Question
My 17-year-old, 800-pound Lipizzan gelding will not gain weight. He is on 24-hour turnout with consistent deworming, and he had his teeth floated in the spring. His diet includes 20 pounds of four-way grain hay, 2 pounds of oats, 1 pound of rice bran, probiotics, and oil. Help, please.
Answer
Getting weight on a horse can be frustrating, especially if the cause for the inability to gain is not known. An underlying condition often makes it hard for a horse to efficiently digest the feeds offered. The most common condition is gastric ulcers, but less common afflictions include damaged intestinal lining from persistent parasitic infections, hindgut acidosis, Lyme disease, colonic ulcers, enteroliths, chronic disease, and cancer.
Horses that crib are sometimes difficult to put weight on, and cribbing has been linked to gastric ulcers in certain horses. Your horse does not sound like one that is at high risk for ulcers (24-hour turnout), but it may be something to consider. If you are interested in a supplement that moderates the pH of the digestive tract (stomach and hindgut), KER makes a product called RiteTrac that will be helpful.
I have entered the information you supplied into MicroSteed, KER’s state-of-the-art ration evaluation software. The report generated from MicroSteed includes graphs that illustrate how your horse’s diet stacks up against his requirements.
Some of my observations:
Because I do not have analyses of the exact feeds you are giving, I used average values for each type, so this is an approximation to identify trends in the diet. The first thing I should explain is that I used oat hay in the evaluation because I could not find information on “four-way grain hay.” The other ingredient I used was rice bran without added calcium. The results of the evaluation would be very different if the rice bran you are currently using has added calcium, because my first observation is that there is a poor calcium-to-phosphorus ratio (0.8:1). This may not be a factor for your gelding’s reluctance to gain weight, but it certainly could be a problem for the health of his bones. A skewed calcium-to-phosphorus ratio, for instance, can lead to nutritional secondary hyperparathyroidism.
The calcium-to-phosphorus ratio should never be below 1:1 and ideally should be closer to 2:1. The diet has sufficient amounts of calcium but way too much phosphorus, due largely to the inclusion of oats and rice bran, which bring the ratio out of balance. You should add more calcium to correct the imbalance. If you feed a rice bran product with at least 2% calcium, there would not be an imbalance issue. If that is not an option, then adding calcium carbonate or limestone at a minimum of 2 ounces per day would bring the calcium-to-phosphorus ratio back to normal.
Your horse is receiving calories well beyond his requirement. This is an indication that the horse has a high metabolism, works harder than perceived, runs a lot in the pasture, or, most likely, that he is not digesting his food well enough to get sufficient calories to maintain moderate weight. This could be due to one of the aforementioned problems or just the way the horse is physiologically hardwired.
The way to deal with this is to increase the energy density (calories) of the diet. There are roughage sources that are more calorie-dense and digestible than cereal hays such as the one you’re feeding. Examples are alfalfa, alfalfa pellets, or beet pulp. For some senior horses, feeding the more digestible forages is the only way to maintain proper body condition. You may want to try to replace 5 pounds of the cereal hay with alfalfa hay. Another option would be to include 1-2 pounds per feeding of alfalfa pellets with the oats and rice bran. If you choose to try beet pulp, soak 1 pound (dry weight) and feed it mixed with the oats and rice bran.
Another option includes increasing the amount of oats and/or rice bran to boost calories, but I am a firm believer in trying to maximize the amount of calories from forage (roughage) before increasing starches or fats.
The vitamin E level in your gelding’s diet is a little low, so you may consider a natural vitamin E supplement like Nano-E. This may have a positive effect on the horse’s immune system. In my nutritional analysis, I assumed light work but if in fact he is in heavier work you may want to consider some type of vitamin/mineral supplement like Micro-Max. This product would supply additional nutrients to meet the requirements, especially those that were borderline for a horse in light work.
