Abstract: Forty Desert ewes were allocated for monitoring the effect of different hormonal treatments and Artificial Insemination (A.I) on their reproductive performance with an regard to oestrous response and fertility rates. The animals were randomly divided into four equal groups (10 ewes each) with average age of 2.00±0.80 years and body weight of 39±3.00 kg. The control group (A) was allowed to cycle naturally and handmated, while the other three groups were assigned to different hormonal treatments.These treatments consisted of a double intramuscular injection of Luprositol (3.75 mg 1) 14 days part (group B); intravaginal sponges impregnated with 40 mg 1 Fourogestone Acetate (FGA) inserted for 13 days (group C) and treatment C plus an intramuscular injection of 500 iu Pregnant Mare Serum Gonatotrophin (PMSG) at the time of the sponge removal (group D). Oestrus was detected by the aid of a vasectomized ram, with an excellent libido, introduced to each group immediately after the end of each treatment. Time elapsed from end of treatment to onset of oestrus, oestrous signs and duration of oestrus were monitored. All the ewes in the three treatment groups were artificially inseminated with fresh semen, diluted with homogenized cow milk, 52 h after the end of treatments. Those returning to oestrus were artificially reinseminated. Conception rates were determined by non-return rates and later on by abdominal palpation (ballotement) on day 90-110 post insemination. The results obtained indicated that all the employed treatments can induce and synchronize oestrus in Sudanese Desert ewes. The percentage of ewes responding to treatment B (80%) by showing oestrous signs was significantly higher (p< 0.05) than the other two treatments, followed by treatment D (55.50%) and C (44.40%). The duration of the induced oestrus was signiticantly longer (p< 0.05) in treatment B (43.40±5.20 h) as compared to treatment C (27.30±2.80 h) and D (27.2±3.00 h). The pregnancy rate to first insemination was significantly higher (p< 0.05) in treatment D (100%) as compared to B (40%), C (77.80%) and the control (40%). However, the overall pregnancy rates, based on abdominal ballotement between 90 and 110 days were significantly (p< 0.05) higer in group C (100%) and D (100%) compared to group B (80%) and the control A (50%). Lambing confirmed the results obtained at abdominal ballotement which was 9.23% less than those obtained by the non - return rates. The twining rates were 20, 37.50, 33.30 and 33.30% for treatments A,B,C and D respectively. There were no significant differences (p>0.05) among the different hormonal treatments.
S.A. Makawi and Z.A. Manahil , 2007. Fertility Response of Desert Ewes to Hormonal Oestrous Synchronization and Artificial Insemination Using Fresh Diluted Semen . Journal of Animal and Veterinary Advances, 6: 385-391.