Effet des probiotiques sur les paramètres zootechniques, hémato-biochimiques et reproductifs chez la vache laitière

Abstract

As part of improving dairy cattle farming, the objective of this study was to determine the effect of supplementing dairy cows with yeast probiotics, yeast cell walls, prebiotics, and a combination of both (synbiotics) on certain immunological parameters (IgG concentration in colostrum), zootechnical parameters (milk yield, and composition including fat, protein, and lactose), hematological, and biochemical parameters during the critical transition period. Additionally, the study aimed to evaluate the Brix refractometer as an effective tool for measuring immunoglobulin (IgG) concentrations in colostrum compared to the reference method, radial immunodiffusion (RID). From 30 days before the expected calving date until 60 days postpartum, forty Montbeliarde cows (5 primiparous and 35 multiparous) were divided into four groups: the control group (CNT; n=10) received a dry period diet (DPD) during the dry period and a lactation period diet without supplementation; the yeast group (SC; n=10) received diet supplemented with 5 g/day/cow of Saccharomyces Cerevisiae yeast (probiotic); the yeast cell wall group (PL; n=10) received 5 g/day/cow of yeast cell wall fractions (mannans and β-glucans; prebiotic); and the MIXED group (Mixte; n=10) received the dry or lactation period diet supplemented with a combination of 5 g of Saccharomyces Cerevisiae yeast and 5 g of yeast cell wall fractions (mannans and β-glucans) (synbiotic). Colostrum samples were collected in sterile universal containers immediately after calving. Body condition score (BCS) assessment and blood samples were taken from the jugular vein in heparinized and EDTA tubes at -30 days, -15 days before calving, the day of calving, and at 15, 45, and 60 days postpartum (PP). Milk samples were collected on days 15, 45, and 60 PP and frozen at -20°C until analysis. Statistical analysis was performed using SPSS "IBM SPSS V. 22.0". Significant differences in colostrum IgG concentration (IgG > 50 g/L) were observed for the yeast and mixed groups compared to the control group (P < 0.01). No influence of body condition score (BCS), age, parity, or sex of the newborns (P > 0.05) on colostrum IgG concentration was detected. The correlation between the results of RID and the refractometer was high and positive (r = 0.785) for colostrum. BCS and hematological parameters were not affected by supplementation (P > 0.05). Milk quality and quantity were influenced by the treatments in the Mixed and SC groups compared to the control group (P = 0.04). No significant differences were observed for biochemical parameters, except for increased protein levels in the PL and Mixed groups on different days (P < 0.05). In conclusion, supplementing dairy cows with Saccharomyces Cerevisiae or yeast cell walls during the transition period, spanning one month before calving to two months postpartum, yields distinct effects depending on the desired objectives. Exclusive use of yeast is particularly beneficial for increasing milk production, while the addition of yeast cell walls leads to a significant increase in plasma protein concentrations. To maximize both aspects simultaneously, a synergistic approach combining the two types of supplements is recommended. This comprehensive strategy optimizes dairy cow performance during this critical phase of their physiological cycle.