Quantitative analysis of the effect of bacterial probiotics on rumen fermentations and performances in dairy and beef cattle

Quantitative analysis of the effect of bacterial probiotics on rumen fermentations and performances in dairy and beef cattle Subacute ruminal acidosis is a major concern in nutrition of high-producing ruminants. Its prevention by supplementing diets with probiotic bacteria (PB) is a potentially effective strategy that should be considered in light of the ability of probiotics to positively modulate the ruminal flora and fermentations. A meta-analysis of 33 experiments (82 treatments) was made to highlight the effect of PB, used alone or associated with the yeast Saccharomyces cerevisiae (PB + SC), on ruminal parameters and animal performance of dairy and beef cattle. Although in beef cattle supplementation with PB or with PB + SC did not affect the average animal performance, in dairy cows, supplementation with PB + SC increased intake (+ 1.7 kg/day) and milk production (+ 2.36 kg/day) without affecting milk composition. The effect of probiotics on ruminal fermentations was inconsistent and relatively weak. However, for low initial mean pH values (pH < 5.75), supplementation with PB alone or PB + SC significantly increased the pH. Finally, although not included in the statistical model because of limited data, animal responses also appear to depend on the type of PB used. LETTAT A., MARTIN C., BERGER C., NOZIERE P., 2012. Analyse quantitative de l'effet des bacteries probiotiques sur les fermentations dans le rumen et les performances des bovins en production. INRA Prod. Anim., 25, 4, 351-360.