Oestrus Cycle - Canine and Feline Flashcards
When does cyclical activity begin in canines?
6-23 months
What adult measurements must be reached before oestrus starts?
height and weight
How long after adult height and weight are reached does oestrus begin?
6 months
What does monoestrus mean?
one cycle per breeding season
how many cycles do dogs have per year?
one to two
How long does a canine season last?
around 3 weeks
What sort of ovulators are bitches?
spontaneous
What are the stages of canine oestrus?
pro-oestrus, oestrus, metoesrus (dioestrus), anoestrus
Are canine oestrus cycles continuous?
yes
What element of oestrus is not typical in bitches?
dioestrus
How quickly do levels of hormones in the body rise and fall?
slowly
What needs to be achieved before next stage of oestrus is triggered?
certain level of hormone concentration in the body
How many days does canine proestrus last?
9
What is the interaction between male and female during canine proestrus?
male is interested in female, female will not accept male for mating
What are the physical signs of canine proestrus?
vulva swollen due to oestrogen production
serosanguinous vulval discharge
what is serosanguinous discharge?
mixture of blood and serum
How do levels of LH and FSH change during canine proestrus?
LH increases, FSH decreases
What is LH?
lutinising hormone
What is FSH?
folicle stimulating hormone
What does LH stimulate?
rupture of folicle and release of egg towards fallopian tube
what does FSH stimulate?
eggs develop in ovary, folicles develop and then release oestrogen
What hormone peaks at the end of canine proestrus?
oestrogen
What effect does peaking of oestrogen at the end of canine proestrus have?
leads to the clinical signs of oestrus
What is the corpus lutium?
remainder of folicle after egg release that becomes solid and releases progesterone
What does progesterone do?
maintains pregnancy/ inhibits LH and FSH
How long does canine oestrus last?
9 days
During what phases of oestrus are bitches classed as ‘on heat’?
proestrus and oestrus
What is male and female interaction like during canine oestrus?
male and female are interested in each other
What is the sexual behavior displayed by females during canine oestrus?
flagging/ winking- standing for male with tail held to the side
How does the level of oestrogen change during canine oestrus?
declines
When does LH level peak during oestrus and what does this cause?
mid oestrus, ovulation of ovarian folicles
What day of canine oestrus does mating occur?
3-5
What are the physical signs of canine oestrus?
lighter/pinky vulval discharge
enlarged/soft vulva
What typically follows canine oestrus?
metoestrus or pregnancy
How long does canine metoestrus last for?
60 days (around the same length as a pregnancy) as corpus luteum will persist for this length of time
What does progesterone inhibit?
production of FSH and LH
What takes over the role of progesterone during pregnancy?
placenta
What is pseudopregnancy?
a false pregnancy, progesterone levels continue and animal thinks that it is pregnant
How long does anoestrus last for in the bitch?
90-150 days
What sexual behavior is displayed during canine anoestrus?
no sexual behavior, male and female have no interest in each other
What are the physical signs of canine anoestrus?
normal external genitalia
What are levels of progesterone are seen during canine anoestrus?
base levels of progesterone
describe the canine oestrus cycle
eggs develop in the ovary during pro-oestrus stimulated by FSH from the pituitary gland. This leads to the development of the folicle which secrete oestrogen and signs of season begins to show. Oestrogen is secreted from the ovaries during oestrus which stimulates the release of LH from the pituitary gland. Ovulation occurs as LH stimulates eggs to be released. Egg moves from ovaries to fallopian tubes. The empty folicle becomes the corpus luteum which secretes progesterone that prepares the uterus for implantation. triggers metoestrus and progesterone maintains pregnancy or returns to normal levels if no pregnancy.
When is feline first oestrus?
6-9 months
What can the start of the first feline oestrus be affected by?
photoperiod (daylight)
What does seasonally polyoestrus mean?
multiple oestrus cycles per season. Continue to cycle as long as the season lasts/if they become pregnant.
How frequent are feline oestrus cycles?
every 2-3 weeks in spring/summer
What does induced ovulation mean in cats?
ovulation is caused by coitus. Barbs on the tom cat’s penis cause a surge of LH that leads to ovulation
What does the period between feline oestrus cycles depend on?
whether or not mating has occurred
What are the stages of feline oestrus?
pro-oestrus, oestrus, dioestrus/pregnancy, interoestrus, meteroestrus/pseudopregnancy, anoestrus
What sexual behavior do female cats exhibit during pro-oestrus?
female does not accept male for mating
Is the female cat attractive to the male during pro-oestrus?
yes
How long does feline pro-oestrus last?
2-3 days
What hormones are released during feline pro-oestrus?
LH and FSH
Is pro-oestrus easily recognised in felines?
not unless a male is present
What are the physical signs of pro-oestrus in the queen?
blood discharge but often cleaned by the queen
how long does oestrus last in felines?
average of 7 days but 2-10
What are the behavioral changes shown during feline oestrus?
vocalisation (calling), lordosis of spine, female rubs along objects, presents back end
are there external genitalia changes during feline oestrus?
not often
When does interoestrus occur?
if ovulation does not occur
how long does feline interoestrus last for?
3-14 days
After feline interoestrus, what happens?
returns to pro-oestrus and then oestrus. Cycle repeats through season
How long does pregnancy last in felines?
56-70 days
What is metoestrus in felines?
pseudopregnancy
How long may it take after metoestrus for the queen to enter cyclical activity?
45 days
When does anoestrus occur?
during the winter
What is anoestrus?
period of oestrus cycle when ovaries are inactive
describe the process of a queens oestrus cycle
pro-oestrus causes release of FSH which leads to development of the folicle. increase in FSH leads to release of oestrogen. During oestrus if coitus takes place it leads to induced ovulation because of an increase in LH. progesterone prepares the uterus for implantation. if no pregnancy, queen enters interoestrus. cycle continues through season.
