Body fat genetic test promises

Longer lived, more fertile cows could be on the cards for UK dairy herds following the launch of a new genetic test by Merial Ingenity.

Poor fertility in dairy herds is often caused by negative energy balance in early lactation, something the new test can select against, explains Ingenity development manager David Bonsall.

The test, Duramax, which is now available in the UK as part of the Ingenity testing package, identifies cows carrying more body fat in early lactation.

“Duramax identifies cows which lay down more body fat no matter what yield they are giving.

The key is being able to identify cows with good body fat levels which still have the high yields needed by today’s dairy farmers.

We need to select cows which can give high yields consistently and get back in calf.”

Animals able to do this are identified by variations in the leptin gene which has three possible genotypes, one with two copies of the Duramax gene, one with one copy and one with none.

Bull Selection

“One of the main uses of the test will be identifying the status of potential breeding bulls.

Those with two copies of the gene and superior genetics for other key traits, such as yield, will leave daughters capable of giving plenty of milk and breeding again within a good timescale.”

Mr Bonsall says limited data means it is difficult to judge the number of UK cattle currently carrying the Duramax gene.

“However, when farmers begin using Duramax select sires there should be rapid improvement in the numbers of cows carrying the gene, leading to significant improvements in herd fertility.

“USA experience also shows cows carrying the Duramax gene are less angular and extreme in type.

These cows tend to have longer productive lives,” he explains.