Abstract
This study was carried out at the Agricultural Experimental Station of Qassim University, Saudi Arabia. Forty eight male lambs (12 wk old, 20 +/- 2.0 kg LBW) from two Saudi Arabian sheep breeds [Najidi (NJ) and Noami (NO)] were used in the study. The animals were randomly allocated into four treatment groups (6 animals/group within a breed). A commercial tannin [Quebracho tannin (QT) contained 75% (w/w) of condensed tannins (CT) in dry matter (DM)] was used in this study. Lambs were fed with alfalfa hay and barley grains with QT at levels of 0 (control), 1, 2 and 3% of DM in four diets for experimental groups (T0, T1, T2 and T3, respectively). The effective levels of CT in DM of these treatment groups were 0, 0.75, 1.5 and 2.25% (w/w), respectively. The mixture of alfalfa hay, barley grains and QT was mechanically pelleted. The basal diet (TQ0) was 70% alfalfa hay and 30% barley grains. Dietary contents of CP were 14.9, 14.6, 14.5 and 14.4%, respectively. Lambs were fed on the experimental diets for 120 days to determine growth performance parameters, namely: total feed intake of dry matter (TDMI), total gain (TG), average daily gain (ADG), relative gain (RG) and feed conversion ratio (FCR). Results showed that total dry matter intake (TDMI/120 days) was higher (p<0.05) for NJ than NO, while RG and FCR were better (p <0.05) for NO than NJ. However, TG and ADG were not affected by breed type. Lambs fed with QT2 showed the highest (p<0.05) TG and ADG and the best FCR, while TDMI and RG were not affected by QT level.