ROLE OF hCG IN THE OESTRUS INDUCTION PROTOCOL USING PMSG IN THE BITCH
Shibu Simon, K.V. Athman and E. Madhavan
With a view to ascertain the role of human chorionic gonadotrophin in the oestrus induction protocol using pregnant mare's serum gonadotrophin in the bitch, a study was undertaken wherein hCG was provided or withheld after PMSG treatment. Eighteen anoestrous bitches were randomly allotted to three groups of six each. While group I received 20 IU/kg of PMSG for five consecutive days, group II received PMSG at the same rate as group I but followed by 500 IU of hCG on the fifth day. Group III served as untreated control. Natural service/artificial insemination with fresh semen was carried out during the induced oestrus based on external signs, exfoliative vaginal cytology and receptivity. Although conception rates of 66.7 and 50 per cent were obtained respectively in groups I and II, the whelping rates in these two groups were only 50 and 33.3 per cent respectively. None of the animals in the control group conceived. These results suggest that treatment with PMSG alone is preferred over a combination of PMSG and hCG. However, the requirement of hCG at later stages needs to be established after detailed studies.