Breeding Cycles Flashcards
What factors can affect seasons?
increase/decrease day length
beginning of the wet season
rise or fall in temperature
What type of oestrus is a bitch?
seasonally monooestrus
What type of oestrus is a queen?
seasonally polyoestrus
What are the functions of the oestrus cycle?
- to produce ova to be fertilised by sperm
- to prepare the reproductive tract to receive the ova
- to produce behavioural patterns in the female that advertise to the male that she is receptive
- to cause the female to stand still to allow the mating to occur
What are the phases of the oestrus cycle?
Pro-oestrus Oestrus Met oestrus Dioestrus Anoestrus
What occurs during pro-oestrus?
preparation for oestrus
ovarian follicles begin to secret oestrogen
What occurs during oestrus?
the period of sexual receptivity
female will stand to be mated!!
What occurs during met-oestrus?
reproductive tract is under the influence of progesterone (from CL)
What occurs during di-oestrus?
CL is established or being fertilised (pregnancy is established)
What occurs during an-oestrus?
period between oestrus cycles
little ovarian activity
What hormones are involved in the oestrus cycle?
Gonadotrophin releasing hormone
follicle stimulating hormone
oestrogen
lutenising hormone
How do hormones affect the oestrus cycle?
- the hypothalamus secretes GRH (in response to light, temp etc)
- GRH affects anterior pituitary to secrete FSH
- FSH acts of the ovaries and stimulates Graafian follicles to produce oestrogen
- oestrogen produces behaviour associated with pro-oestrus and prepares the repo tract
- oestrogen inhibits production of FSH and stimulates secretion of lutenising hormone
- LH causes ovulation
- falling levels of oestrogen and rising progesterone causes behaviour associated with oestrus and allows mating
- progesterone prepares the repo tract
- also inhibits production of GRH by -ve feedback
How long its a bitches season?
21 days
What signs may be present if a bitch is ready to mate?
moving tail to one side
lordosis
arching her back
