Food is Not Love, Part 1: Equine Obesity
By: Sarah Thatcher-Mason, DVM
Almost everyone who has owned a horse has heard the term: “easy keeper”. No matter what you do – or don’t feed them, they seem to maintain a figure which can only be described as “Rubinesque”. The simple fact that most horses are able to carry an extra amount of weight well may help to disguise the fact that they are indeed overweight and in some instances obese.
A horse can be described as obese when they have a Henneke body condition score of greater than 8 out of 9. Horses with a body condition score are described as having an obvious crease down the back, fat covering the ribs, fat pads around the tailhead, over the withers, behind the shoulders and along the neck. The inner buttocks may touch and there is no noticeable tuck at the flank. A horse can be considered overweight when he has exceeded his ideal body condition score. The “ideal” body condition is when the ribs can be felt but not seen, the withers are rounded and the shoulders and neck blend imperceptibly into the body. There may or may not be the beginnings of small fat pads around the tail head. This is usually a 5 or 6 out of 9. The ideal weight and body type for any particular horse will vary by frame size and breed so it is easier for the purposes of comparison to use body condition scoring when assessing body fat composition. A full description of the Henneke System can be found online at: http://www.umext.maine.edu/onlinepubs/htmpubs/1010.htm
Just as in humans, obesity in our equine companions places them at risk of many other disease processes such as Metabolic Syndrome (condition of impaired insulin sensitivity and glucose metabolism) and laminitis. The extra weight will also exacerbate pre-existing conditions such as osteoarthritis, degenerative joint disease, and Cushing’s syndrome as well as complicate recovery from athletic injuries by reducing exercise tolerance. The overweight horse is also predisposed to the development of pasture-associated laminitis, a condition which is commonly seen in the heavy horse or on lush pasture in the early spring. The added weight combined with the likely complication of insulin resistance can result in varying degrees of laminar inflammation. While a full discussion on insulin resistance and laminitis is beyond the scope of this article, it is well documented that horses and ponies that have a history of founder when put out to pasture are often those that can be described as the easy-keeping horse.
You can prevent obesity in your horses by paying attention to their body condition and adjusting feed and exercise levels accordingly. Just as in humans, each horse will have a unique metabolism and thus unique feeding requirements. The basics remain the same however; a diet composed primarily of grass hay (>60%), plenty of fresh water, and free access to trace mineral/salt source or daily mineral supplementation. Supplementation with any additional feed such as grain or alfalfa hay should be done on an individual basis and tailored to meet the needs of that particular horse. See you local veterinarian for advice on feeding and nutrition for specific situations. Remember to factor in any pasture time that your horse gets as additional feed – they may be walking all day, but they are also eating all day! Even dry pasture can provide a significant amount of nutrition.
As it can always be said, an ounce of prevention is worth a pound of cure! Remember that it is always easier to maintain an ideal body condition so keeping an eye on your horse’s waistline before there is a problem will save you time and effort in the long run!