27 Stallion Infertility

1. kicked

2. mount over a fence or wall

3. leg caught in breeding hobbles (which are on the mare to prevent her from kicking him)

4. injury to penis during collection on phantom like rupture of dorsal artery of penis or damage to shaft

Name a few ways breeding injuries can occur in stallions?

Dorsal surface

Where is the normal venous plexus located on the stallion penis?

NORMAL venous plexus on stallion penis

What is this? Is it normal or abnormal?

Massive hematoma from rupture of dorsal artery on penis

What happened in this stallion penis?

"Truss"es or a supportive bandage or apparatus used to apply pressure to prevent edema accumulation in penises after injury

What is this?

Age is the most common cause but THERMAL INJURY is also a very common cause

note: caused by things like systemic infection or scrotal insulation like edema or hemorrhage

Testicular degeneration is common in older stallions. It may be unilateral, bilateral, temporary, or permanent. What causes it most of the time?

Causes low concentration with high morphologic defects

What does testicular degeneration do to the sperm?

PRIMARY

Testicular degeneration causes low concentration of spermatozoa with high morphologic defects. Are these defects normally primary or secondary defects?

Mild and severe degeneration

What are the different types of testicular degeneration in stallions?

Hypoplasia

What do you need to differentiate testicular degeneration from in stallions?

b. normal to slightly small testicle

d. soft consistency

Select the characteristics of mild testicular degeneration in stallions:

a. firm consistency

b. normal to slightly small testicle

c. markedly decreased testicle size

d. soft consistency

e. connective tissue replaces normal parenchyma of testicle

a. firm consistency

c. markedly decreased testicle size

e. connective tissue replaces normal parenchyma of testicle

Select the characteristics of severe testicular degeneration in stallions:

a. firm consistency

b. normal to slightly small testicle

c. markedly decreased testicle size

d. soft consistency

e. connective tissue replaces normal parenchyma of testicle

Tunica albugiena

What structure becomes palpably wrinkled with testicular degeneration in stallions?

Standardbreds

What breed is testicular torsion most common in in stallions?

Recurring

Testicular torsion tends to be an isolated incident or recurring.

Colic, sudden painful onset

What kind of symptoms may a stallion with testicular torsion present with?

Orchiectomy

What is the typical treatment for testicular torsion in stallions?

#1 = faces caudally

Which one is the tail of the epididymis?

#2 = faces cranially

Which one is the head of the epididymis?

Dorsolateral aspect

Where is the epidydimal body attached on the testicle in stallions?

Palpate entire length of epididymis and identify position of the tail

May also ultrasound

How do you diagnose testicular torsion in stallions?

Hemiorchiectomy and hemicastration

(since the risk of damage to other testis is possible and recovery to the affected testis is rare)

Sometimes, you may be able to get away with treating stallion orchitis with long term antibiotics and NSAIDs. However, with acute cases, what may you have to do?

Orchitis, hematogeous normally

note: neoplasia would be a differential, but orchitis is more smooth and neoplasia is bumpy normally. ultrasound to differentiate

What is this? What is the spread normally like?

Epididymitis

What is this?

Streptococcus equi zooepidemicus

Primary bacterial epididymitis is uncommon in horses. Though, when bacteria is involved, most recorded cases are caused by WHAT bacteria?

Orchiectomy/hemicastration, unilateral

What is the only feasible clinical treatment approach to equine epididymitis?

Seminoma, teratoma

What are the two common types of testicular neoplasia in stallions?

SEMINOMA: older stallions, over 2 years old

TERATOMA: younger stallions, under 2 years old

What is the difference in ages that seminomas and teratomas are commonly seen in in stallions?

Testicular neoplasia

What is this?

Testosterone

Interstitial cell tumors of the testicles produce what hormone in stallions?

Estrogen

Sertoli cell tumors of the testicles produce what hormone in stallions?

Testicular neoplasia. Because it has a "lumpy appearance". Orchitis is normally more smooth, but it would still be a differential.

Is this more likely orchitis or testicular neoplasia in a stallion? Why?

Scrotal hernia

With which differential for enlarged scrotum in a stallion would you see guts on ultrasound?

Varicocoele

What is the term for dilation of the pampiniform plexus in stallions, which is a differential for an enlarged scrotum?

Squamous cell carcinoma (more common in geldings)

What is the MOST COMMON NEOPLASIA OF THE EQUINE PENIS/PREPUCE

Debulk because the cancer is not in the free part of the penis

What is the probable treatment of choice of squamous cell carcinoma in this equine penis?

Amputate, because there would not be enough skin to recover the incision

What is the probable treatment of choice of squamous cell carcinoma in this equine penis?

Amputation

What is the probable treatment of choice of squamous cell carcinoma in this equine penis?

Habronema and squamous cell carcinoma

What are your differentials for this?

Ivermectin or Moxidectin (because of ivermectin resistance recently)

What is the effective treatment for summer sores or habronema in stallions?

Urethral process or preputial orifice

Where does habronema more commonly affect the equine penis?

Habronema

Squamous cell carcinoma differential

What is this?

Habronema

Squamous cell carcinoma differential

What is this?

Paraphimosis

What is the term for when an inflamed prepuce displaces the penis ventrally, meaning the horse cannot retract the penis?

Paraphimosis

What is happening here, where the flaccid penis is unable to retract into the prepuce?

Paraphimosis

Penile prolapse or paralysis in stallions may cause...?

Because paraphimosis may follow exhaustion, which in this case, the horse is skinny and has no muscle strength to pull the penis back into the sheath and having been out for so long led to edema

Why is this horse suffering from paraphimosis (apart from the edematous penis)?

Summer sores

Habronema muscae larvae lesions in equine penises cause what?

Support the penis immediately

Daily massage or hydrotherapy for at least a month

How do you treat paraphimosis in horses?

It gets worse as the condition persists

What happens to the prognosis the longer a horse has paraphimosis?

Do not attempt penile amputation without prior castration

You should not attempt penile amputation in a horse with paraphimosis if what procedure has not been done previously?

Phimosis

What is the term for retention of the penis within the prepuce, where the horse cannot extend the penis from the prepuce and often dribbles urine?

Priapism

What is this called if the condition won't go away?

Priapism

What is the term for unnatural penile tumescence, where an erection will not go away in a horse?

Priapism

Failure of the sympathetic or parasympathetic regulation of blood flow to the equine penis causes what?

Proud cut

What is it called when a stallion is castrated but some testicular or epidydimal tissue is left behind, causing a gelding to have "stallion like behavior"

Because the epididymis is only loosely associated with the testicle and doesn't even actually have cells that produce testosterone. This is mostly a wives tale

Why is "proud cut" not very likely?

If a stallion has had a sexual experience, he may continue to display sexual behavior because it is a learned response

What might be the ACTUAL cause of stallions displaying sexual behavior after gelding?

A gelding castrated at an older age that has performed pasture breeding with mares will likely continue to behave as though he is a stallion in pasture with mares

What do you need to keep in mind with older stallions that are castrated and has been pasture bred with mares before?

TRUE (making proud cut a wivestale)

TRUE OR FALSE: leaving a portion of the epididymis does NOT allow for testosterone production because testosterone is not produced in the epididymis