The yearling year is a critical growth year for young horses. Selecting the feed to give during that year is even more critical: Too much feed or the wrong type can lead to problems such as epiphysitis and osteochondritis, while too little feed of even the correct type will not allow optimum growth. Add to the equation that some yearlings are being fitted for show or sale, and providing the essential nutrients becomes even more difficult.
Nutrient Requirements of Yearlings
During the yearling year, most horses will reach 90 per cent of their adult size. However, that does not necessarily mean that large amounts of grain should be fed. Ideally, good-quality pasture or hay should make up the bulk of the yearling diet. If the quality of hay is in doubt, have it analysed by an agricultural university or county extension service. In general, yearlings will need an overall ration of 12 to 14 per cent protein. While grain can supplement hay or pasture to provide the necessary minerals and protein, the yearling should not be fat, but should have his ribs slightly visible.
In general, most yearlings on hay or pasture will need some grain supplementation. According to the University of Kentucky, yearlings on a legume hay such as alfalfa, lespedeza or clover will require a concentrate of 12 to 14 per cent protein, while those on grass hay such as brome or timothy will require a concentrate of 15 to 17 per cent protein. Most yearlings will need .5 to 1.5 pounds of concentrate per 45.4 Kilogram of body weight each day.
While many companies manufacture equine feeds for all life stages or you can mix your own, certain nutrients are essential for optimum growth and a minimum of developmental problems. A balanced ration for yearlings will contain .5 per cent calcium to .3 per cent phosphorous according to the University of Minnesota. In addition, copper and zinc should be present in 10 parts per million and 40 parts per million respectively. Also, 910 international units of vitamin A per pound are needed along with 37 international units of vitamin E per pound. Access to a salt block and clean water should be available at all times. Always check feed labels closely to make sure the necessary nutrients are present.
Yearlings are very susceptible to orthopaedic problems if the feed ration is unbalanced or lacking in essential nutrients. Probably the two most common problems are epiphysitis, which is an inflammation of the growth plates in the legs, and osteochondritis dissecans, a failure of the cartilage in the growth plates to turn to bone. Either of these can result in permanent unsoundness. Laminitis and insulin resistance are other possible problems.