A Poundmaker is a beef animal with greater than 25% influence of South Devon genetics. Breed type is not discriminated against as long is there is at least 25% South Devon represented in the animals pedigree. These animals are registered by the North American South Devon Association.
Why Crossbreeding is important
Crossbreeding not only allows cattle producers to compliment the best traits from multiple breeds of cattle, there is an added bonus to production that has long been held dearly by commercial cattlemen, heterosis.
Purebred cattle bred over long periods of time develop an increase in homozygosity for gene pairs of certain traits, thus allowing for more consistent distinguishable characteristics. However, this homozygosity leads to a reduction in some performance traits such as reproduction and fitness, which is called inbreeding depression. Crossbreeding, and more importantly the results of crossbreeding increasing the heterozygosity for performance traits, allows most crossbred calves to perform at a higher level. This recovery from inbreeding depression is termed heterosis or hybrid vigor.
"The cumulative effects of heterosis on traits that contribute to weight of calf weaned per cow exposed to breeding have been shown to be 23.3% for crosses among breeds of Bos taurus cattle and 50% or more for crosses between Bos taurus and Bos indicus breeds of cattle"
- Gregory and Cundiff, 1980
Heterosis affects traits differently, where the amount of heterosis expressed for a particular trait is inversely related to the heritability (the amount of variation for a trait attributed to genetics). Heritability gives producers insight to the degree at which they can select for a given trait for genetic progress to be realized. For traits such as maternalness, reproduction and longevity, crossbreeding offers a quicker alternative to selection to improve those traits within a herd.
Maximum benefits for heterosis can be realized in 2-way, 3-way crosses and 4 way crosses. With the introduction of rotating 4 breeds of cattle, maximum heterosis will be achieved.