Breed-Specific Obstetric and Neonatal Parameters in Labrador Retrievers: Factors Influencing Early Neonatal Survival

This study evaluated reproductive parameters, parturition characteristics, and early neonatal survival in 42 pregnant Labrador Retriever bitches and their 346 puppies between June and December 2024. The mean age of the bitches was 4.06 ± 1.59 years, and their average body weight was 33.14 ± 3.72 kg. Litter size averaged 8.24 ± 1.88 puppies, with an almost equal sex ratio (50.2% males; 49.8% females). Mean labour duration was 743 min, and intervals between successive births shortened initially before increasing in late parturition. In 57.1% of litters, all puppies were born alive. Early neonatal mortality was low: 0.6% within the first hour and 8.4% by day seven postpartum. A significant association was detected between prolonged parturition and a higher percentage of stillborn puppies (p = 0.001). Maternal body weight showed a substantial negative correlation with the number of live-born puppies (r = -0.554) and a positive correlation with stillbirths (r = 0.499). The exploratory Q coefficient, expressing the ratio between puppy and maternal body weight, differed significantly across survival categories (p = 0.0027), with surviving puppies displaying the highest ratio. Birth order significantly influenced mortality (p = 0.008), with a marked increase from the sixth puppy onwards. No effect of bitch age was observed on parturition length or puppy birth weight (p > 0.05). Overall, these findings suggest that maternal body weight, parturition duration, and birth order are important determinants of neonatal outcomes in Labrador Retrievers and may assist in improving perinatal management practices.