The effect of pregnancy on the interval between one oestrus and the next in the tammar wallaby, Macropus eugenii

Abstract

In females mated to vasectomized males the interval between estrus periods was 30.6 .+-. 1.17 (SD) days but when mated to intact males and pregnancy intervened, it was 29.4 .+-. 1.26 days (P < 0.025). After removal of pouch young, females carrying diapausing blastocysts gave birth 26.2 days later and came into estrus 26.4 .+-. 0.57 (SD) days later. When post-partum fertilization was prevented, removal of pouch young was followed by estrus 30.4 .+-. 0.99 days later (P < 0.0005). An influence of the conceptus upon the estrus cycle of M. eugenii is evident.