Abstract:
Objective Effect of forage with varied ratios of refined concentrate and roughage on the growth and health of lambs was studied.
Method Thirty 3-month-old Dumeng male lambs with body weight of (25±2.14) kg were randomly divided into groups fed with a forage of low concentrate/roughage ratio at 30/70 (C30), one with medium concentrate/roughage ratio at 50/50 (C50), and another with high ratio at 70/30 (C70). Each group had 10 replicates to be fed initially on a 15 d pre-feeding followed by a treatment period that lasted 60 d. Growth performance and serum biochemicals of the lambs were monitored during the treatment.
Results (1) The average daily gain (ADG) of the lambs under C50 and C70 were significantly higher, while the feed/gain (F/G) rate significantly lower, than those of C30 (P<0.01) with that of C50 lambs 24.12% higher than that of C70. The average daily feed intake (ADFI) of C50 group was significantly higher than those of the other two groups (P<0.01). (2) The apparent digestibility of the lambs under C50 and C70 were extremely significantly higher (P<0.01) on crude protein (CP) and significantly higher (P<0.05) on neutral detergent fiber (NDF) than those under C30; while that of the animals under C50 on acid detergent fiber (ADF) significantly higher than those of the other two groups (P<0.05). (3) The serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), albumin (ALB), blood glucose (GLU), and direct bilirubin (DBIL) of the C50 and C70 group were significantly (P<0.05) or extremely significantly (P<0.01) higher than those of C30. (4) On the 30th day of treatment, the serum immunoglobulin A (IgA) in C70 lambs was significantly higher than that in C30 (P<0.01). However, on the 60th day, the IgA and immunoglobulin M (IgM) in the lambs under C70 were significantly lower than those under C50 (P<0.05) but the serum interleukin 6 (IL-6) significantly higher under C70 than under C30 (P<0.05).
Conclusion Feeding Dumont lambs with a 50/50 ratio of refined and roughage forage appeared to benefit the growth and health of the animals more than the other mixing combinations.