Craig Wood, University of Kentucky
Feeding horses at work
Work can be divided into three levels:
- Light work includes trail riding and activities performed by the pleasure or equitation horse (English or Western).
- Moderate work includes draft or ranch horse work, rodeo timed events, and jumping.
- Intense work includes racing and training, polo, and three-day eventing.
Some events can be considered intermediate (between two intensities), such as show jumping. A Grand Prix show jumper is performing at both a moderate and high intensity level, combining both speed and skill. The most important nutrients needed for the working horse are water, energy, and electrolytes. The requirements for these nutrients are dependent on work intensity.
The higher energy requirement for the working horse means increasing the grain amount or feeding a more energy-dense grain that includes corn or dietary fat. At the same time, forage should constitute at least half of the total diet. The only exception is during very high-intensity events, when the horse cannot consume enough dry matter to meet its energy requirements. Consequently, many of these athletes are consuming diets composed of 65 percent concentrate and 35 percent forages. Forage is important in the diet of the working horse in order to maintain normal gut function and minimize the incidence of colic. From what you have learned so far, do you think that horses exercising at high intensities are more or less at risk for colic? If you said more, you are right. The amount of concentrate fed may be minimized by feeding a high-quality legume or grass hay. Or, a fibrous energy source such as beet pulp may be added.
Poor quality hay or hay that is stored for a period of time may lose its vitamin content. Therefore, additional vitamins may be needed in the diet to meet the horse’s requirements. Feeding grain at about 2.0-1.5 lb grain/100 lb body weight in addition to a good quality hay is a good guideline to follow. Try to make sure that the horse is consuming at least 50 percent of its diet as forage. If not, decrease the grain until the horse consumes more forage. Starch overload by a high grain diet is one cause of colic. High grain starch overload can be prevented by feeding fibrous feeds. Another way to provide energy without increasing the grain amount is to add corn oil to the diet. Corn oil should not exceed 10 percent of the total diet. Corn oil contains twice as much energy per volume as oats and is highly palatable to horses. Feeding fat conditions the horse to utilize fat stores more efficiently and allows the horse to consume less grain. Fat is also useful during prolonged exercise, such as endurance rides, because blood glucose levels are maintained for much longer due to the higher use of fat as an energy source.
Depending on the quality and type of forage being used, a protein source may also be needed in the athletic horse’s diet. Soybean meal is the most common protein source, but any source that is a proper balance of the essential amino acids may be used. Protein requirements of approximately 10 percent crude protein for working horses are not much greater than horses at maintenance. Too much dietary protein can lead to poor performance. Excessive protein intake leads to an increase in water consumption (which increases body weight) and excretion of ammonia or nitrogen from the body.
Vitamins and minerals should be provided in the diet or through other sources such as a trace mineralized salt block. The salt block should ensure that all electrolytes lost via sweat are replenished. The calcium and phosphorous ratio should be at least 1:1. Feeding a grain high in calcium should ensure that the phosphorous level never exceeds the level of calcium. Sodium and chlorine are important to replenish because they are lost in sweat. This loss can be as high as 1/5 lb of salt! Selenium and vitamin E supplements are also popular due to their antioxidant properties, which aid in the prevention of tissue damage during intense work.
Overall, working horses should be fed as individuals to ensure that each is consuming enough feed to meet its specific requirements for the intensity of work performed. The Nutrient Research Council (NRC) requirements should be used as a general guideline, and adjusted to meet the needs of each horse.
