And soy hulls can supply economical fiber From just before she calves until just after, a dairy cow has a lot of things on her mind. Eating isn't usually one of them.
"Through calving, a cow's appetite is depressed, but she still needs energy," says Jim Spain, University of Missouri dairy specialist. "She needs something she will eat; something she can readily digest and utilize. Soybeans are sort of like chicken soup for a cow with a poor appetite."
With funding help from the Missouri Soybean Merchandising Council, Spain studied the milk production and reproduction of dairy cows fed different levels of raw cracked soybeans in a total mixed ration (TMR).
He says whole soybeans deliver almost as much protein as does soybean meal. But they have much more fat, which is a good source of energy and polyunsaturated fatty acids. Fatty acids may have a beneficial role in the formation of reproductive hormones, says Spain.
"There's been some concern that you shouldn't feed raw soybeans to cattle," he says. "Or whole soybeans, whether they're heated or not, because the fat has an adverse affect on reproduction. We're finding that's not the case at all."
He fed up to 15% cracked soybeans in the TMR, or 7.5 lbs of beans/cow/day.
"These were cows in early lactation," says Spain. "They averaged 80 lbs of milk per day, fat-corrected to 4% butterfat. Feed intake stayed up and the cows milked extremely well."
He also fed lower levels of cracked soybeans (3.5 and 5 lbs/cow/day) and says feed intake and milk production stayed above those of cows on more conventional rations containing soybean meal.
The health and productivity of a hard-working dairy cow depends on her plane of nutrition, which depends on her feed intake, Spain notes.
"We want to look at when and how many soybeans to feed for the best benefit," he adds. "We may conclude that we should feed beans all the way through - including the dry-cow period, which typically is 60 days."
Earlier, Spain and his colleagues studied how soybean hulls (a byproduct of soybean milling) contribute to reproductive efficiency of dairy cows and heifers. They found that cows fed a ration where soy hulls replaced 30% of the grass hay increased intake before calving and maintained body condition through calving and the postpartum period.
"In many dairy operations, lower-quality forage is fed to dry cows," Spain says. "With soy hulls, we replaced a low-digestible forage fiber with higher-digestible soybean hulls and intake went up considerably.
"The economics are there, too," Spain continues. "Hay typically is packaged in ways that contribute to wasted feed. Pelleted soy hulls or hulls mixed in a ration are almost totally useable. In terms of nutritional value per dollar spent, soy hulls are an excellent bargain."
Perhaps as important, soybean hulls enhance reproduction, which bears heavily on a dairyman's bottom line.
"Reproductive efficiency means a cow should stay open for no longer than about 120 days," says Spain. "If the average days open in a herd widen to 140-150, you begin to lose serious money."
As a rule of thumb, a dairyman loses about $3/day on a cow that remains unbred for more than 120 days. A 100-cow herd with an average open span of 170 days is losing $l5,000.
"Our goal in this whole area of study is to find out what we can do to prescription feed to let cows express their genetic production potential, as well as maintain their general health and reproductive efficiency," Spain explains. "We now think we should feed soybeans for more of a dairy cow's life."
Melvin and Larry Blase produce registered Angus cattle on their central Missouri farm. They feed prospective herd sires to test for gain performance.
"We use whole raw soybeans in all of our bull test rations," says Melvin Blase. "We don't grind or crack the beans; we feed them in a mixed ration with either ground corn or flaked milo. At levels we're feeding, there are no palatability problems with soybeans."
For some time, Blase had been bothered by the price difference between raw soybeans and soybean meal. He talked with Monty Kerley, University of Missouri animal scientist, who had studied raw beans in diets for feedlot steers.
Kerley found that whole soybeans are economical to feed anytime the soybean price is less than 95% of the price of soybean meal.
"We decided to start by substituting soybeans for half of the soybean meal in our bull rations," says Blase. "The cattle did so well that midway through the feeding period, we switched to all raw soybeans."
Raw soybeans average 38% protein and 18% oil. The Blases blend enough beans into their bull rations to make a 15%-protein feed.
"On that ration, our bulls gain 3.5-4 lbs/day for the 140-day test period," says Blase. "When you use soybeans to balance the protein in a ration, you get the oil content of the beans essentially free, and oil is a concentrated source of energy."
There may be problems with the availability of whole soybeans in some areas.
"Not all elevators have soybeans, or may not want to pull them out of storage to mix in a ration," says Blase. "I buy soybeans at harvest and grain-bank them for our use."