Effect of sodium butyrate administered in the concentrate on rumen development and productive performance of lambs in intensive production system during the suckling and the fattening periods

Sodium butyrate (SB) has been shown to improve growth rate, rumen development and health of calves. In intensive lamb production systems, the fattening period starts after a relative short suckling period, and lambs are fed a high concentrate diet. The objective of this experiment was to determine the effect of supplementing SB in the concentrate on rumen development and productive performance of lambs during the suckling and the fattening periods. During suckling, 66 lambs were distributed with their mothers in four pens. Treatments were: control concentrate (CON), and concentrate supplemented with 3.6g of SB/kg of DM (SBC). At weaning, nine lambs were slaughtered for sample collection, and 47 lambs were distributed into 12 pens for the fattening period. Treatments were: (1) CON–CON for lambs fed CON in both periods; (2) CON–SBC for lambs fed CON in the suckling and SBC in the fattening period; (3) SBC–CON for lambs fed SBC in the suckling and CON in the fattening period; and (4) SBC–SBC for lambs fed SBC in both periods. At 88 days of age all lambs were slaughtered. In both periods, concentrate dry matter intake (DMI), average daily gain (ADG), body weight (BW), hot carcass weight (HCW), dressing percentage (DP), reticulum-rumen weight (RRW), rumen fluid pH, and density, length, width and keratinization of rumen papillae were measured. Feed conversion ratio (FCR) was calculated for the fattening period. During the suckling period, SBC lambs had higher DMI, ADG, HCW and DP (P<0.05), and tended to have higher rumen papillae length and lower RRW (P<0.10). During the fattening period, no difference was found among treatments. Results indicate that the supplementation of SB in the concentrate improved rumen development and productive performance of lambs during the suckling period. However, at 3 months of age, the administration of SB did not improve production in lambs reared in an intensive production system.