Evaluation of two commercially available rumen buffers derived from calcified seaweed for grazing dairy cows: Pilot trial in commercial farms

Resumo

Calcified seaweed (CS) based products have been proposed as an alternative ruminal pH buffer to sodium bicarbonate. It has been reported that magnesium can aid in ruminal pH control too, especially those natural marine forms. We assessed the rumen buffer capacity and milk production and milk composition of two CS: Acid Buf (AB) compared with M12 (a natural marine magnesium enriched CS) on grazing dairy cows in a replicated Latin Square design involving 2 farms with the dairy herd in good sanitary and health status, 2 supplements and 4 measurements periods of one month each. Holstein Friesian dairy cows fed with a partial mixed ration (PMR) were supplemented for 30-d periods with either AB or M12. Total milk production and milk composition were measured in each farm, and five cows in each herd had rumen boluses for the monitoring of ruminal pH, allowing us to identify and monitor total subacute ruminal acidosis (SARA) events (i.e., = 2 h with pH < 5.8). The average pH during the experimental period was 2% greater (p < 0.05) and the number of SARA events per cow was lower (p = 0.007) for cows supplemented with M12 compared to AB. If only the cows that developed SARA events were considered, M12 showed a trend (p = 0.068) to reduce the number of SARA events and their duration compared to those cows supplemented with AB. Milk production and composition were similar between both rumen buffers at all periods.