Mar 27, 2009
by WLJ

MIDLAND BULL TEST RFI gaining attention

As ranchers face everclimbing input costs, there is hope among some that producers will no longer have to sort through countless expected progeny difference (EPD) tables to assess the potential gains in profitability offered by a particular sire. Most agree that the quickest way to see a positive genetic shift within a herd is to introduce better genetics from a proven sire. The challenge, however, is finding the bull which offers the best chance of making his progeny more profitable than the generation before.

Weighing and balancing even a few EPDs is difficult enough, given the vast array of genetic options available. Fortunately, there are those within the industry who would like to see EPDs which directly translate to a reduction in input costs providing a simple measure for how much money can be placed back in the rancher’s pocket.

Leo McDonnell has been continuing the work started by his father when he founded Midland Bull Test in 1962. Starting with the goal of collecting and publishing as much data on purebred cattle as possible, the Mc- Donnells and others around the country have helped make breed information today more complete and accurate than it otherwise would have been. McDonnell has been gathering information on an EPD known as RFI, or Residual Feed Intake, for a few years now and began testing for RFI when he placed 400 bulls on an RFI feed test in the fall of 2007, a number that has since grown.

RFI can be considered an EPD which directly affects profitability as the difference between cattle with favorable (low) RFI values perform the same while using significantly less feed. Simply put, RFI is a measure of net feed efficiency which can be defined as the difference between an animal’s actual feed intake and its expected feed requirements. Efficient animals eat less than is expected and have a negative or low RFI, while inefficient animals eat more than expected and have a positive or high RFI. McDonnell’s commitment to place a high number of bulls on test has placed him as one of the largest suppliers of RFI data to date. A number of other bull testing operations around North America and the world are using similar technology to glean numbers from bulls on feed, but the equipment and testing involved are cost prohibitive in many cases, and many technical challenges stand in the way. “We have a number of people cooperating with us on this project and without their knowledge and expertise, we wouldn’t be able to do what we’re doing,” explained McDonnell.

“We are taking so many measurements and being so thorough, it is amazing. We get ultrasound data, take a weekly ration sample, weather data, bull weights every two weeks, etc. It’s a lot of work.”

McDonnell says his goals for the project are to gather enough data for a reliable EPD, one which could help breeders and commercial operators alike.

“What we’ve seen out of RFI research so far, it appears that there is potential for the ability to select cattle which are 15-25 percent more efficient than average,” says McDonnell.

“That’s a huge improvement. I also believe that low RFI cattle would do better in tough range conditions and during drought years.

Our test conditions are fairly tough and include very little grain and a high amount of roughage. If it translates to a cow in the pasture as well as we think it will, it would be a major benefit to ranchers to begin using low RFI sires.”

“I think it has the potential to completely change the way people select cattle,” McDonnell continued. “What the industry has already seen is cattle which are selected to gain well on high roughage diets do even better when they get put on a high grain diet. We haven’t really seen it the other way around. RFI has the potential to actually show us which genetics will produce feed efficient cattle, no matter what their diet is.” Gordon Carstens, professor of animal nutrition at Texas A&M University, says that while the idea of RFI was proposed long ago, the need for such an EPD and the technology to measure it have only recently come together.

“Broadly speaking, measuring efficiency in seedstock animals is expensive. RFI is one of the most difficult things to measure, but gives us useful indicator traits other than just pure feed intake, things like feeding behavior traits,” says Carstens. “The cost of measuring growth traits is very small, and the technology is such that anybody can do it. Weaning weights are not technically difficult to collect. To measure RFI, it takes technical expertise and an appreciation for the technology.”

Carstens explained that the work of translating RFI data into an EPD should move fairly quickly, but like any EPD, information in equals information out. “The data we are collecting from Midland Bull Test is going to be very solid and will be easily converted into an EPD, but it will always be a situation where the more information we have, the better,” said Carstens.

For those who see little difference between RFI and feed-to-gain ratios, Carstens says it is fairly simple to understand the differences and benefits of RFI. “A very key advantage of RFI over feed-to-grain ratio is that RFI is not genetically linked to growth. What it means is that we can select for efficiency without selecting for—or affecting— growth characteristics,” said Carstens. “We can select for improved RFI independent of growth, meaning things like frame score and feed intake are independent of each other.”

Carstens says he is optimistic about the possibility of seeing an accurate EPD for RFI in the near future. “I would say the horizon for seeing really usable RFI information is maybe analogous to some of the research we see going on trying to track down reproductive traits like heifer pregnancy.

We know how to do it, it’s just that we need a lot of data to produce an accurate EPD,” Carstens said. “We’re definitely getting there, and I think we’ll see some usable EPDs come out in the near future. When we do, it will be because people like [Leo] McDonnell knew that it was important for the industry to begin to select for input traits, as opposed to only output traits, and because of the different types of technology coming together all at once which will improve the identification of feed efficient cattle.” — Tait Berlier, WLJ Editor