News Update
April 15, 2009

K-State Beef Research Examines Effects of Breeding for RFI in Heifers

With feed costs such a significant portion of beef production, animal scientists at Kansas State University  (K-State) recently finished a study on heifers that were sired by bulls chosen for their genetic residual feed intake (RFI) merit.

What they found, said Jennifer Bormann, a researcher with K-State Research and Extension, was that although RFI has been shown to be moderately heritable, heifers that were sired by bulls with low RFI merit performed no differently than heifers sired by bulls with high RFI merit.

RFI is the difference between what an animal eats, and what it is predicted to eat, based on its size and growth. Animals with negative or low RFI eat less than is expected for their level of production, and are more efficient than animals with a high RFI. A low RFI is more desirable because that animal can more efficiently and inexpensively turn feed into beef.

“RFI has become the measurement of choice in the beef industry, but there is not a lot of research about how cows (dams) fit into the picture or if the heifers would fare differently on a more concentrated diet than the one we fed,” she said. She presented the study’s findings at K-State’s Cattlemen’s Day in March.

 “Previous research has shown that RFI is moderately heritable,” the researcher said. So she, along with colleagues Dan Moser, of K-State, and Twig Marston at the University of Nebraska-Lincoln, studied how heifers sired by bulls with high and low RFI ratings would fare when it came to their own RFI ratings.

To begin the study, bulls with low or high genetic merit for RFI were selected from the Australian Angus Association sire summary and mated to Angus cross commercial cows at K-State’s Cow-Calf Unit in 2005 and 2006.

“There were no significant differences between heifers sired by low or high RFI EBV (estimated breeding values) system bulls in RFI, feed intake, feed conversion ratio or gain,” Bormann said.
Heifers in the study were developed at a relatively low rate of gain, she noted. Genetic differences in RFI calculated in growing bulls may not have been expressed on the lower plane of nutrition of the developing heifers.

Heifers sired by low RFI bulls in the study also had more rump fat and tended to have more ribeye area and intramuscular fat.

“Our results indicated that selection for RFI should not negatively impact carcass quality,” she said.

There is no doubt, Bormann said, that a producer would prefer to breed for animals that are as efficient as possible at converting feed to high-quality beef. But there is much still to be learned about selecting for RFI in beef breeding programs. Several other universities are also studying various aspects of the practice. K-State will continue studying the issue to try to determine the best practices when selecting for RFI.

“The bottom line,” said Bormann, “is that as selection for RFI becomes more adopted by the industry, the relationships between diet, growth rate, body composition, and RFI in heifers need to be better understood.”

More information about beef research at K-State is available on the university’s Department of Animal Science and Industry web site: http://asi.ksu.edu.

— Release provided by K-State Research and Extension.

Fertilizing Pastures

After adding a 100, 60, or even just 40 pounds (lb.) of nitrogen (N) per acre to your pastures in past years, did your grass grow really nice in April and May? Then did it get stemmy in June with cows trampling and laying on it more than eating it? And by August was most of the grass brown or dead, much of it matted down, with the only green material so short that cows could barely get any of it?

If this describes your pastures, do something a little different this year. For starters, don’t fertilize all your pasture right away. You’re stimulating more spring growth than your cows can eat, so only fertilize half or three-quarters of your pasture now. Be sure, though, that the unfertilized area is fenced off from the rest of the pasture.

Now, go ahead and have your cows graze pretty much like you normally do but be sure to graze the unfertilized area so you finish with it sometime in mid-May. Then check the weather and soil moisture. If you think there will be enough moisture for some good regrowth, then fertilize this previously unfertilized area. Let it regrow for six weeks or longer and you should have some really good grazing available for July or August.

What if it’s dry in mid-May with poor prospects for regrowth? In that case, save your money and don’t apply any more fertilizer. You still will have produced about as much pasture growth as if you had fertilized everything to begin with, but without spending as much.

If your pastures are overgrown in spring and run out in summer every year, change fertilizer timing. You’ll get more grass when you want it or maybe save some money.

— by Bruce Anderson, professor of agronomy, University of Nebraska-Lincoln

JBS to Sell $400M in Bonds

JBS S.A. said Tuesday the company is offering $400 million in bonds to raise cash amid an international credit crisis, according to Meatingplace.com.

“Through this offering, the company intends to balance debt with revenue geographically and improve its short-term liquidity. The offering also intends to increase the cash position of the company,” JBS said in a statement.

The notes will be offered and sold to buyers in the United States through its JBS USA unit and are scheduled to mature in 2014, Meatingplace.com reports.

— Information provided by Meatingplace.com.

— compiled by Crystal Albers, associate editor, Angus Productions Inc.