equine science reproduction

Question 0

Infertility in Stallions

Answer 0

Poor health/ nutrition
Injury
Stress
Overuse (mismanagement)
Masturbation
High testicular temperature
Cryptochidism
Age

Question 1

Stallion physiology

Answer 1

Fairly straightforward
Puberty
– 11-15 mo
– Spermatozoa production at ~12 mo
– Fully productive by ~4 years
Hormones
– Testosterone – male characteristics, libido
– Follicle Stimulating Hormone – spermatogenesis
– Luteinizing Hormone – testosterone production

Question 2

Estrous Cycle

Answer 2

More complex
Puberty
– 15-24 mo
Seasonally polyestrous
– 15-20% cycle year-round
Two phases – 21-23 d
– Estrus – 4-6 d
– Diestrus – 17-19 d
Ovulation near end of estrus phase

Question 3

Behavioral changes

Answer 3

Diestrus – resentment of stallion

Estrus – accepting of stallion
– Raises tail
– ‘Winking’
– Urination
– Flexion of pelvis – Cervix relaxed

Question 4

Teasing

Answer 4

Confirms mare receptive
Stimulates the stallion
Methods
– “Natural” – Fence/Rail – Stall/Chute – Cage

Question 5

Breeding Methods

Answer 5

Pasture,
Corral
Hand
Artificial Insemination
– On site
– Shipped
Cooled Frozen

Question 6

Breeding considerations

Answer 6

Safety, animal behavior 
Disease
Facilities, equipment 
Cost, labor, efficiency 
Shipping semen 
Technical expertise 
Registry requirements # 
mares to be bred

Question 7

Infertility in mares

Answer 7

Pneumovagina (windsucking)
– Conformation
Scars, abrasions, ulcers
– Old damage
Infections
– Pooled urine in older mares
Ovarian cysts, tumors
– Follicles don’t ovulate

Question 8

Gestation and Lactation

Answer 8

335-340 d gestation
– Debate on nutritional requirements in early
gestation
Lactation peaks ~2 mo, tapers until weaning
– Nutritional requirements high, but depends on mare
Deworming, vaccines, exercise

Question 9

General costs

Answer 9

Stud fees   
– Booking fees
Vet costs
Mare costs 
     – Shipping 
    – Mare care
Ballpark
– $1500-$3500 + stud fee
Embryo Transfer
      – $3000-$5000
Cloning
– $1500 to freeze tissue 
– $150/yr to store
– Cloning \$\$$