Choices in Feeding Young, Growing HorsesBy Kentucky Equine Research Staff · September 30, 2013
Proper feed management is critical for those who are feeding young, growing horses. Type and availability of forage, variation in amount and frequency of grain meals, and each horse’s individual metabolism and body type must be considered in order to meet the needs of these young equines. Fortunately, there are many ways to design feeding programs that will provide the necessary nutrition in a variety of settings.
In many areas of the world, growing horses are individually given a measured amount of feed on a daily basis. This is the best case scenario for feeding young horses. Unfortunately, many breeders of horses are unable to feed their young stock individually. In these situations, young horses are fed in groups where one horse can potentially monopolize the feed. A feed product destined for use in this type of situation would need to have either a low energy content or a low intake to prevent excessive growth, but still have a safe level of fortification to provide each horse with critical nutrients for growth. This type of product is commonly called a ration balancer. Each of these variables provides a series of challenges for delivering the proper amount of diet fortification. Once this information is put together, a properly balanced grain or ration balancer can be designed to create a suitable diet.
The following are samples of diets that can be used for a 12-month-old yearling weighing 715 lb (324 kg), gaining 1.1 lb (0.5 kg) per day with an expected mature weight of 1,100 lb (500 kg).
The first feeding situation is an example for supplying critical nutrients using three different levels of grain intake (moderate, low, and minimal). In this example, the yearling diet consists of free-choice access to good-quality pasture, with concentrate feeding twice daily. Variations in this example could have the yearling is on a moderate grain intake (8 lb or 3.5 kg/horse/day) with an estimated intake of pasture dry matter of 12 lb or 5 kg/horse/day. The yearling could also be on low grain intake, receiving 4.5 lb (2 kg) of grain/horse/day with pasture dry matter intake estimated at 15.5 lb (7 kg)/horse/day. Since the yearling is eating less grain per day, the concentration of nutrients in that grain must be higher to satisfy the nutrient requirements, which will require a different concentrate with a lower feeding rate. Finally, for owners who want to feed the absolute minimum amount of grain necessary to their horses on good-quality pastures, it is possible for the yearling in this example to consume enough pasture to satisfy requirements for digestible energy and protein to maintain a moderate level of growth. However, the concentration of critical nutrients (calcium, phosphorus, copper, and zinc) is often inadequate in a pasture-only diet. To properly balance the diet in this situation, it is estimated the yearling will consume nearly 16 lb (7 kg) of pasture dry matter/day along with 1.25 lb (0.5 kg) of a ration balancer/horse/day.
In this scenario, the horse owner is free-choice feeding good-quality alfalfa hay to our example yearling. The alfalfa diet is supplying adequate energy, protein, and calcium to support the desired moderate growth rate, but is marginal in phosphorus, copper, and zinc. This is a common situation for young, growing horses in the western United States where high-quality alfalfa hay is common. To properly balance this diet, one would want to feed a ration balancer that provided essential phosphorus, copper, and zinc but did not add a significant amount of energy, protein, or calcium since these nutrients are already in excess. A diet might consist of alfalfa (15.5 lb or 7 kg/horse/day) and 1.5 lb (0.7 kg) of a specially formulated ration balancer to be fed with alfalfa hay. This type of mixing pellet is unique since it contains low protein (9%), an inverted ratio of calcium to phosphorus, and high trace mineral concentrations. This type of ration balancer should be used only in diets for horses eating predominantly alfalfa hay (greater than 50% of the forage consisting of alfalfa).
Despite the best efforts of the owners, our example yearling has been diagnosed with developmental orthopedic disease (DOD). The veterinary surgeon involved has suggested an energy-restricted diet to avoid any further rapid weight gain. It is important to realize that an energy-restricted diet will decrease the rate of gain; however, the skeleton of the yearling will continue to grow. The end result is a yearling that has grown taller, but has become progressively thinner. Since the skeleton of the yearling continues to grow even on an energy-restricted diet, it is important that the horse receive adequate levels of essential nutrients required for growth. To feed this yearling at approximately 70% of energy requirements with adequate nutrients to support continued skeletal growth, the diet would consist of 11 lb (5 kg) of mixed hay (alfalfa/grass) plus 2.5 lb (1.1 kg) of a ration balancer.
The directions on the feed bag suggest that our example yearling should receive the grain concentrate at a minimum rate of 8 lb or 3.6 kg/horse/day. These directions were designed to provide adequate dietary fortification. Unfortunately, the owners of the horse do not want to feed any more than 5 lb (2 kg) of grain/horse/day. If they feed 5 lb (2 kg) of this grain/horse/day along with a mixed hay (14 lb or 6.3 kg/horse/day), the yearling will be marginal in phosphorus, copper, and zinc intake. To provide essential nutrients while still adhering to the owners’ maximum of 5 lb (2 kg) of grain/horse/day rule, the intake of mixed hay remains constant while the level of grain concentrate is dropped from 5 lb/day to 4 lb/day. The remaining 1lb, which has been set aside for grain intake, is provided as a ration balancer rather than the normal grain. The finished diet will then consist of 14 lb or 6.3 kg of mixed hay/horse/day, 4 lb (1.8 kg) of grain concentrate, and 1 (0.45 kg) lb of ration balancer.
Because nutritional imbalances have been recognized as one potential cause of DOD in young, growing horses, it is important that the diets of young horses be properly balanced with nutrients known to be critical to proper development. Understanding the essential nutrients and their requirements is the first step in properly feeding young horses. One must also understand the many variables associated with feeding these growing equines. Once this information is put together, a properly balanced grain or ration balancer can be designed to make the diet appropriate.