SOME STUDIES ON IMPROVING FERTILITY IN BARKI SHEEP RAISED IN SIWA OASIS

Abstract

The present experiment was designed to improve fertility, lambing and twinning rates of Barki ewes and to evaluate the efficiency of several protocols such as PMSG and/or GnRH injection after vaginal sponges treatment on some reproductive and productive traits in Barki ewes. The present study was carried out at Siwa Oasis Research Station (Tegzerty Experimental Farm for Animal Production), which belongs to Desert Research Center, Ministry of Agriculture and Land Reclamation, Egypt. This station is located at 330 Km southwest of the Mediterranean shoreline and at 65 Km east of the Libyan borders. This study included two experiments (basic experiment and supportive applied experiment) the basic experiment was during the period from September 2012 till May 2013, while the applied supportive experiment was during the period from August 2013 until April 2014. In the basic experiment, Sixty-six non-pregnant and non-lactating Barki ewes (3-5 years old and averaged 41.80 ± 0.559 kg live body weight) were used. Animals were randomly divided into three groups (22 ewes of each). The estrus of the ewes in each group were synchronized using one of the following hormonal treatments: First group (G1) received double injections of prostaglandin F2α 10 days apart (1 ml Synchromate, each 1 ml solution containing 250 mg Cloprostenol, Coopers Co., Germany). On the other hand, ewes of the second group (G2) received double injections of prostaglandin F2α 10 days apart, and after 10 days, intravaginal progestagen impregnated sponge (40 mg fluorogestone acetate, FGA, Chronogest®, Intervet International, B.V. Manufactured in the European Union) was inserted. Sponges remained in situ for 14 days. On the day of sponge removal, each ewe received an intramuscular injection of 750 IU PMSG (Folligon, Intervet, International, B.V. Manufactured in the European Union). While, ewes of the third group (G3) were given double injections of prostaglandin F2α 10 days apart and after 10 days intravaginal progestagen impregnated sponge were inserted. Sponges remained in situ for 14 days. One day before sponge removal each ewe injected intramuscularly with 2 ml, 0.004 mg, GnRH. (Receptal, Intervet International, B.V. Manufactured in the European Union). In supportive applied experiment, Forty-five Barki ewes (4-6 years old and averaged 40.66 ± 0.97 kg live body weight) were used. Animals were randomly divided into two groups, 15 ewes in group one (G1) and 30 ewes in group two (G2). First group received similar as G1 in the basic experiment, while second group received similar as G2 in the basic experiment. In the basic experimental, the results showed that, the percentage of estrus exhibition in G2 reached 95.45% (P<0.05), while the lowest percentage (86.36 %) was observed in G3. The conception and lambing rates increased to 100% in G2 but there were no significant differences among experimental groups. Weaning rate was higher (P<0.05) for ewes in G2 than those of other groups. Litter size was higher (P<0.05) for ewes in G2 (1.38) compared with other groups. The highest fecundity rate was recorded for G2 (1.38) and the lowest rate was for G3 (0.94). No significant differences in birth weight, weaning weight, average daily gain and mortality rate were found among groups. Gestation period was shorter (P<0.05) for ewes in G2 as compared with other groups. The percentage of ewes bearing twins was higher for ewes in G2 (28.57 %) than G1 (5.26), while G3 did not give twins. Moreover, G2 gave one triplet twins, while no other groups gave triplets.