High Dosage of Live Yeast for Transition Dairy Cows: Nutrition and Health Benefits

Two groups of 23 cows from a French commercial dairy farm (Control and Yeast) were constituted. Yeast cows received 10 g/d of live yeast (Saccharomyces cerevisiae Sc47 CNCM I-4407, Phileo Lesaffre Animal Care, France) during close-up phase and 20 g/d/cow for 21 d postpartum. Individual milk yield was recorded daily whereas fat and protein contents were evaluated monthly. Blood BHB content was evaluated +8 and +22 d after calving (Free Style Optium, Abbott). Body condition score (BCS) was evaluated -22, +8 and +22 days. Ruminal filling (RFS) was also evaluated on the basis of a scoring scale (1 to 5). Means comparison was done by student or Chi² test with significant difference reported for P ≤ 0.05 and trend discussed for 0.05 < P ≤ 0.15. Cows calved on 2016/01/21 with an averaged lactation rank of 2.11 (P > 0.9). Milk yield over the first 3 months of lactation was numerically higher for Yeast cows (34.6 ± 7.8 kg/d) than for Control (32.6 ± 10.2 kg/d). Milk fat and protein contents were not affected by treatment (Fat = 42.5 g/kg and Protein = 30.8 g/kg on average, P > 0.9). Blood BHB content at +22 days was significantly lower (P = 0.024) for Yeast cows: 0.79 mmol/L vs. 1.41 mmol/L, showing clearly less subacute ketosis cases. RFS and BCS at +8d were significantly higher (P < 0.01) for Yeast cows than control: 2.81 vs. 2.10 and 2.94 vs. 2.42, respectively. A total of 18 cows per group was returned to breeding (the others were culled) with a success rate at first insemination of 27.8% and 50.0% (P = 0.13) at 120 days of lactation whatever is the group (P > 0.8). High dosage of Live Yeast in peri-parturient dairy cows goes beyond the nutritional impact. In addition to improve animal performance, less lipid mobilization and better BSC in the first week of lactation led to better health and reproductive performances.