Vaginal cytology and semen evaluation

What can vaginal cytology tell us?

Stage of the estrous cycle, best breeding time, and reproductive failure.

What can semen evaluation tell us?

Chances for reproductive success, best breeding time, and reproductive failure.

Can vaginal cytology predict the exact time of ovulation?

No.

What is a more accurate predictor of ovulation?

Progesterone measurement in the blood.

What are the two primary hormones responsible for cytological changes during the estrous cycle?

Estrogen and progesterone.

Can one vaginal cytology evaluation determine the optimal breeding time?

No, multiple evaluations may be needed.

Why may repeat vaginal cytology exams be necessary?

The estrous cycle is a continuum, and exams every few days may be needed.

What are normal findings on vaginal cytology?

Epithelial cells, neutrophils, RBCs, and bacteria.

Are RBCs normally present in queens during any stage of the estrous cycle?

No.

Why may bacteria be present during estrus?

They are normal flora of the distal genital tract and may enter during mating.

What are the three types of vaginal epithelial cells?

Parabasal, intermediate, and cornified.

What do parabasal cells look like?

Small and round, with more nucleus and less cytoplasm.

What do intermediate cells look like?

Larger than parabasal cells, with less nucleus and more cytoplasm.

What do cornified cells look like?

Largest cells, with small pyknotic nuclei and irregular, flat, or boxy borders.

What does pyknotic mean?

A shrunken, condensed nucleus.

During proestrus, is the female attractive to males?

Yes, but she is not receptive to mating.

What are the physical exam findings during proestrus?

Swollen vulva with reddish discharge.

During estrus, is the female receptive to males?

Yes, she is attractive and receptive to mating.

What are the physical exam findings during estrus?

Pinkish/reddish discharge that becomes whiter as metestrus approaches.

During metestrus, is the female attractive or receptive to males?

No.

What are the physical exam findings during metestrus?

Decreased vulvar swelling and discharge.

During diestrus, is the female attractive or receptive to males?

No.

What are the physical exam findings during diestrus?

No vulvar swelling or discharge.

During anestrus, is the female attractive or receptive to males?

No.

What are the physical exam findings during anestrus?

No vulvar swelling or discharge.

What cells predominate during early proestrus?

Parabasal epithelial cells.

What happens to RBCs during early proestrus?

They are present in large numbers.

Are neutrophils present during early proestrus?

A small number may be present.

What cells predominate during late proestrus?

Parabasal epithelial cells.

What happens to intermediate cells during late proestrus?

Their numbers increase.

What happens to RBCs during late proestrus?

Their numbers decrease.

Are neutrophils present during late proestrus?

A small number may be present.

What cells predominate during estrus?

Squamous epithelial cells.

What happens to the nuclei of epithelial cells during estrus?

Some have pyknotic nuclei; most have no nucleus.

How much bacteria is present during estrus?

Abundant bacteria.

Can RBCs be present during estrus?

Yes, a few may be present.

Are WBCs present during estrus?

No.

What cells predominate during metestrus?

Intermediate and parabasal epithelial cells.

Are squamous epithelial cells present during metestrus?

Yes, but only a few.

What happens to bacteria and debris during metestrus?

Abundant bacteria and other debris are present.

What happens to neutrophils during metestrus?

They increase, then decrease as bacteria and debris are removed.

Are RBCs present during metestrus?

No.

What color should discharge be during metestrus?

White.

What cells predominate during diestrus?

Parabasal epithelial cells.

How much bacteria is present during diestrus?

Few bacteria.

How many WBCs are present during diestrus?

Few WBCs.

Are RBCs present during diestrus?

No.

What cells predominate during anestrus?

Parabasal epithelial cells.

Can bacteria be present during anestrus?

Yes.

Can neutrophils be present during anestrus?

Yes, a few may be present.

Are RBCs present during anestrus?

No.

Can cytology distinguish diestrus, pregnancy, and anestrus?

No, they look the same cytologically.

What are the three basic methods of semen collection?

Artificial vagina, manual massage, and electroejaculation.

Which semen collection method yields higher fluid volume and lower sperm concentration?

Electroejaculation.

What usually produces samples with the highest sperm concentration?

Teasing prior to collection.

What happens with repeated semen collection or breeding?

Fluid volume and sperm concentration may decrease.

Why should rest periods be provided between collections?

To allow fluid volume and sperm concentration to recover.

What does the semen collection method affect?

Sample volume, gross appearance, and sperm concentration.

What conditions are sperm sensitive to?

Extreme temperatures (especially cold), water, disinfectants, and pH variations.

How should semen collection equipment be prepared?

Cleaned, dried, and warmed to body temperature.

What temperature should stains and diluents be before use?

Body temperature.

Where should semen evaluation be performed?

In a warm room, as soon after collection as possible.

What are the components of a complete semen evaluation?

Volume, gross appearance, wave motion, motility, concentration, live:dead ratio, morphology, and foreign material or cells.

What information should be included in a complete semen evaluation?

Collection method, signalment, history, PE findings, and suspected abnormalities.

Does semen volume vary between species?

Yes.

Does semen volume necessarily correlate with fertility?

No.

What might a small semen volume indicate?

A possible problem if the species normally produces a larger volume.

What are the three fractions of an ejaculate?

Sperm-free watery, sperm-rich, and sperm-poor.

What is the sperm-free watery fraction composed of?

Secretions from accessory sex glands.

What is the sperm-rich fraction composed of?

Sperm cells.

What is the sperm-poor fraction composed of?

Secretions from accessory sex glands.

Which species produce a very large sperm-poor fraction?

Boars, dogs, and stallions.

Why should the sperm-poor fraction be collected separately in boars, dogs, and stallions?

To reduce dilution of sperm concentration.

Which species require all three semen fractions to be collected together?

Bucks, bulls, rams, and toms.

What two characteristics are evaluated during gross semen appearance?

Clarity/transparency and color.

What does semen clarity provide?

A subjective assessment of sperm concentration.

What happens to semen appearance as sperm concentration decreases?

It becomes milky to clear.

What does opaque, creamy-white semen indicate?

High sperm concentration.

Which species typically have opaque, creamy-white semen?

Bucks, bulls, and rams.

What colors can normal semen appear in dogs, boars, and stallions?

Clear, white, or gray.

What does pink or red semen indicate?

RBCs are present, which is abnormal.

What is wave motion?

A subjective evaluation of sperm motility.

What magnification is used to evaluate wave motion?

40X (high power).

What does very good wave motion look like?

Vigorous swirling.

What does good wave motion look like?

Moderate to slow swirling.

What does fair wave motion look like?

Barely swirling.

What does poor wave motion look like?

Lack of swirling, but sperm are still motile.

What percentage of progressive motility is needed for adequate fertility?

At least 70%.

What is sperm motility?

An objective assessment of progressive motility of individual sperm.

How is microscopic sperm motility evaluated?

Diluted semen under a coverslip at 100X oil immersion.

What does very good sperm motility look like?

Rapid linear activity (80-100%).

What does good sperm motility look like?

Moderate linear activity (60-80%).

What does fair sperm motility look like?

Slow linear or erratic activity (40-60%).

What does poor sperm motility look like?

Very slow, erratic activity (20-40%).

What does sperm oscillating in place indicate?

Poor progressive movement.

What dilution is used for sperm concentration evaluation?

1:200.

Why must semen be diluted before counting sperm?

So individual sperm cells can be visualized.

What device is used to count sperm cells?

Hemacytometer.

What is a hemacytometer?

A special microscope slide used for counting cells.

At what magnification are sperm counted on a hemacytometer?

100X.