Induction of Follicular Development and Ovulation in Thai-native Goat Using Decreasing Dose of FSH with hCG

Abstract

The objective of this study was to evaluate induction of multiple follicular growths and ovulation in Thai-native goats treated with decreasing dose 2 or 3 days of follicle stimulating hormone (FSH) and human chorionic gonadotrophin (hCG). Thai-native non pregnant goats (n = 20; 14 months of age) received two treatments: 2 days FSH (2D-FSH) and 3 days FSH (3D-FSH). Group of 2D-FSH was intramuscularly injected with twice daily FSH for 2 days (18 mg), starting on day 18, 19 and with 300 IU hCG on day 20 of estrous cycle. Group of 3D-FSH was injected with twice daily FSH for 3 days (24 mg), starting on day 17, 18, 19 and with hCG on day 20. Goats underwent laparotomy at 24 h after injected hCG to count corpora hemorrhagica (CH) and at 72 h to count corpora lutea (CL). Blood samples were taken to determine plasma progesterone (P4) concentrations on day 17, 18, 20, 21 and 23. Ovulation rates at 24 h of 3D-FSH were as 66.66 % greater than 2D-FSH as 56.09% (P<0.05). Numbers of follicles in class 1-3, 4-6 and 7 mm at 24 h were not statistically different between 2D-FSH and 3D-FSH groups (P>0.05). However, the number of follicles in class 7 mm of 3D-FSH group was greater than 2D-FSH group (4.10 ± 1.52 vs 2.80 ± 1.47; P <0.05) but were not differ in class 1-3 and 4-6 mm at 72 h (P>0.05). Plasma P4 concentrations were high on day 17 and 18 then decreased on day 20, 21 and 23. However, The plasma P4 were not statistically different between groups (P>0.05). These results indicate that superovulation with decreasing dose FSH (3D-FSH) and 300 IU hCG can be an effective protocol in goats for inducing multiple follicular development and ovulation in order to achieve successful development of reproductive technologies in small ruminants.