Q: I have a very easy keeper who is overweight, and the vet says he is borderline obese. He is currently on a ration balancer and gets hay when he is in his stall but goes out on pasture in a group for most of the day. He is in light work year-round as a pleasure horse. Is it more valuable to adjust his feed and pasture time, increase his workload, or both? What is the safest way to help him lose weight?

A:  I applaud you for realizing that your horse is not his healthiest if he is overweight. Some owners readily recognize a malnourished horse as unhealthy but like horses to be “pleasantly plump”; however, we now know that an overweight horse is more prone to laminitis, joint issues such as arthritis, exercise intolerance, heat stress in hot weather, and other health problems. It is important to keep your veterinarian involved as you consider feed and exercise changes for your horse  because they can tell you if the extra weight might be related to a metabolic condition or disease.

You will need to monitor your horse’s weight and body condition throughout this process. I usually recommend doing this twice a month to recognize changes quickly. A scale is the most accurate way to measure weight. It is also important to work with a reputable equine nutritionist to make sure you are meeting your horse’s nutrient requirements. Your local extension office can probably recommend a nutritionist if you don’t know one already.

Monitoring diet, turnout, and exercise is great when helping a horse lose weight. Decreasing diet or increasing exercise can both help a horse lose weight, but combining the two will yield the fastest results.

You are doing the right thing by keeping your horse on an all-forage diet with a ration balancer. The ration balancer will help ensure you are meeting your horse’s nutrient requirements. I recommend giving your horse a mature, mostly grass hay because it is lower in calories than some other hays, and decreasing calorie intake is essential for weight loss. If your horse consumes the hay quickly, you might try a hay net with small holes or a slow feeder. Taking longer to consume hay will help your horse feel full and can discourage development of stereotypies. If you notice the horse becoming bored in the stall, consider giving him a toy to keep him busy. Horses are a herd species, so having turnout with other horses is important. Instead of decreasing turnout time, consider fitting your horse with a grazing muzzle to decrease pasture intake. This is especially important when pasture is lush and growing rapidly. 

If possible, increase your horse’s workload. Some studies recommend a minimum of 30 minutes of trotting, 3-5 days a week, as ideal for encouraging weight loss. If you are doing mostly trail riding and walking, then increase the total time each week. As you increase workload, make sure your horse doesn’t start eating more, or you will not see weight loss. 

It might make you feel a little better to know that you are not alone! Some studies suggest that 51% of horses in North America are overweight, and 8% are considered obese. A combination of diet modification and increased work will give you the most rapid results, but don’t expect a dramatic change to happen quickly. In general, it will take about two months for a horse to safely drop a single body condition score, which is about 50 pounds.