Reproductive Cytology Flashcards
Canine Estrous Cycle
Length
Average: 6-7 months
Estrous Cycle Stages
(in order)
- Proestrus
- Estrus
- Diestrus
- Anestrus
Determine Time of Breeding
- Serum levels of P4 and LH
- Microscopic evaluation of vaginal cells
Hormones of Estrous
- Follicle Stimulating Hormone (FSH)
- Estrogen
- Luteinizing Hormone (LH)
- Progesterone (P4)
Follicle Stimulating Hormone
(FSH)
- Hormone of anestrus
- Promotes growth of follicles in ovary
- Required for production of estrogen; triggers next stage
Estrogen
- Rises early in proestrus
- Peaks prior to estrus
- Declines in estrus
- Suppresses LH release
Increased Estrogen
Clinical Signs
- Vaginal edema (swelling)
- Swelling vulva
- Bloody discharge
- Vaginal lining thickens
Luteinizing Hormone
(LH)
- LH surge starts estrus
- Surge causes ovulation in about 2 days
- Turns follicle into corpus luteum (CL) - secretes progesterone
Ovulation
- Ova not mature upon ovulation
- Takes 2-3 days to mature
- Peak fertilization after LH surge is 4-6 days after
Progesterone
Hormone that helps maintain pregnancy
* levels begin to rise after LH surge
* more produced after CL formed (secreted)
* continues to rise and peaks 2-4 weeks
* rapid declines right before whelping (occurs within 24 hours)
Identify Estrous Stage
Anestrus
* Period of least reproductive activity (FSH working)
* Lasts about 4 months
* Parabasal cells (low cellularity)
* Hard to tell from diestrus and pregnancy
Proestrus
- bloody discharge
- swollen vulva (estrogen)
- males attracted, but can’t breed
- lasts 9 days
- early vs late
Identify Estrous Stage
Early Proestrus
* high number of RBCs
* parabasal epithelial cells
* neutrophils
Identify Estrous Stage
Late Proestrus
* nearly all epithelial cells are intermediate cells
* RBCs and neutrophils present, but less
Identify Estrous Stage
Estrus
* “in heat”
* discharge becomes whiter as stage progresses
* lasts 9 days
* cornified squamous epithelial cells; usually anuclear
* neutrophils gone (increase at end)
* small amount of RBCs (decrease at end)
Identify Estrous Stage
Diestrus
* decreased swelling and discharge
* lasts 2-3 months
* parabasal and intermediate cells
* neutrophils increase initially, then decrease
* bacteria may be present
* no RBCs
Identify Vaginal Cytology
Vaginitis and Metritis
* inflammation of vagina and uterus
* pinkish-white discharge without swelling
* noncornified cells
* high neutrophil count
* may or may not be bacteria
Feline Reproduction
- Polyestrus - cycle in and out until bred
- Similar findings of cells and neutrophils as dogs
- No RBCs at any stage of cycle
Time of Breeding
Cytology
Start cytology a few days after signs of vaginal bleeding
* breed when >50% of cells are cornified
* breed EOD until diestrus, or when females stop allowing males
Time of Breeding
Vaginoscopy
Vaginal mucosa becomes crenulated (wrinkled) as estrogen decreases
* wrinkles increase after ovulation
* prominent folds after ovulation (breed here)
Time of Breeding
LH Assay
In-house testing with blood
* short peak; 16-24 hours
* do every day to not miss peak
Time of Breeding
Progesterone Test
Outside lab testing
* can do in-house, but not as accurate
* need to do every day, same time of day
Semen Evaluation
Motility
- Drop of semen on warm slide (cold reduces motility)
- Check 100 sperm; note speed and direction
- Should have rapid forward movement in straight line
Semen Evaluation
Morphology
- Classify by site of defect (head, midpiece, tail)
- Primary vs Secondary defects
- Primary = sperm developement (more serious)
- Secondary = sperm traveling
