Some aspects of the aetiology, diagnosis and treatment of infertility in the bitch.

The nature of the infertility in 19 bitches was investigated: 10 animals were considered to be normal on the basis of their sexual behaviour, vaginal cytology and plasma oestrogen and progesterone concentrations. Successful conception and whelping occurred for 6 of the 10 bitches. The previous apparent infertility was probably attributable to defective mating management by the owners. Although follicular development and ovulation occurred in 4 of the remaining bitches, oestrus was not exhibited: AI resulted in 3 conceptions. The other 5 animals exhibited only some of the normal characteristics of pro-oestrus. Another group of 10 anoestrous bitches (normal and pathological) was treated with PMSG or stilboestrol. PMSG induced follicular development in 5 of 6 bitches treated. The magnitude of the induced plasma oestrogen peak varied considerably. Delay in the initiation of oestrous behaviour occurred relative to the plasma gonadal steroid pattern in 2 of the 3 bitches that showed oestrus. Stilboestrol induced a sequence of behavioural changes and plasma steroid concentrations and patterns similar to those found in the normal oestrous bitch, but none conceived.