Agriculture Reference
In-Depth Information
Heredity and crossbreeding
Many farmers turn to the practice of crossbreeding to improve their herd performance. For ex-
ample, you might mate a cow from a high-yielding breed with a bull that is known for its fer-
tility or for its resistance to disease. Many farmers in the South use Brahman genes so their
herds can tolerate the heat. Farmers in the North may prefer breeding the Galloways for their
thick coat. Farmers who try to produce both milk and meat have success breeding traditional
dairy breeds with traditional beef breeds; for example, you could cross an Angus bull with a
Jersey cow. In crossbreeding programs, the best traits of each breed often surface in the off-
spring. A weakness in one breed can be offset by mating it to a breed that is strong in that
trait.
Mating two purebred animals can result in healthy, high-performing offspring by bringing out
the best from both breeds. Bringing out the best in both breeds is called
heterosis
, also known
as
hybrid vigor
. It is worth noting that purebred livestock does not mean registered purebred
livestock. Registered purebreds are bred for reasons other than performance on the farm, such
as lineage or because they look good in a show ring.
Should you decide to crossbreed your cattle, there are several strategies you can implement.
•
Crossbreeding using two breeds
:Forexample,youcouldcrosstwobreedsandthenmate
the resulting heifers with a purebred bull of one of the two original breeds.
•
Crossbreeding with three breeds
: You could cross two purebred breeds and then mate
the resulting heifers with a third breed. Some experts say combining three breeds can
bring out the best traits in all three breeds. For example, animals sired by Holstein bulls
would always be bred to Jersey bulls, and then those mixed offspring would be bred to
a Guernsey. The University of Kentucky recommends using colored ear tags to identify
the offspring of each sire — using one color for the Holstein's offspring, another color
for the Guernsey's, and another for the Jersey's.
•
Terminal crosses
: A terminal cross is the offspring of two purebreds that will be used for
beef but will not be rebred. The reason for terminal crosses is that the offspring of cross-
bred animals can be unpredictable. If you breed two crossbred animals, the calves could
comeoutlookinglikepurebredsofeitherbreed,orsomekindofmixture—therewillbe
no way to know beforehand.
