Which hormone is associated with stimulating oestrus or heat in females?

Oestrogen is the hormone associated with stimulating oestrus or heat in females. This hormone plays a crucial role in the reproductive cycle, particularly in preparing the female body for mating. During the follicular phase of the estrous cycle, increasing levels of oestrogen promote behavioral changes associated with heat, such as increased receptivity to males and changes in physical appearance, like swelling of the vulva and discharge.

In contrast, progesterone is primarily involved in maintaining pregnancy and preparing the uterus for embryo implantation, rather than inducing oestrus. Growth hormone facilitates growth and metabolism in organisms and does not have a direct role in reproductive behaviors. Luteinising hormone is involved in the final maturation of ovarian follicles and triggers ovulation after oestrogen levels reach a certain threshold but is not the hormone that stimulates oestrus directly.

Therefore, oestrogen is the key hormone responsible for signaling the onset of estrus in females, leading to increased sexual activity and readiness for reproduction.