Advantages of composite cattle
April 15, 2010
Composites are gaining in popularity today because they simplify the breeding program for a producer who wants the advantages of several breed traits. Instead of having to work at an elaborate crossbreeding program he/she can simply select the composite that most closely provides those traits; the animals are already mixed in a desired combination.
A composite is an animal created by mating two animals that have crossbred parents of similar breeding; in other words the breed “mix” is the same in sire and dam and has been standardized into a predictable blend over several generations of breeding crossbred to crossbred. The animals are all the same percentage of certain breeds, such as half and half of two breeds, or 3/8 of one breed and 5/8 of another, or a certain blend of three or even four or more breeds. Some of the “breeds” in use today like Brangus (a stabilized percentage of Angus and Brahman), Santa Gertrudis (Shorthorn and Brahman) and Beefmaster (Brahman, Shorthorn and Hereford) were some of the first composites. There are a number of very popular composites today, such as Angus and Gelbvieh, Angus and Salers, Angus and Chianina, several combinations of British and continental breeds, etc.
Traditional crossbreeding utilizes the rotational use various bulls of different breeds in a two or three breed rotation. This necessitates extensive record keeping and separate breeding pastures for the females in various stages of the program – and some uniformity is always lost because of the swings in percentage of the various breeds when using purebred sires. A more recent answer to some of these problems has been the development of composite blends of breeds. Using a composite bull on composite cows reduces the need for separate breeding pastures or rotating breeds of sire. The composite animal embodies the desired traits from two or more breeds. If the breeds chosen complement one another, and the composite has been created with careful selective breeding and enough genetic potential to avoid inbreeding, the calves are uniform and consistent – like a “super” breed. There is not quite as much heterosis as in F1 crosses, but still a significant gain over straightbred cattle. A composite utilizing two breeds that contribute equally to the mix will consistently deliver 50 percent heterosis. When four breeds are used equally to create the composite, heterosis is 75 percent, in each generation, continuing over time. The initial loss of heterosis in any crossbreeding program occurs between the F1 and F2 generations, but with a composite the remaining heterosis is maintained in subsequent generations of crosses – and how much is maintained depends largely on how may breeds are in the initial mix.
As pointed out by Dr. Michael MacNeil (research geneticist at USDA Agricultural Research Service at Miles City, MT, in 1998), a composite doesn’t need to have equal genetic contribution from the breeds involved. If one breed is better in certain desired traits than another, it can be represented more extensively in the mix. For instance, one of the composites developed early on at the Fort Keogh Livestock and Range Research center is made up of 50 percent Red Angus genetics, 25 percent Charolais and 25 percent Tarentaise. With this combination of the three breeds, the consistent heterosis is about 63 percent, in each successive generation.
The heterosis in a composite herd is retained indefinitely unless the crossbreds are inbred again. Inbreeding in a composite can happen if the composite was originally formed by using just a few purebred bulls from each contributing breed. In the formation of a composite, animal scientists recommend that the mix be based on at least 15 to 20 sires from each contributing breed. Once the composite has been established (all of the calves are a certain percentage of each parent breed, and the cows and bulls being bred are this same percentage), the vigor of the composite can best be maintained by using at least 25 bulls per generation, to keep the rate of inbreeding very low. Thus it is easier to create a viable composite using thousands of animals than it is for a rancher with a small number of cattle to create his/her own composite. It can be done, but will necessitate more infusions of “new” genetics (in the form of unrelated crossbred bulls added to the mix) every now and then. A number of ranchers are doing this, however, using an “open” composite approach, by continually evaluating/selecting and bringing in new sires (purebred or crossbred) or using AI, choosing new bulls and sometimes new breeds. In this way, much of the heterosis is on-going in each new generation.
Combining several breeds that complement one another (one breed adding strengths where another is weak) enables the stockman to match the cow herd more perfectly to various conditions and/or produce the type of calves that best meet a target market. For instance, many stockmen feel that using a mix of British and continental genetics comes closer to meeting some market requirements than either can do alone.
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Utilizing composites or crossbred bulls is often more beneficial to the cow-calf producer than using a terminal cross (breeding crossbred cows to a bull of a third breed that produces heavily muscled beef calves for market). The latter program creates super beef calves for market, but no replacement heifers. You have to buy your heifers; thus the genetic fate of your whole operation is in someone else’s hands. Many stockmen prefer to use a system in which they can retain some of their best heifers as cows, and most composite blends enable them to do this.
Composites also allow a stockman to reach a desired mix of breeds much more quickly than traditional crossbreeding, in fewer generations. For instance, if the goal is to have a herd that embodies 75 percent British and 25 percent Continental genetics (and starting with a British breed cow herd), achieving this mix would require two generations when using purebred bulls, and only one generation with a crossbred bull or composite bull embodying the two desired breeds to complement the cow herd and produce those percentages.
Some stockmen are still wary about composites, thinking that genetic variation (expressed as non-uniformity in the calves) would be greater than in a purebred herd. But Dr. Jim Gosey (retired Extension Beef Specialist, University of Nebraska) points out that a study of three composite blends and their parent breeds (research at USDA’s Meat Animal Research Center in Clay Center, NE) found no significant difference in the coefficients of variation for certain measured traits (reproduction, weaning weight, carcass weight, retail product percent, marbling, shear force and other carcass traits). The herds of composites had as much uniformity in the end product as the purebred herds.
According to Gosey, the commercial breeder can manage a composite herd just like straightbreds (with one breeding pasture), yet composites allow each stockman to use the genetic differences among various breeds to select, achieve and maintain a high performance level for many economically important traits – in a wide range of production environments and market targets. Composites enable a stockman with any size herd to use breed differences and heterosis simultaneously to tailor a cow herd for any specific climate adaptation, creating cows with optimum mature size, fertility and milking ability, producing calves with desired growth rate and carcass traits.
In one group of composites developed by the University of Nebraska at the Gudmunsdsen Sandhills Laboratory – in which the foundation bulls were carefully selected using bulls that were better than average in calving ease, average in milk production, average or below in mature size and above average in marbling and other carcass traits – the steers produced from this composite averaged 87 percent USDA Choice or better, and 66 percent yield grade 1 and 2, which meets the beef industry’s goals for finished cattle. Thus composites can provide the commercial cattleman with a practical way to enhance management efficiency and still increase profitability.
Many composites now take advantage of statistical methodology with EPDs that can be compared with the EPDs published for purebred bulls of the parent breeds. Producers who want to use composites have the same selection tools at hand for choosing their composite bulls as they do for choosing purebreds.