had significantly smaller litter sizes than bitches inseminated with fresh semen (5.4 ± 3.1 vs 6.2 ± 3.0 pups per litter respectively; P = 0.02). Smaller breeds had significantly smaller litters (4.4 ± 2.1 pups) than medium (5.2 ± 2.9 pups), large (5.9 ± 2.9 pups) or giant (6.7 ± 3.8 pups) breeds. For each advancing year of age, litter size decreased by 0.13 pups per litter. The mean (SD) gestation length from LH0 was 65 ± 1.9 d. Greyhounds had a significantly longer pregnancy duration (68.0 ± 1.5 d) than other breeds. For each additional year of bitch age, gestation length increased by 0.11 days (P < 0.01), and for each additional pup per litter, gestation length was reduced by 0.08 days (P < 0.05). Of the 890 bitches for which whelping outcomes were recorded; 409 (46%) whelped normally without assistance, 249 (28%) had an elective C-section, 205 (23%) underwent an emergency C-section and 27 (3%) were medically managed or required veterinary assistance for dystocia. Brachycephalic breeds were 11.3 (95CI = 9.3–17.9; P < 0.001) times more likely to have a C-section compared to all other breeds. Bitches with litter sizes of one or two pups had a C-section rate of 83%, whereas bitches with litter sizes of three or more pups had a C-section rate of 43% (P < 0.001). This study provides important clinical information to optimise whelping rates, litter size and the prediction of whelping in certain breeds for clinicians working in canine reproduction.
Article
The aim of this retrospective study was to compare simple linear regression and mixed linear regression on data grouped by breed or maternal weight group. The comparison was done to find the most accurate model for predicting day of parturition in pregnant bitches in clinical practice. The retrospective data consisted of fetal biparietal diameter determined by ultrasonography and day of parturition for all included bitches. The study population was divided into five maternal weight groups (miniature (≤5 kg), small (>5 to 10 kg), medium (>10 to 25 kg), large (>25 to 40 kg), and giant (>40 kg)) with three breeds in each group with 26 miniature-breed bitches, 13 small-breed bitches, 19 medium-breed bitches, 22 large-breed bitches, and 20 giant-breed bitches. The data was used to develop models to determine the number of days before parturition based on fetal biparietal diameter. A statistically significant effect was seen for grouping by maternal weight group (p<0.0001) and by breed (p=0.0057). Breed-specific models were derived and compared to each other within the same maternal weight group. Statistically significant differences between some miniature-breed and small-breed bitches were found using mixed linear regression analysis. The accuracies of all models were given as number of births within ±1 and ±2 days of estimated day of parturition and compared to an acceptable limit of 80% at ±2 days. All breeds and maternal weight groups except Dogue de Bordeaux and giant-breed bitches met the limit. Poor accuracies were seen when applying data from each breed to the maternal weight grouped model. Simple linear regression analyses were compared to mixed linear regression analyses. The simple linear regression analyses obtained the best accuracies for most of the breeds which is most likely to be caused by overestimation. Comparison of Chihuahua and German Shepherd to other studies showed similar accuracies between the highest reported and the two linear models. We recommend the use of breed-specific models based on mixed linear regression analysis in clinical practice. Further research is needed to analyze the differences between the two linear models and to confirm the tendency of more accurate predictions of day of parturition for medium
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The variation in the duration of gestation, defined as the period from mating to parturition, was studied in 113 bitches of six breeds (31 Dobermans, 31 Labrador retrievers, 14 German shepherds, 13 Bernese mountain dogs, 12 golden retrievers and 12 West Highland white terriers). The bitches were mated once on the optimal day for mating, which was established by measuring the plasma concentration of progesterone. The duration of gestation varied between 58 and 65 days with a mean of 61.4 +/- 1.5 days (+/- SD). The mean duration of gestation in West Highland white terriers (62.8 +/- 1.2 days) was significantly longer than that of German shepherds (60.4 +/- 1.7; P < 0.001), Labrador retrievers (60.9 +/- 1.5; P < 0.001) and Dobermans (61.4 +/- 1.0; P < 0.025). The variation in the duration of gestation in any one of the six breeds was low, ranging from 4 to 7 days, or less when litters of one pup (n = 4) were excluded. The number of pups per litter varied between one and 15 with a median of eight pups. In the total population, the duration of gestation was negatively correlated with litter size (r = -0.73; P = 0.005) for litters (n = 112) containing < or = 13 pups. However, within each breed multiple regression analysis failed to show any influence of litter size on the duration of gestation. The median litter size of different breeds and the mean duration of gestation were negatively correlated (r = -0.78; P = 0.03; n = 6). Therefore, although it was not conclusively proven, the results indicate that the breed is a major determinant of the duration of gestation in bitches and that the influence of breed may be ascribed to breed-related differences in litter size.
