30 June 2000

Cow genotypes and production systems probed

By Emma Penny

THE influence cow genotype and environment play on cow performance is what SAC researchers are trying to discover in their project on matching dairy cows to production systems.

Speaking at last weeks Highland Show, SAC dairying specialist Mike Coffey said cows of different genotypes could not be expected to perform identically in the same system.

"This is an important issue. For instance, semen imported from North America is bred and tested in one environment, but we use it in the UK under completely different production conditions. We have assumed that genotypes perform identically in different countries, but that is not so."

The impact of different systems on genotypes could have an effect on health and fertility, said Mr Coffey.

"For each pedigree index unit increase for genetic production, cows can only eat half as much feed as they need, they make up the difference by mobilising body tissue, particularly in high concentrate systems."

While the project has been running for several years, the emphasis is about to change, with researchers taking a closer look at body tissue mobilisation and its effect on health and fertility.

"We are looking at whether we need different cows for different systems. It could be argued that most UK systems are similar, but some – such as organic systems – are significantly different. We hope to find out whether we need an alternative type of cow for these systems." &#42

BREEDING PROJECT

&#8226 Effect of environment?

&#8226 Cow genetic make-up?

&#8226 What about organics?