It has been shown that heat stress can also increase adrenal gland weight and reduces pituitary, testis and seminal vesicle weights in rats and consequently decreased spermatozoa count and cause male infertility [5,6]. Arancibia et al. [7]. Found a decrease in prenatal healthy follicles and appearance of a new population of follicles after 2 weeks of heat stress while formation of follicular cysts a long side increased plasma hormone levels, irregular oestrus cycle and decreased ovulation in female rats were evident [8,9]. The availability of these rats and their survival rate for experimental purposes has been a major challenge throughout most research institutes and universities across Nigeria. Hence, it is imperative to carefully evaluate the suitable season to rear these animals for maximum reproductive activity considering the fact that Nigeria is located at tropical region of the globe where temperature can significantly generate heat stress in the animals that could possibly result into traumatic effect on the reproductive cycles as well as the survival rate of the new born.