Feed efficiency research for the beef cow
Much of the discussion regarding feed efficiency has always centered on the feedlot animal while ignoring the fact that roughly 70 percent of the production costs in a beef cattle herd go towards feed-related costs of the cows. Seventy percent of that figure goes to the cow’s maintenance feed costs with the remaining 30 percent spent to elevate the cow’s ration during the reproductive phase of her cycle.
The Residual Feed Intake to Improve Lifetime Productivity of the Beef Cows under Forage Based Beef Cattle Production Systems OR The Cow Efficiency Project began three years ago studying both young bulls and females to determine their individual residual feed intake (RFI). It focuses on forage-based rations that are typical of western Canadian beef operations as opposed to feeding high grain rations that many research projects have used in the past. The research is scheduled to run four to five years in length with continued monitoring throughout the life of the females involved. It is a tri-provincial project between Alberta, Saskatchewan and Manitoba.
The heifer phase of the program is now into its second year with 420 heifers of mixed breeds being fed and tested at the Lacombe Agriculture and Agri-Food Canada research farm, Kinsella (University of Alberta research farm) and the Brandon AAFC research farm. The individual feed intake data are accomplished using the GrowSafe individual feed intake measuring system. The beef breeds include Black Angus, Red Angus, Hereford, plus Gelbvieh, Charolais and Simmental crosses.
“While a group average for feed to gain is useful in a feedlot situation, it is of little value to a breeding herd where you want to make progress through genetic selection,” says Dr. Susan Markus, ARD Beef Research Scientist, and co-researcher on the project.
“RFI is the difference between an animal’s actual feed consumed, and the animal’s calculated feed requirements based on its body weight and ADG during a standardized test period. So RFI describes the variation in feed intake that remains after the requirements for maintenance and growth have been met. Efficient animals eat less than expected and have a negative or low RFI, while inefficient animals eat more than expected and have a positive or high RFI”.
Researchers have calculated that even a five percent improvement on feed efficiency could have an economic effect four times greater than a five percent improvement on average daily gain (ADG). If they can identify efficient cows or optimize the feed efficiency how she utilizes her feed, it translates into a huge saving for the cow/calf industry.
Using predominantly maternal breeds in the research which have proven more suited to a higher forage-based ration, the scientists hope to discover the relationships between RFI and female fertility and productivity. Because 20-30 percent of replacement heifers are culled from the breeding herd each year at the development cost of around $1,000/heifer, the cost to the industry is huge with these animals having no calf production.
The research team, partnering with Livestock Gentec, will use genomic technologies to genotype close to 1000 heifers to try to discover early indicators for long-term female fertility and productivity.
“The maternal beef breeds are historically best suited to a forage based diet and can perform extremely well under limited feed resources typical to the prairie conditions as opposed to the terminal,” says Markus.
“If we want to get a more accurate ranking we need to feed these animals the way they were designed to be fed while reserving that higher grain ration for the terminal breed in the feedlot. The heifers in this study will be fed a high forage-based diet of 90 to 100 percent barley silage.”
The research group recognizes that although there is now great tool to measure feed efficiency with RFI, it has to be taken into account with the other traits of economic value. For a cow/calf producer, fertility is 10 times more important than carcass traits and 5 times more important than growth traits. Single trait selection is never a wise decision or a practical goal to pursue.
“Measuring and selecting for the inputs and not just the outputs (i.e. weaning and slaughter weights) needs some attention for the beef operation to continue generating income, but also to enhance sustainability and reduce costs,” says Markus.
Dr. John Basarab, an ARD Beef Research Scientist, and lead researcher on this project has been studying the feed efficiency trait for about 15 years. He and collaborating scientists from countries such as Australia, Brazil, the U.S. and Ireland have come to the conclusions about what selection for feed efficient cattle means to the beef industry.
Selection for RFI (low efficient) cattle will:
• Have no effect on growth, carcass yield & quality grade
• Reduce feed intake at equal weight and ADG
• Improve feed to gain ratio by 10-15%
• Reduce net energy of maintenance and reduce methane and manure production (reducing the carbon footprint of cattle)
• Have little effect on age at puberty
• Have no effect on calving pattern in first calf heifers
• Have no negative effect on pregnancy, calving or weaning rates
• Have little effect on bull fertility
• Have a positive effect on body fatness or weight particularly during stressful periods
• Will reduce feed costs
To further make the point about the lower cost associated with feed efficient females, Fig. 6 shows two March 2011 born heifers from the AAFC research station in Brandon, Manitoba. On the left –RFI 0.483kg. Adj Yearling wt. 811 lbs., ADG=0.98 and on the right +RFI 0.333 kg. Adj yearling wt. 869 lbs., ADG 0.94.
NOTE: The heifer on the right will eat 204 kg. more feed to reach the breeding season (at approximately 1100 lbs.) than the efficient heifer on the left. For every five heifers like this in your herd, you use an extra tonne of feed over the winter period.
Fig. 7 with the two bottom cow/calf photos weaned calves of similar weights. Yet without knowing their feed efficiency, many producers would likely choose the deep-bodied, more feminine looking cow on the right as more appealing. But when you are told that this cow ate 2.83 kg. more per day (6.2 lbs.) than the average cow in the herd and 5.4 kg. (11.9 lbs.) more than the other cow (Figure 7), you may reconsider your choice after penciling out the impact on feed costs for a herd of inefficient cattle. Confirmation alone does not tell the whole story.
“The argument has been made by some producers that their 1100 lb. mature cow is more efficient because they are smaller,” says Markus. “But it’s important to remember that RFI is independent of body size and weight, average daily gain and backfat thickness and variation and extremes exist in all populations.”
Funders for this research include ALMA, Manitoba Rural Adaptation Council, Manitoba Agriculture, Food and Rural Initiatives, Alberta Beef Producers, Saskatchewan Cattlemen’s Association, Manitoba Cattle Producers. Plus in-kind support is acknowledged from Alberta Agriculture and Rural Development, Agriculture and Agri-Food Canada – Lacombe, Livestock Gentec, University of Alberta, University of Manitoba, Brandon Research Centre and Western Beef Development Centre.
By Bonnie Warnyca
Dr. Susan Markus, ARD Beef Research Scientist, and co-researcher on the project.