Plasma progesterone and body weight in the pregnant and non-pregnant kowari, Dasyuroides byrnei (Marsupialia:Dasyuridae).
Female kowaris are seasonal breeders (May-November) with a gestation of 32.5 +/- 1.8 days (mean +/- s.d., n = 35). The oestrus cycle including pregnancy is 59.0 +/- 6.7 days in duration (mean +/- s.d., n = 12) and is not significantly different from the non-pregnant cycle of 60.3 +/- 7.1 days (mean +/- s.d., n = 15) (P greater than 0.1). Animals maintained on a fixed diet show an increase and fall in body weight before oestrus and again at the end of the oestrous cycle or a pregnancy; these changes correlate closely with progesterone concentration. Plasma progesterone concentration and body weight were measured in six kowaris undergoing an oestrous cycle then a pregnancy in the breeding season of 1981. The basal concentration (mean +/- s.d.) of progesterone prior to the breeding season was 0.35 +/- 0.21 ng mL-1. There were mean rises of 1.84 +/- 1.1 and 2.47 +/- 1.5 ng mL-1, respectively, before the first and second oestrous periods which had declined to near basal levels by the day of oestrus. Peak values of 9.9-11.5 ng mL-1 were measured between days 23 and 30 of oestrous cycle and pregnancy. The pattern of changes in body weight and plasma progesterone concentration was similar in pregnant and non-pregnant animals but the decline in weight and progesterone occurred earlier in pregnant kowaris.
Fletcher
T P
TP
Zoology Department, La Trobe University, Bundoora, Vic., Australia.
D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight; D004847:Epithelial Cells; D004912:Erythrocytes; D004971:Estrus / Q000097:blood* / Q000502:physiology; D005260:Female; D007962:Leukocytes; D008098:Litter Size; D008394:Marsupialia / Q000097:blood* / Q000502:physiology; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000097:blood* / Q000502:physiology; D011374:Progesterone / Q000097:blood*; D012621:Seasons; D014556:Urine / Q000166:cytology; D014621:Vagina / Q000166:cytology
D011374:Progesterone