Although most horses these days seem to be overweight, it is not uncommon for veterinarians to see horses for lack of weight gain. Many times a horse is examined and seems to be fairly normal. Certainly a complete nutritional history is important and often a problem with the diet causes the problem. I assign a body condition score to each horse and this score is a number ranging from 1 to 9, with 1/9 being extremely thin to 9/9 being extremely obese. Normal horses are a 5-6/9. If the physical exam is normal, Dr. Harold Schott indicates in DVM 360 that a rectal exam by your vet is important to check for internal abscesses and cancer. Certainly, a good oral exam under sedation with a full mouth speculum is required to make sure there are no diseased teeth or foreign bodies in the mouth that could affect eating.
And this may seem simple but you need to monitor how much the horse is eating and make sure the horse is actually eating adequate amounts of feed. Many times this requires separating the horse from others to measure food intake. Also, look at the entire herd because if all the horses are thin, it is likely a nutritional problem but if all others are fat and only one loses weight, then quality of feed is not likely involved. Blood work consisting of a complete blood count and blood chemistry are important to check for internal abnormalities. The blood count checks for low red blood cell count, or anemia, and the white blood cell count can indicate infection. The chemistry profile can determine health of the liver, kidney, and protein levels and these values can give the vet an idea of the location of the horse's problem. Join us for the next program on specific causes of weight loss in horses.