Prevention of acute ruminal lactic acidosis in sheep by probiotic or monensin supplementation: clinical aspects

The aim of this study was to evaluate the effects of two additives (probiotic and monensin) over clinical parameters of sheep submitted to acute ruminal lactic acidosis (ARLA). Eighteen sheeps were divided into three groups of six animals each as follows: probiotic group, supplemented with 4x10(9) CFU/animal/day of Saccharomyces cerevisiae; monensin group, supplemented with 33 mg of monensin sodium per kg of diet; and control group, without any supplementation. After 30 days of diet (75% of Coast-cross hay and 25% concentrate with 14% of crude protein) and additive intake, ARLA was induced in the all animals by intraruminal administration of 15g of sucrose per kilogram (kg) of body weight. Complete physical examinations to assess the vital signs of the animals were conducted at the following times: baseline (T0), six (T6h), 12 (T12h), 18 (T18h), 24 (T24h), 36 (T36h), and 48 (T48h) hours after ARLA induction. At those times, blood samples were obtained to determine the plasma volume deficit (PVD) and ruminal content for pH measurement. All animals experienced clinical signs of ARLA with ruminal pH lower than 4.9 at T24h. The heart rate and PVD were lower (P < 0.05) in the probiotic group at T36h. Compared to the control and monensin groups, the probiotic group experienced milder ARLA characterized by lower degrees of dehydration and fewer clinical symptoms.