Abstract

Most cows fed fresh forages containing clover or lucerne have a foamy rumen digesta. When the foam becomes persistent (stable), gasses from fermentation become trapped and the cow bloats. Samples of foam and rumen liquor from bloated and non-bloated cows fed freshly cut lucerne or red clover were analysed to determine differences that may account of foam stability. In a bloated cow the density of rumen digesta falls from about 950 to 600 or 700 g/l and the foam has a density of 200 to 300 g/l. Analysis of foams showed no difference between bloat and non-bloat samples in dry matter (DM)(7.8%) nitrogen (94 mg/g DM) or chlorophyll (7.4 mg/g DM), but bloat foams had a higher lipid concentration (57 mg/g DM) than non- bloat foams (40 x 10 7/gDM). The significance of these observations are discussed in relation to foam stability.

BJ, McKay

Proceedings of the New Zealand Society of Animal Production, Volume 48, , 127-130, 1988