The present paper begins with an introduction in which several considerations of the great advance of the use of hormone analysis technologies in the field of Endocrinology have been reviewed. We also review the features of the female reproductive cycles. The last part of the paper consisted in our experimental studies, which include the steroid profiles of oestradiol-17β, progesterone and testosterone in several domestic species, such as, cows, mares, sows, sheep and nanny-goats, using the competitive enzyme linked immunosorbent assay (ELISA) method. This assay is idoneus for the steroid hormone analysis because of its great sensitivity, specificity and detectability; furthermore it is easy and rapid to perform with low cost, and adaptable under field conditions that it is an additional advantage for the Veterinary Endocrinology. In those experiments we used large number of samples of each species, that allowed us to establish significant parameters on the steroid Endocrinology of common domestic species. The validation of the methodology performed in our laboratory for the mentioned species led us to obtain reliable results. We trust that henceforth these values may serve as basic or standard points of reference for any future work on Reproductive Endocrinology.