SA: Cycles Flashcards
Hypothalamic Pituitary- Gonadal axis
Light → eye → pineal gland → hypothalamus → pituitary → gonads → physical changes
What is the trigger for overt cyclicity?
Puberty happens @ the final stage of growth (plateau of growth)
changes with nutrition, daylight hrs, etc
Anatomy of the bitch (intact female)
Paired ovaries surrounded by a bursa (with fat)
Elongated uterine horns (litter species)
Small uterine body
Simple cervix
Vagina + common outlet through vestibule
The urethra terminates in the ___________ of the vagina and lies _______ to the opening of the cranial vagina
Vestibule
Ventral
Clinical significance of the vestibule
Urethral tubercle/ papilla can cause problems in passing an AI pipette or swab for cytology
Anatomy of a male dog
Paired testes in a scrotum between the legs
Tail of the epididymus through the tail of the dog
Os penis (entering vag)
Prostate (only accessory sex gland)
Testes rotating 190 degrees or more can cause …
Occlusion of the blood vessels (torsion)
Bitch estrous cycle
Effectively polyestrous (cycle a few times a year)
4 phases
Interestrus interval
One heat cycle to the next heat cycle (min of 4 m, max 12m)
Clinically important
Proestrus (bitch)
Initiation of overt activity
7-9d ave, up to 21d
Estrogen is the dominant hormone
Physical changes during proestrus (bitch)
Swelling of vulva, hemorrhagic vulvar discharge
Non-acceptance of male dog (aggression in the beginning, ↑ progest. less aggressive)
Estrus (bitch)
Time of breeding
7-9d ave, up to 21d
Fall of estrogen and rise of progesterone (determine standing behavior)**
Estrus behavior (bitch)
Stand to be mounted
Tail deviated to the side (flagging) → muscle of the vag contracts and raises, helps with penis alignment
Stiffening of back legs and rolling of skin on back
Diestrus (bitch)
Time of pregnancy or pseudopregnancy (2m)
Progesterone dominant hormone (support pregnancy) @ first then prolactin supports CL in second half
Diestrus behavior (bitch)
Abrupt change from acceptance to non acceptance of male
Scant purulent discharge
When does progesterone peak for the bitch?
25- 35d
___________ is normal in the bitch
Pseudopregnancy
origin- wolf
Estrogen
Peaks in proestrus (only species) due to pre-luteinizing their follicles (progest. produced before ovulation occurs)
Causes edema in the vagina
Vaginoscopy
20-30 cm length and 5-8 mm diameter with a light source
Tells you stage of estrous cycle and source of discharge
Anatomy of the Queen
Paired ovaries with NO ovarian bursa
Anatomy of the Tom
Paired testes and dorsally displaced scrotum (don’t rotate)
Tail of epi. towards tail or the ground
Prostate and bulbourethral gland
Fibroelastic spines on penis from Testosterone (mating)
Estrous cycle of the queen
Seasonally polyestrous (no transition phases)- long day breeders
5 phases of the cycle
Induced ovulators
Timeframe for cycles of the queen
- Proestrus: 0-2d + Estrus: 2-19d (heat)
- Proestrus (not stimulated) → 8-10d (quiet period)
- Diestrus pseudopregnancy (bred or induced to OV chemically) → 40d
- Diestrus pregnancy → 60 d
- Anestrus 30-90d (shorter days, not cycling)
Proestrus in the queen
Estrogen levels rising
↑ activity, vocalization, and affection towards people
Estrus in the queen
Estrogen is high
Vocalization, rolling behavior, breeding position, treading with hind legs
What happens when breeding takes place in the queen?
Reflex release of LH from pituitary (aggressive)
T/F: It takes 4 or more breeding to ensure 100% OV in queens
TRUE
Post-estrous in the queen
Non-OV cycle with no sexual receptivity
8-10d
Diestrus in queen
Progesterone dominant hormone
Only occurs when OV induced by breeding
Pregnancy: 9 w
Pseudopreg: 40-45d
Anestrus in queen
Classic winter anestrus of seasonal breeding
No cycling activity
Oct-Nov through Jan
