Hay Sampling: What to Know

Though the weather may not feel like it, still in the high 90s here, but the fall season is upon us. The soon to be changing weather reminds us of the changing season. Along with a new season comes a new need for supplementation for your pasture cattle.

It is during this time of year when many producers are hauling hay to their storage lots to use for winter. On top of this they are also pricing and buying any additional hay that they may need. Seems everyone has it figured out though they may not be aware of problems lying just below the surface.

A major problem for producers is that there is a large range in hay quality depending on many conditions. Things like level of maturity, fertilization. growing conditions, harvest conditions, and storage  methods all play a part. Accurately sampling and testing hay is the only way to get a real understanding of the nutritional value of your hay.

This is not really something you want to guess at. Using values from previous years or a “book value” can be costly since a producer may incorrectly develop a ration using values that aren’t even present. Here are some tips to follow in order to get an accurate hay sampling.

Guideline for Hay Sampling

Getting a representative sample is a critical first step when hay sampling. Samples must accurately represent the entire lot of hay you are going to use. When you are getting a sample for analysis it should be kept separate from other lots of hay. The UNL NebGuide “Sampling Feeds for Analysis” says that a lot of hay should be harvested from the same field containing similar types of plants. The cutting dates, maturity level, variety, weed contamination, type of equipment used, curing methods, and storage conditions should also be similar. Whenever these conditions are different they should be separated and sampled as a different “lot”.

Use a hay probe or core sampler

You should should either a hay probe or a core sampler to get to the correct part of the bale when hay sampling. The hay probe should penetrate at least 12-18 inches into the bale. In order to get an accurate sample size the probe should  have an internal diameter of 3/8 of an inch. Using your hand to grab a sample will not consistently provide you reliable results.

Tips of the hay probe should be kept sharp to cut through the hay and prevent selective sampling. Avoid getting the hay probes hot when using a drill to drive the probe into the bale. This is because friction from high speeds can heat the probe to a point where it damages the hay sample.

Select a number of bales from each lot

To get a representative hay sample from a lot select 15-20 bales in the lot. Knowing the total number of bales that are present can help identify a random method that could be used. Such a method could be collecting a sample from every 4th bale in order to obtain an accurate sample.

Once all of the samples for a lot have been collected in may be necessary to sub-sample what you have. This is in order to get the feed down to a sample size that can be sent in for analysis. The guide I linked above will walk you through a step-by-step process to do this. Making sure that the sub-sample you submitted is representative of your lot is important.

Store sample correctly

Once the hay sampling is done store them in a plastic sealed bag in a cool dry place until it is ready to be submitted. If your samples contain over 15% moisture they should be frozen. This is to prevent the moisture from breaking the hay down and not giving you an accurate reading.

Make sure to label the bag with your name, address, lot identification, and feed type. Most commercial labs will provide an information submittal form that allows producers to select a standard feed test for forages. If possible send samples into the lab early in the week to avoid having the sample sit over the weekend.

What to Analyze

Analyze for moisture, protein, and energy

Cattle feeds should be analyzed for moisture, protein and energy. Producers may also want to have their forages tested for key minerals as well. Feed sample results are usually reported on an as-is and dry-matter basis.

When developing a ration for cattle or comparing feeds to one another always use dry-matter basis. Since types of feeds will have different moisture content this will give you a more accurate comparison. After you have formulated the ration you can then convert to an as-is basis using the moisture content of the feed. This will tell you how much feed you will actually need to use.

Analyze forages for nitrates

Things like moisture, protein, and energy may not be all that you need to analyze. Annual forages harvested for hay like oats, sudan grass, and sorghum-sudan hybrids should be analyzed for nitrates.

These annual forages can accumulate high levels of nitrates under various growing conditions that can potentially reach toxic levels. The only way to know if high levels of nitrate accumulation have occurred is to test for it.

Don’t neglect hay storage

Though a lot is covered on how to get your hay samples and how to have them tested I do not think there is usually enough emphasize on hay storage after. If they are not properly stored hay bales can lose up to 50% of their nutritional value through improper storage.

I went over in previous post “5 Rules for Proper hay Storage” the ways that you can go about making sure that your bales will retain as much of their nutritional value for as long as possible. Here are some cliff notes:

• Make sure that the bale is packed tightly
• Place bales under a roof if possible or cover with a tarp
• Store them on an elevated platform or on crushed rock
• Put the bales in a north-south direction with plenty of space between rows
• If possible feed the oldest bales first