Forage is the foundation of any equine diet. If a horse is on pasture, the place to start when formulating a balanced ration is to know that pasture’s nutrient levels (especially protein, carbohydrates, and certain vitamins and minerals). If you are working with an equine nutritionist to build a ration to fit the needs of a horse that spends time on pasture, he or she might recommend a pasture analysis.
Collecting a Sample
Paul Siciliano, PhD, in North Carolina State University’s Department of Animal Science, in Raleigh, says how you take a pasture sample to send to the lab can affect its results. “Pasture might contain a variety plants, some of which the horse prefers and others that won’t be eaten,” he says. “Your sample may not reflect what the horse is eating.”
Watch and see what the horses are eating and the height at which they are harvesting a particular plant. “Then use scissors to cut the forage at that height, taking samples of what they are actually eating,” says Siciliano.
“The lab will usually tell you how much to send. Get several different clippings from various sites where horses graze. Put the clippings in a zip-close bag, and freeze the sample quickly.”
Interpreting the Results
When you select a lab to analyze your sample, make sure it’s a certified lab that’s well established. “Most of them are, but your extension agent can direct you to a good one,” says Siciliano. “For interpreting the results and the way you’d apply them, make sure you have help. There are also resources available that you can access on line or from the forage testing labs. The forage lab will have information defining what each of the measured variables means. Almost every land-grant university has some of this information on their websites or a brochure on interpreting forage analysis.”
A nutrition professional or an extension agent can also help guide you regarding what to do with the information you receive from your pasture sample.
“Trying to figure this out by yourself is like trying to repair your car with just a manual,” he adds. “Without some background and experience, you may do more harm than good. The important things are to first get a good sample. Second, get some help to interpret the result, and third, figure out how to apply that information.”
The good news is most labs today report horse-specific numbers. “A lab called Equi-Analytical (part of a larger company called Dairy One) gives the information back to the horse owner in terms that the horse owner can understand,” he says.
Take-Home Message
Pasture can provide a great deal of the nutrients horses need, even if they only graze a few hours a day. “The two main things a horse will get from pasture are calories and protein,” Siciliano says. “Minerals may be variable, depending on the forage and region. Pasture is also a good source of vitamin E and vitamin A.”
As pasture plants mature, changes can occur rapidly and nutritional value declines. A plant in a growing, vegetative state has a higher nutritional value than the same plant at maturity. A sample gives a brief snapshot for a short period. Sampling pasture in different seasons at different stages of maturity can provide a baseline from which to work. “You can’t take a one-point-in-time sample and base everything on that,” says Siciliano. “At minimum, the samples should be taken quarterly.”
