Analyzing Feed and Forage for Horses
Awareness of what your horse is eating can help you determine if his dietary needs are being met and, if not, what can be added to meet those needs. With respect to the nutritional needs of a horse, it is important to know the meaning of the chemical analysis on the feed and supplement labels and the chemical analysis results.
A horse's daily nutrient needs will vary because of several factors, including age, activity or performance level, health status, and, in broodmares, stage of pregnancy or lactation. Estimates of dietary requirements can be found in a variety of publications, such as the National Research Council's Nutrient Requirements of Horses, 6th Edition (NRC, 2007), in extension publications such as http://extension.missouri.edu/publications/DisplayPub.aspx?P=G2807, on websites such as www.extension.org/pages/Nutrient_Requirements_for_Horses, or in materials produced by state extension specialists or equine nutritionists.
Once you determine a horse's requirements, you can analyze feeds for what nutrients they provide. This will help you decide if what you're feeding meets or exceeds the horse's needs. Benefits of this information include:
- Determining what is being fed and if anything needs to be added or deleted;
- Deciding if you're feeding the horse in the most cost-effective way; and
- Determining if changes need to be made.
What is Analyzed
What to have analyzed depends on a variety of factors, including what nutrients are of interest and how much you are willing or able to spend on the analysis. Routine analysis can be as little as $10 for an individual nutrient and as much as $80 for analysis of about 30 nutrients. The most common nutrients analyzed include crude protein, fat, soluble carbohydrates, fiber, and the minerals calcium, phosphorus, potassium, magnesium, sulfur, copper, zinc, and selenium.
The crude protein content measurement gives an estimate of a feed's protein content, but it doesn't give much information on the quality of the protein. Fat is a nutrient that provides energy, as do soluble carbohydrates. Soluble carbohydrates can be analyzed as water-soluble carbohydrates, ethanol-soluble carbohydrates, fructan, and starch, and this analysis is important for horses with a variety of disorders (such as equine metabolic syndrome, laminitis, or equine polysaccharide storage myopathy). The two most common fiber analyses are for acid detergent fiber (ADF) and neutral detergent fiber (NDF), which can be used to estimate forage quality.
The various minerals listed are involved in a variety of body functions. The balance between calcium and phosphorus is important in maintaining bone quality, and you should keep it around two parts calcium to one part phosphorus.
Magnesium levels are important to ensure that a variety of enzymes throughout the body function properly. Sulfur is important in maintaining hoof and hair quality, as well as a variety of other functions. The micromineral copper is important in bone development and hemoglobin formation, and zinc is needed for protein synthesis and metabolism. Selenium is important for maintaining healthy cell membranes, but a horse only requires it in very small amounts.
Although these are some of the more commonly analyzed nutrients, a variety of others might be of interest. An equine nutritionist or veterinarian can help you decide what should be analyzed.
Where Are Samples Analyzed?
There are a variety of ways to have samples analyzed. Some feed companies will help clients collect samples, have the samples analyzed for a small fee, and then assist the client with interpreting the analysis. Another option is to contact your state extension specialist or a county extension agent, who will be able to help with the sample collection process and might recommend sending samples to laboratories located at a university within the state where you live.
You can also contact companies such as Equi-Analytical (www.equi-analytical.com), Holmes Laboratory Inc. (www.holmeslab.com), or Dairy One (www.DairyOne.com) for grain and forage analysis. These companies provide information on their websites about how to collect samples, and they can provide prepaid packaging for sending samples to their laboratory for analysis.
In cases where you need to analyze the samples for specific nutrients, such as the various soluble carbohydrates, the laboratory options are more limited. These samples must be handled differently to yield an accurate analysis. You can get more specific information from companies that conduct this type of analysis, such as Rocky Mountain Research and Consulting Inc. (www.safergrass.org/CertiCarb.html).
How to Collect Samples
How you collect the samples depends on the type of feed. The three main types of feed that are routinely analyzed are grain, pasture, and hay. Collection methods vary depending on the lab, so make sure to ask the lab you choose about the exact sampling method and amount to collect.
Grains are probably the easiest type of feed to sample. Take feed samples from at least 10 bags until you've collected one pound of feed. Place all samples in a clean bucket and mix the grain thoroughly. Then place the sample in a plastic bag, removing as much air as possible. Finally, ship the sample in the company-provided mailer or use priority mail. The sample needs to arrive at the laboratory as soon as possible so it does not spoil before analysis.
