The Effect of Different Levels of Tannic Acid on some Performance Traits in Holstein Dairy Calves

The aim of this study was to evaluate the effect of inclusion of tannic acid on some performance traits and nutrient digestibility in Holstein dairy calves. A total of 20 seven days old Holstein calves were randomly assigned to 4 experimental treatments with 5 calves each. The treatments were as follows: 1) basal diet for-mulated to meet all nutritional requirement of calves according to NRC (2001) and milk without any addi-tive, 2) basal diet and milk supplemented with 4 mg tannic acid/L, 3) basal diet and milk supplemented with 6 mg tannic acid/L and 4) basal diet and milk supplemented with 12 mg tannic acid/L. The result showed that dietary inclusion of different levels of tannic acid improved feed intake, body weight gain and feed conversion ratio in treated calves. Dry and organic matter intake, and digestion of crude protein, natural detergent fiber and acid detergent fiber were improved in treated calves with tannic acid compared to the control group. The fecal consistency score showed that Inclusion of tannic acid resulted in improved fecal consistency from0 to 50 days of age (P≤0.05). In conclusion, tannic acid inclusion in milk could be benefi-cial for Holstein dairy calves with positive effects on their feed intake, body weight gain, feed conversion ratio and nutrient digestibility.