الفهرس 
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Abstract
5. SUMMARY AND CONCLUSION 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) to investigate improving fertility and twinning rate in Barki ewes raised in Siwa Oasis; 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.
A- The basic experiment:
Sixty-six non-pregnant and non-lactating Barki ewes with 3-5 years old and 41.80 ± 0.55 kg average live body weight were used. Animals were randomly divided into three equal 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 (1 ml Synchromate each 1 ml solution containing 250 mg Cloprostenol, Coopers Co., Germany) 10 days apart. On the other hand, ewes of the second group (G2) received double injections of prostaglandin F2α 10 days apart, and after 10 days later, 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, ewes 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 later intravaginal progestagen impregnated sponge were inserted. Sponges remained in situ for 14 days. One day before sponge removal ewes was injected intramuscularly with 2 ml, 0.004 mg, GnRH. (Receptal, Intervet International, B.V. Manufactured in the European Union). All The experimental ewes were checked twice daily (morning and evening) to ensure that sponges remained in their position during the treatment period.
B- Applied supportive experiment:
Forty-five Barki ewes with 4-6 years old and 40.66 ± 0.97 kg average 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. The present experiment has been carried out to improve fertility, lambing and twinning rates of Barki ewes and to evaluate the efficiency of several protocols such as PMSG or GnRH injection after vaginal sponges treatment on some reproductive and productive traits in Barki ewes. The main results could be summarized as follows: A- The basic experiment:
1- The results showed that there was a significant difference in the response to estrus synchronization where the largest proportion of ewes which appeared upon estrus in the second group (95.45%), which treated with PGF2α, FGA sponge and PMSG, while the lowest percentage in the third group (86.36%), which treated with PGF2α, FGA and GnRH.
2- Also, the results showed that 76% of the second group exhibited signs of estrus after the end of treatments up to 48 hours later compared to 47% of the first group and 68% of the third group over the same period, which means the positive impact of vaginal sponges by rapid onset of estrus on the ewes.
3- There were no significant differences in conception and lambing rates, where the proportions of conception rates were (95,100 and100%) while the lambing rates were (95,100 and 94.74%) for the three groups, respectively.
4- There were no cases of abortion in the first and second groups while, the third group showed the abortion rate
5- Weaning rate was significantly higher in the second group (89.66%) compared with the first group (85%) and the third group (83.33%).
6- The results showed that there is a significant difference in litter size between the groups where the second group recorded highest proportion in litter size (1.38) compared to (1.05 and 1.00) for first and third groups, respectively. While fecundity
rates were the highest for the second group (1.38) compared to (1.00 and 0.94) for the first and the third groups respectively. The highest proportion in litter size at weaning was the second group (1.23) compared to (0.89 and 0.83) for the first and the third groups, respectively.
7- The results showed no significant differences in most of productive traits among groups, where birth weight was (3.34, 3.01, 3.27 kg) for the three groups, respectively. While weaning weight was (13.21, 12.55, 13.24 kg) for the three groups, respectively. The average daily gain was (163.62, 158.14, 166.44 g) of the three groups, respectively.
8- Mortality rate from birth up to weaning, there was no significant difference among the three groups, but the second group was the lowest in mortality rate (10.34%) compared to (15 and 16.66%) for first and third groups, respectively.
9- The results showed that the pregnancy period was significantly shorter in the second group, which recorded (149.95 d) compared to (150.21 and 151 d) for the first and third groups, respectively.
10- The percentage of ewes had twins was higher significantly in ewes of the second group (28.57%) compared to (15.26%) for the first group, while the third group not recorded any twinning births. Also the second group recorded percentage of ewes lambing triplets (4.76%) while, no triplets were found in the other groups.
11- There were no significant differences in the sex ratio of (males: females) in the three groups, which amounted to (40:60, 44.8: 55.2 and 50:50) in the three groups, respectively.
12- The P4 blood plasma concentrations were measured by ELISA. Ewes that received PMSG at sponge withdrawal gave higher P4 concentrations as compared to other groups. PMSG administration at sponge withdrawal would affect the
concentrations of blood plasma P4 in synchronized ewes and subsequently would affect the reproductive performance in ewes. Blood determination of progesterone indicated that plasma P4 was decreased after the 2nd PGF2α injection and FGA sponge removal from vagina and these times were proper times for natural mating in control and treated groups, respectively.
B- Applied supportive experiment:
1- The results showed that there was a significant difference in the response for estrus synchronization where the proportion of ewes appeared in estrus in the second group (100%) compared with the first group (86.67%).
2- The results showed that 70% of the ewes of the second group have shown signs of estrus immediately after the end of treatment and up to 48 hours later compared to only 46% of the first group.
3- There were no significant differences in conception and lambing rates, where the proportions of conception rates (100%) for second group compared to (92.31%) for first group, lambing rates were the same proportions as conception rates for both groups.
4- There were no cases of abortion in the first and second groups.
5- There was no significant difference for weaning rate, which was in the second group (85%) and the first group (83.33%).
6- Also, results showed that there is a significant difference in litter size between the two groups as is the case in the basic experience where recorded the second group litter size (1.33) compared to the first group (1.00). While the proportion of fecundity rate was higher for the second group (1.33) compared to the first group (0.92). Litter Size at weaning was higher in the second group (1.13) compared to the first group (0.83).
7- The results showed no significant differences in productive traits for both groups, where birth weight was (3.45 kg) for the first group compared to (3.28 kg) for the second group. Weaning weight was (13.13 kg) for the first group compared to (12.77 kg) for the second group. While the average daily gain was (162.66 g) for the first group compared to (157.64 g) for the second group.
8- Mortality rate from birth up to weaning, there was no significant difference among the two groups, but the second group was the lowest in mortality rate (15%) compared to (16.66%) of the first group.
9- The results showed that the pregnancy period was significantly shorter in the second group, which recorded (149.9 d) compared to the first group, which was (151.4 d).
10- The percentage of ewes had twins was higher significantly in ewes of the second group (33.3%) compared to the first group which did not record any twinning births.
11- There were not significant differences in the sex ratio of males and females, which amounted to (42:58 and 45:55) in the first and second groups, respectively.
In conclusion, Barki is an excellent local breed of sheep if well managed. Results of the trials indicated that reproductive performance of Barki sheep can be improved by applying estrus synchronization and super ovulation practices despite living under the harsh conditions. Barki ewes were capable of being breeding and lambing using different estrus synchronization protocols. Application of PGF2α, FGA sponge and PMSG protocol to Barki ewes appeared to be more effective in improving fertility and twinning rate than other protocols. In this respect, some modifications (such as studying the durations between GnRH and PGF2α administrations) for synchronization protocols were suggested to achieve further improvement in the fertility.