Plenty of Plump Horses
Overfed horses in United States are much more common than previously believed. A 1998 estimate by the USDA National Animal Health Monitoring System (NAHMS) figured about 1.4% of horses in the US were overweight or obese. More recently, researchers assessed horses in Virginia and discovered the proportion of plump horses there is closer to 50%.
The 2006 survey involved 300 mature light breed mares, geldings and stallions attended to by the Virginia-Maryland Regional College of Veterinary Medicine. Researchers took detailed measurements of the horses' girth, height, length and neck circumference. They also assessed Body Condition Score on a scale of one to nine.
Nearly half (47%) of the horses were in optimal condition, with a Body Condition Score of four to six. Just six horses scored less than this, indicating they were underweight.
The rest of the horses that were measured could stand to lose a few pounds. One-third of the horses rated as being over condition. Another 57 horses (19%) were classified as obese, with a Body Condition Score of 7.5 to 9. These overfed equines also had the largest neck circumference, body mass index and weight.
While horses do like to eat, obesity has its costs, including greater risks of acquiring insulin resistance and laminitis.
C.D. Thatcher, R.S. Pleasant, R.J. Geor, F. Elvinger, K.A. Negrin, J. Franklin, L. Gay and S.R. Were. 2008. Prevalence of obesity in mature horses: an equine body condition study. Journal of Animal Physiology and Animal Nutrition. 92(2): 222-222.