SA: Cycles

Question 1

Hypothalamic Pituitary- Gonadal axis

Answer 1

Light → eye → pineal gland → hypothalamus → pituitary → gonads → physical changes

Question 2

What is the trigger for overt cyclicity?

Answer 2

Puberty happens @ the final stage of growth (plateau of growth)
changes with nutrition, daylight hrs, etc

Question 3

Anatomy of the bitch (intact female)

Answer 3

Paired ovaries surrounded by a bursa (with fat)
Elongated uterine horns (litter species)
Small uterine body
Simple cervix
Vagina + common outlet through vestibule

Question 4

The urethra terminates in the ___________ of the vagina and lies _______ to the opening of the cranial vagina

Answer 4

Vestibule
Ventral

Question 5

Clinical significance of the vestibule

Answer 5

Urethral tubercle/ papilla can cause problems in passing an AI pipette or swab for cytology

Question 6

Anatomy of a male dog

Answer 6

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)

Question 7

Testes rotating 190 degrees or more can cause …

Answer 7

Occlusion of the blood vessels (torsion)

Question 8

Bitch estrous cycle

Answer 8

Effectively polyestrous (cycle a few times a year)
4 phases

Question 9

Interestrus interval

Answer 9

One heat cycle to the next heat cycle (min of 4 m, max 12m)
Clinically important

Question 10

Proestrus (bitch)

Answer 10

Initiation of overt activity
7-9d ave, up to 21d
Estrogen is the dominant hormone

Question 11

Physical changes during proestrus (bitch)

Answer 11

Swelling of vulva, hemorrhagic vulvar discharge
Non-acceptance of male dog (aggression in the beginning, ↑ progest. less aggressive)

Question 12

Estrus (bitch)

Answer 12

Time of breeding
7-9d ave, up to 21d
Fall of estrogen and rise of progesterone (determine standing behavior)**

Question 13

Estrus behavior (bitch)

Answer 13

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

Question 14

Diestrus (bitch)

Answer 14

Time of pregnancy or pseudopregnancy (2m)
Progesterone dominant hormone (support pregnancy) @ first then prolactin supports CL in second half

Question 15

Diestrus behavior (bitch)

Answer 15

Abrupt change from acceptance to non acceptance of male
Scant purulent discharge

Question 16

When does progesterone peak for the bitch?

Answer 16

25- 35d

Question 17

___________ is normal in the bitch

Answer 17

Pseudopregnancy
origin- wolf

Question 18

Estrogen

Answer 18

Peaks in proestrus (only species) due to pre-luteinizing their follicles (progest. produced before ovulation occurs)
Causes edema in the vagina

Question 19

Vaginoscopy

Answer 19

20-30 cm length and 5-8 mm diameter with a light source
Tells you stage of estrous cycle and source of discharge

Question 20

Anatomy of the Queen

Answer 20

Paired ovaries with NO ovarian bursa

Question 21

Anatomy of the Tom

Answer 21

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)

Question 22

Estrous cycle of the queen

Answer 22

Seasonally polyestrous (no transition phases)- long day breeders
5 phases of the cycle
Induced ovulators

Question 23

Timeframe for cycles of the queen

Answer 23

1. Proestrus: 0-2d + Estrus: 2-19d (heat)
2. Proestrus (not stimulated) → 8-10d (quiet period)
3. Diestrus pseudopregnancy (bred or induced to OV chemically) → 40d
4. Diestrus pregnancy → 60 d
5. Anestrus 30-90d (shorter days, not cycling)

Question 24

Proestrus in the queen

Answer 24

Estrogen levels rising
↑ activity, vocalization, and affection towards people

Question 25

Estrus in the queen

Answer 25

Estrogen is high
Vocalization, rolling behavior, breeding position, treading with hind legs

Question 26

What happens when breeding takes place in the queen?

Answer 26

Reflex release of LH from pituitary (aggressive)

Question 27

T/F: It takes 4 or more breeding to ensure 100% OV in queens

Answer 27

TRUE

Question 28

Post-estrous in the queen

Answer 28

Non-OV cycle with no sexual receptivity
8-10d

Question 29

Diestrus in queen

Answer 29

Progesterone dominant hormone
Only occurs when OV induced by breeding
Pregnancy: 9 w
Pseudopreg: 40-45d

Question 30

Anestrus in queen

Answer 30

Classic winter anestrus of seasonal breeding
No cycling activity
Oct-Nov through Jan