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Variation in canine gestation length was studied in a Beagle colony (n = 290) in which apparent gestation length, estimated as the interval from the day of first mating to the day of parturition, ranged from 57 to 72 days, and averaged 65.3 +/- 0.2 days. The interval from the day of the peak in luteinizing hormone (LH) to parturition was less variable and ranged from 64 to 66 days and averaged 65.1 +/- 0.1 days (n = 54). Apparent gestation lengths less than or equal to 61 days all resulted from mating greater than or equal to 3 days after the LH peak; those greater than or equal to 68 days all followed initial or single matings occurring greater than or equal to 2 days before the LH peak. Fertile single matings 3 days before the LH peak provided evidence that the potential postcoital fertile longevity of canine sperm is at least 6 days and thus contributed, along with variability in the onset of estrus, to the observed variation in apparent gestation length in the dog. The limited range in the interval from the day of the preovulatory LH peak to the day of parturition (64, 65, or 66 days) demonstrates a considerable regularity in the sequential events of gestation in the dog.
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The variation in the length of gestation, the period from mating until parturition, was studied in 77 dogs of different breeds; the time for mating was determined by measuring peripheral blood progesterone levels. The mean length of gestation was 62.1 +/- 0.2 (S.E.M.) days, with a variation of 11 days. The number of pups appeared to influence the length of gestation. Length of gestation was negatively correlated (r = -0.96, P < 0.001, n = 44) with litter size in litters with 7 or fewer pups. The intra-breed variation in length of gestation in the five breeds represented by five or more bitches was 3-6 days. The mean gestation of Alsatians (60.1 +/- 0.5, n = 9) was shorter (P < 0.005) than that of the other breeds combined (62.3 +/- 0.3, n = 68). The primiparous/multiparous status of the bitch did not influence the length of gestation.
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Parturition is a process which, when set into motion, occurs to completion. This review concerns the control of parturition in ruminants. Parturition is an endocrine event, dependent upon the activation of the fetal hypothalamus-pituitary-adrenal (HPA) axis. In sheep and other ruminants, increases in plasma concentrations of cortisol induce the activity of 17-hydroxylase and 17,20 lyase in the placenta, increasing the biosynthesis of oestrogen relative to progesterone. The increase in the so-called E:P ratio increases myometrial activity and culminates in labour and delivery. Much work has been done to identify the mechanism of the endogenous activation of the fetal HPA axis. Recent work suggests that production of prostanoids within the fetal brain influences fetal ACTH secretion, and that induction of prostanoid biosynthesis at the end of gestation might be important in the process of parturition. Oestrogen and androgens, secreted by the placenta at the end of gestation, augment activity of the fetal HPA axis by increasing fetal ACTH secretion and by decreasing negative feedback sensitivity to cortisol. Although significant progress has been made concerning the neuroendocrinology of parturition, many significant questions remain. Is parturition regulated or simply programmed? Is parturition the ultimate result of neuronal maturation within the fetal hypothalamus, or is there a complex interplay between the placenta and fetal hypothalamus? Answers to these and other important questions await further research, but may provide key information which will prove useful in understanding general principles of parturition in many mammalian species.
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Fertility data from 327 artificial inseminations (AIs) using frozen-thawed dog semen are presented here. The AIs were performed in 274 bitches using semen from 185 males of 76 breeds. The data cover all AIs conducted during 1983 through 1995 at Cryogenetic Laboratories (CLONE) in the United States with AKC-registered and research bitches, and all AIs carried out at the Department of Obstetrics and Gynecology at the Swedish University of Agricultural Sciences in Uppsala, Sweden, using semen frozen by CLONE, in 0.5-mL straws. Semen was frozen using a standardized, three-step liquid nitrogen vapor freezing method. Whelping rates > 70% were obtained when post-thaw motility was 40% or higher. The inseminations were made either directly into the uterus using transcervical catheterization with the Norwegian catheter (NIU; 167 AIs) or a fiberoptic endoscope (EIU; 19 AIs), or in the cranial vagina (VAG; 141 AIs). Resulting whelping rates were 84.4% (NIU), 58.9% (VAG; P < 0.001), and 57.9% (EIU). Increasing the number of VAG AIs per cycle from 1 to 2 enhanced the whelping rate (P < 0.05). The mean interval from the first AI to whelping was 61.8 +/- 2.4 d, and was longer for VAG AIs (62.7 +/- 2.7 d) than for NIU AIs (61.2 +/- 2.1 d; P < 0.001). The mean interval from the last AI was 60.1 +/- 1.9 d, and did not differ between VAG AIs (60.2 +/- 2.2 d) and NIU AIs (60.0 +/- 1.6 d). Gestation length was not influenced by breed or litter size. A total of 1158 pups resulted from the 327 AIs. Litter size was 5.4 +/- 3.0 (NIU), 4.0 +/- 2.7 (VAG; P < 0.001), and 6.0 +/- 2.1 (EIU). Litter size was also influenced by breed (P = 0.006) and, for VAG AIs, by the number of inseminations performed per cycle (P = 0.009). This study is the largest that has been carried out on frozen-thawed dog semen AI. It shows that using a good method for cryopreservation, together with nonsurgical intrauterine AI employing the Norwegian catheter, can yield whelping rates and litter sizes similar to those reported from well-controlled natural matings. Furthermore, this is the first study to show that intrauterine deposition of frozen-thawed dog semen results in a significantly higher whelping rate and larger litter size than vaginal deposition.
