Journal of American Science, 2011;7(6) http://www.americanscience.org http://www.americanscience.org editor@americanscience.org 884 Improving Reproductive Performance by Glucose Injection in Damascus Does Goat during Early Summer Anas A. Salem 1 , Hassan A. H. 2 , Nasrat Abd El-Ati 1 , and Gamal B. M. 1 1 Department of Animal Production, Faculty of Agriculture, Assiut University, Egypt 2 Department of Theriogenology, Faculty of Veterinary Medicine, Assuit University, 71526 Assiut, Egypt anas12eg@yahoo.com Abstract: Goats are seasonally polyestrous having estrous activity during late summer, fall, and winter and showing no activity during summer and spring. The objective of the present study was to improve reproductive performance of Damascus doe goats in early summer including: estrous activity (EA), ovarian follicular (OF) growth, corpus luteum (CL) development, and progesterone (P 4 ) profile by injection of glucose (Glu). A total of twelve apparently healthy Damascus doe goats were used in this experiment and were classified randomly into two equal groups. Animals in group A were injected by Glu via j.v.; each animal of the treated group received 94.584 g Glu daily for nine days before the expected day of ovulation. The second group (B) was injected with saline solution and used as control. All animals in both groups were synchronized by PGF 2 α (cloprostenol) three times (10 days between each interval and other) with notice that Glu was injected in the second interval. Blood samples were collected from each animal; the blood was then centrifuged and the serum was analyzed for P 4 determination. All does were subjected to ultrasonographic examination on days 5, 9, and 19 after the third injection of PGF 2 α and post-treatment by Glu. The results revealed that Glu injection achieved estrous activity higher than in the control (100% vs. 50 %, p>0.05). All animals showed the estrous activity through 24-72 hours after each dose of PGF 2 α and post-treatment by glucose. The number of follicles (≤5mm) in the treated group was higher than in the control group (111 vs. 94 follicle, p>0.05), while the follicular diameter did not differ between the two groups. Left ovary was more active than in right ovary (107 vs. 98 follicle, p>0.05) and the ovulation rate detected from the number of corpora lutea and progesterone level was higher (p>0.05) in the treated group than in the control. Moreover, the ovulation was significantly higher in the right ovary than in the left ovary (19 vs. 9 follicles). Corpus luteum diameter in the treated group was significantly larger than in the control group (1.2±0.11 cm vs. 0.97±0.13 cm, p>0.05). The average progesterone concentration increased significantly (2.36±0.84 ng/ml) in the treated animals than in the control (0.96±0.23 ng/ml). It could be concluded that Glu treatment led to improvement of number of estruses, ovarian follicles, corpora lutea and progesterone concentration in Damascus doe goats during early summer. Therefore, treatment by energy-yielding nutrient (glucose injection) on the estrous and ovarian activity may be recommended in periods of reproductive activity impairment in goats. [Anas A. Salem, Hassan A. H, Nasrat Abd El-Ati, and Gamal B. M.. Improving Reproductive Performance by Glucose Injection in Damascus Does Goat during Early Summer. Journal of American Science 2011;7(6):884- 892].(ISSN: 1545-1003). http://www.americanscience.org . Key words: Doe goat, EA, OF, CL, Glu, PGF 2α and P 4 1. Introduction: The estrous activity of Damascus does goat occurs in autumn and winter and not in spring and early summer (Mahmoud, 2010). This means that ovarian activity during spring and early summer in these animals is lacked. Away from the use of known hormonal treatments (gonadotropins) which evoke on the ovarian activity, high energy-yielding nutrients are used for increasing ovulation rate in sheep (Teleni et al.,1989b, Downing & Scaramuzzi, 1991) and rising FSH levels during the estrous cycle (Rhind et al., 1985, Rhind & McNeilly 1986). In contrast, findings obtained by Findlay & Cumming (1976), Rhind et al. (1989), Xu et al. (1989), Smith and Stewart (1990) were not compromised with the previous reports. Whereas, Vin˜oles et al. (2002) reported that effect of nutrition on daily follicular development led to an increase in ovulation rate and FSH secretion and a decrease in estradiol-17β concentration during the follicular phase of the estrous cycle in ewes with a high body condition. Further, ewes fed high energy-yielding nutrients from days 8 to 14 of the estrous cycle owned increased ovulation rate by 14% (Vin˜oles, 2003). For this reason, we prefer in this experiment to use the high energy-yielding nutrients (glucose injection) to test if it is able to resume the estrous and ovarian activity of Damascus does in early summer or not, since administration of exogenous hormones is a costly treatment and may cause severe health problems (Grøndahl, 2008). The physiological mechanism of immediate energy-yielding nutrients (glucose) on the follicular development has been investigated. Glucose may work in direct way on the ovary and metabolic hormones such as insulin-like growth factor I (IGF-I),