JOURNAL OF THE HELLENIC VETERINARY MEDICAL SOCIETY, cilt.74, sa.2, ss.5789-5798, 2023 (SCI-Expanded)
This study aimed to compare the effect of
hCG administered at 24 or 36 h following a short-term estrus synchronization
treatment on the ovulation time and estrus parameters in non-lactating Saanen
goats during the breeding season. The estrus cycles of does were synchronized
with an intravaginal sponge containing 60 mg of medroxyprogesterone acetate
(MAP) for six days, and an injection of 125 µg of d-cloprostenol at the time of
sponge insertion in addition to an injection of 300 IU of eCG 24h before sponge removal. After removal of the sponges, does were
injected intramuscularly either 1 ml physiological saline (0.9% NaCl) solution
after 12 h (Group1/Control; n=10),
100 IU hCG after 24 h (Group2;
n=9) or 100 IU hCG after 36 h (Group3; n=9). Estrus behavior after
sponge removal was observed twice daily for 84 h using teaser bucks and transrectal
ovarian ultrasonography was performed twice a day for seven days to determine
small, medium and large follicle numbers, luteal development and the
time of ovulation. Blood
samples were collected on the same days to determine serum progesterone (P4)
and estradiol (E2) concentrations. No significant differences were observed in
terms of estrus parameters, ovarian structure and serum P4 and E2
concentrations between the hCG-treated groups and the control group. Average
values observed for all groups: estrus response (53.57%), the interval from
sponge removal to estrus and ovulation (35.2 h and 67.86 h, respectively),
duration of estrus (18.4 h), the interval from estrus onset to ovulation (50.37
h), ovulation rate (96.43%), number of ovulations (1.36), ovulatory follicle
diameter (6.86 mm), corpus luteum diameter (8.22 mm), follicle and luteal
growth rate (1.17 and 0.68 mm/day, respectively). In conclusion, administration
of hCG at 24 or 36 h following a short-term estrus synchronization protocol
does not affect ovulation time, estrus parameters, and serum P4 and E2
concentrations in goats during the breeding season.