Science - November 5, 2009

Less trans fatty acids could improve fertility of cows

The dairy industry in the Netherlands could breed Holstein-Friesian cows that produce less trans fatty acids in their milk. A lower concentration of trans fatty acids does not only improve the nutritional quality of the milk for human consumption, but is also likely to improve the reproductive performance of the cows.

This conclusion was drawn by Animal Breeding and Business Economics researchers of Wageningen University in the latest issue of Journal of Dairy Science, after analyzing data from 1745 Holstein-Friesian cattle.
Researcher Robert Demeter examined whether changing the fatty acid composition of milk by selective breeding would influence the reproductive performance of the cattle. Most unsaturated fatty acids have a positive effect on human health, human nutritionists state, but the trans fatty acids increase the chance of coronary heart disease and bad cholesterol. Cows produce several fatty acids, Demeter examined the influence of nine groups of them on the reproduction of the cows. He showed that cows with lower levels of trans fatty acids had a significantly better reproductive performance, whereas the other fatty acids had no influence on the animals’ fertility.
Milk Genomics
The research was part of the Dutch Milk Genomics Initiative, sponsored by the dairy industry and Dutch government, that aims to improve the quality of milk.
‘This is a promising result’, says Demeter. ‘The dairy industry can start breeding programs to produce milk with higher level of unsaturated fatty acids or lower levels of trans fatty acids with no negative impact for the animals’ reproduction.’