Pasture samples are relatively easy to collect, and special equipment is not required. A basic method requires a pair of scissors and a clean bucket for collection.
Imagine an "X" going through your field. Walk the "X," clip a sample every 10 steps, and place it in the bucket. Clip the sample to the height a horse would graze (around two inches). You should not take a sample in an area where it is obvious that horses have urinated or defecated, and do not clip samples in an area that contains plants the horse will not eat, such as thistles and other inedible weeds. In these instances you can collect samples a bit further out than the 10 steps.
Do not sample areas of the pasture that are obviously not utilized by the horse, because ideally the sample should represent what the horse is likely to consume. It might be of interest to sample such a section independently, and possibly take a soil sample, to determine why horses aren't grazing this part of the pasture.
Once you've sampled the entire pasture, thoroughly mix the clippings and remove approximately one pound to ship for pasture analysis.
As with the grain sample, put the pasture sample in a plastic bag, removing as much air as possible. Depending on the analysis desired, you can pack the sample in a mailing envelope or on dry ice before shipping.
Hay sampling can be a bit more complicated and is best done with some specialized equipment. Farm owners can purchase a hay core sampler from many agriculture supply companies, such as NASCO or Gempler's, for prices ranging from $120 to $250.
If you're not going to take hay samples routinely, it might be more cost-effective to rent the sampler or borrow one from the local extension office. Some feed companies might loan this type of equipment to their clients.
The hay core sampler attaches to a drill and you drill it into the small end of multiple bales. Sample at least 20 randomly selected bales from throughout the stored hay to give a more representative sample.
Drill a core out of a bale and place it in a clean bucket. Collect at least one pound of sample and mix it thoroughly before placing it in a plastic bag for shipping. As with the previous samples, remove as much air from the bag as possible. If a hay sampler is not available, then it is possible to collect samples manually by working your hand into the center of multiple bales and grabbing hay from within. However, the analysis of this sample will not be as accurate.
Feeds from commercial companies have an analysis attached either as a separate tag or printed directly on the container, and that gives guaranteed minimum and/or maximum amounts of certain nutrients.
However, these analyses are sometimes an average for several regions of the country, and there might be some variation for a specific region. There can also be some nutrients of interest that are not routinely evaluated. You can also find approximate nutrient contents on a specific feed company's website, or you can make an estimate of nutrient content using tables available at the Equi-Analytical website: (www.equi-analytical.com/CommonFeedProfile/default.asp).
Hay analysis might not always be necessary or cost-effective. Sometimes the average analyses for a "type" of hay might give enough information, especially for mature horses in light work. If you purchase hay in small amounts, for example only a one-month supply at a time, then routine analysis will probably not be cost-effective and you might not receive results in time for them to be of use.
Some suppliers might routinely have their hay analyzed, providing the information free of charge to clients. Again, if exact analysis is not required, you can find a reasonable estimate at the previously mentioned web-site.
How to Use the Information
Once you've collected the information on nutrient content, you can determine if your horse's nutrient requirements are being met. Additional information to make the determination includes the amount of feed and forage the horse is consuming on a daily basis (in pounds). Since most nutrients on the analysis are given either in a percentage or amount per pound, you can make a few simple calculations to determine if the horse's needs are being met.
There are a variety of websites that allow you to make the calculations automatically or provide step-by-step instructions:
- National Research Council, http://nrc88.nas.edu/nrh
- Equi-Analytical, www.equi-analytical.com/PuttingResultsToWork/Nutrient_Requirements/default.asp.
Editor's Note: The Equi-Analytical website, as of the writing of this article, was using nutrient requirement recommendations from the Nutrient Requirements of Horses, 5th Revised Edition, which was published in 1989.
There are a variety of extension publications you can use help make final calculations, such as this one from The Ohio State University (http://ohioline.osu.edu/anr-fact/0006.html).
Another option is to work with an equine nutritionist or extension specialist to calculate if the diet is meeting your horse's needs.
You can't know if your horse is getting what he needs in his feed if you don't know what's in the feed. While testing feed and forage can take time and money, the end result can actually save you money, as well as help you ensure your horse is getting the nutrients his body and work require.
National Research Council (NRC). 2007. Nutrient Requirements of Horses, 6th Revised Edition. The National Academies Press, 500 Fifth Street N.W., Washington, D.C. 20001.
About the Author
Janice L. Holland, PhD, PAS is an associate professor of Equine Studies at Midway College in Midway, KY. Her main academic interests are equine nutrition, pasture management, and behavior.
POLL: University Equine Hospitals