Harrisburg, South Dakota

Excellence in Large Animal Medicine and Surgery since 1981!

The basis of any horse’s diet should be hay. but what is good hay for horses? Hay has several characteristics, that we can examine.

(1) STAGE OF MATURITY: Earlier cut hay will generally have more protein, minerals, vitamins, and energy than later cut hay. Legumes (alfalfa) should be cut (weather permitting) in the late bud stage to early bloom stage. Grass hay should be cut in the heading out or early bloom stage. If harvesting a mixture of grass and legume, cut at the proper legume stage of development. A rule of thumb is that feed value drops 1% for each day delay in cutting after the optimum stage of plant growth.

(2) PERCENT OF LEAVES PRESENT: The leaf of the plant contains the highest nutrient value therefore good hay has all the leaves remaining.

(3) STEMINESS: The larger and woodier the stems the less desirable the hay. High quality hay is fine stemmed and pliable.

(4) COLOR: Green color indicates less bleaching of vitamins and other nutrients and is more acceptable to horses. But remember stage of maturity at harvest is more important than color.

(5) SMELL: High quality hay should have a pleasing fragrant aroma. Moldy smells are not desirable. Horses are very susceptible to heaves, an allergic condition affecting their breathing. Moldy hay is the most common way a horse develops heaves.

(6) FOREIGN MATERIALS: Hay should be free of weeds, stubble, sticks, dirt, dust, etc. Particularly watch out for weed awns, pigeon grass, etc. in hay. Weed awns have prickly ends like arrow heads that can get stuck in the sensitive skin inside their mouths. Which can create large bleeding ulcers.

The other way that hay is analyzed is by chemical analysis. A representative sample (preferably taken with a corer) is sent to the lab for analysis to determine things like crude protein, TDN (total digestible nutrients), calcium, phosphate, selenium, copper, etc. We can look at charts and see what the normal values for normal hay is but these can vary substantially with different types of hays, stage of growth at which the hay was put up, weather condition when the hay was cut, soil type make up. It is best to have each cutting and each type of hay analyzed to know the contents.

RFV (relative feed value) is a new term which measures the quality of hay. the higher the RFV the better the hay. RFV of the 140 range indicates good quality (early cut alfalfa). Values in the 100 range indicates less feed value (ex: later cut alfalfa or mature grass).

As you can see hay isn’t just hay. A great deal of variability exists and it is important to visually check hay and chemically analyze it to know what you are feeding. We need to pay particular attention to the quality of nutrition (particularly minerals) in pregnant mares and in young growing horses.

Send mail to dlacsd@midconetwork.com with questions or comments about this web site.
Last modified: 02/13/08