Facts About Protein in the Horse’s Diet
By Dr. Dan J. Burke, Ph.D.
Director of Equine Nutrition, Tribute Equine Nutrition/Kalmbach Feeds, Inc.
When determining the amount of protein supplied in a horse’s diet, all the feeds must be taken into consideration. How much protein is in the forage and how much is in the grain? Are there supplements to be considered? How much of each is being fed? What ingredients are used to make the grain and the supplements?
Inadequate protein in the diet can influence the horse’s ability to form and repair muscle and other body tissues, which will in turn affect his ability to perform. There are often other ways to address a horse’s needs without cutting out the protein.
Protein quality is very important. It is determined by the amounts and balance of essential amino acids. Essential amino acids cannot be synthesized in the horse’s body, thus they must be supplied in the diet. The most important amino acids for the horse are lysine, threonine, and methionine.
People are often more concerned with the percentage of protein in a feed than with the actual amount of protein supplied by a feed. The National Research Council 2007 recommendations are stated in amounts, not percentages.
For crude protein, recommendations range from 540 grams (1.2 pounds) per day for an idle mature horse to 1,535 grams (3.4 pounds) per day in a lactating mare for horses weighing 1,100 pounds (500 kilograms). Recommendations for working and growing horses are in between these two values.
We must do the calculation of amount fed x percent crude protein (using the percent as the decimal) to determine if we are meeting the recommendation.
A 28% protein feed is designed to be fed at 2 pounds a day.
The TOTAL intake of protein for the 28% feed is: 2 pounds of feed x 0.28 (% crude protein) = 0.56 pounds of crude protein.
A 12% protein feed is designed to be fed at 6 pounds a day.
The TOTAL intake of protein for the 12% feed is: 6 pounds of feed x 0.12 (% crude protein) = 0.72 pounds of crude protein.
Neither of the above products alone meet the recommendation, but there is more TOTAL protein intake in the lower percent feed.
The balance of the protein comes from hay and/or pasture.
A 12% protein hay fed at 1.5% of the horse’s body weight.
The TOTAL intake of protein for the 12% protein hay at 15 pounds per day is: 15 pounds of hay x 0.12 (% crude protein) = 1.8 pounds of crude protein.
This hay actually exceeds the recommendation for the idle, mature horse. In this case, we’d use the lower intake feed to balance the amino acids and supply the nutrients likely to be deficient in the hay, such as selenium (in many parts of Canada and the US) as well as copper and zinc, so the horse does not get obese.
A similar approach should be used for all nutrients.
This information was contributed by Tribute Equine Nutrition.
For more information, please visit the Tribute Equine Nutrition website.