Trimming the grocery bill
By John Maday
| Thursday, January 15, 2009
As the cost of food rises, we hear about consumers economizing. They’re switching from name-brand products to store brands, buying chuck roasts instead of steaks and shopping at Walmart instead of Whole Foods. Eating the same for less is the typical strategy, rather than eating less.
But in beef production, where producers have long pursued least-cost rations, the most effective way to reduce the cost of feed might be to feed less of it. Fortunately, research increasingly shows that some genetic lines of cattle can achieve the same performance as others but with significantly less feed.
Input costs have dropped considerably since their highs last summer, but margins remain tight at every production stage. “The value of improving feed efficiency does not depend on $7 corn,” says Colorado State University beef geneticist Denny Crews. “It’s always a good idea.”
New measures for a “new” trait
Crews, who was a research scientist at Alberta’s Lethbridge Research Center prior to recently moving to CSU, says interest in feed efficiency among researchers and seedstock breeders has grown over the past decade, and especially over the past two years with the dramatic increase in input prices. Feed, after all, represents up to 70 percent of variable costs in beef-cattle production.
At the same time, advancements in science and technology, including radio-frequency identification and data management, make the process of measuring and evaluating feed intake more practical and cost-effective.
GrowSafe Systems, an international company based in Alberta, developed technology for monitoring individual intake among groups or pens of cattle, using feeding stations that allow one animal to eat at one time. An RFID reader identifies the animal as it visits the feeder, while load cells under the feeder accurately measure changes in the weight of the feed. All the information is transmitted to a computer system using specialized software to track each animal’s daily intake. Users periodically weigh each animal, allowing the system to correlate individual intake with weight gain.
Crews says the GrowSafe system, or similar, custom-built systems, found initial use in research facilities. But as interest in selection for feed efficiency grows, commercial seedstock breeders and bull-test stations increasingly invest in the technology. CSU is preparing to install a GrowSafe system in its research feedlot and will join several other universities in conducting feed-efficiency research in coming years.
Another advancement toward selection for feed efficiency is application of the concept of net feed intake, also called residual feed intake, which is a more useful selection tool than feed-conversion ratios alone. Scientists define NFI as the variation in feed intake remaining after the requirements for maintenance and growth are accounted for. It is the difference between actual feed intake and the amount of feed the animal would be expected to eat based on its size and growth rate. An efficient calf eats less than the expected amount of feed and has a negative NFI.
The trait is moderately heritable, and by using the NFI measurement, breeders can improve feed efficiency with little or no change in growth or mature size. This contrasts with selection for feed conversion alone, which favors growth rate and leads to larger mature-cow size and higher maintenance requirements in the cow herd.
Lack of past selection pressure for NFI means wide variation among the cattle population and also offers potential for relatively rapid genetic progress.
Tracking intake and gain
One commercial operation that has invested in facilities for measuring individual intake is Leachman Cattle of Colorado. Manager Lee Leachman began evaluating bulls for feed efficiency several years ago, by maintaining small sire groups in research pens holding five to 10 animals. The group data was useful, he says, but they have since moved to a system for tracking individual intake.
With technical specialists on staff, the operation built its own system, using RFID, load cells on the feeders and proprietary software to collect and analyze 70,000 measurements per day. Leachman tested about 250 yearling bulls in the intake-monitoring facility this fall and plans to evaluate another 200 next summer.
The staff feeds 900-pound bulls at a rate of 2.5 percent of bodyweight, but Leachman says individual daily feed intake ranges from 15 to 30 pounds. On average, bulls in the test consume 7 pounds of dry matter for 1 pound of gain, but last year’s trial identified 13 bulls that converted feed at a 4.5-to-1 ratio.
Using artificial insemination, Leachman bred those bulls to more than 1,000 cows and will bring their bull calves back to the facility this year for progeny testing. He also turned eight of the efficient bulls out for natural service in a commercial cow herd and plans to collect performance data on resulting steer calves through slaughter and reproductive data on heifer calves as they enter breeding herds.
The goal, he says, is to demonstrate that by selecting for efficient bulls, producers also select for efficient progeny, in the feedlot or in the breeding herd.
Finding value in efficiency
Multiple studies have shown wide variation in efficiency. Leachman cites a trial at the USDA’s Meat Animal Research Center comparing feed intake and gains. Over a 140-day feeding period, one animal gained just under 600 pounds, while consuming an average of 18 pounds of dry matter per day. Another animal with the same intake gained just 440 pounds. Another steer gained 600 pounds but at an average intake of 25 pounds of dry matter per day.
Besides balancing efficiency with maternal traits, Leachman stresses the need to look at overall performance. His tests have shown that high-intake, high-growth bulls often turn out to be the least efficient, while some others that are well above average for efficiency fall short on performance. “Avoid extremely low consumption, low gaining cattle,” he says, “and any extremes in size and type. Make sure you are looking at total profit, not just part of the picture.”
For cow-calf producers, much of that profit potential needs to come primarily from more efficient cows. Crews says there is clear potential for commercial producers to improve returns by selecting replacement heifers from efficient sires, but the benefits are difficult to measure.
During his time in Canada, Crews participated in a feed-efficiency study relating performance of individual feedyard steers back to their dams. Over several years, researchers measured NFI in steer calves whose dams were part of a study population. After rating steers for NFI through finishing, they went back and looked at 10 years of performance data, including feed intake, on each calf’s mother. They found a strong correlation between efficient steers and low-intake dams.
Also, the mothers of efficient steers had no significant difference in birth rates, weaning rates, calf survival or calf growth compared with mothers of inefficient steers. The results mirror those of other studies that have found no negative or antagonistic effects between NFI and economically important maternal or carcass traits.
A 10 percent improvement in feed efficiency could provide significant savings to a cow-calf operation, Leachman points out. “One way to look at it is that you could run 110 cows for every 100 that you currently run. With 10 percent more cows and no change in feed costs, assuming an 85 percent calf crop and a calf value of $600, that’s $5,100, or $51 per cow returned to the operation.” Another way to look at it, he says, is that if your annual feed and land costs are about $300 per cow, a 10 percent savings amounts to $30 per cow.
Those benefits extend to efficient progeny through finishing. “What if we could reduce feed consumed per pound of gain by 1 pound, from six-to-one down to five-to-one?” Leachman asks. “If we assume yearling cattle will gain 500 pounds in the feedlot, that’s a savings of 500 pounds of feed on a dry-matter basis. At a dry-matter ration cost of $250 per ton or 12.5 cents per pound, that adds up to a $62.50 per head difference. For a 600-pound calf fed to 1,400 pounds, the savings is $100 per head.”
Continuing evolution
Practical application is the next step, Crews says. We know we can measure NFI, and we can improve efficiency through selection. Now we need to incorporate the data into a practical, meaningful selection system. Several breed associations are funding projects to build FE databases, toward the eventual goal of offering EPDs for intake, NFI or both.
Along with phenotypic measurements of actual individual intake, Crews says genetic evaluation of NFI using DNA markers is a technology of growing viability. Companies including Igenity and Pfizer Animal Genetics now offer ratings for NFI or feed efficiency in their DNA tests. Marker-based selection will continue to improve and become more cost-effective as companies add more markers to their tests and correlate their results with phenotypic measurements. Crews says the tests currently explain about 20 percent of the variation in feed efficiency, but just a few years ago, the tests probably accounted for just 1 percent of variation for the trait.
