An alternative to get to a similar point of capturing a substantial level of heterosis in the cow herd and blending breeds for the strengths and to mask weakness, is to utilize hybrid or composite bulls. In general the term hybrid is used to describe crossbred parents and composites are the result of mating among crossbred parents. By utilizing crossbred bulls the herd can be managed very simply breeding as if purebred without a need to segregate cows by sire breed or sourcing outside replacements. After a period of years the breed percentages represented in the composite will stabilize and heterosis will be sustained at about 50% of potential for a 2 breed composite and 60 to 75% for a four breed composite depending on the percentage individual breeds are represented in the four breed composite.
While there are concerns and constraints associated with using hybrid and composite bulls, availability and use seems to be increasing significantly with research data, breeder promotion, and advancing genetic evaluation technology. Many bull sales in the northern plains now feature hybrid bulls, often finding strong market acceptance by producers. Breeding research with composites at the Meat Animal Research Center have found little differences between purebred and three MARC composite lines for variation in measured reproduction, production or carcass traits. Data collected on composite sired calves at the university on Nebraska teaching herd has further illustrated the value of blending of breed types in hitting both marbling and yield targets of finished steers, with 87% USDA choice or better with 66% yield grade 1 and 2.
The confounding effect of heterosis on an individual bull's performance record and the lack of accurate EPD's has and continues to be a concern. The adoption of multiple breed evaluations and cooperation amongst some breed associations to produce EPDs on a single base with appropriate adjustments for heterosis and utilization of genetic information on purebred parents are moving forward and will make it easier for genetic evaluation of hybrids.