Factors contributing to the decision to perform a cesarean section in Labrador retrievers

Maternal and fetal factors for determining the cesarean section type (scheduled/emergency) in bitches

One hundred and forty bitches and their offspring (689 puppies) were involved in this study. The influence of different maternal features such as age, breed (brachycephalic/non-brachycephalic), previous births (primiparous/multiparous), health status (complete/incomplete) and litter size over the type of cesarean sections (scheduled/emergency), the neonatal survival, and the incidence of congenital malformations were also examined. Scheduled cesareans were predominant (104/140), of which 90 % were brachycephalic breeds and females were mostly between 2 and 4 years old (54.8 %), multiparous (88.4 %) and with a correct health status (67.3 %). Emergency cesarean sections mainly involved non-brachycephalic breeds (80 %) and were carried out mostly in females under 4 years of age (72.2 %), primiparous (77.7 %), with incomplete health status and a large litter size (47.2 %). Perinatal mortality was notably higher in emergency C-sections (3.25 % and 13.3 %, scheduled and emergency C-sections, respectively); the highest incidence of neonatal mortality was recorded in young females (<2, 2-4 years old), primiparous and with incomplete health status. Congenital anomalies were observed in 4.50 % (31/689) of the puppies, with anasarca (38.71 %) and cleft palate (29.03 %) being the most frequently observed malformations. A higher incidence of congenital malformations was detected in puppies from dams with incomplete sanitary health and from inbreeding cross. Overall, the study provides valuable insights into the complex interplay between maternal characteristics and cesarean outcomes. Appropriate genetic selection, good sanitary health conditions, and the age of the reproducers, are pivotal factors in planning for gestation and improving the survival of neonates.

Incidence and concomitant factors of cesarean sections in the bitch: A questionnaire study

Dystocia in the canine species is a common problem, and elective cesarean sections (C-sections) have become more frequent in breeds that are at risk. The aim of this study was to evaluate the incidence of C-section and contributing factors and to compare data on elective and emergency C-sections (e.g., regarding stillbirth). Using a questionnaire, a total of 423 bitches of 80 breeds and their 899 litters were included. The mean number of litters per bitch was 2.1 ± 1.1 litters. The overall rate of stillbirth was 6.7%. Of all litters, 194 were born via C-sections (21.6%), of which 35 were declared as elective and 159 as emergency due to dystocia. Significantly more C-sections were performed in either small litters (1-2 pups) or large litters (&gt;12 pups) (p &lt; 0.001). Bitches that have had prior C-sections had a 4-fold increase in the risk of successive C-sections (RR = 4.54 (95%CI 2.56–7.70; p &lt; 0.001). Furthermore, primiparous bitches of advanced age had a significantly higher incidence of emergency C-sections (p = 0.004). Stillbirth was significantly higher in emergency C-sections compared with that in elective C-sections (p = 0.003). Also, timing of intervention had a significant impact on stillbirth in emergency C-sections (p = 0.025). Within a breed-specific evaluation, significant differences were observed between breeds regarding incidence of C-section and stillbirth. Lesser-known breeds were represented in the population, and the results showed that the Norwich Terrier had the highest (51.6%) and the Gordon Setter had the lowest (4.8%) incidence of C-section (p &lt; 0.001). The inclusion and evaluation of lesser-known breeds regarding incidence of C-section is of importance as it shows that certain breeds without phenotypical traits such as brachycephaly may also have an increased incidence of emergency C-section and stillbirth. We further conclude that more importance may be given to the age at first parturition concerning the occurrence of dystocia and the decision making regarding possible elective C-sections.

