How to determine nutrient quality in forages

The sight of a fresh-cut hayfield with tightly rolled bales dotting the pasture can bring feelings of satisfaction to the heart of a farmer. But in order to get the most out of that hay, experts suggest testing it to determine its nutrient content. “A hay test tells you what nutritional holes you have for the class of animals that you are feeding and the productivity that you want them to achieve,” Gene Schmitz, University of Missouri Extension livestock specialist, said.

The hay test gives producers information to determine what nutrients they don’t need to add to their animals’ diets and what they do need to add. 

“The value of a hay test is that we don’t feed nutrients that are unnecessary and we only provide the nutrients that are missing at the appropriate amounts for the cheapest costs,” Schmitz explained.

It’s important to keep in mind, that a forage test provides the information about the nutrient content of the forage. It is then up to the producer or an expert, to analyze the results in order to determine what steps need to be taken to supplement missing nutrients. University extension livestock specialists are a resource for producers looking for assistance in interpreting the hay test results and guidance in nutrition decisions. 

Hay Testing Steps

Sample different lots. When testing hay, collect samples from different lots of hay and sample them separately. A lot of hay is a particular cutting off of a specific field. The reason for separate sampling is to test plant maturity at different harvest times. Also note, the stage of maturity at harvest dictates the nutritional value of the hay. 

Test close to when feeding. Though hay can be tested at any time after harvest, a month post-harvest should be the earliest it is tested, if it is being stored in a barn or shed. If hay is stored outside uncovered, it is ideal to test it six to eight weeks prior to feeding it. The smaller the window between when the hay is tested and when it is fed, the closer the analysis will be in regards to what the animals are actually consuming. This is especially true for hay that is stored outside since it loses nutritional value over time in the elements. 

If producers are feeding haylage, silage or baleage, those forages should be tested six to eight weeks prior to it being fed. At the minimum, producers need to give the haylage, silage or baleage at least four to six weeks, for it to go through the fermentation process, before it is tested. 

“The value of a hay test is that we don’t feed nutrients that are unnecessary and we only provide the nutrients that are missing at the appropriate amounts for the cheapest costs.”

– Gene Schmitz,
University of Missouri extension livestock specialist

How to collect a sample. There is a variety of different tools that can be used to test hay. Most of the tools are stainless steel tubes with serrated teeth on the ends. Many local extension offices have hay testing tools farmers can borrow. 

If collecting a sample from a wrapped round bale, make a cut in the wrap or plastic on the side of the bale. Then push the coring tube into the bale about 18 inches. If sampling a square bale, push the corer in the butt end of the bale. It is important when sampling to get a cross section of the bale. Cutting across the sections of the bale, helps to get a full representation of the forages included in the bale.

Remove the corer and use a wood dowel to plunge the sample into a clean plastic container. Experts recommend sampling 10 percent of each lot of hay. Once 10 percent of the lot of hay has been collected, mix the samples together in the plastic container. 

The next step is to send off the sample to a certified lab. Some labs provide their own plastic mailers. However, a sealable gallon plastic bag will also work for sending in samples. Prices for the hay test range from lab to lab and depend on what analysis is conducted. 

 At the minimum a hay test should include information on moisture content, fiber levels which will provide energy value information, protein levels and in some cases the percentage of major minerals.


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