Cheque drops were a very good solution to the hormone cycles of a competing female. And you could use them for several years without harming the bitch, in fact the bitches uterus would be in better condition when its time to breed her. As the assault of progesterone being hammered on the uterus like a firing squad does not occur because you are stopping the cycle all together.

As far as I've been able to determine they are no longer on the market (cheque drops), but if someone knows a pharmacist who still compounds this, I'd be highly interested.