Hybrid vigor, known as heterosis, describes the superiority in performance of crossbred animals compared to their parents. Crossbreeding, in which males and females of different breeds mate, allows breeders to obtain a genetically superior animal by combining the virtues of selectively chosen parents.
The different strength of characteristics of some cattle breeds is well suited to crossbreeding and the resulting hybrid vigor. For example, crossbreeding Black Angus and Hereford produces a hybrid known as a Black Baldy which are noted for their good mothering abilities.
The extra performance observed through hybrid vigor is simply the recovery of production losses that occurred through inbreeding in the parental breeds. However, hybrid vigor is reduced when crossbred cattle are mated together.
In Australia, many pure breeds have been crossed for hybrid vigor to create calves better suited to specific conditions, notably Angus and Devon cattle. Many northern cattle producers use Angus bulls to improve meat quality characteristics into their slaughter stock and aid breeding herd performance. The premiums paid in most markets for Angus have been a major incentive for many producers. Meanwhile, Devon cows possess many attributes that complement weaknesses in other breeds, including high weaning percentages, excellent feed conversion and high milk production. They are also credited with high resistance to bloat, no eye problems and an ability to adapt and survive in all Australian environments.
An example of a crossbred that has flourished in Australia is the Santa Gertrudis. Originally a mix of Shorthorns with Brahmans developed in Texas at the start of the nineteenth century, a Queensland ranch introduced the breed in 1952 with the importation of 75 bulls and 200 heifers. From these small numbers, it has spread to all States of Australia and many breeders have now reached the fourth cross, producing purebreds for classification and registration.
With the challenging economic climate of the cattle industry, crossbreeding is an increasingly useful tool to help reduce wasted costs and enhance productivity. It has been used throughout the world and there is ample evidence to support the production gains possible from crossbreeding.
Industry experts argue a well-designed, manageable crossbreeding system is vital in making genetic progress in the various economically important traits that drive profitability in today's beef industry. The key characteristics in cattle that can benefit from such programs are reproductive efficiency, maternal performance, growth and feed efficiency and quality of meat.