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Accurate prediction of parturition date is useful for clinical management of canine parturition. For nearly all normal canine pregnancies, parturition occurs 64-66 days from the LH peak, the timing of which cannot be differentiated from the initial sharp rise in serum progesterone (P4) concentrations. We sought to determine by retrospective analysis if prebreeding serum progesterone concentrations could accurately predict parturition date. Serum progesterone concentrations recorded as serial samples from 63 bitches (19 breeds) were analyzed. Progesterone concentrations were measured by radioimmunoassay (RIA) or chemiluminescent immunoassay (CLIA). The CLIA method was validated for use in determining P4 concentrations in canine serum and results were comparable to those obtained with RIA. Bitches were grouped by nonpregnant body weight (BW) and litter size (LS). Day 0 (D0), the day of preovulatory rise in serum P4, was defined as the day that P4 concentration rose to > or =l.5 ng/ml and was at least twice the baseline concentration. The predicted parturition date, 65 days following the day of preovulatory rise in serum P4 (D65), was compared to actual parturition date, the day the first pup was delivered. We determined that mean P4 concentration at D0 for all BW groups was 2.02+/-0.18 ng/ml and there was significant variation in P4 concentrations between BW groups after D1. In addition, we determined that the accuracy of parturition date prediction within a +/-1, +/-2, and +/-3 day interval using prebreeding serum progesterone concentrations was 67, 90, and 100%, respectively, and that the accuracy was not affected by body weight or litter size.
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The length of canine gestation is 65 days from the luteinizing hormone (LH) surge. Early and accurate determination of canine gestational age is useful for predicting and managing parturition. We performed a retrospective study on fetal measurements obtained by transabdominal ultrasonographic examination of 83 bitches (32 breeds) to estimate gestational age. Gestational age was estimated using two published tables correlating either (1). embryonic vesicle diameter (EVD), crown-rump length (CRL), body diameter (BD), and biparietal diameter (HD) to the LH surge in mid-gestational beagles or (2). BD and HD to parturition in late-gestation retrievers. Parturition date was predicted by obtaining the difference between the gestational age estimate and 65 days. Bitches were divided into four body weight (BW) groups based on nonpregnant body weight: small (<or=9 kg), medium (>9-20 kg), large (>20-40 kg), and giant (>40 kg). Mean+/-S.D. litter size (LS) was calculated for each BW group. The BW groups were then divided into small, average, or large LS groups. The accuracy of the prediction was not affected by LS but was affected by maternal body weight for small and giant BW groups only. When adjusted for weight, the accuracy of prediction within +/-1 day and +/-2 day intervals was 75 and 87%, respectively. Using stepwise logisitic regression, the most accurate prediction of parturition date was obtained when fetuses were measured at 30 days after the LH surge, regardless of body weight or LS. Parturition date predictions made after 39 days of gestation using only biparietal and BD fetal measurements were <50% accurate within +/-2 days.
Determination of the period of fertilization in bitches using hormonal assays and A.I. with frozen semen
  • F Badinand
  • A Fontbonne
  • Mc
  • Siliart
Badinand F, Fontbonne A, Maurel MC, Siliart B. Determination of the period of fertilization in bitches using hormonal assays and A.I. with frozen semen. In: Proceeding 12th International Congress on Animal Reproduction, vol. 1. 1992; 1755–7.
Determination of the period of fertilization in bitches using hormonal assays and A.I. with frozen semen
  • F Badinand
  • A Fontbonne
  • M C Maurel
  • B Siliart