Improved digestibility | Research shows cutting hay into shorter lengths has advantages
Research shows that cattle feed efficiency and rate of gain improves dramatically when hay pieces are about four inches long, says a U.S. forage expert.
As a result, he is advising livestock producers to adopt baling technology that cuts hay into shorter lengths.
“The machinery does cost a little bit more initially… but the data has been quite clear, that we get better feed intake (for) beef cattle,” said Dan Undersander, a University of Wisconsin extension forage agronomist.
“The (same) applies to dairy. You get better animal gain and you have less feeding loss.”
Undersander told the Manitoba Hay and Silage day in Neepawa June 11 that he was initially skeptical about bale pre-cutters, or choppers, which are a set of knives on the front of a baler that cuts forage into shorter lengths before the hay enters the machine.
Yet, after reviewing research on the technology, Undersander has be-come convinced it does reduce feeding loss and increase feed intake.
“If you’re feeding from a bunker, you know that a cow reaches in (and) grabs a bite-full and backs out, (then) chews a bit off and drops the rest,” said Undersander.
“If you’ve got it cut to a four inch length, you don’t have that feed loss…. (And) because she’s taking a bite-full at a time and isn’t having to chew as much to get it swallowed … she’s going to eat more.”
New Holland claims on its website that its bale slice system makes forage more digestible and can increase average daily gain in yearling heifers by 23 percent.
Francis Fluharty, an animal science professor and ruminant nutrition expert at Ohio State University, said New Holland’s claim is accurate.
“That is really reasonable,” Fluharty said. “Let’s think of animals on a forage diet, what is the limiting factor of a ruminant on a forage diet for intake? The gut-fill.”
He said cutting hay into shorter lengths increases the amount of surface area on the forage, which allows bacteria and fungi in the rumen to digest the hay more rapidly.
New Holland likely based its claim on research done by Gabriella Varga at Penn State, Fluharty added.
“(She) showed that … 30 to 70 percent of cellulose may never be digested. And this (cutting forage) increases the percentage that can (be digested).”
Research at Ohio State suggests that improvements in weight gain may be even more dramatic.
Scientists at the Ohio Agricultural Research and Development Centre in Wooster, Ohio, determined that steers fed a chopped hay diet gained 2.5 pounds per day, while steers fed the same hay in round bales in a rack gained 1.5 lb. per day.
Undersander said data clearly shows that cattle eat and digest more forage when the hay is cut to a shorter length. In an ideal world, he added, alfalfa or grass should be cut into four-inch lengths before entering the bale.
Undersander said bale cutters typically have knives spaced at one and three quarters to two inches apart.
“I recommend taking out every other knife and making these bale re-cutters, on the front (of balers), cut your hay into hay into a four inch length; possibly even a six inch length is fine,” he said.
“Four is about the width of the cow’s mouth … and the bales hold together better. There’s no reason to go shorter than that.”
Tyler Fulton, who operates a 500 head cattle herd near Birtle, Man., asked Undersander if the benefits of cutting forage applied to bale grazing.
“Your results are based on a (total mixed ration) or a bunker to feed those bales. We do a lot of bale grazing here…. Would your recommendations change based on that practice?”
Undersander said he hasn’t seen research on bale grazing but thought feeding losses would likely be reduced if the lengths of hay particles were shorter.
“The animals are still pulling a bunch of hay out of the bale when they need it. They’re chewing and swallowing a portion of that and dropping the rest on the ground. A lot of what they drop on the ground, it gets trampled and … they’re not going to eat again.”
However, Fulton said he wasn’t convinced because longer hay fibres keep bales intact. They would fall apart and more hay would be lost on the ground if the pieces were only four inches long, he added.
“There are a lot of (producers) that set out a paddock of bales for four days,” said Fulton, who also runs a hay export business.
“I would argue in that circumstance, with so much available to them, there would just be more waste (of feed) because it would just get spread out (more rapidly).”
Ray Bittner, a farm production adviser with Manitoba Agriculture, agreed that cattle digest more feed when they eat shorter pieces of forage.
A few dairy farmers in Manitoba do have pre-cutters on their balers, but beef producers don’t use the technology, he added.
“Most beef farmers take the opportunity to bale straw, when they can,” he said.
“If you chop (straw) up with a re-cutter, the bale won’t hold together.” Bittner said that would force cow-calf producers to require two balers.
As well, there is the risk that a rock will break a knife on the cutter.
“When you start breaking knives, bad things happen. You don’t want something sharp rotating through your belt baler,” he said.
“Under ideal fields (that are) well drum-packed … it’s an option, (but) not a lot of people take that option.”
Several calls to Manitoba ag equipment dealers confirmed that few beef producers buy balers with pre-cutters.
Beef producers have also been reluctant to adopt the technology in the United States because cattle producers don’t buy new balers often.
Fluharty said a new chop cut baler costs about $10,000 more than a regular baler. Nonetheless, he said the digestive improvements and feed efficiency gains compensate for the additional cost.
As an example, a friend of Fluharty’s in Ohio started using a baler with a chop cutter three years ago to feed a 300 cows.
The producer significantly reduced the amount of forage required to feed his herd by feeding shorter pieces of hay, in combination with a microbial feed additive called Amaferm.
“He has saved about 20 percent of his forage (use) during the winter … and cut his supplemental feed bill, two years ago, by $16,000.”