Source: North American Limousin Foundation
Every crossbreeding system has its advantages and disadvantages, cattle experts agree, so producers must evaluate programs in terms of providing the best possible performance within their own unique situations.
Scott Greiner, Ph.D., an Extension animal scientist at Virginia Tech, said an ideal crossbreeding program should optimize, but not necessarily maximize, hybrid vigor (heterosis) in both the calf crop and, particularly, the cow herd; use breeds and genetics that match the enterprise's feed resources, management and marketing strategy; and be easy to apply and manage.
Cattle producers should find a way to capture heterosis in their herds, said Gary Hansen, Ph.D., an Extension livestock specialist for North Carolina State University. He noted that breeds from diverse genetic backgrounds will express higher levels. For example, British breeds crossed with each other will result in less hybrid vigor than when crossed with Continental or Bos indicus breeds.
Cathy Bandyk, Ph.D., an animal scientist at Quality Liquid Feeds, Dodgeville, Wis., said some basic points always apply when selecting breeds: local availability of breeding stock that meet the specifications; complementarity of the breeds used; cows and calves that fit available resources and the local environment; and crosses that produce animals suited for the target markets.
Concerning that last point, Greiner advised, "specifically include the targeted carcass-merit end point. Considerable differences between breeds exist and may be effectively utilized by crossbreeding.”
When constructing a crossbreeding plan, each breed should help meet marketing objectives and enhance the quality of calves, said Matt Spangler, Ph.D., a beef geneticist at the University of Nebraska-Lincoln. He cautioned, however, that expected progeny differences (EPDs) are not helpful in selecting between breeds because EPDs from one breed are not directly comparable to those of another.
He noted, although, that producers can use the U.S. Meat Animal Research Center's (USMARC's) across-breed adjustment factors to categorize breeds based on their genetic potentials for certain traits. He suggested looking at the existing herd composition then choosing another breed that complements those cattle.
Hansen also encouraged producers to use the breeds that are the most economically productive for their enterprises and management styles, reminding them that no single breed is best at everything.
For example, Greiner offered, coupling the British breeds' general advantages in marbling potential with the Continental breeds' red-meat–yield advantages results in offspring that have desirable levels of both quality grade (marbling) and yield grade (retail yield).
Today's genetics offer the opportunity to stabilize coat color and polled status while maintaining a crossbreeding program, he added. Technological advances, such as DNA genotyping, have made it possible to manage such qualitative traits in several breeds; therefore, they do not need to be limiting factors.
Hansen encouraged commitment: "Use breeds that complement each other. Do not become the ‘bull of the month' club with your bull battery.”
Utilize the various breeds' strengths for a viable crossbreeding system, Greiner said, and maintain uniformity from one generation to the next with sire selection – both within and between the breeds.
"Bull selection within a breed is equally important,” he explained. "EPDs are very useful and important tools in accomplishing that task.”
Spangler agreed that EPDs and economic indexes are necessary for choosing individual animals.
"Those tools really center on the genetic aspects of individual animals,” he said.
A crossbreeding program requires quality cattle if it is to outperform straightbreeding and produce a product that meets consumer demand, Hansen stated.
"Crossbreeding will not overcome poor genetics,” he said. "Use quality animals when selecting the bulls to use in your herd.”
Greiner noted several factors and challenges to consider when evaluating different crossbreeding systems: the number of cows in the herd; the number of available breeding pastures; labor and management; the amount and quality of feed available; the production and marketing systems; and the availability of high-quality bulls of the various breeds.
Bob Hough, Ph.D., executive vice president for the North American Limousin Foundation (NALF), listed a few more items: a source of replacement females, identification and recordkeeping systems, matching biological types, and fitting the production environment.
"The ‘ideal cow herd' and breeding program vary depending on the area in which the enterprise is located, the product and the target market,” he explained. "Once you have analyzed those aspects, you can design and implement a crossbreeding program that will help you achieve your production goals and marketing plans. The system must fit practical constraints.”
Overall, the cumulative effect of crossbreeding when you consider several traits is more important than the effect on any one particular trait, Greiner reiterated, so you must design effective crossbreeding programs to optimize performance, not necessarily maximize it.
"Still, a major challenge to making a crossbreeding program work is keeping the system sustainable without sacrificing optimum levels of heterosis and breed complementarity,” he cautioned. "A well-designed, manageable crossbreeding system is an important aspect in making genetic progress in the various economically important traits that drive profitability in today's beef industry.”
The North American Limousin Foundation (www.nalf.org), headquartered in Centennial, Colo., provides programs and services – including genetic evaluation of 5,000 active sires – to more than 4,000 members and their commercial customers.