Feed intake, growth performance and carcass characteristics of Damara lambs fed bush-based rations from four encroacher bush species

The objective of this study was to evaluate the effects of feeding the four encroacher bush species as alternative roughage source on the feed intake, growth performance and carcass characteristics of Damara lambs

The effect of feeding bush-based finishing rations on the performance of Damara lambs was studied. Thirty weaned lambs weighing 16.7 ± 1.9 kg were allocated to five treatments in a completely randomized design over a 90-day feeding period. The control diet (T1) consisted of Lucerne (10%), grass hay (30%) and concentrate mix (60%). The other diets consisted of roughage (40%) from the milled bushes Senegalia mellifera (T2), Dichrostachys cinerea (T3), Terminalia sericea (T4) and Rhigozum trichotomum (T5) and concentrate mix (60%). At the end of the feeding trial, the lambs were slaughtered and carcass characteristics were evaluated. The average daily feed intake (ADFI) was affected (P < 0.05) by sex, treatment, week and treatment x week interactions. The ADFI for T1 exceeded (P < 0.05) that for T2 and T3, at most time points. The ADFI of T1 and T4 were similar (P > 0.05) at weeks 6 to 10, but differed (P < 0.05) at other time points. The average daily gain (ADG) and feed conversion ratio (FCR) were affected (P < 0.05) by sex and treatment. The ADG (g/day) least squares means (± S.E) for T1 – T5 were 148.0 ± 6.9, 156.4 ± 6.9, 124.2 ± 6.9, 133.7 ± 6.9 and 133.7 ± 6.9, respectively. Treatment T2 had a better (P < 0.05) FCR compared to other bush-based treatments. Males had heavier (P < 0.05) final, hot and cold carcass weights than females. Lambs fed T4 had greater (P < 0.05) rib eye area than T1 (8.3 ± 0.5 vs. 5.9 ± 0.5 mm2). Bush-based diets can serve as production diets for weaned sheep and result into acceptable weight gain and carcass quality