Effect of Propionibacteria Supplementation on Yield of Milk and Milk Components of Dairy Cows

A well-managed, high-producing commercial dairy herd was used to test the impact of dietary propionibacteria (Propionibacteria freudenreichii, P169) supplementation (6 × 1010 cfu/d per cow). Inclusion of propionibacteria in the diet increased (P < 0.05) milk production (44.31 and 43.06 kg/d for propionibacteria and control diets, respectively), especially in early lactation (0 to 100 DIM) and in older cows (3rd lactation and greater). The production of 3.5% fat-corrected milk and milk protein percentage were not affected by treatment. Overall milk true protein production (kg/d) was not affected by propionibacteria supplementation. Propionibacteria supplementation did, however, positively impact (P = 0.01) milk true protein (kg/d) in late lactation cows (>201 DIM). Daily DMI were excellent considering the summer heat and humidity during the study (23.16 vs. 22.39 kg/d per cow consumed by propionibacteria and control cows, respectively). Pregnancy rate was numerically greater (P = 0.12) with propionibacteria supplementation (15 vs. 23% for control vs. treatment). Feeding a specific propionibacteria (P169) at 6 × 1010 cfu/d per cow had beneficial effects on high producing dairy cows. Further research is needed to better understand the complete mode of action.