Search

Twelve normal healthy anoestrous bitches belonging to larger breeds between 2 and 4 years and at least 12 weeks after the onset of previous oestrus were selected for the study. These animals were assorted randomly into two groups of 6 animals each. While six animals in the group I were given 50 mg clomiphene citrate daily for 5 consecutive days, group II animals were kept as controls. In group I, three animals had slight vulval oedema without any other• signs of pro-oestrus. Even though one of them accepted the male dog it did not conceive. None of the animals in the control group showed any changes. Thus, clomiphene citrate could not induce fertile oestrus in anoestrous bitches when used in the dose rate and schedule of the present study.

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

The oestrous cycle of six bitches which did not conceive on previous two or more matings were monitored using exfoliative vaginal cytology. Four of the six bitches had one anuclear cell peak and the remaining two bitches had two anuclear cell peaks. Maximum anuclear cell peaks ranged from 51 and 83 per cent. When they were mated on the basis of anuclear cell peaks, four of the six bitches whelped with a mean litter size of 7.3 ± 1.9 (SD) pups. LH peaks were calculated retrospectively in all bitches after whelping. Based on the results of the present study it is recommended that bitches be bred two days after first anuclear cell peak and thereafter on alternate days (maximum two or three matings) for optimal fertility.