Hay Testing for Beef Cattle

You cannot tell what is in a bale by looking at it. A hay test costs little compared with the feed it helps you manage.

Key points

Hay looks can fool you; a lab test shows what it supplies.
Sample each lot separately with many cores from many bales.
Have a nutritionist help read the results and plan supplements.
Call a vet and nutritionist if nitrate or poisoning is a concern.

Why a test beats your eyes

Color, smell and leafiness tell you something, but they do not tell you protein or energy. Two bales that look alike can feed very differently. A lab test measures what the cow will actually get.

Tests also protect you from surprises. Hay cut late or rained on can be much poorer than it looks, and hay grown on different fields can vary widely.

Many ranchers are surprised the first time they test. Hay they thought was excellent turns out only fair, and hay they nearly sold turns out to be useful for the right group of cows.

How to take a good sample

A test is only as good as the sample. Sample each lot of hay separately, meaning hay from the same field and cutting. Use a hay probe if you can, and take cores from a number of bales across the lot. Your extension office can lend or tell you where to find a probe.

Mix the cores together, fill the sample bag and label it clearly. Send it to a lab that your extension office recommends.

Sample by field and cutting
Probe many bales, not just one
Mix cores into one sample
Label with date and lot
Send promptly to the lab

Reading the report in plain terms

A hay report lists measures of moisture, protein, fiber and energy, and often minerals. You do not need to memorize them. What matters is comparing what the hay supplies against what your cows need at their stage.

Ask your nutritionist or extension specialist to go through the report with you. They can tell you whether your hay meets needs, whether it is short in something and what to do about it.

Ask your nutritionist what to do if results are low in something important. The answer may be a supplement, a different group of cows or a different hay, and the cheapest fix depends on your numbers.

Nitrate and other warnings

Some forages can carry nitrate, and certain forages can produce prussic acid under some conditions. These are poisoning risks, and a test can flag nitrate. If your lab report or a field condition raises concern, call your veterinarian and a nutritionist before feeding.

Do not guess at safe feeding amounts. Ask the experts, and keep a record of what was tested and when.

Use the results to plan

Once you know what the hay offers, match it to your cows. Feed better hay to cows with the highest needs, such as late-pregnant or lactating cows, and poorer hay to cows in better condition. Add supplement only where the test shows a gap.

Keep reports with your records so you can compare year to year and field to field.

Moisture matters too. Hay stored wet or baled too wet loses quality and can mold, so write down the storage conditions beside each test.

Buying and selling hay

If you buy hay, ask the seller for test results and ask where and when it was cut. If you sell, a good test helps buyers and builds your name.

Prices and terms vary, so check with your extension office or local hay market information rather than using a rule of thumb. USDA AMS publishes market reports that you can ask about.

Hay that is bought and sold by weight or by test can be priced more fairly. Ask the seller how the hay was cut, cured and stored, and keep a copy of any tests you are given.

Common mistakes and what to ask

Common mistakes include testing one bale and calling it good, mixing lots, sampling after feeding has begun, skipping tests in a drought year and never using the results.

Ask your lab or extension office which tests fit your needs, ask a nutritionist how to read the results and ask your veterinarian about any nitrate concern.

Plan to retest if hay is stored a long time, gets rained on or comes from a new field. Results describe that lot on that day, and they do not last forever.

Testing one bale only
Mixing different lots
Not using results
Ignoring nitrate warnings

When to get help: Ask your extension office where to get a hay probe and a lab recommendation, and a nutritionist to read the results. Call your veterinarian before feeding hay that raises nitrate or poisoning concerns.

Sources and further reading

Organization homepages are linked so you can search them for current guidance on this topic.

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