Question
A new fodder system on our Thoroughbred farm produces about 1,400 lb (640 kg) of fodder morning and night, and we are replacing about 80% of the hay and grain in the diets of horses with fodder. I feed one flake of grass hay a day to give horses something to nibble on. Other than this, they get only fodder. I followed the feeding scheme for several months and now have skinny horses. Some horses were found to have very low phosphorus levels. I would like to learn how to feed fodder properly to all classes of horses (weanlings, yearlings, broodmares, racehorses) without jeopardizing the horse’s condition.
Answer
The use of fodder, or fresh forage sprouts, has increased in recent years. The advantages of feeding fodder in the diet are undeniable, especially for horses without access to green grass. Fodder is a high-quality forage; on a dry matter basis, it is nearly as high as grain in calories yet higher in fiber. The high water content encourages smooth passage of ingesta through the gastrointestinal tract and could potentially reduce the risk of colic and digestive upset. The vitamin content in fodder is also much better than in hay. Evidence suggests that fodder fosters a balance of microbes in the digestive tract and may increase digestibility of other nutritional components of the diet.
In a recent research study on fodder, mature, unexercised Quarter Horses were fed 1% of their body weight in hay, 2% in fodder, and no grain. One interesting result of the study: the horses maintained their weight on this diet. Normally, a horse would consume 1.5-2% of body weight in forage daily, but because of the high water content of the fodder (about 85% water), these horses appeared to be consuming 3% of body weight. On a dry matter basis, however, they were only getting at most 1.3% of body weight. The horses were able to maintain their weight on lower dry matter intakes than normal because of the high quality of the fodder. The researchers did not attempt to feed solely fodder and offered more than 50% of the horses’ dry matter requirement in the form of hay. True, a horse can survive on pasture grasses alone, but there are some characteristics of fodder that make a fodder-only diet unsuitable.
When feeding the racehorse, I am skeptical that fodder can serve as the only feedstuff for several reasons. Because fodder is very low in dry matter, around 15%, a horse not getting any other forage would have to eat a lot of fodder to get the same amount of calories. For that reason, it would be nearly impossible for a performance horse, particularly a racehorse, to eat enough to fulfill its nutrient requirements. For example, for a 1,200-lb (545-kg) racehorse consuming a fodder-only diet, it would take 170 lb (77 kg) of fodder per day to meet the energy requirement of race training. Even if 12 lb (5.5 kg) of a concentrate feed was added, the horse would need an additional 92 lb (42 kg) of fodder to meet its energy requirement. Therefore, I think it prudent to feed hay and a concentrate feed along with fodder, as these feedstuffs are much lower in water content (about 10%) and more concentrated in calories.
Fodder is typically very low in calcium and high in phosphorus, resulting in a poor calcium-to-phosphorus ratio (0.125:1). The recommended ratio for calcium to phosphorus in the horse is >1:1. An inverted ratio of fodder can lead to some severe bone problems with long-term intake. A concentrate feed will correct the problem to some extent, but feeding hay in addition to the fodder could totally resolve the issue.
The problem you mention about low blood phosphorus is likely related to low calcium intake. You’re probably asking yourself this: if fodder is so rich in phosphorus, how can these horses become deficient in phosphorus? The levels of minerals like calcium and phosphorus in blood are homeostatically maintained by the body and not a direct measure of mineral intake. When minerals are out of balance in the blood, it indicates there is an imbalance in consumption.
Since it is similar in calories to concentrate feed, you should be able to feed less concentrate if you were to incorporate some fodder into the rations of horses. However, I don’t think a racehorse can perform optimally without some concentrate under these circumstances. Remember, feeding at least the minimum suggested by the feed manufacturer ensures the horse consumes the daily recommended requirement of many important nutrients, including several vitamins and minerals. A reduction in concentrate should not, therefore, drop below the minimum feeding rate. Other horses on the farm, like broodmares and growing horses, would also be best served by a combination of hay, concentrate, and fodder.
In summary, fodder is an excellent addition to a horse’s diet if there is no access to fresh pasture, but it is not an ideal replacement for all concentrates or forage in the diet, particularly for a hard-working horse.
