Tall or short, stocky or leggy; dogs come in all shapes and sizes. Each is special in their own way, but do they all grow at the same rate? The team at WALTHAM collaborated with the University of Liverpool, University College London, and Banfield Pet Hospital to find out. The aim was to develop evidence-based growth standards for dogs, and the results have been published in the journal PLOS One.
Regular weigh-ins are important to track a dog's health, especially during puppyhood when their weight is always changing. It's been shown that growth which is too slow or too rapid at this stage can result in lifelong problems for pets. At Banfield Pet Hospitals - Mars Petcare’s 975 veterinary clinics across the USA - dogs’ weights are routinely recorded as part of general health checks. This gave WALTHAM scientists access to the health records of over 6 million dogs visiting Banfield hospitals over the past few years.
The centre’s statistics experts refined the data until they were left with measurements from 50,000 dogs that met a list of stringent criteria, including being under 3 years of age, in ideal body condition and with no health complaints. The weight data were then used to create graphical curves, plotting the pattern of growth for dogs from early life to adulthood. Because the data came from only healthy dogs in optimal body condition these growth curves represent an ideal rate of growth, and are known as "growth standards".
The researchers began by grouping dogs by breed. However, for many of the less popular varieties there weren’t enough dogs represented to generate breed-specific curves. On further analysis of the data, the scientists concluded that dogs of different breeds with a similar adult weight grow at more or less the same rate. They grouped the dog data into five weight ranges and created curves that followed the growth rate for dogs in those ranges. This size-category approach made the curves suitable for more than just the breeds initially included and, crucially, also to mixed-breed dogs.
Perhaps unsurprisingly, the data showed that male and female dogs grow at different rates; males grow more rapidly than their female counterparts. Separate male and female curves for each weight range were created to account for this difference.
The detailed health records from Banfield allowed researchers to study the impact of neutering on growth rate. They found that neutering before 37 weeks of age was associated with a slight increase in the rate of growth, whilst neutering after 37 weeks was associated with a slight slowing of the growth rate. However, these changes were small enough to conclude that separate curves for neutered dogs were not needed.
“The growth phase is fundamental to the lifelong health and wellbeing of dogs” said Alex German, Professor of Small Animal Medicine at University of Liverpool. “Growth standards for babies and children have become an essential component of the human paediatric tool kit but until now there’s been limited information available on what constitutes optimal growth in dogs. This is a real step forward”
These curves form the basis of the WALTHAM Puppy Growth Charts, available free of charge to UK puppy owners through their veterinary practice. The charts allow pet owners to partner with their vet to track their dog’s growth and rapidly spot any problems. If veterinary professionals can ensure that more dogs are in optimal body condition upon entering early adulthood, this will help to promote the maintenance of a healthy weight through lifelong, regular weight monitoring.