STUDY OF SURGICAL INTRAUTERINE ARTIFICIAL INSEMINATION EFFICIENCY IN SUDANESE DESERT SHEEP

Artificial insemination in sheep is currently limited by the poor fertility obtained following the traditional methods of insemination (vaginal artificial insemination, cervical artificial insemination and transcervical artificial insemination). The reduced fertility after artificial insemination can be due to the difficulty of traversing the cervix and the cervical trauma caused by the instruments designed for artificial insemination. The objective of the present study was to test the competence of intrauterine artificial insemination in Sudanese Desert sheep via surgical interference. In the first part of this study, it was important to select only one ram to be used for conducting the artificial insemination and natural mating to eliminate the ram effect as a source of variation on fertility. Three Hamari rams of an average age, body weight, and body condition score (B.C.S.), 24 months, 52.5 kg and 4 respectively, were selected. The 3 rams were trained for semen collection by the mean of artificial vagina. They were subjected to semen collection 3 times/week for 10 weeks. The semen samples were evaluated and analysed for quality by standard laboratory procedures and the effect of time lapse after collection on semen quality was also assessed. The results showed that no significant difference (p>0.05) appeared for the ejaculate volume for the 3 rams. Ram no. 2191 was significantly better (p<0.001) than the other tested rams in terms of mass motility, individual motility, percentage of the motile spermatozoa and the percentage of live normal spermatozoa. Both ram no. 2191 and ram no. 2193 had significantly higher (p<0.001) sperm concentration per ml, total number of sperms and the number of the straws obtained, as compared to ram no. 2190. The results of time lapse after collection on semen quality revealed that ram no. 2191 maintained good semen quality up to one hour. Accordingly, ram no. 2191 was chosen for the purpose of this study. In the second part of this study, Hamari ewes (n = 30), of average 27 months of age, average body weight of 30 kg and body condition score of 3, were used. They were randomly allocated into 3 groups to conduct intrauterine artificial insemination (IUAI), intracervical artificial insemination (ICAI) and control group for natural mating (NM). Oestrous was induced and synchronized in all ewes using progesterone and pregnant mare serum gonadotrophin (PMSG). The ewes were fitted with controlled internal drug release device (CIDR), which contains 0.3 g progesterone, for 12 days. At the time of CIDR withdrawal, ewes received 300 IU of PMSG intramuscularly. Artificial insemination (IUAI & ICAI) was performed using 0.25x10 freshly diluted spermatozoa with skimmed powder milk. Intrauterine artificial insemination was conducted 50-54 hours post progesterone and PMSG treatment, while the intracervical insemination was conducted at heat detection after progesterone and PMSG treatment. Ewes those assigned for natural mating were left with the ram just after the hormonal treatment. Most of the ovulatory follicles of ewes undergone surgery were found in the right ovary (80%) with a diameter ranging between 0.5 to 0.8 cm. The conception rate as detected by the non-return rate and confirmed by progesterone assay was significantly higher (p<0.001) for ewes undergone intrauterine insemination (100%) and natural mating (100%) compared to cervical insemination (60%). In contrast, the lambing rate of the ewes undergone surgical intrauterine insemination was significantly lower (p< 0.001) as compared to those received cervical insemination or undergone natural mating. There was a significant difference in the twining rate for ICAI and NM (66.7 % and 16.7 %, respectively), where no twins were born from the ewes assigned for the intrauterine artificial insemination. There was no significant difference for the litter size and the gestation length between all types of insemination. In conclusion, the present results indicate that the intrauterine artificial insemination was an efficient method in ewes to achieve high conception rates; however, a suitable non-invasive mean is to be invented.