Hay growers should know the quality of forages that horses need to stay healthy and happy. That’s in part because, while horse owners are being encouraged to get hay analyzed using an equine analysis, “most need help interpreting the results of their analysis,” says Krishona Martinson, University of Minnesota regional extension educator.

Horse hay should be 10-17% moisture and about 10% crude protein. “Crude protein is not likely to be a limiting part of the diet except in lactating mares, foals or performance horses, which would require higher levels,” Martinson says.

Hay with an acid detergent fiber (ADF) value of 30-35% is good for horses. “The lower the ADF value, the more digestible the nutrients in the hay are,” she says. Hay at 45% or more ADF is of little nutritional value. Neutral detergent fiber (NDF) levels should be 40-50%, and most horses won’t eat anything above 65%. Good-quality hay at around 65% NDF can sometimes be given to horses -- if they quickly eat higher-quality hay -- to keep forage in their digestive systems and keep them busy.

Equine analyses also provide non-fiber carbohydrate (NFC) estimates to help select feed for horses that show sensitivity to starches and sugars and measure digestible energy (DE) in the hay. “For a light working horse, DE should be about 20 Mcal/day, and most hays range from 0.76 to 0.94 Mcal/lb of DE,” she explains. Calcium and phosphorus ratios can vary among different types of hay. Martinson says an adult horse in a maintenance phase should have a calcium-to-phosphorus ratio of 3:1 to 1:1.

Rained-on hay may be fine for horses in spite of the color, Martinson told horse owners at last weekend’s Minnesota Horse Expo. “Rained-on hay may be faded in color, but I still urge horse owners to have it tested,” she said. “If it isn’t moldy and it tests okay, it should be fine to feed because horse owners should be supplementing for the vitamins that tend to be lost in rained-on or older hay anyway.”

Visit the U of M’s Horse Information Web site at www.extension.umn.edu/horse/index.html. Contact Martinson at bjork026@umn.edu.