VN March 2023

Vetnuus | Maart 2023 40 5 Overfeeding of puppies Excess weight in puppyhood predisposes dogs to adult obesity with lifelong associated risks. Overfeeding puppies as early as eight weeks onwards may contribute to hip dysplasia 24 , elbow dysplasia 25 and chondrosis 26 in genetically predisposed individuals through stimulating too rapid growth. There is a tendency for breeders to overfeed young puppies to ensure that they look “good” prior to sale. There is, unfortunately, an expectation of puppy owners that fat stocky puppies are indicative of strength and good health. Large breed puppies are particularly victim to this practice of overfeeding and are also the ones genetically predisposed to osteoarthritic diseases. In addition to the desired heavy-set look of young puppies, owners of large and giant breeds also have the belief that nutrition may influence the ultimate size of the dog. This erroneous deduction is due to the observation that overfed puppies may indeed be heavier set and larger than their thinner counterparts of identical age whilst still growing. However, puppies that have not been overfed grow to comparable sizes but take longer to get there. Puppies belonging to hip and elbow dysplasia-prone breeds should not be overfed from the ages of 6 weeks to 10 months. Despite the availability of breed-specific diets and diets that cater specifically for the requirements of large and giant breeds, there are still owners that insist on feeding excess dietary calcium and vitamin D (or bone meal) in addition to overfeeding their puppies, whilst others believe that high dose vitamin C supplementation in growing puppies prevents hip dysplasia. These practices should all be strongly discouraged 24 . Food intake should be regulated to maintain a slender figure, and it is crucial that veterinarians emphasize the need to restrict growth in susceptible puppies and educate both breeders and owners in this regard. 6 Impact of obesity on fertility and reproduction Obesity influences reproductive functions in both sexes by altering the activity of the hypothalamic-pituitary-gonadal axis. Adipose tissue acts as a reservoir of sex hormones and may modulate circulating concentrations and the relative ratios of oestrogens and androgens. In obese male dogs, total and free testosterone concentrations decrease as body weight increases, whilst in female dogs, the testosterone concentrations increase. These altered testosterone concentrations adversely affect fertility. Obesity in males is associated with infertility, and a trend for a decline in semen parameters parallels the increasing prevalence of obesity. Obesity also decreases libido. In bitches, obesity increases the prevalence of low birth weight and mortality more than twofold 35 . Obese animals have more difficulty in thermoregulating, and this may adversely affect gametes. Obese bitches also accumulate fat in the uterus, and this may increase uterine inertia developing 36 . Pathological importance of obesity in pet owned dogs and cats and breeding animals - Part 2 By Kurt G.M. De Cramer BVSc MMedVet (Gyn) PhD