Effect of microencapsulated sodium butyrate in the close-up diet on performance of dairy cows in the early lactation period.

Two trials were conducted to determine the effect of sodium butyrate microencapsulated within triglyceride matrix (Na-butyrate) in the close-up period on performance of dairy cows and rumen papillae development. In trial 1, 26 Holstein-Friesian cows were randomly allocated to 2 groups (13 cows/group) and fed prepartum a total mixed ration (TMR) without or with 300g of Na-butyrate/d from 30 d before expecting calving to parturition. After calving, the same lactational TMR without Na-butyrate was offered to both treatments. Dry matter intake and milk yield were monitored daily to 60 d in milk, and body condition of cows was scored on d 30, 21, and 4 before parturition and d 14, 31, and 60 after parturition. On d 15, 10, and 5 before parturition blood samples were collected from 6 cows randomly chosen from each group and analyzed for plasma β-hydroxybutyrate and nonesterified fatty acids concentrations. No differences in dry matter (DM) intake, milk yield, body condition score, or plasma β-hydroxybutyrate and nonesterified fatty acids concentrations was observed between treatments; however, in the last 5 d before parturition the cows receiving Na-butyrate ate 1.7kg of DM/d more, on average, as compared with control cows. In trial 2, 12 Holstein-Friesian growing bulls (404±48; body weight ± SD) were used to determine the effect of Na-butyrate inclusion in the diet on rumen papillae development. Bulls were randomly allocated to 2 groups (6 bulls/group) and fed TMR without or with 2% (on a dry matter basis) of Na-butyrate for 21 d. At the end of the study, bulls were killed and rumen fluid and rumen tissue samples from dorsal and ventral sac of the rumen were collected. No effect of Na-butyrate supplementation on BW of bulls and DMI during the trial period was observed. Sodium butyrate supplementation increased total short-chain fatty acid concentration in the rumen but had no effect on rumen pH, molar proportions of short-chain fatty acids, and NH3-N concentration. In dorsal sac of the rumen, papillae length and papillae cross-section surface area were increased as a result of Na-butyrate supplementation, whereas in the ventral sac a reverse effect was observed (significant treatment × location in the rumen interaction). Both in the dorsal and ventral sac of the rumen, dietary Na-butyrate increased rumen muscle layer thickness. Altogether, results of this study suggest that Na-butyrate supplementation in the close-up diet may have a potential to enhance rumen papillae growth and rumen adaptation to postpartum diet but lactation performance was not affected under conditions of the current study.