Heat shock protein(s) may serve as estrus indicators in animals: A conceptual hypothesis

The estrous cycle consists of episodic phases that eventually regulate reproduction in non-primate mammals. Females are sexually receptive to males only during estrus phase, which lasts from few hours to 2 days. Estrus detection is crucial for reproductive management of animal herd; however, precise estrus detection method/tools are not available. The analysis of body fluids, e.g., facets of proteomics during recent years is promising in the progression of estrus markers. Specifically, heat shock proteins (HSPs) present in body fluids and reproductive organs could be possibly used as markers of estrus. We note the possible vital roles of hyperthermia, stress and steroid hormones during estrus that could positively regulate the expression of HSPs. To validate our hypothesis, we explained the possible mechanism of production of HSPs, specifically during estrus phase. We recommend intensive research on HSPs to develop credible estrus detection tools in animals.