Meta-Analysis Study of the Effects of Yeast Probiotic Supplementation on Milk Production and Energy Corrected Milk of Lactating Dairy Cows

Abstract

The aim of this study was to use a meta-analytic approach to evaluate the effect of commercially available yeast probiotic “Actisaf &#174 ; Sc 47” (Saccharomyces cerevisiae CNCM I-4407) produced and marketed by Phileo by Lesaffre on milk performance in dairy cows. Data from 22 trials including 17 with parallel designs and 5 with cross-over designs were collected, and only data with parallel designs were analyzed. From those trials, 4 are published and 13 are from technical reports. In total, 34 comparisons and 1074 dairy cows met the criteria for inclusion in the final analysis of milk yield (MY). For energy corrected milk (ECM), six trials with 12 comparisons and 476 dairy cows met the criteria for inclusion in the final analysis. Because the data are from different trials with different conditions, the statistical model defined includes the fixed effect of the treatment (with vs. without Actisaf ® Sc 47) and the random effect of the trial. The meta-analysis showed a moderate heterogeneity for MY and ECM. The random effect meta-analysis showed an estimated mean difference +1.72 kg/d [95% confidence interval (CI): 1.01 to 2.44] and +2.45 kg/d (95% CI: 1.73 to 3.17) for MY and ECM respectively, in favour of Actisaf ® Sc 47. The analysis of data without trials conducted under heat stress conditions showed positive effect of Actisaf ® Sc 47. The random effect meta-analysis showed an estimated mean difference of +1.69 kg/d [95% CI: 1.24 to 2.14] and +2.92 kg/d (95% CI: 2.45 to 3.40) for MY and ECM respectively, in favour of Actisaf ® Sc 47. These observations provide strong evidence that this commercially available yeast probiotic can significantly improve milk performances of dairy cows under different conditions.