In my previous post, Hay Forage, What to Look For, I mentioned equine hay testing. It is impossible to know what is needed to balance your horse’s diet without a complete analysis of the hay being fed. Soil fertility, texture and pH, environmental conditions during growth and hay curing, stage of growth when cut, species and variety of the forage, all affect the nutrient content of the forage. As well, mineral content varies between the different forages as well as from one geographic area to another.
Equine researchers are finding links to disease and excessive amounts of carbohydrate fractions in the diet. Orthopedic Development Disease (Glad 1984), laminitis (Longland, 2006), Insulin Resistance (Treiber, 2006), Equine Polysaccharide Storage Myopathy all require minimizing sugar and starch in the diet, so why guess, test your hay!
Many labs cater to the cattle industry, therefore the specific tests offered and the calculations for Digestible Energy and Total Digestible Nutrients are based on the requirements for cattle...not horses. To get the results that you, the horse owner would want, you need to use a lab that offers tests geared specifically for horses. Some labs only do a very fast, minimal kind of testing based on a method called NIR (Near Infrared Reflectance.) A word of caution: This will not give you information about trace minerals and may not be accurate for the sugar or starch content in the hay as well.
What are the tests that will be most useful to you, the horse owner?
Crude Protein (CP): This really isn’t a test for protein, but a test for the nitrogen content. Nitrogen has a set ratio in forage protein, they multiply the N content by 6.25 to get the percentage “crude” protein. This is accurate most of the time except when the hay might have high levels of nitrate, example hay grown under drought conditions, over fertilized or subjected to frost. If the CP looks too good to be true, well, you know the saying, if it is too good to be true, it's not. Call the lab and request a nitrate test.
Sugar and Starch: This test is relatively new to the forage testing industry and only a few labs offer it. Many horses are just fine eating larger amounts of sugar, but if you have a horse with a metabolic condition, this component is a very important part of your hay test. Water Soluble Carbs (WSC) will include sugar and all the fructans. Ethanol Soluble Carbohydrates (ESC) include sugars and the shorter chain fructans. If cost is a concern for you, test just for sugar content and skip the starch unless you are feeding a Bermuda or another tropical grass hay where the starch content can be high.
Minerals: Calcium (Ca), phosphorus (P), Potassium (K), Magnesium (Mg), Sodium (Na) are all needed in large amounts and are usually reported as a percentage. Generally all hay tests include major minerals.
Trace Minerals: Iron (Fe), Zinc (Zn), Copper (Cu), Manganese (Mn), Molybdenum (Mo), Sulfur (S) are minerals needed in mg per day and are usually reported as PPM (Parts Per Million). These sometimes are not included in the cheaper tests but are necessary in maintaining optimum health. Trace minerals are commonly deficient and are important in the body. Copper and zinc deficiency shows as a rough, dry hair coat or poor hoof texture.
Selenium is another important nutrient. But it’s worth noting that blood tests (about $12) for selenium concentration are reliable and may be more cost effective than testing for hay (about $30). But some people would rather have everything on one sheet of paper.
Test for aluminum if you live in a high acidic soil area. Cobalt, an essential component of vitamin B-12 may be lacking in some areas as well, so this may be a test worth considering.
When your hay results are received, you need to figure out what your horse is eating (hay, grain, etc) and compare it to what your horse needs and the difference is what you need to supplement, so some math calculations are required or you can hire an equine nutritionist to do the hay testing and calculations for you.