ABSTRACT
This study was performed to evaluate the influence of Yucca schidigera powder (YSP) as feed additive on productive and reproductive performance and some blood constituents of Zaraibi dairy goats. Twenty- four Zaraibi dairy goats aged >3 years and weighed averagely 34.49±2.15 kg were used. Does were randomly selected and divided into three similar groups (8 does each). This experiment was conducted 21 days before breeding season and continued till early lactation stage. The three experimental groups were; G1 as control group fed the basal rations without any addition, G2 received the basal rations plus 250 mg YSP/h/d while, G3 nourished the basal rations plus 500 mg YSP/h/d. The basal rations consisted of 60% concentrate feed mixture (CFM) + 40% roughage "berseem hay (BH) + rice straws (RS)". The obtained results elucidated that G2 and G3 had (P<0.05) heavier live body weight (LBW) during trimester time, at 140 days of gestation, post- kidding, post-weaning and at 6 weeks of lactation than does in G1. In addition, LBW of does in G2 and G3 had similar (P>0.05) improvement through other weights compared to G1. The data demonstrated that all measured reproductive parameters had changed (P<0.05) among groups and affected by YSP intake. The conception rate was 87.5, 100 and 100 % and fertility rate showed 62.50, 75.00 and 87.50% for G1, G2 and G3, respectively. The present results showed better (P<0.05) milk harvest during suckling period and the early 6 weeks of lactation with G2 and G3 than G1. Regarding oestrus resumption (days) and oestrus duration (hours), does in G2 and G3 had shorter (P<0.05) oestrus resumption and longer (P<0.05) oestrus duration either post-kidding or post- weaning than those in G1. The blood concentrations of cholesterol, triglyceride and urea were lower (P<0.05) in G2 and G3 than in G1. However, the lowest (P<0.05) glucose andcalcium levels were occurred in G1 compared to the both treated groups G2 and G3. These results suggest that addition of YSP to diets of nanny goats at levels 250 or 500 mg /h/d had positive and beneficial effects on reproductive performance and some blood parameters. Consequently, results supported the hypothesis that feed additives such as YSP can be successfully used to modify milk harvest during suckling and early lactation stages as well as live body weight for dairy Zaraibi goats.