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

## TL;DR

This study identifies factors affecting the birth and survival of Labrador Retriever puppies, including maternal weight, birth order, and labor duration.

## Contribution

The study provides breed-specific insights into Labrador Retriever parturition and neonatal survival, offering actionable data for breeders and veterinarians.

## Key findings

- Prolonged labor is strongly linked to higher stillbirth rates in Labrador Retrievers.
- Higher maternal body weight correlates with fewer live-born puppies and increased neonatal mortality.
- Puppies born later in the litter (sixth and beyond) face significantly higher mortality risks.

## Abstract

Labrador Retrievers are among the most popular dog breeds worldwide, yet comprehensive data on their normal whelping patterns and neonatal outcomes remain limited. This study analysed 42 bitches and their 346 puppies to identify factors that influence the course of parturition and early survival. Prolonged labour was strongly associated with a higher proportion of stillborn puppies, although overall neonatal survival remained high, with 91.6% of puppies alive at seven days postpartum. Higher maternal body weight was associated with fewer live-born puppies and increased neonatal mortality, and puppies with a lower body-weight ratio relative to their dam were more likely to die shortly after birth. Birth order also played an important role, with mortality increasing notably from the sixth puppy onward. These findings provide breed-specific reference values that may help clinicians and breeders optimise monitoring and neonatal care in Labrador Retrievers.

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.