The addition of Na-lactate (50-150 mmol/l) to media with glucose had o
nly marginal effect on the growth of rumen lactate-producing bacteria
al pH between 6.5 and 5.8. Butyrivibrio fibrisolvens was somewhat more
sensitive to external lactate than Streptococcus bovis, Lactobacillus
fermentum and Selenomonas ruminantium. It can be concluded that rumen
lactate producers, which proliferate at the onset of rumen lactic aci
dosis, are not influenced by the lactate accumulation, except some non
-specific osmotic effects.