Effect of yeast cell wall supplementation on production performances and blood biochemical indices of dairy cows in different lactation periods.

AIM: This experiment was conducted to determine the effect of yeast cell wall (YCW) supplementation on production performances and blood biochemical indices such as liver enzyme activities, energy metabolites, and electrolyte concentrations of dairy cows in different lactation periods (LP). MATERIALS AND METHODS: Thirty-two lactating Holstein cows were assigned into 2×2 factorial arrangement, in which the factors were the treatment (TM) (control [n=16] vs. YCW [n=16]) and the LP (early lactation [n=14] vs. mid-lactation [n=18]). The cows with day in milk (DIM) <120 (81±7 DIM) were defined as early lactating cows, whereas the cows with DIM >120 (179±5 DIM) were assumed as mid-lactating cows. The YCW (SafMannan; Phileo, Lesaffre Animal Care, France) was used as the dietary supplement (10 g/cow/day) in this experiment. The statistical analysis of the data was performed by the two-way analysis of variance using the general linear model procedure to determine the main effects (TM and LP) and their interaction (TM×LP) on production performances and blood biochemical parameters of experimental cows. RESULTS: No significant effects (p>0.05) of YCW supplementation on production performances and blood biochemical indices of cows in TM groups (control vs. YCW) were observed; however, some obvious effects were detected in LP (early- and mid-lactation). Milk and milk component yield of cows in early lactation were significantly higher (p<0.05) than in mid-lactation, whereas somatic cell count and milk urea nitrogen were not different (p>0.05) with the YCW supplementation. The higher level (p<0.05) of serum albumin was found in mid-lactating cows after YCW supplementation. Before the experiment, the higher (p<0.05) non-esterified fatty acid (NEFA) and NEFA/total cholesterol (T-Cho) ratio, and the lower (p<0.05) calcium (Ca) concentration were observed in early lactating cows comparison with mid-lactating cows; however, there were not different after YCW supplementation. CONCLUSION: The positive effects of YCW supplementation on milk and milk component yields, energy metabolite, especially NEFA and NEFA/T-Cho ratio and Ca concentration were observed in early lactating cows rather than mid-lactating cows.