Effect of Monensin on the Milk Production, Milk Composition, Rumen Metabolism and Blood Biochemical Profile in Crossbred Cows

Ten lactating crossbred cows depending upon the body weight, lactation number and days in milk (DIM) from GADVASU dairy farm were divided in two equal groups. One group was supplemented with 300 mg monensin daily. For rumen studies 3 non-producing non-pregnant animals were fed 300 mg of monensin for 30 days. Rumen liquor samples from these animals were taken before start of monensin feeding and after 30 days of feeding. Blood samples of all animals were collected via jugular vein puncture at the start and at the end of experiment. The TDMI and digestibility coefficient data showed that there was no significant difference in any parameter within two groups. The perusal of rumen metabolite data revealed that propionic acid, butyric acid and TVFA's were significantly (P<0.05) higher and the A/P ratio was lower (P<0.05) in treatment group. The concentration of all the parameters in the blood as well as the enzyme activities were within the normal physiological limits. The concentrations of glucose, cholesterol and TG increased, and the activity of AST were significantly decreased by the treatment. Milk production was similar in both the groups. There was significant (P<0.05) improvement in the efficiency of milk production (kg milk/kg DMI) in the treatment groups.