1993 Volume 46 Issue 3 Pages 231-235
A total of 58 domestic bitchs were subcutaneously injected with proligestone (S-C-39) fromone to seven times. To investigate the effects of estrous control, harmful aftereffects, changes in clinical findings and blood characteristics, and return to estrus after the final injection were observed once a month during the study. Plasma levels of progesterone were measured by radioimmunoassay once a month. Due to the results obtained from clinical findings and plasma progesterone levels, it could be seen that estrus and ovulation were suppressed in 35 bitchs out of 38 (92.1%) injected four times or more with proligestone. Amongthe remaining three bitchs (7.9%), estrus was not fully suppressed, namely two showed heatjust before the 4th injection. In addition, in one, it seemed that estrus would return dueto the temporary high levels of plasma progesterone, although no visible signs of estrous behavior could be observed. Abnormal findings were noted in three cases: the first case with maceration of fetus, the second case with pyometra-like syndrome and the final case with abortion detected during injections. However, the former two cases may have been affected before the first injection. Estrus did not return in 30 bitchs out of 40 during more than 5 months after the final injection. In the remaining 10 bitchs, estrus returned after 7.6 months on the average. The present results demonstrate that proligestone is sufficient for estrous control without any harmful aftereffects in bitchs.
