Weaning in dogs: within- and between-litter variation in milk and solid food intake

Several studies indicate that the weaning process is affected by costs and benefits linked with getting milk or solid food for the young. It has even been proposed that optimal weaning time would vary within litters and that it may be possible to identify different weaning strategies for the young. In the present study the within-litter and between-litter variations in milk and solid food intake in domestic dog pups were described, and possible existence of different weaning strategies of pups was examined. Four litters of the breed Swedish Dachsbracken and their mothers were observed during Weeks 2–7 post partum, by manual observations. All pups were weighed regularly in connection with suckling and eating solid food and measurements of amount of milk ingested per pup and suckling and of solid food intake per pup and meal were made. The variations in milk intake and solid food intake were high throughout the period. In general, the correlations between milk intake and solid food intake were small but negative. Pups with a higher intake of solids tended to weigh more at Day 49 and had a significantly larger weight gain between Days 21 and 49. In total, there seemed to exist a certain compensation between milk and solid food intake, but it was not obvious within litters. No direct support was found for the theory of weaning strategies, but there was a trend that pups getting more milk were also more active towards the mother. Furthermore, there was a highly significant consistency between solid food intake and weight of the pups and in solid food intake between weeks throughout the period. This could be an indication that weaning strategies exist, even though the importance of the psychological satisfaction of suckling itself in such a complicated process as weaning should not be underestimated in social animals like the dog.