Factors influencing ease of whelping and its relationship with maternal behaviour and puppy perinatal mortality in commercially bred dogs

For dog breeders, parturition is a critical stage in the reproductive cycle of the dam. Evidence in other mammals suggests that a difficult labour can influence maternal behaviour and offspring viability during the first hours postpartum. However, the effect of whelping difficulty on the onset of maternal behaviour has not yet been investigated in domestic dogs. Here we developed an ease of whelping (EoW) index in dams maintained within a Commercial dog Breeding Establishment (CBE) environment and investigated the relationship between intrinsic and extrinsic factors (breed group according to size/weight, litter size, parity, whelping season and origin of the dam), EoW, early maternal behaviour and puppy perinatal mortality. The behaviour of 30 dams was observed throughout the whelping process, starting 24 h before delivery of the first puppy until birth of the last puppy. Parturition duration, birth interval, and behaviours indicative of distress, restlessness, and general activity were scored and included in a Principal Component Analysis to construct the EoW index. Subsequently, mother-pup interactions and puppy perinatal mortality were recorded during the first 24 and 72 h postpartum respectively. Results showed that EoW was significantly affected by whelping season, litter size and origin of the dam (whether she was born and raised within the CBE or brought in). Furthermore, mothers that experienced more difficult parturitions (higher EoW score) spent more time lying in contact with their puppies during the first 24 h postpartum. Time in contact with puppies was also significantly affected by breed group. Nursing duration was significantly affected by breed group and origin of the dam. Additionally, medium-size breed (10-20 kg) puppies were significantly less likely to experience perinatal mortality than large breeds (> 20 kg). These findings are particularly relevant for the welfare of breeding dams maintained in large-scale CBEs where the staff-to-dog ratio might be insufficient to adequately manage multiple simultaneous parturitions.

Blood Biomarker Profile Alterations in Newborn Canines: Effect of the Mother's Weight

This study aims to determine the effect of the weight of bitches on liveborn and stillbirth puppies from eutocic births, and physiological blood alterations during the first minute postpartum. A total of 52 female dogs were evaluated and distributed in four categories: C1 (4.0-8.0 kg, n = 19), C2 (8.1-16.0 kg, n = 16), C3 (16.1-32.0 kg, n = 11), and C4 (32.1-35.8 kg, n = 6). The dams produced 225 liveborn puppies and 47 were classified as stillbirth type II. Blood samples were taken from the umbilical vein to evaluate the concentration of gases, glucose, lactate, calcium, hematocrit levels, and blood pH. The liveborn puppies in C2, C3, and C4 had more evident physiological alterations (hypercapnia, acidosis) than those in C1 (p < 0.05). These signs indicate a process of transitory asphyxiation. The stillborn pups in all four categories had higher weights than their liveborn littermates. C3 and C4 had the highest mean weights (419.86 and 433.79 g, respectively) and mortality rates (C3 = 20.58%, C4 = 24.58%). Results suggest that if the weight of the bitch is >16.1 kg in eutocic births, there is a higher risk of intrapartum physiological alterations and death. The results of this study allowed us to identify that the weight of dams before birth determines the weight of the puppies at birth.

Production and Reproductive Management

Programs breeding high-quality dogs are now able to use newer technologies in order to maximize use of genetic material and improve the efficiency of the production program. Missed estrus cycles and failure to conceive are costly in canine production programs, and parameters should be established to help minimize these failures. This article outlines lessons learned over the last 20 years in a medium-sized production program and also reviews other current production programs. Common pitfalls are discussed, including the implications of each, as well as management strategies to help avoid pitfalls.

Canine fertility: The consequences of selection for special traits

Pedigree dogs and cats are bred aiming to conform breed standards with very poor consideration for breeding stock fertility. At the same time, the genetic asset underlining reproductive traits could be effectively analysed like in other species under selection. The definition of selection targets is very important in breeding protocols determination. The aim of the present work is to present an overview of the different correlations between reproduction and genetics, starting from selection procedure and inbreeding coefficient moving to genomic and the application of SNPs and GWAS on population study and identification of genes involved in phenotypical variation of reproductive traits in dogs. Particular relevance has been given to the concept of inbreeding which effects on canine reproduction have been presented. The use of genomic information in inbreeding coefficient calculation can be considered an improved effective procedure in the evaluation of the genetic variability loss in canine population and its negative effects on reproductive traits.

Heritabilities for the puppy weight at birth in Labrador retrievers

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.