Consumption of food, body weight, perineal colour and levels of progesterone in the serum of cyclic female chinchillas.

Abstract

Venous blood of eight cyclic female chinchillas (Chinchilla laniger) was collected twice weekly during all stages of the oestrous cycle and levels of progesterone were determined by radioimmunoassay. Consumption of food, body weight and perineal colour were also monitored in 25 cyclic female chinchillas. Cyclic trends were significant for feed consumption (P < 0.01), colour of the perineum (P < 0.001) and body weight (P < 0.001). Analysis of data used a standardized cycle of 36 days which was arranged according to vaginal perforation. This was subdivided into six periods with 6 days in each. Values of progesterone in the serum ranged from 0.07 to 6.27 ng/ml (n = 64 samples, each in duplicate), and the period of 6 days with the lowest mean progesterone value was that which included the first day of vaginal perforation. The pattern of fluctuations of progesterone resembled that of another hystricomorph rodent, the guinea-pig.