Hormones in Oestrus

During oestrus, levels of oestrogen remain high. Oestrogen is produced by the follicle and transported via the bloodstream, causing the typical oestrus behaviour and changes in the genitals. Towards the end of the main phase of oestrus or in early post-oestrus, rising levels of LH (luteinising hormone) trigger ovulation. Luteinising hormone is produced in the pituitary gland (hypophysis) and is carried to the ovary via the bloodstream.
Oestrus is triggered by rising levels of the oestrus hormone (oestrogen) in a complex pattern of hormonal interaction.

See right to view the effects of individual hormones or the hormone curves.