Cm. Hearn et al., EFFECTS OF CABERGOLINE ON REPRODUCTION IN 3 FAMILIES OF AUSTRALIAN MARSUPIALS, Journal of Reproduction and Fertility, 113(1), 1998, pp. 151-157
The effects of the prolactin inhibiting drug, cabergoline, on pregnant
and lactating marsupials were investigated in four species from three
diverse families: the tammar wallaby, Macropus eugenii, the quokka, S
etonix brachyurus, the brushtail possum, Trichosurus vulpecula, and th
e fat-tailed dunnart, Sminthopsis cassicaudata. In tammar wallabies, 2
0 mu g cabergoline kg(-1) injected intramuscularly I day before expect
ed birth did not alter the timing of parturition but neonates died wit
hin a day of birth, suggesting that the onset of lactation was comprom
ised. During early lactation in tammars (56-69 days post partum), an i
ntramuscular injection transiently retarded growth of the young, altho
ugh they subsequently survived. This treatment induced reactivation of
the quiescent corpus luteum and the blastocyst from diapause, so a ne
w birth occurred 26-27 days later, despite the continued sucking of th
e young in the pouch. Intramuscular injection during late lactation (1
66-199 days post partum) apparently suppressed milk secretion since po
uch young lost up to 20% of their bodyweight or died within 7 days of
treatment. Oral administration of cabergoline had no effect on the gro
wth of the young or on the quiescent corpus luteum and diapausing blas
tocyst. Quokkas showed similar responses to tammars after treatment in
late lactation. Possums and dunnarts were less sensitive to injected
cabergoline than the two macropodid species, and possums showed no res
ponse to oral administration. The lack of response of these marsupial
species to oral cabergoline treatment suggests that accidental ingesti
on of baits, containing 20 mu g cabergoline kg(-1), used to control in
troduced eutherian pests such as the red fox, Vulpes vulpes, or the fe
ral cat, Felis cattus, should not affect the reproduction of native ma
rsupials.