21 June 2002

Copper poisoning and better use of rape meal in dairy

cow diets were just some of the topics discussed at the

Society of Feed Technologists/Home Grown Cereals

Authority conference last week. Marianne Curtis reports

Could polyunsaturates influence cow fertility?

POLYUNSATURATES are beneficial for human health, but certain types could also help dairy cow fertility too, according to a recent study.

Royal Vet College researcher Claire Wathes fed first lactation dairy heifers diets containing either an n-3 polyunsaturated fatty acid (PUFA) supplement, LinPreme, an n-6 PUFA supplement SoyPreme or a control diet.

The initial objective of the study was to determine whether these could help make milk healthier for humans, but Prof Wathes also noticed the supplements had different effects on fertility of cows in the study.

"Cows on the diet supplemented with Soypreme had more variability in their ovulation time making it more difficult to time insemination correctly than those on LinPreme and the control. Those on the n-3 supplement were also more likely to show signs of oestrus than the other groups.

"In recent years, the n-6 PUFA content of cattle diets has increased with more oils being fed whereas the n-3 PUFA content has fallen, with a smaller proportion of the diet coming from grass."

However, Prof Wathes urges caution over interpretation of these results. "The study was only conducted on a small number of heifers. At least 200 would be required to draw conclusions."