Abstract
Thirty new born crossbred (Bos taurus${\times}$Bos indicus) calves, divided randomly in a $3{\times}2$ factorial design, were fed calf starters containing one of three protein sources i.e., groundnut cake (GN), cottonseed meal (CS) and meat and bone meal (MB) along with either raw (M) or gelatinized maize (MG) for 90d. Milk was fed upto 56d of age. Green oats and respective calf starters were offered from 14d of age onwards ad lib. Clinical profile of serum suggested significantly (p<0.05) higher albumin and lower alanine aminotransferase activity due to CS feeding. Alklaine phosphatase activity varied significantly (p<0.05) among dietary treatments showing interaction between protein and starch sources. Inclusion of gelatinized maize resulted in significantly higher concentration of serum globulin (p<0.05) and alkaline phosphatase activity (p<0.01). reduced (p<0.05) ruminal pH was accompanied by a significant decrease (p<0.01) in $NH_3-N$ concentration in the strained rumen liquor (SRL) of MG fed calves. Ruminal amylase activity was lower (p<0.05) on MG diets. Alanine aminotransferase activity in the rumen exhibited a significant (p<0.01) interaction between protein and starch sources. While feeding of CS significantly (p<0.01) reduced alanine aminotransferase activity, inclusion of thermally processed maize reduced (p<0.01) both aspartate and alanine aminotransferase activities in the rumen. The overall blood picture was similar among treatments, whereas rumen metabolites especially enzyme activities, seems to be altered with source of degradable protein an starch.