A system that injects nutrients into round bales does increase hay palatability but not forage quality, according to Louisiana State University (LSU) feeding and quality trials.

The HayMaster Nutrition Injection System injects a molasses-urea mix into hay bales using probes. Tests showed a 59% improvement in bermudagrass hay intake and a 27.3% intake increase in lower-quality, mature johnsongrass-crabgrass hay, says Mike McCormick, coordinator of the LSU Agricultural Center's Southeast Research Station in Franklinton.

“The forage-quality data was not as positive as the feeding data, and it doesn't surprise me, because if you look at it from a mathematical standpoint of what's being added or introduced in the bale, it's not really much nutrition,” he says.

At the same time, McCormick stresses, forage-quality testing is an inexact science. “Anytime you're trying to sample something that weighs 1,250 lbs and take only 3-4 oz out, you always question whether you have a representative sample of what the cow is actually consuming.

“There were slight improvements in protein, but nothing that you could consistently count on,” he says. “Small quantities of molasses and urea have been shown to stimulate fiber digestion and we do an in vitro technique to evaluate that. But in this case, either the quantities were too small or the samples were not representative, because we really did not see a kick in digestibility that I had hoped we would see.”

The two types of hay, which had been stored outside, were each evaluated over a four-week period.

A molasses-urea mixture, containing 20% crude protein equivalent diluted 2:1 with water and thoroughly mixed, was injected in both hays. A group of 30 drylot-confined Holstein heifers was offered treated and untreated hay free choice in addition to 5 lbs of a 20%-protein corn-soybean meal-mineral supplement daily.

When less than 25% of the hay remained, usually within three to four days, it was weighed.

Treated bales were preferred, McCormick says. “The heifers definitely can smell them. They will go to those bales quicker than to non-treated bales, and that has the potential ramifications for improved performance and economics.

“We know that the protein and energy in forage is about a fourth to a third the cost of adding concentrate. So anytime they eat more of that, and they can get more of their nutrition from that than from concentrates, that's a good thing.”

The heifers ate less of the more mature, lower-quality treated hay than the injected bermudagrass, but that's normal, McCormick says. “The more fiber you have, the slower it's digested, and the less they eat.”

The molasses solution injected into the lower-quality hay leaked, possibly because the hay was more stemmy, with fewer leaves to absorb the material. “So it may be that they didn't get the full dose of the product with the lower-quality hay.”

More study is needed, he says. McCormick would like to test the system with milk cows. For more info, call 478-521-0856, visit www.haymastersystems.com or see our first story on it, called “A Shot Of Sweetness.”