Fertility of Libyan Barbary Sheep Treated with Prostaglandin F2α (PGF2α) in Different Seasons

Abstract

Bearing in mind the objectives of this study to investigate the Barbary sheep fertility under our climatic conditions and to evaluate the efficiency of the prostaglandin F2α (PGF2α) injection in induction of fertile estrus in different seasons. For these objectives some experiments were performed during the period from July 2008 to March 2009. A total number of 300 Libyan Barbary ewes (3 – 6 years old weight 40 – 60 Kg) was used in this experiment. Ewes were kept in privet farms fed and managed similarly. Ewes were divided to four season groups (summer, autumn, winter and spring groups) each season group was divided into treated and control. Animals in the treated groups were injected with double injection of 125μg of prostaglandin F2α intramuscularly (IM) 11days apart. While those in the control groups were injected with two injections of 1.0 ml of 0.9%NaCl saline solution simultaneously with the treated ewes. At the same day (day 11) rams wearing painted sponges on their briskets regions were introduced for natural mating. Treated groups showed shorter estrus response time than control groups in all seasons (P<0.05). Estrus duration was longer in winter and spring than in summer and autumn (P<0.001) but no difference was found between treated and control groups inside seasons. Treated group showed higher pregnancy rate (P<0.001) in winter season than control group. Percentage of ewes lambed in winter was significantly high (P<0.001) among treated ewes than control (80% Vs 38%). Lambing rate differed significantly (P<0.001) among treated groups in all seasons. Data were collected and calculated statistically using SPSS system for percentages, means, standard deviation (mean ±SD) analyses of variance (ANOVA), Chi squire and Duncan's test were used accordingly. Other values were measured, calculated and analyzed similarly.