RUMINAL RESPONSES TO LEVELS OF CALCIUM SALTS OF PALM OIL AND CORN SILAGE FED TO DAIRY HEIFERS

the objective of this study was to determine the effects of three levels (0, 2.2 and 4.4% of the ration dry matter) of calcium salts of palm oil (CSPO) and three levels (42, 32 and 22% of the ration dry matter) of corn silage on rumen parameters and in situ digestibility. Five ruminally cannulated Holstein heifers were fed five diets in a 5×5 Latin Square during five periods of 27 days. The concentration of butyrate (1.42, 1.24, 1.04 meq/dL; for 0, 2.2, 4.4% CSPO) was linearly decreased (P<0.01) with increasing CSPO, and proportions of propionate (21.9, 22.1, 23.3%; for 0, 2.2, 4.4% CSPO) and butyrate (18.2, 16.5, 14.6%; for 0, 2.2, 4.4% CSPO) were respectively increased (P<0.05) and decreased (P<0.01) linearly with increasing CSPO. The concentration (11.1, 9.34, 7.27 mg/dL; for 0, 2.2, 4.4% CSPO ) of rumen fluid N-NH 3 was decreased (P<0.05) linearly with increasing CSPO. The concentration (1.24, 0.97, 0.88 meq/dL; for 42, 32, 22% corn silage) and proportion (16.5, 13.8, 12.7%; for 42, 32, 22% corn silage) of butyrate were linearly decreased (P<0.01), and proportion of propionate (22.1, 22.8, 24.9%; for 42, 32, 22% corn silage) was linearly increased (P<0.01) with decreasing corn silage. The data indicate that 4.4 and 22% of the ration DM as CSPO and corn silage, respectively, showed to be the best combination fed to dairy heifers.