ABSTRACT
This study examined the mechanism by which calcium soaps of long chain of fatty acids [CSFA] and recombinant bovine Somatotropin [rbST] affect production and reproduction of Baladi goats [does]. The present study was carried out on 16 multiparous pregnant Baladi does aged 2.5 - 3 years. The treatments were initiated approximately four weeks before lambing until eight weeks post-lambing. Animals received 1 kg /head/day basal diet and allocated into four groups [n = 4 does /group]: without any treatment [control group I], plus 50 gm/head/day of CSFA [group II], 1 mg /kg body weight of rbST S/C injection every 14 days [group III], or a combination of CSFA supplementation and rbST injection [group IV]. It was found that a significantly shorter mean intervals [days] from lambing to first luteal activity and to conception and a higher percentage of ovarian cyclicity [100%] in group II and IV than in group I and III [75%]. Conception rate was also higher in group II and IV [100%] than group III [75%] and I [50%]. All kids of the treated groups had a significantly increase in their birth and weaning weights when compared with those from control group. There were significant increases in serum insulin in group II and IV and in serum leptin in all treated groups throughout the trial. Prolactin concentration was significantly higher in all treated groups than in the control one especially in rbST injected does. Also serum progesterone level showed a significant increase in all treated groups. Meanwhile, there was a significant effect of CSFA and rbST on T3 level during the first two weeks only of post-partum period and on T4 at day of lambing and during the second month of post-partum period. There was a significant increase in milk fat in all treated groups than control one, but showed highly significant increase in groups II and IV than in group III. Meanwhile, there was a non-significant effect of treatments on percentage of milk protein, total solids or solid not fat throughout the trial. In addition, there was a significant decrease in milk urea content in the three treated groups than in the control group. In conclusion, using of CSFA and rbST have a positive effect on lamb performance and milk composition. Meanwhile, CSFA supplementation has a more positive effect on reproductive performance, lamb performance and milk composition than injection of rbST. So, we recommend that using CSFA for does during late pregnancy and early post-partum period as a feed supplement at a level of 50 gm/head/day to improve reproductive performance, enhance metabolic profile, enhance lamb performance [in terms of birth weight, weaning weight and growth rate] and improve milk quantity and quality