PINE BLUFF, Ark. – With winter approaching, most livestock producers have already purchased winter hay supplies, but did they purchase enough hay that meets the nutritional requirements of their herds. To answer this question, Dr. David Fernandez, Cooperative Extension Program livestock specialist at the University of Arkansas at Pine Bluff, suggests testing one’s hay for its nutritional quality.

Ruminants eat between 2 percent to 3 percent of their body weight in dry matter (DM; feed minus the water in the feed) each day. For example, a 1,100-pound cow consumes about 22 pounds to 33 pounds of DM per day. Feeding 100 cows each weighing 1,100 pounds for 90 days will require 99 to 149 tons of feed.

“Usually ranchers think of buying enough hay to provide the number of pounds of hay each cow eats per day; rarely, do we think of hay in terms of pounds of nutrients needed per head per day,” says Fernandez.

To get the amount of nutrients in your hay, take a core sample from several bales with a hay probe and put the samples in a quart-size plastic bag, says Fernandez. Keep it out of the sun so it does not become bleached or “cooked” on a dashboard, and take it to your county Extension office. The county office will even loan you a hay probe, says Dr. Fernandez. A hay analysis costs $18.

The analysis tells you how many pounds of nutrients are in each ton of hay. Then, check the nutritional needs of your animals against the nutritional content of your hay. Typically, ranchers should be concerned about TDN, a measurement of the energy in feed, and crude protein (CP). A 1,100-pound pregnant cow needs about 11 pounds of TDN and 1.5 pounds of CP daily. If the hay analysis shows that your hay is 60 percent TDN and 9 percent CP, and you feed your cow 22 pounds of dry matter (about 25 pounds of hay) each day, she will get 13.2 pounds of TDN (22 x 60 percent) and 1.98 pounds of CP. This hay more than meets the cow’s needs.

On the other hand, if the analysis shows that the hay contains 45 percent TDN and 6 percent CP, she is only getting 9.9 pounds of TDN and 1.32 pounds of CP, which is not enough.    “These numbers are not uncommon in Bermuda grass hay in Arkansas,” says Fernandez. “Each bale costs the same, but you did not get as many nutrients for your money in the second bale; you will have to provide supplements to your livestock in the form of grain, pellets or cubes.”

Your cow still needs about 1.1 pounds of TDN and a quarter pound of CP each day with the second bale of hay. But, she will be already full of hay, so you now have to substitute supplements for some of the hay in her diet. How much depends upon the quality of the supplement, says Fernandez.