6 November 2008

3 minute read

Europe

Using a new method – genomic selection – can save cattle breeding huge amounts of money and provide much quicker genetic progress.
Photo: Janne Hansen

A bull does not yield milk, does not get mastitis and does not give birth to calves. So how does one go about evaluating if a bull can pass genes for high milk yield, healthy udders and fertility on to its daughters? Until now, dairy cattle breeders have had to wait for the results from progeny tests, which are physical proof of what kind of daughters the bull can produce. It normally takes five to six years before evaluation of a bull’s breeding value is accurate enough to decide whether he should sire thousands of calves or be slaughtered.

The time-consuming progeny tests may soon be a thing of the past. Instead, the crucial decision about the bull’s future can be taken already at birth. This can be done with the aid of a new tool called genomic selection.

- The effect of using genomic selection is a quantum leap for cattle breeding and perhaps the greatest technological advance since the introduction of artificial insemination, says the team behind the project. The team consists of scientists from the Department of Genetics and Biotechnology at the Faculty of Agricultural Sciences, Aarhus University.

The project is financed by the Danish Food Industry Agency (Innovation Law), Danish Meat Association, and VikingGenetics. The latter are already prepared to use the first version of the new technique.

The team of scientists has great expectations for the new technology, which they believe can increase genetic progress by 50 percent, corresponding to an increase in just over three S-index units per cow compared to the present two units per year. The additional breeding progress for the Danish dairy breeds corresponds to almost one billion Danish kroner over a period of 10 years.

At first the technique will be used to select bulls for progeny testing. This means that the poorest bulls can be culled at a very early stage. Holstein in Denmark and Sweden is the first breed on which the new technique will be used. Later on, it will be used on the red breeds in Denmark and Sweden as well as on Jersey cattle.

Technique ready

The technique is based on calculating the total effect of the bull’s genes using a large number of marker genes. The Danish team of scientists used reference material that includes about 2,000 bulls that have had approximately 54,000 markers genotyped to build up the model. The bulls each have about 100 daughters contributing information about a wide range of production traits.

- When the cattle genome was sequenced a few years ago it resulted in an explosion in the number of markers on the genome. We can now use the method for just about all traits in the breeding goal, that is, milk yield, resistance to mastitis, calving ability, fertility, and longevity, says head of research unit Mogens Sandø Lund, who is one of the scientists on the team from the Faculty of Agricultural Sciences.

One of the strong points of Danish cattle breeding is that there is systematic registration not only of production traits, such as milk yield, but also mastitis and other diseases. This means that genomic selection can already now be used for these traits in Denmark – as the first place in the world.

- This could be a bit of a revolution in breeding work, predicts Mogens Sandø Lund.

- Theoretically, the accuracy with the new method is much higher than with progeny testing, but science has not progressed that far yet. We are therefore planning a five-year project in order to achieve the full benefits of genomic models, he says.

TheCattleSite News Desk