Equine reproduction practical by Kavak Flashcards
Stallions reach sexual maturity at
10-24 mo (avg 18)
Life span of sperm in mare repro.
tract
2-4 days
Survival time with fertilizing capacity: 1-2 days
Stallion Semen volume/ejaculate
Stallion Semen volume/ejaculate 20-100 ml
but there are exceptions, those who produce more.
Sperm concentration X 106 30-800 ml
Stallion Sperm concentration
Stallion Sperm concentration X 106 30-800 ml
Stallion Semen volume/ejaculate 20-100 ml
Stallion Sperm Output and Production is influenced by: (5)
– Season (stallions are also seasonal breeders, sperm production is much lower out of season)
– Testicular size
– Animal age
– Frequency of ejaculation (too often equals lower sperm counts)
– Behavior/hormones (if testosterone is low, stallion behavior is also low)
The concentration of the semen is influenced by the season as well.
What all sperm attributes does season affect? (8)
- Ejaculate volume
- Sperm numbers
- Total sperm/ejaculate
- Sperm motility
- Willingness to breed
- How many mounts before breeding
- Scrotal size
- Testosterone production
Most common collection method for stallions.
Artificial vagina collection most common.
Describe Semen Collection and Storage
Avoid contact with air, sunlight, and extreme heat and cold.
- Fresh
– Use within 24 hours - Frozen
– 0.5 ml straws
– 500 million progressively motile sperm per
insemination
General Semen Analysis includes: (8)
- Appearance
- Volume
- Concentration of sperm
- Number of sperm
- Sperm morphology
- Live sperm %
- Sperm motility
- pH (7.2-7.5)
Mare artifical insemination: the semen is deposited where exactly?
Inseminate pipette into the uterus
Multiple inseminations 24 to 48 hours
apart are done.
Its common to use ultrasound to monitor follicular growth in mares.
Which accessory sex glands do stallions have?
ampullary
prostate
paired bulbourethral
vesicular
Fresh semen: semen concentration requirement?
Insemination with fresh should be ? h before ovulation.
Cooled semen: semen concentration requirement?
Insemination with cooled should be ? h before ovulation.
Frozen semen: semen concentration requirement?
Insemination with frozen should be ? h before ovulation.
Fresh semen: 500 million progressively motile
Insemination with fresh should be 24-72 h before ovulation.
Cooled semen: 500 million progressively motile
Insemination with cooled should be 12-48 h before ovulation.
Fresh semen: 200 million spermatozoa
Insemination with frozen should be 2-6 h before and/or AFTER ovulation.
Describe fresh stallion semen.
In extender at room temp., lasts 6h.
Can use 1 ejavulate to inseminate multiple mares.
What temp. is chilled semen stored at?
+4-5’C
What temp. is frozen semen stored at?
-196’C
Lower fertility quality than fresh and chilled.
is stored in liquid nitrogen
Describe mare insemination protocol using fresh semen.
Stocking means putting into horse stocks for restraint.
Describe mare insemination protocol using cooled/chilled semen.
No need to warm the semen before insemination.
Describe mare insemination protocol using frozen semen.
Several protocols: can inseminate either before or after ovulation.
Can also use ovulation inducer drugs like hCG and GnRH.
Perform deep uterine insemination. Deposit the semen on the side where the pre-ovulatory follcile is.
What is the protocol post AI?
U/S 4h after: assess ovulation and accumulation of uterine fluid (post AI endometritis).
Tx the fluid accumulation with uterine lavage. The embryo is not in the uterus yet so its safe.
Ultrasound evaluation of mares: ovary size at time of ovulation.
- Size ca 40 mm
- Become softer before ovulation.
- Painful on palpation.
- Change of shape: round to irregular.
Normal insemination volume for mares.
10-25 ml
Describe Granulosa-theca cell tumor (GTC).
Granulosa-theca cell tumor (GTC) is the most common ovarian tumor in mares, typically affecting one ovary while the other becomes inactive. It arises from the granulosa and theca cells of the ovarian follicles and can produce hormones, leading to behavioral changes such as prolonged anestrus, persistent estrus, or stallion-like aggression.
Affected mares often have an enlarged ovary with a honeycomb-like appearance on ultrasound. Diagnosis is confirmed through hormone testing, including elevated anti-Müllerian hormone (AMH), inhibin, and testosterone levels.
Surgical removal of the affected ovary (ovariectomy) is the treatment of choice, with a good prognosis for return to normal reproductive function if the opposite ovary remains healthy.
Normal ovary size in mare.
5 cm
