In this study, seven adult crossbred bitches, copulated with healthy dog after andrologic exam, were used with the objective of studying progesterone and estradiol 17-b serum concentrations during late proestrus, estrus and pregnancy. During the phases, except on late proestrus, mean cortisol levels were measured. Vaginal citology were used to indicate the interval to submit the bitch to mate, based on the presence of superficial cells into the smears. By the results, serum progesterone concentrations were reduced in late proestrus, reaching gradually ascending levels during estrus up to 36.90ng ml-1 in mid gestation; in late gestation levels were obtained around 4ng ml-1. Serum estradiol was high in late proestrus (18.81pg ml-1) but decreased in estrus (1.57pg ml-1). In late pregnancy estradiol levels were reduced behind the limits of detection, probably because the laboratory methods. Elevations in maternal cortisol levels were seen prepartum (22.27ng ml-1), releasing after whelping (6.52ng ml-1), when progesterone had manteined basal levels.
bitches; pregnancy; progesterone; estradiol; cortisol
