EFFECT OF RUMEN PROTECTED CHOLINE SUPPLEMENTATION ON DIGESTIBILITY, RUMEN ACTIVITY AND MILK YIELD IN LACTATING FRIESIAN COWS

Abstract

Twelve lactating Friesian cows at 2 nd to 5 th lactating season, with body weight of 500±15 kg were fed a basal ration consisting, on a dry matter (DM) basis, of 40% concentrate feed mixture + 40% fresh berseem + 20% rice straw supplemented with rumen-protected choline (RPC) in the form of choline chloride at levels of 0, 15 and 30 g/head/day. The cows were used 8 weeks after calving in a complete switch-back design. The digestibility coefficients and nutritive values significantly increased (P 0.05) affected by RPC supplementation. Rumen-protected choline supplementation led to increased actual milk yield by 1.32 and 2.24 kg/head/day or 8.75 and 14.85%, and 4% fat corrected milk (FCM) by 1.55 and 2.60 kg/head/day or 10.86 and 18.31% for 15 and 30 g RPC compared with un-supplemented RPC, respectively (P<0.05). The contents of fat and total solids (TS) and the yield of all milk constituents except ash increased significantly (P<0.05) with RPC supplementation. Rumen-protected choline supplementation decreased the quantities of DM, TDN and DCP per kg 4% FCM (P<0.05). The feed cost per kg 4% FCM decreased, but the average income of milk yield increased by 3.11 and 5.20 LE or 10.94 and 18.28% for 15 and 30 g RPC compared with un-supplemented RPC, respectively (P<0.05). It could be concluded that rumenprotected choline supplementation at 30 g/head/day to lactating Friesian cows improved digestibility, milk yield and composition, feed conversion, and economic efficiency.