Estrus 1

Question 1

Clinical Usage of Vaginal cytology

Answer 1

A. Used to determine stage of estrous cycle
B. Assists with optimal timing of mating or artificial insemination in small animals
C. Not of practical use in large animals – too much debris
D. Used in conjunction with history and clinical exam
E. Optimal breeding is 3-10 days before onset of diestrus. Fully cornified mature epithelial cells
F. Recommended breeding pattern = every 4th day during interval when more than 90% of cells are superficial
G. Canine sperm is viable 4-6 days in female

Question 2

Vaginal Cell Types

Answer 2

A. Basal Cells
B. Parabasal Cells
C. Intermediate Cells

Question 3

Basal Cells

Answer 3

1. Next to basement membrane
2. Precursor to all vaginal epithelial cells
3. Uniform, small, round, basophilic cells, little cytoplasm
4. Rarely observed on smears made at any stage of the estrous cycle

Question 4

Parabasal Cells

Answer 4

1. Smallest epithelial cells seen in routine smears
2. Large, round nucleus, uniform in size
3. Seen in low numbers, only in diestrus, early proestrus, and anestrus

Question 5

Intermediate Cells

Answer 5

1. Large amounts of cytoplasm in relation to nucleus
2. Approximately twice the size of parabasal
3. Large intermediate cells are sometimes referred to as superficial intermediate cells or non-cornified cells

Question 6

Superficial Cells

Answer 6

Superficial Cells

1. These are the largest cells seen
2. Nuclei – if present are faded or pyknotic, and cell borders are angular and folded. Lots of cytoplasm
3. Also known as cornified

Question 7

Red Blood Cells

Answer 7

1. Associated with early proestrus

2. Not considered to be a reliable indicator of stage of estrus

Question 8

Metestrum Cells and Foam Cells

Answer 8

1. Metestrum cells are parabasal cells that contain a neutrophil in the cytoplasm and can be seen whenever neutrophils are present
2. Foam cells are parabasal cells that contain cytoplasmic vacuoles of unknown significance

Question 9

Proestrus

Answer 9

1. Swollen vulva, reddish vulvar discharge. Attracts but does not accept males
2. Smear: Neutrophils, red blood cells, parabasal, intermediate, and superficial cells
3. Background may be dirty blue caused by mucus. Bacteria are frequently observed.
4. Toward the end of proestrus, neutrophils and red blood cells decrease, whereas intermediate and superficial cells predominate
5. 4-20 days, average 9 days

Question 10

Estrus

Answer 10

1. Swollen vulva, pinkish to straw colored discharge. Accepts males
2. Smear: Neutrophils absent, background is clear
3. Red blood cells usually absent – but can be present throughout estrus and diestrus
4. 95% or more of cells are superficial. Some may not have a nucleus at all
5. Bacteria may or may not be numerous and adhere to the surface of the superficial cells. Not accompanied by leukocytes unless inflammation exists
6. 4-13 days, average 9 days

Question 11

Diestrus

Answer 11

1. Also known as metestrus
2. History of recent estrus
3. Vulvar swelling and discharge decreased, no longer attracts males
4. Smear: Parabasal cells and intermediate cells increase
5. Neutrophils present. RBC may be seen – early diestrusand proestrusmay be difficult to differentiate with one smear.
6. 2-3 months

Question 12

Anestrus

Answer 12

1. No vulvar swelling, does not attract males
2. Parabasal and intermediate cells the predominant cells
3. Absence of superficial cells and RBC
4. Neutrophils and bacteria may or may not be present
5. Variable in length, but generally lasts less than 4.5 months

Question 13

Feline Estrous Cycle

Answer 13

1. Reflex ovulators – ovulate after mating
2. Estrous cycle similar to dogs, but RBC not present at any stage
3. Changes associated with diestrus do not occur unless the cat is bred.