The stallion Flashcards
What is a stallion?
An entire male horse over 4yo
What is a colt?
An entire male horse less than 4yo
Describe the normal sexual development of male horses
- Testis normally descended into scrotum at or shortly after birth.
- If not descent may occur up to 24 months of age.
- Puberty occurs at 12-24 months
- Maximal sexual maturity reached at 4-5 years and retained until about 20 years.
How long does spermatogenesis take?
60 days
Semen quality is influenced by a wide range of factors, what are they?
Testicular size
Testicular efficiency
Age
Season
Frequency of ejaculations
General health/injury
Testicular size correlates to?
The amount of sperm
How is seasonality linked to reproduction in stallions?
Horses are “long-day breeders” – this is true of stallions as well as mares
Less semen produced over winter
How is age linked to semen production?
Younger stallions produce less sperm and run the risk of being overworked
With each successive ejaculation the number of sperm …?
Halves
How many mares can a stallion mate?
- Very variable – depends on huge number of factors.
- Sperm output may not be the limiting factor, Libido maybe more important
- 500 million motile sperm suggested as suitable dose for natural service and perhaps 150-500 million for A.I.
- Suggested rates include no more than 15 matings a week or two mares a day .
- Some really busy stallions may mate up to 6 mares in a day.
- A book of 80-90 mares a season is often quoted – but very variable
How is a stallion examined for breeding soundness?
Physical exam of external genitalia
Exam of internal genitalia
Observation of libido and mating ability
Semen evaluation
Testicular biopsy
Stallions are swabbed for which disease?
Contagious equine metritis
Where are stallions swabbed for Contagious equine metritis?
Urethra
Urethral fossa
Penile sheath
Pre ejaculatory fluid – if available
Stallions are vaccinated against…?
Equine viral arteritis
Why are stallions vaccinated against equine viral arteritis?
EVA causes abortion
Stallions (only) become carriers.
Notifiable in Stallions.
Blood test before first use to prove seronegative