Selected Conditions in Breeding Stallions

Question 1

Stallion infertility

Answer 1

Thorough BSE should identify likely causes of infertility

• sperm production: numbers, motility, morphology
• sperm delivery: ejaculation dysfunction

Question 2

Hemospermia

Answer 2

Presence of blood in the ejaculate

• does not always infer subfertility
• lacerations, abrasions of penis/urethra
• urethral rent
• habronema lesions (common locations at tip of urethra)
• inflammatory conditions of accessory sex glands

Question 3

With hemospermia, the source of blood is from the _______

Answer 3

Corpus spongiosum

Question 4

Hemospermia - diagnosis

Answer 4

Diagnosed via endoscopy

• treated with sexual rest, surgery, antibiotics
• prognosis is fair for return of normal ejaculate

Question 5

Cryptorchidism

Answer 5

Failure of descent of both testicles into the scrotum (5% of horses)

• inguinal or abdominal
• 85% unilateral, 15% bilateral
• R/L occurrence is equal
• spermatogenesis is affected but not hormone secretion

Question 6

Cryptorchidism diagnosis

Answer 6

• cox test: challenge testicle to produce testosterone via GnRH
• estrogen levels in older stallions
• anti-mullerian hormone (if present, there is a testicle present)
• US

Question 7

Inguinal hernia

Answer 7

Intestines enter vaginal sac

• congenital conditions in some foals (hereditary, standardbreds are overpresented, surgery not required)
• palpation, US is used for confirmation
• colic seen in mature stallions

Question 8

Penile trauma

Answer 8

Caused by injuries incurred when breeding

• can be kicked by mare before/during breeding
• excessive swelling, bruising leading to edematous penis
• massage, NSAIDs, antibiotics, hydrotherapy, sling

Question 9

Penile paralysis

Answer 9

Leads to inability to retract penis

• paraphimosis/priapism
• secondary to trauma, tumor or ace administration
• benstropine mestylate
• phenylephrine in CCP
• heparin lavage of CCP
• slings, massage, NSAIDs, antibiotics, topicals

Question 10

Penile tumors

Answer 10

• squamous cell carcinoma –> aged horses, unpigmented skin, geldings more so than stallions
• melanoma
• sarcoid
• lymphoma

Question 11

Penile tumor treatments

Answer 11

• surgery
• cryotherapy
• topical or local therapy

Question 12

Urospermia

Answer 12

Urine contaminates semen during ejaculation

• significant reduction in fertility
• incompetent urethral sphincter
• partial or complete
• diagnosed via odor or urine in semen or BUN strips
• no effective cure
• open ended AV to collect sperm rich jets

Question 13

Hydrocele/hematocoele

Answer 13

Accumulation of fluid within vaginal cavity

• fluid insulates testicle
• painless fluid filled scrotal enlargement
• some resolve, some need surgery
• prognosis for fertility is poor unless corrected
• adjacent testicle can be affected
• hemicastration is an option

Question 14

Coital exanthema

Answer 14

Equine herpes virus-3

• pox like lesions on penis
• no effect on fertility
• transient condition

Question 15

Habronemiasis

Answer 15

Affects moist tissue of penis/prepuce

• larva of equine stomach worm
• larva incites tissue rxn
• typical lesion on urethral process
• deep granulation tissue like lesion
• summer sores
• ivermection to treat

Question 16

What is the most common testicular neoplasia?

Answer 16

Seminoma

• germinal testicular tumor
• teratomas also possible
• non-germinal tumors are rare
• poor/no association w/ cryptochidism