Effect of protected fatty acid supplementation on ovarian activity, reproductive hormone profiles and reproduction of Barki ewes under semiarid conditions

Abstract. The objective of this experiment was to evaluate the impact of dietary supplementation with rumen-protected fat (calcium soaps of fatty acids, CSFA) and/or hormonal superovulation using equine chorionic gonadotropin (eCG) on ovarian activity, changes in ovarian hormones, and reproductive performance in Barki ewes under semiarid conditions. A total of 39 non-pregnant Barki ewes, with an average body weight of 34.7 ± 0.25 kg and an average age of 3–4 years, were divided into four groups. The first group (9 ewes) served as the control, while the second group (10 ewes) received double doses of PGF2α, administered 9 d apart, and was superovulated with 600 IU (international unit) eCG. The third group (10 ewes) was supplemented with 30 g per head per day of rumen-protected fat. The fourth group (10 ewes) underwent the same superovulation protocol as the second group and was also supplemented with 30 g per head per day of rumen-protected fat. All the ewes were fed a basal diet. Ovarian activity was detected using ultrasonography during the estrus phase in all the groups, after which all the ewes were naturally bred with Barki rams. The results demonstrated significant (P<0.05) increases in estradiol 17-β (E2) and progesterone (P4) levels in the treated groups compared to the control group. Ewes in all the treated groups exhibited large follicles, with an overall mean diameter (≥5 mm) significantly higher than that of ewes in the control group. Although there were no significant differences between the treated and control groups, the ewes treated with CSFA and/or the eCG hormone showed tendencies to improve the reproductive traits of Barki ewes. Overall, the findings of this study demonstrated a positive effect of CSFA alone or in combination with an estrous synchronization protocol on ovarian activity in Barki ewes, as indicated by the number and size of follicles and the presence of large-sized follicles.