Crossbreeding for profit
Crossbreeding is probably the most misunderstood and underappreciated practice in commercial livestock production. Crossbreeding is the mating of males and females of different breeds or breed types. Purebreeding is the mating of individuals of the same breed or type. Crossbreeding is the recommended breeding strategy for commercial meat sheep and meat goat production.
As a breeding practice, crossbreeding does not denote the indiscriminate mixing of breeds. Rather, it is the systematic use of breed resources to produce offspring of a specific type. For example, a "terminal" crossbreeding program uses a male of superior growth and carcass merit (e.g. Suffolk or Boer) to produce lambs or kids for the slaughter market, while maintaining moderate sized females that excel in fitness and reproductive performance. All offspring from a terminal cross are sent to the slaughter market (i.e. "terminated"). Another crossbreeding scheme could be aimed at producing crossbred females of a specific type (e.g. Spanish x Kiko or Dorset x Finn) for breeding.
Crossbreeding offers two distinct advantages over purebreeding: heterosis and breed complementarity. Heterosis or "hybrid vigor" is the superiority of crossbred offspring to their purebred parents. Mathematically, heterosis is the percentage increase in a specific trait (e.g. weaning weight) that progeny have over the average performance of their parents. Heterosis is highest for traits that do not respond well to selection, e.g. fitness and reproductive traits, and lowest for traits that respond well to selection, e.g. carcass and fleece characteristics. Heterosis occurs in both the crossbred offspring and the crossbred female. Crossbred lambs and kids grow faster and have higher survivability than their purebred counterparts. Crossbred ewes are more fertile and wean 15 percent more pounds of lamb than purebred ewes. Less is known about heterosis in crossbred males, but it is believed that...
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