Lecture 41 (Repro 3) Cyclicity 2 Flashcards
What age do dogs enter puberty?
6 to 9 months
What is the mean interestrus interval in dogs?
7 months
True or false: There is no seasonal influence on the cyclicity of dogs.
True. Dogs are non seasonally monoestrus
Does endometrial sloughing occur in dogs?
No!
What marks day 0 of the canine estrous cycle?
LH surge
What hormone is measured in dogs to determine start of estrous cycle?
Progesterone - indirect measurement (not LH which is the mark of day 0).
In the dog, what are the names of the two estrous stages that make up the follicular phase? How long do these stages last?
Proestrus and estrus (both 9 days long)
What stage comprises the luteal phase of estrous in the dog? How long does this stage last?
Diestrus. 2 months
Estradiol concentration _________ (Rises or falls?) during proestrus in the dog.
Rises
When does estradiol in the dog reach its peak?
24-48 hours prior to LH surge
What causes proestrus bleeding in dogs?
Extravasating of erythrocytes by diapedesis from the hyperaemic endometrium under estrogen stimulation.
Do dogs allow mounting in proestrus?
No! Do not allow this until they are actually in estrus.
What are the earliest cytological finding for proestrus in dogs?
presence of red blood cells and intermediate cells.
What is the only fixed point of the bitch’s Repro cycle?
LH surge
What is flagging (dogs)?
Upon perineal stimulation, bitch will deflect tail
What is lordosis reflex?
Female animal responds to lumbar pressure by standing still and firmly and arching back slightly.
During estrus, how does the vaginal discharge of the bitch change?
From serosanguinous to straw coloured
What are the predominant cells in vaginal cytology during estrus?
Keratinized superficial epithelial cells (psychotic, fragmented or absent nucleus, and an eosinophilic cytoplasm)
On what day will ovulations in the bitch’s estrus be complete?
Day 3
Where is the dog’s oocyte arrested at the time of ovulation? what is the significance of this
Prophase 1 - not fertilizable at this point
On what day will fertilization be complete in the dog?
Day 6
What hormone being secreted in non pregnant bitches can initiate pregnant like behaviour (AKA Pseudopregnancy)
Prolactin
What characterizes the appearance of vaginal cytology in the diestrus stage of the bitch?
Appearance of parabasal and intermediate cells with large number of leukocytes (neutrophils primarily)
About when does P4 (progesterone) secretion peak in the dog’s cycle and what happens after this peak?
15 to 25 days. after this P4 decreases to below 1ng/ml by days 55 to 60 by gradual luteolysis
What compound is the CL susceptible to?
PGF2 alpha (prostaglandin)
Among the following, which physiological process is most reliable for predicting breeding time in the bitch: A) proestrus breeding B) Keratinization of superficial epithelial cells C) Ovulation D) LH surge
D - LH surge