World Journal of Agricultural Research, 2015, Vol. 3, No. 5, 174-178 Available online at http://pubs.sciepub.com/wjar/3/5/4 © Science and Education Publishing DOI:10.12691/wjar-3-5-4 Fertility of Libyan Barbary Sheep Treated with Prostaglandin F2α (PGF2α) in Different Seasons Aboulgasem Elmarimi * , Najmi Mariol, Jamil Ahmed, Mokhtar.F. Sassi, Abdurraouf Gaja Department of surgery and Theriogenology, Tripoli University, Tripoli, Libya *Corresponding author: drelmarimi2005@yahoo.com Received July 21, 2015; Revised September 01, 2015; Accepted October 08, 2015 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. Keywords: fertility, Barbary sheep, PGF2α, seasons Cite This Article: Aboulgasem Elmarimi, Najmi Mariol, Jamil Ahmed, Mokhtar. F. Sassi, and Abdurraouf Gaja, “Fertility of Libyan Barbary Sheep Treated with Prostaglandin F2α (PGF2α) in Different Seasons.” World Journal of Agricultural Research, vol. 3, no. 5 (2015): 174-178. doi: 10.12691/wjar-3-5-4. 1. Introduction In small ruminants, estrus synchronization (ES) is affected by the seasonal breeding patterns in most temperate breeds of sheep [15]. Estrus may not only have to be synchronized, but also initiated. Systems requiring the regression of an active corpus luteum will not be effective under these conditions [28]. Estrus Synchronization of ewes has been accomplished using several methods with various degrees of success. The progesterone impregnated intravaginal sponges, left in situ for 12-19 days in the breeding season, is a widely used method. Intravaginal sponges can usually induce inflammation with adherence to vaginal mucosa [18]. Following the withdrawal of the sponge, a rich discharge with unpleasant odour is usually observed. It is now well established that the injection of prostaglandin (PGF2α) or one of its analogues at any time between Days 5 and 16 of the bovine estrous cycle will result in luteal regression with a consequent return to estrus within 2-3 days [5,14]. Once prostaglandin (PGF2α) was identified as a uterine luteolytic factor in the estrous cycle of the ewe [6,21], synthetic forms were developed which can be used to induce premature luteolysis. The injection of an analogue of PGF2α to a flock of randomly cyclic ewes is effective to induce luteal regression in most ewes with a consequent return to estrus [5]. However, the responding ewes present a greatly variable interval to estrus and some of the ewes do not respond, which precludes a more extensive use of the product, particularly if ES is used associated with timed artificial insemination. The variability of the response was attributed to differences in ovarian status among the ewes at the time of the treatment. The day of the cycle on which PGF2α was given influences the interval to onset of estrus [17]. Early treatment was followed by shorter intervals to estrus. This was attributed to the different time span necessary to reduce progesterone concentrations to basal level as the luteal phase progresses and corpus luteum (CL) acquires its full endocrine functionality [17,29]. The variation in the interval between PGF2α administration and ovulation could also be attributed to the wave giving origin to the ovulatory follicle [27]. The changes which occur in plasma concentrations of LH and progesterone at the induced