Abstract

A simplified method to measure foam volume (V infinity) and stability (1/k2) was used to investigate the influence of saliva on foam properties and its relationship to bloat susceptibility. Significant differences in V infinity and 1/k2 were observed between samples of rumen fluid (within-sample CVs were 9% and 18%, while between sample CVs were 57% and 70% for V infinity and 1/k2, respectively). Mixing bovine saliva with rumen fluid or diluted clover juice resulted in a large increase in V infinity and 1/k2 (4.6- and 7.8-fold, respectively). This effect was strongly synergistic as saliva alone produced essentially no foam. The assay was used to quantify the efficacy of a paraffin-based anti-bloat drench (V infinity and 1/k2 were decreased by up to 4-fold and 6-fold, respectively). Saliva from non-bloating cattle, four each from herds bred for low- or high-bloat susceptibility, was measured for the effect on the foam parameters of a rumen fluid sample. No significant differences due to herd-of-origin were observed.

SA, Hurd, TT Wheeler, and CA Morris

Proceedings of the New Zealand Society of Animal Production, Volume 60, Hamilton, 277-280, 2000