1. PROFESSIONALISM
“No man ever reached to excellence in any one art or profession without having passed through the slow and painful process of study and preparation.”
-Horace

2. THE REPRODUCTIVE SYSTEM
THE ESTROUS CYCLE

3. NORMAL ESTOUS CYCLE: THE BITCH
Estrous Cycle: Defined as the time from the beginning of ________________ at period to the beginning of the next.
Onset of puberty: 6-24mths; Avg.: _________________

4. ESTROUS CYCLE Proestrus : leading to __________ (Avg: 9-10 days)
Estrus: ______________ (Avg: 9-10 days)
Metestrus: 2 phases in ________________
Diestrus: _________________ is established (Avg: days)
Anestrus: time when _______________________________ (Avg: 2-5 months)
PAGE 374 (Figure 14-1)

5. Causes GnRH release > LH surge
HORMONE
Hypothalamus
GnRH
Anterior Pituitary
FSH
Ovarian Follicle
Estrogen
Causes GnRH release > LH surge

6. HORMONE CHANGES

7. Typical morphological
features of the vaginal mucosa
and endometrium in
anestrus (A),
proestrus (P), estrus (E),
and early diestrus (D).
H&E. Original magnification 200X.

8. PROESTRUS
PROESTRUS: the period when the bitch is _______________________ active, but __________ the male’s advances
Physical signs of proestrus:
_______________ vaginal discharge
Vulvar swelling
Vaginal edema
Internal physical signs:
Lengthening and hyperemia of the uterine horns
Enlargement of the cervix
Thickening of the vaginal wall

9. PROESTRUS

10. PROESTRUS Hormonal signs of proestrus:
Increasing serum concentrations of ______________ (estrogen)
estrogen is responsible for the physical signs of proestrus
Estrogen is being produced by the maturing follicles in the _______________ (under the influence of Follicle Stimulating Hormone or FSH)
As proestrus progresses, the estrogen levels begin to peak and initiate the onset of estrus.

11. PROESTRUS Cytologic signs of proestrus:
Vaginal Cytology
_______________________ and intermediate cells predominate; wbc’s and rbc’s present
Duration of proestrus: 3-17 days; Avg.: 9 days

12. VAGINAL CYTOLOGY
Part the lips of the vulva and gently insert a swab at a relatively steep angle. Some people suggest using a speculum (e.g. the cone from an otoscope) and some like to moisten the swab with saline prior to use, but neither of these is critical. After 1-2 inches of the swab have been inserted, the angle of insertion can be altered to roughly 45 degrees and insertion continued.

13. VAGINAL CYTOLOGY

14. VAGINAL CYTOLOGY

15. PROESTRUS
INTERMEDIATE CELLS
RED BLOOD CELLS

16. THE NORMAL ESTROUS CYCLE: ESTRUS
ESTRUS: The period of _______________________ of the male
Physical signs of estrus:
The swollen vulva is __________________
The vulvar discharge is usually ____________ bloody
The bitch allows mating
“standing” heat
“flagging” behavior (tail deviated to the side)

17. ESTRUS

18. ESTRUS Hormonal signs of estrus:
Serum estrogen peaks in late proestrus and early estrus. The estrogen peak initiates a surge of ________________________________
LH results in ovulation (rupture) of the mature follicle and release of the oocyte. LH also stimulates the cells left behind in the empty follicle to multiply into the corpus luteum (See metestrus)
serum _________________________________ levels begin to increase toward the end of estrus (and beginning of metestrus)
Progesterone is produced by the corpus luteum which is forming from the _____________________ follicle (see metestrus)
Progesterone is the hormone that maintains __________________________________________________

19. ESTRUS Cytologic signs of estrus:
Vaginal cytology:
Superficial and superficial ____________________________ predominate (aka cornified cells); rbc’s usally present, wbc’s ___________________________
Duration of estrus: 3-21 days; Avg.: 9 days

20. ESTRUS: VAGINAL CYTOLOGY
CORNIFIED EPITHELIAL CELLS

21. METESTRUS
METESTRUS: The period _________ ovulation when the ________________ develops.
Internal signs of metestrus:
Lining of the uterus is ______________________ and “juicy” in preparation for implantation of a fertilized ovum
Loss of the cornified epithelial lining that developed in the vagina during proestrus and estrus

22. METETRUS

23. DIESTRUS
DIESTRUS: the period when the corpus luteum has reached ________________ size and _______________ . Begins with the bitch’s _________ to mate
Physical signs of diestrus:
None except the cessation of signs of estrus
Hormonal signs of diestrus:
Serum _______________________ levels continue to increase and peak during diestrus
In a pregnant bitches, there is a rapid pre-partum drop in progesterone ~ _____________ hours before parturition
In non-pregnant animals, the decline may be more gradual

24. DIESTRUS Cytologic signs of diestrus: Duration of diestrus: ~2mths
Vaginal cytology:
A sudden __________________ in the number of superficial cells and a reappearance of intermediate and parabasal cells, and wbc’s.
Duration of diestrus: ~2mths
Dogs and cats are unique in that their corpora lutea appear to have _______________________ life spans.

25. DIESTRUS: VAGINAL CYTOLOGY
INTERMEDIATE CELLS
PARABASAL CELLS

26. DIESTRUS PSEUDOPREGNANCY: A prolonged ______________________
Animal may show signs of pregnancy:
Nesting behavior
Mammary enlargement
Lactation in extreme cases
Clinical signs ______________ with time

27. ANESTRUS
ANESTRUS: Follows ___________ and ends with the onset of proestrus; criteria vary
First time plasma progesterone reaches a level below _____________ nmol/L
The moment that the influence of progesterone on the ____________________________ is no longer evident.
Cytologic signs of anestrus:
Samples are almost ___________________
The cells present are _____________ and ______________________ cells.
Duration of anestrus: Avg.: ~4.5mths.