26 April 1996


UK cows could theoretically go from 0 to 100 PIN in 12 years by choosing the right bulls. Jessica Buss visits a Devon herd that is well on the way to securing that progress

MILK producers can have both type and production when selecting bulls for the herd, claims ADAS senior consultant Nick Holt-Martyn.

He does not believe that anyone should choose bulls on index alone – and advises a balanced approach to breeding. "Select for production first for that pays the bills, and then for type," he says.

He advocates selecting bulls first on PIN, ITEM or net present value (NPV: an ADAS value-for-money rating). Then choose for type, line breeding and also semen price, he says.

"It is important to accept that type has little economic value despite the best efforts of the statisticians." He cautions against thinking that because animals are culled when they breakdown to mastitis, for example, that can be related back to a particular udder trait."

He admits that bad experiences with extremely poor type Holstein bulls in the 70s encouraged the belief that high production bulls have poor type and longevity. But says that Holstein Friesian Society classifications now show a positive link between index and type.

Type traits Mr Holt-Martyn considers important for the future are foot angle, although generally this is improving, and udder depth. There are still too many bulls that are poor for udder depth, he says.

Generally Mr Holt-Martyn advises choosing bulls with a reliability of over 70%. The proof of a new bull can fall, he says, but equally their proofs can also rise and they could become an elite sire.

He approves of the Cogent bull proving scheme and predicts it has good potential because it is testing numbers.

Back to individual breeding policies, the herd should be assessed and bull selection criteria set. These should include production and one or two type traits. The list of selected bulls should then be ranked according to their economic value for that herd.

Mr Holt-Martyn then recommends selecting bulls from this ranked list that meet any further criteria, such as high reliability. "For commercial milk producers breeding each cow individually is a lot of trouble with a low chance of getting a heifer," he says. "It may be lower risk option but will result in herd variation (see box).

"When you are going to be open minded the list will include bulls from all sources and different companies," he says. "There is no single company that has the best production or type."

And he feels strongly that bull adverts should adhere to one system and that the data should be the latest available.

He warns that price is no indication of a bulls value. "American bulls are often expensive because they have low availability and high desirability," he says.

Mr Holt-Martyn also feels that now the distribution network is good and semen can move quickly, there is no longer a need to have bulls on stock and flasks full of semen. "Semen may be out-classed quite quickly unless it is from the very top bulls," he says.