Termination of pregnancy in cats using a combination of cabergoline, a new dopamine agonist, and a synthetic PGF2 alpha, cloprostenol.

The objective of this study was to increase efficacy of treatment with the dopamine agonist, cabergoline, for inducing abortion in cats by combining it with a synthetic PGF2 alpha analogue, cloprostenol. Side effects of cloprostenol were avoided by using low doses. An oral formulation of cabergoline was chosen to facilitate administration. Cabergoline was given daily (5 micrograms kg-1 day-1) while s.c. injections of cloprostenol were administered every 2 days (5 micrograms kg-1) (2 days)-1). Plasma concentrations of progesterone, side effects and pregnancy outcome were compared with those of five untreated pregnant queens. The treatment was administered from day 30 after first mating in five queens confirmed as pregnant and lasted a mean of 11 +/- 1 days. All treated animals aborted in 9 +/- 1 days without any side effect, except a mild haemorrhagic vulvar discharge. Subsequent fertility of the queens was not compromised. Abortion was mediated by an abrupt and constant decrease in plasma concentrations of progesterone. Progesterone concentrations were lower than 1 ng ml-1 from day 38 onwards in all treated animals and remained at this value thereafter, except for one queen which showed a further increase in plasma progesterone concentration from day 44 without any clinical consequence. In conclusion, a combination of daily oral administration of cabergoline and cloprostenol injections every 2 days appears to be a reliable, safe and practical method for terminating pregnancy in cats at day 30 of pregnancy, when a diagnosis of pregnancy by palpation or ultrasonography can easily be made.