Authors : W.A. Riad, Ghada S. El-Esawy, A.M.A. Mohy El-Dein, M.F.E. Ali and H.M.A. Gaafar
Abstract: Twenty lactating Friesian cows with average live body weight of 500 kg and at 2-4 season of lactation were used after calving and divided into four similar groups (5 each) assigned randomly to four treatments. Cows were fed the basal ration consisted of 40% Concentrate Feed Mixture (CFM), 40% Fresh Berseem (FB) and 20% Rice Straw (RS), on Dry Matter (DM) basis. The 1st group was unsupplemented and served as control (T1) while 2nd-4th groups were supplemented with Zinc methionine (Zinpro) and Manganese methionine (Manpro) at 100 mg Zn/head/day (T2), 100 mg Mn/head/day (T3) and 50 mg Zn+50 mg Mn/head/day (T4), respectively. Results indicated that the digestibility of all nutrients as well as nutritive values increased significantly (p<0.05) with zinc and manganese methionine supplemented treatments than control. Average daily intake was higher markedly (p<0.05) in T2 compared to T1. Total Volatile Fatty Acids (TVFA's) concentration increased significantly (p<0.05), however, ammonia nitrogen (NH3-N) decreased significantly (p<0.05) with chelated zinc and manganese supplements. Plasma total protein and globulin concentrations increased significantly (p<0.05), however, AST and ALT enzymes activity decreased significantly (p<0.05) with chelated zinc and manganese supplements. Also, actual milk and 4% Fat Corrected Milk (FCM) yield and the contents of fat, protein, lactose, solids not fat and total solids in milk were increased significantly (p<0.05), however, somatic cell count decreased significantly (p<0.05) with chelated zinc and manganese supplements. Chelated zinc and manganese supplements improved feed conversion ratio. Average daily feed cost of cows in T2 was significantly higher (p<0.05) than that of T1. Whereas, feed cost per 1 kg 4% FCM decreased significantly (p<0.05), however, the output of daily 4% FCM and net revenue increased significantly (p<0.05) with chelated zinc and manganese supplements. Chelated zinc and manganese supplements improved decreased days to first estrus and service, service period, days open, calving interval and number of service per conception and increased conception rate (p<0.05). In conclusion, chelated zinc and manganese supplements for dairy Friesian cows improved digestibility, feed intake, rumen fermentation activity, some blood plasma parameters, milk yield and composition, feed conversion ratio and economic efficiency as well as postpartum reproductive traits.
W.A. Riad, Ghada S. El-Esawy, A.M.A. Mohy El-Dein, M.F.E. Ali and H.M.A. Gaafar, 2018. Effect of Supplementary Zinc and Manganese Methionine Chelateson Productive and Reproductive Performance of Dairy Friesian Cows. Journal of Aquaculture Feed Science and Nutrition, 10: 1-7.