Creating Growth Standards for Domestic Pets

Monitoring and managing the weight gain of growing puppies and kittens is crucial for gauging their health and wellness, since a rate that's abnormally quick or slow can indicate inappropriate feeding or underlying disease, which itself can predispose a pet to obesity and related health issues later on. However, historically, information on optimal growth in domestic dogs and cats has been limited, with few tools to help monitor this aspect of development. Taking cues from paediatric medicine, the goal of the papers underlying this thesis was to establish evidence-based growth standards through analysing a large dataset pertaining to client-owned pets from a network of primary care veterinary hospitals in the United States, using methods parallel to those utilised in developing the World Health Organisation (WHO) Child Growth Standards. Initially, growth standards were developed for dogs from over six million electronic medical records, which required the creation of strategies specific to pets – considering the impact of neutering on weight gain and addressing the wide variety of sizes across breeds. The finalised standards, which covered male and female dogs of five custom size categories (up to an adult weight of 40kg), were then compared with various populations including healthy weight dogs from two European research colonies, client-owned dogs that were over/underweight during growth, and those diagnosed with health conditions related to growth. Notably, larger deviations from the puppy growth standards were shown to be more likely in the latter two populations, and the level of deviation that could be expected in 'healthy' growth established. Subsequent growth standards were then formulated for domestic shorthair cats, using data from the same veterinary network. These standards were again compared with healthy research colony cats and over/underweight cats from the client-owned population, with similar results. However, a notable finding was that neutering in cats was associated with a more pronounced tendency towards weight gain compared to dogs. Furthermore, a re-analysis of a prior study indicated that most weight gain post-neutering in cats is likely adipose tissue. These studies have, for the first time, created growth standards for dogs and cats based on large-scale observations in a substantial population of healthy weight, client-owned pets. Moreover, guidelines have been established regarding what degree of deviation from these trajectories might be considered unusual and warrant further investigation, along with what to expect post-neutering/spaying. This innovative approach facilitates veterinarians and pet owners to effectively monitor pet growth using straightforward bodyweight measurements, enhancing early detection and intervention for potential health issues.