VMD 513: Pet animal Breeding, Management, Nutrition and Health Care (1+1)

SIGNS DURING PROESTRUS

• The proestrus is typically defined as the day on which a blood-tinged vaginal discharge first appears. This is accompanied by enlargement and swelling of vulva. At the beginning of proestrus, the vulva is turgid.
• If mating ware attempted during proestrus, intromission would be impossible or very difficult.
• As proestrus proceeds, the vulva becomes softened and more pliable, eliminating this impediment to mating.
• The bloody discharge that is seen during proestrus is due to the loss of red blood cells by diapedesis of vessels lining the uterus into the lumen of the uterus.
• As proestrus proceeds, female often act playful and may even tease males but will not allow mounting or mating by male dogs. Late in proestrus, the bitch often becomes increasingly passive about the male’s approach.
• The length of proestrus usually varies between 6 and 11 days, with an average of 9 days.
• The hormones like FSH and LH from pituitary gland act on the ovaries to stimulate the follicle development. Follicles are the primary site for estrogen synthesis and the estrogen is responsible for the behavioural changes. It prepare the uterus and vagina for mating and pregnancy.
• Proestrus ends with the onset of estrus, which is characterized by the female allowing a male dog to mount and breed.