An examination of the effects of level of fish oil inclusion in the diet on rumen fermentation parameters in cattle

Abstract

The current milk quota regime within the European Community restricts both the volume and butterfat content of milk supplies from farms. Reduction in the butterfat concentration of milk enables an increase in liquid milk supplies, provided that the national butterfat base has been exceeded. In a concurrent study (Keady and Mayne, 1998) inclusion of fish oil in the diet of lactating dairy cows depressed butterfat content by up to 15 g/kg, consequently increasing the volume of milk which may be supplied in a quota situation by 0.27. The aim of the present study was to examine if the effects of fish oil inclusion on milk fat content were mediated via changes in rumen fermentation parameters.