Induction of abortion in queens by administration of cabergoline (Galastop) solely or in combination with the PGF2alpha analogue Alfaprostol (Gabbrostim).
The efficacy of cabergoline solely or combined with a PGF2alpha analogue in inducing abortion at different stages of pregnancy was investigated in 18 queens. The queens were assigned to two treatments: Group I ( n=10 )-cabergoline (15 microg/kg; daily, orally) and Group II ( n=8 )-cabergoline (15 microg/kg; daily, orally) combined with alfaprostol (10 microg/kg; every other day, subcutaneously). Each group was divided into two subgroups according to the duration of pregnancy when treatments started: Group IA ( n=8 ) included queens from Days 34 to 42 after mating. Group IB cats ( n=2 ) started treatments on Day 45 post-mating. Similarly, the combination of cabergoline and PGF2alpha analogue was first given to Group IIA ( n=6 ) from Days 25 to 40 of pregnancy and to Group IIB ( n=2 ) on Days 45 and 47, respectively. Termination of pregnancies was successful in all cats of Group IA, while treatments failed in both cats of Group IB, even though seven and eight treatments, respectively, were given. Mean (+/-S.D.) plasma progesterone concentrations before the start of treatments were 85.0+/-12.3 nmol/l and decreased within 3 days to 8 nmol/l and subsequently to basal values, when the queens aborted (Group IIA, n=6 ) or gave birth prematurely (Group IIB, n=2 ). When abortions failed (Group IB, n=2 ), progesterone concentrations remained elevated (16.9 and 9.8 nmol/l). Duration of combined therapy during late pregnancy in Group IIB ( n=2 ) lasted about 10 days. In both cases, premature birth occurred and the kittens died within 16 h after birth. Overall, treatments starting on Days 25-42 of pregnancy (Groups IA and IIA) had abortion rates of 100%. The average duration of treatments was 5.6+/-1.5 days (range, 3-8). Side effects seen were vomiting and occurred in 6 of the 109 (5.5%) treatments. In conclusion, pregnancies were successfully terminated in the second trimester of feline pregnancy by daily application of cabergoline solely or combined with the PGF2alpha analogue alfaprostol (given every other day). Cabergoline alone was ineffective in inducing abortion at later stages of pregnancy.