Spoiled teenagers certainly aren’t a rarity, and the same can probably be said of the cow equivalent of a teenager —the yearling heifer. However, 10 years of research at the USDA-ARS Ft. Keogh Research Facility in Miles City, Mont.,
has shown that spoiling developing heifers with a bounty of feed is about as productive…and financially sound…
as spoiling the average teenager.
“Industry guidelines for the last three to four decades have been to develop a heifer to 60 to 65 percent of expected grown cow weight,” says Andy Roberts, USDA research scientist. “Many animals can get by on a lot less feed than what is required to reach that weight. By feeding the whole group to that level, we are actually propagating inefficiency.” Reducing feed. Instead, Roberts encourages producers to gradually reduce feed rates to developing heifers,hopefully sifting out inefficient heifers that won’t perform on rangeland or when conditions are harsh.
The big concern with cutting feed to developing heifers is that it will reduce conception rates. But Roberts disagrees. “To me, the best time to challenge reproduction is on heifers because open heifers are still a very high dollar commodity item.”
A decade of research on thousands of calves, however, shows that conception isn’t dramatically impacted by restricting feed. Calf groups receiving 27 percent less feed than control groups weighed 5 percent less at turn out, but conception rates on both groups averaged 88 to 90 percent.
Rich Roth recorded similar results when he cut back heifer rations on his family’s Big Sandy, Mont., ranch.
With 3,100 cow/calf pairs, the IX Ranch weans 1,500 yearling and raise a calf on rangeland.
“We want to develop heifers that are genetically predisposed to breedup in rangeland conditions. Instead,we were falsifying conditions early in life and expecting them to perform the same when conditions weren’t so ideal,” Roth says of his experience. In 2009, the IX Ranch stopped feeding their replacement heifers a grower ration. Weights at turnout dropped from about 685 pounds to 626 to 660 pounds (the result of a combination of selection and feed). Their 30-day breeding season conception rates averaged 76 to 84 percent —not much different from years past.
Trade-offs. The USDA study continues following heifers and their offspring that received restricted rations.
Roberts reports that calves coming from the more efficient cows, even years down the line, seem to be more efficient, too. But they can be a little lighter. Cows developed on restricted feed and fed less during the winter
that were themselves products of a restricted diet dam produced calves that were 3 to 4 pounds lighter at birth and 10 pounds lighter at weaning. However, less money went into feeding that cow, and she’s more likely to produce
a calf — an efficient one at that. heifers…a lot of hungry mouths to feed. Prior to
2009, replacement heifers were weaned in lots and fed a grower ration. But the rest of their lives, they were expected to breed up“Calves from cows that had a restricted diet are changed. The simple way to describe it is that they’re drought resistant,” Roberts says. “They perform better with less feed.” Heifers that have been restricted in lots also convert forage more efficiently when turned out on pasture. “Their organs are smaller,
and organs are what use the majority of calories,” he explains. “Smaller organs
mean more will go toward gain.” From 2007 to 2009, IX Ranch heifer development cost $1,500 to $1,700.
Now it’s $1,100 to $1,200 due in part a reduced feed bill. “We have reduced what it costs to develop heifers and haven’t seen an adverse impact,” Roth says. “We’re realizing there is some wiggle room in our rations.”