Effect of undegradable dietary protein level and plane of nutrition on milk yield and serum biochemical constituents in crossbred cattle

Abstract

Lactating crossbred cows (24) yielding around 10 kg/day, were divided into 4 groups of 6 animals in each. Each group was fed with concentrate mixture with either 59:41 or 52:48 RDP: UDP ratio and either in normal plane (to meet 100% NRC requirements) or in higher plane (to meet 115% NRC requirements), in a 2x2 factorial experiment. Green jowar fodder was fed ad lib. The lactation trial lasted for 105 days. The total dry matter intake (DM1) did not differ significantly due to both UDP level and plane ofnutrition and also due to their interaction. Increase in milk yield with increased UDP level and also with increased plane of nutrition was observed consistently throughout the experiment. The overall daily average milk yields in cows fed with low and high UDP diets were 7.91 and 8.99 kg, respectively, and for normal and higher plane ofnutrition, the milk yields were 8.15 and 8.75 kg/d respectively. The daily milk yields in groups did not differ significantly among each other. The feed conversion efficiency was also considerably better in cows fed ration containing high UDP level at higher plane of nutrition than in cows fed ration containing low UDP at normal plane. Blood samples collected on 0, 45th and 90th day of experimental period were analyzed for total protein, albumin, globulin and ammonia nitrogen and for activities ofAST and ALT. There was no effect on any of the studIed blood parameters due to either UDP level or plane of nutrition except AST activity that increased significantly (P