Some people have suggested that young thoroughbreds are overfed and are reared on high carbohydrate feeds which makes them look big and shiny as yearlings at sales, but contributes to ‘weakness’ as racehorses.
This question needs to be separated into 2 parts – feeding in the paddock when they are on the mare and after weaning and how they are fed during yearling prep.
Unlike other animals they aren’t ‘force fed’ or even given ad lib access to concentrate feeds. The only free choice feed access is grass, except during summer or winter when hay is fed to replace the missing pasture in the diet.
In 2021 during their time in the paddock, young Thoroughbreds in Victoria are fed less carbohydrates than they were 30 years ago, and less than in most other countries. Back then most weanlings and yearlings were fed on Oats as their main energy source, often as much as 1lb per month of age. Nowdays many young horses are not fed oats, and are fed low starch, higher fat feeds so they get less energy from carbohydrates and more from fat and fibre. Some are fed moderate intakes of oats, much less than a racehorse would get, but others are just fed 1kg of a concentrated mineral and vitamin balancer pellet if they have access to good pasture. They are usually fed twice a day and meal sizes are small. One change in that time is the development of very productive pastures and sometimes they can be too good, so that its hard to regulate growth. Many breeders seek professional advice from qualified nutritionists and aim for a well balanced diet.
When it comes to yearling prep, the consigner takes the raw yearling from the paddock and presents it in a way that the market demands. This involves increased feed intake so there is usually a significant weight gain, but again horses are fed less grain than they used to be 30 years ago. Many aren’t fed oats at all. Vendors get a premium for presenting a well grown, well muscled, well conditioned shiny yearling. Ironically some trainers like to buy yearlings that eat a big concentrate feed, as they think this yearling will then be a good eater in the stable.
Are Australian yearlings bigger than counterparts overseas? Yes they are! Kentucky Equine Research has investigated growth in Thoroughbreds in different countries for over 25 years and we have found that Australian foals, weanlings and yearlings are the biggest in the world. Partly this relates to genetics, partly climate and partly management, including feeding; but market demand in the sale ring is a big factor. Buyers want big, strong, early maturing types and pay accordingly, although in recent years very tall yearlings are marked down. In contrast in Kentucky, bigger is better in both weight and height terms at the yearling sales.
Breeders search for optimum growth, as they try and find the sweet spot between yearling sales appeal, racetrack success and the related risks of developmental orthopedic disease (DOD). Rapid growth may increase the risk of certain DOD, but a very small yearling will have lower value in the sale ring and less success on the track, especially in stakes races. Monitoring growth by weighing and measuring horses does enhance the assessment that the breeder or manager can get by eye, and this is done on an increasing number of farms.
Kentucky Equine Research is currently conducting global research into the relationships between growth, skeletal disease, sales and racing performance in a number of countries. Our preliminary findings from a pilot study In Kentucky are very interesting as we have found associations between size and growth and certain DOD, price in the sale ring and racing performance. We also found that some skeletal disorders had no detrimental effect on performance, in fact yearlings with hock OCD sold better than the median price in the sale and raced accordingly, winning more races and more stakes races. Yearlings with sesamoiditis were marked down in the sale ring in terms of price, but were more likely to start and win than those with normal sesamoids
The ultimate aim for most breeders is success on the racetrack with yearlings getting to the track, winning races and then getting blacktype for the mare’s pedigree page. Astute breeders manage their operation accordingly so they find the balance between sale ring and racetrack success and optimum growth is a key part of that puzzle.
Dr Peter Huntington
Director of Equine Nutrition at Kentucky Equine Research.
About Dr Peter Huntington
Dr Peter Huntington holds a veterinary degree from the University of Melbourne. After he completed his degree, he was employed by the Victorian Department of Agriculture as the horse specialist veterinary officer. In this role, he conducted research and investigation into the nutrition of horses.
In the mid-80’s, Dr. Huntington co-created the body condition scoring system with Let Carroll, which is widely used for horses across the country.
He is a past president and editor of the Australian Equine Veterinary Association and has been a Trustee of the Australian Horse Industry Council for a number of years. In 1993 he joined Rhone-Poulenc Animal Nutrition (RPAN) as Director of Equine Nutrition to spearhead their horse nutrition division. This commenced a relationship with Kentucky Equine Research, who provided consultancy services to RPAN. In 1999, Kentucky Equine Research established an Australasian operation with Dr. Huntington as Director of Equine Nutrition.
Dr. Huntington is the author of the popular book Horse Sense – The Guide to Horse Care in Australia and New Zealand 2nd edition published in 2005 and is a respected author of many articles and papers on a variety of topics relating to equine nutrition.