17 August 2001

Four-way cross keeps vigour

Putting US research on beef

breed performance into

practice may be the key to a

profitable future for small-

scale suckler producers, as

Jessica Buss finds out

PRODUCING home-bred four-way crosses will maintain hybrid vigour in suckler herds that move away from dairy-bred stock, says one West Sussex breeder.

Gordon Bell explains breeding four-way cross females with four-way cross sires produces stock which keep 75% of the hybrid vigour of a first cross animal. The result is a higher weaning weight/cow put to the bull and longer lasting cows than are achieved by any of the pure breeds, while keeping cow maintenance costs as low as a Hereford x Angus.

"This has been proven in US research where four-way crosses were monitored for five generations to see if hybrid vigour was eventually lost," he says. US research at the Clay Centre, Nebraska, shows a 23% rise in weaning weight/cow put to the bull. This performance measure also takes into account maternal abilities as well as growth.

In addition, the US grading scheme favours a carcass of 50% British and 50% Continental composition because it has both tenderness and good conformation. Should this, or a similar scheme, be taken on in the UK, composites will grade better than either a Continental or British-bred animal, says Mr Bell.

"Rotational breeding has been tried in many US herds, small herds run into difficulties because too few of each cross means they have to keep extra bulls for ideal matings on all groups. These herds also produce a wide spectrum of animal types so there is no uniformity in progeny. These problems do not happen with a four-way cross, which is a quarter of each breed."

There is a concern, that crossbred sires will not produce uniform progeny either. It has also been suggested that eventually the progeny of crossbred bulls will revert to one of the breeds making up the cross. But Mr Bell says there are hundreds of genes at many different locations on the chromosomes that control aspects of performance, such as growth.

In a four-way cross, broadly, one-quarter of the genes is derived from each of the breeds involved. It is inconceivable that breeding from such an animal could result in progeny with genes from only one of the original pure breeds. But it is possible for some four-way cross animals to have a white face, as this is controlled by only a small number of genes, he adds.

Composite animals are now being brought into the UK. Mr Bell has used some imported composite embryos, but he believes that four-way crosses could be successfully bred using genetics available here. This will remove the need to go back to the US to buy in new bloodlines that are essential to prevent inbreeding and the consequential cost of losing hybrid vigour.

Using the US composite technology and applying it to breeds successful in the UK will also allow animals to be bred to suit farm circumstances. "In part of the UK with harsh weather, producers may want to select a hardy breed as one of the four used," he suggests. The original composites in the US were designed on paper using the results of the individual breeds. This allowed the researchers to predict the performance of various possible crossbreds and match this to the desired traits of suckler cows.

To produce composites, two crossbred animals are mated, so that the result is a quarter of each breed. Mr Bell has begun the process of producing the first crosses at Home Farm, Summers Place, Billingshurst.

His 125-cow Simmental-based suckler herd, which includes 30 pedigree animals, has now been bred to a Red Angus bull to produce two-way crosses. He has also contracted a Hereford breeder to use a Gelbvieh sire. Next year, he will cross these to produce his own four-way crosses. These initial four-way cross heifers will be flushed for embryos to increase the number in the herd quickly.

But the performance of these crosses is yet to be seen. Stock will continue to be recorded through Signet, so imported and home-bred composites can be compared, says Mr Bell. This will allow him to check that home-bred animals will perform adequately compared with imported ones. "If they do not we will need to grade up their performance by using bulls with imported genetics," he says.

FOUR-WAYCROSS

&#8226 Good hybrid vigour.

&#8226 Using UK genetics.

&#8226 Aiming for fast-growing calf.