Effect of Using Some Feed Additives (tw- Probiotics) in Dairy Cow Rations on Production and Reproductive Performance

This study aimed to evaluate the effects of supplementing commercial yeast culture (S. cerevisiae) namely BGY 35 or a product of lactic acid bacteria and enzymes namely AVI-BAC® to the diet of lactating crossbred cows, for the last 2 months pre-partum and the first 4 months post-partum (from July to October), on body weight, feed and water intakes, milk production, some blood parameters, reproductive performance and physiological response. A total of 12 cows with average live body weight (LBW) of 440 kg and 2-6 parities, were used in this study. Cows were divided into three groups, 4 animals in each group. During preand post-partum period, cows in the 1 st group (G1) were fed the control diet (untreated), while those in the 2 nd (G2) and 3 rd (G3) groups were fed the control diet daily supplemented with 3 g AVI-BAC/cow and 20 g BGY 35/cow, respectively. During preand post-partum, LBW, feed and water intakes, rectal temperature (RT), respiration rate (RR) and pulse rate (PR), yield and composition of milk were recorded. Blood samples were collected for determination of total proteins (TP), albumin (AL), creatinine, urea and glucose concentrations in serum. Activity of transaminases (AST and ALT) and alkaline phosphatase (ALP) as well as concentrations of thyroid hormones (T3 and T4), estradiol (E2) and progesterone (P4) were also determined in blood serum. Post-partum 1 st estrous interval (PPFEI), number of services/conception (NSC), days open (DO) and conception rate (CR) were calculated. Results showed insignificant effect of probiotics supplementation on LBW of cows during prepartum, calving and post-partum as well as on birth weight of produced calves. During pre-partum, both probiotics supplementations increased (P<0.05) feed intake of rice straw (RS) and total DM relative to LBW. Intakes from concentrate feed mixture (CFM), corn silage (CS), total DM/h or total DM relative to metabolic body weight were not affected. During post-partum period, probiotics supplementation increased (P<0.05) RS and total DM intakes. Total DM intake relative to LBW or metabolic body weight was not affected. There was insignificant effect of probiotics supplementation on milk yield and milk composition, although average daily milk yield tended to increase by about 17 and 15 % and all milk components increased for G2 and G3 as compared to G1. During pre-partum period, concentrations of all blood biochemicals were not affected by probiotics supplementation. During post-partum, only serum AL concentration was increased (P<0.05) in both supplemented groups as compared to the control one. Activities of AST, ALT and ALP were not affected by probiotics supplementation during preand post-partum periods. There was a reduction (P<0.05) in T4 concentration in G2 during pre-partum, and reduction (P<0.05) in T3 and T4 concentrations in both supplemented groups as compared to the control group during post-partum period. Within 120 days postpartum, PPFSI was earlier by about 21.5 and 25 d, NSC was less by about 0.5 and 0.75 and DO was shorter by about 21.0 and 36.5 d in G2 and G3 than in G1. The CR was higher in G3 (100%) than in G2 and G1 (50% in each). Probiotics supplementation resulted in slight reduction in RR, RT and PR of cows during preand postpartum periods as compared to un-supplemented diet, but the differences were not significant. Both probiotics supplementation decreased water consumption as compared to control diet, but the differences were significant (P<0.05) only between G2 and G1. In conclusion, dietary supplementation of probiotics AVI-BAC (3 g/h/d) to diet of dairy cows, during 2 months pre-partum and 4 months post-partum, seemed to have a beneficial effect on milk yield and fat yield, while BGY 35 (20 g/h/d) seemed to have pronounced improvement on reproductive performance of dairy cows in terms of increasing conception rate and shortening days open.