Performance and physiological responses of milk-fed calves to coated calcium butyrate supplementation

The aim of this study was to determine the effects of coated calcium butyrate (CCB) on calf performance and some blood parameters. Sixteen female Holstein calves with a mean age of 3 +/- 1 d were divided into two equal groups and fed a milk replacer supplemented with 3 g of coated calcium butyrate (CCB)/day or with no coated calcium butyrate (NCB). The calves had free access to solid feed and water. Body weight was measured at days 3, 12, 24, 36 and 48 (weaning day). Respiratory rate and rectal temperature (within first 4 weeks of life), feed intake and faecal score (during the whole experimental period) were recorded daily. Rumen fluid was taken for volatile fatty acid (VFA) determination on days 33 and 48, and structural growth (rump height, withers height and hip width) was recorded on days 3, 24 and 48. Blood samples were collected on days 1, 12, 24, 36 and 48. Feed intake, average daily gain, feed conversion ratio and structural growth of calves were improved by CCB supplementation. There were no significant differences on rectal temperature, respiratory rate and faecal score between the treatments. Rumen concentration of total VFAs increased and the VFA profile was affected on days 33 and 48 by CCB supplementation. The supplementation of milk replacer of calves with coated calcium butyrate significantly increased serum concentrations of glucose, insulin and beta-hydroxybutyrate. Serum concentration of cortisol in the CCB calves was numerically lower than in NCB. In conclusion, supplementation of calves' milk replacer with the coated calcium butyrate could improve calf performance.