Effects of direct-fed microbial supplementation on growth performance and metabolic profile of newborn lambs weaned at different ages

The aim of this study was to investigate the effects of direct fed microbial (DFM) supplementation on growth performance, metabolic profile and mortality rate of newborn lambs at different weaning ages. Five days old sixty Najdi male lambs (5.40 ± 0.10 kg BW) were randomly assigned to 1 of 4 treatments (15 lambs each): lambs received either no DFM and weaned at 60 days of age (control) or oral dose of DFM (5 ml) at 5, 10 and 15 days old, and weaned at 30 (DFM30), 45 (DFM45) or 60 (DFM60) days old, respectively. Final body weight was higher (P=0.05) and tended to be higher (P=0.09) in DFM30 and DFM45 lambs, respectively whereas body weight gain was higher (P=0.01) in DFM45 and DFM60 lambs. The mortality rate was declined from 33.3s% to 6.67% in DFM30 and DFM45 lambs compared to control ones. Serum cortisol and creatinine levels tended to be reduced (P=0.07 and 0.11, respectively) in DFM30 and DFM45 lambs. The serum total cholesterol was highest (P=0.02) in DFM60 lambs and lowest in both DFM45 and control lambs. Similarly, the DFM30 and DFM45 lambs showed a declined serum triglyceride compared with control and DFM60 lambs (P=0.02). Serum phosphorus declined (P=0.04) in DFM30 treated lambs while serum zinc and copper levels decreased (P=0.02 and 0.05, respectively) in all treatments compared to control lambs. These results indicated that DFM supplementation may enhance the growth and health of early weaned lambs.