16 February 1996

CROSS-BREEDING ADDS WEIGHT TO ARGUMENT…

CROSSBREEDING not only allows producers to use different breed characteristics, it also increases kg weaned a cow by 25% over the average merits of the parents, says Lee Leachman.

The disadvantage is that hybrid vigour affects reproductive efficiency. To overcome this, Leachman Cattle Company operates a tight mating programme which dispenses with the needs of synchronisation – yet still achieves a 92% success rate to first service on 2000 cows.

"We are able to do that because we AI all the cows. And the reason we do it is so that we can hand mate each of those cows," explains Mr Leachman. "We base those matings on estimated breeding values. Thats important because over time 87% of your genetics are explained by your bulls. So over three generations, if you keep all your replacements, 87% of genetics in your herd are determined by your bull."

Cows are kept in a 1214ha (3000-acre) paddock over the eight-week mating period. Six cowboys ride round from 6am to 11am and again from 5pm to 11pm watching for bulling cows. Their job is helped by Longhorn bulls which are used as markers.

"They are white so easy to spot against the cows which are either red or black. They also have horns so they dont bunch up and stay dispersed through the cow herd. They also dont get very big so they dont hurt the cow," he says

"Once a cowboy finds a cow in heat, she is trailed into a kraal. Twelve hours later she is AIed.

A computer print out which states which bull to breed to that specific cow so all he need do is pick his semen from the tank. That way you determine your future genetics on objective criteria." &#42