Common Diseases and Surgery of the Stallion / Gelding Flashcards
Why are male horses castrated? When does this happen?
- Most male horses are castrated for behavioural reasons
- Reduce aggression towards other horses and people, mounting mares, ability to handle and training
- Early castration preferred (6-12 months)
- Time of year important (restricted exercise post op, and no flies)
Describe the procedure of an open standing castration in a stallion?
Why is open picked for a standign castraion?
- Hold neck scrotum with left hand
- Bold incision into most dependant part through skin, dartos, vaginal sac
- Squeeze with left hand and testis emerges
- Apply traction with left hand
- Emasculate across cord and part of vaginal sac
- Leave for 1 minute (don’t let them hang)
- Repeat other side
- Pull scrotal skin over the sac
- There is often haemorrhage from skin
- If constant stream after 15 mins pack wound
- If continues may need to re-explore
- Restrict exercise for several days after the procedure
as the horse is standing the risk of contamination is higher and therefore wound left open for drainage
What pre-steps and preperations are needed before a castration?
- Restraint: Sedation, Twitch
- Parental antibiosis first
- TAT
- Clean scrotum
- Stand on left and hold neck of scrotum
- Inject 10ml 2% lignocaine (2inch 19G needle)
- Redirect into 2 or 3 sites
- Leave 15 mins
- Re-clean scrotum
how is a closed castraion performed in the horse?
- Incise into scrotum
- Blunt dissect tunic (dry swabs works well)
- Transfixing ligature across vaginal sac
- Emasculators placed distal to ligature
Why do you need to palpate before a castration?
Can you castrate if the animal is cryptorchid?
Which testical is often cryptorchid?
- Make sure you carefully palpate castration cases pre-op, and plan surgery
- Palpate under sedation and do not go ahead if you cannot feel both testes
- Do not remove the descended testes and leave the other one!
- most commonly right testis
- Commonly testis is within inguinal canal
- The vaginal tunic is small and it may be difficult to push testis into scrotum
How is cryptorchidism diagnosed in horses?
how are cryptorchid testicals removed?
- Palpation of scrotum / inguinal region
- Rectal palpation of inguinal ring
- Endocrine testing
- Testosterone response to hCG administration
- High basal oestrone sulphate
Removal - surgical:
* Inguinal
* Para-inguinal
* Laparoscopic
What are the reasons for poor libido in stalions?
How is this investigated?
- Some cases are due to testicular hypoplasia or to testicular degeneration (see later)
- In these cases diagnosis is obvious because of the small size of the testes
- Mounting or thrusting may be prevented by painful conditions
- E.g. trauma, cauda-equina neuritis, ilio-femoral thrombosis, laminitis, arthritis, coital exanthema
- Some stallions that are ‘over-used’ may temporarily have poor libido (this is more commonly observed in older animals)
Investigation: Observe animal working and perform a careful physical examination
What are the most common types of penile tumours?
Why do penile tumours occur?
Where on the penis do tumour occur?
- Most common are squamous cell carcinoma (49-88%); other types are papillomas (1.6-8.5%), adn melanomas (4.8-5.1%)
- Commonly seen in older geldings as smegma appears to be carcinogenic
- The tumours arise at the urethral fossa/diverticula and there are commonly kissing lesions onto the preputial ring
What do neoplastic changes look like on the stalion penis?
What to the initial changes look like?
How do they progress?
- White depigmented plaques probably represent pre-neoplastic changes
- Initial lesions may be small pink and cauliflower -like
- Later lesions may become very large and pedunculated
What is the prognosis of penile tumours?
Where to penil tumours often metastasise to?
- Prognosis depends on the stage of the tumour – identify early, assess extent of involvement and biopsy lymph nodes
- Metastasis ->inguinal lymph nodes -> abdomen. No treatment if general metastasis has occurred
How do you assess and investigate penile tumours?
- Physical examination – nature and extent of lesions, including palpation (+/- usound) of corpus cavernosum and spongiosum and lymph nodes
- Biopsy penile lesions and FNA lymph nodes
- Palpate (and ultrasound abdomen) - inguinal and sublumbar lymph nodes, (spleen and liver)
- Radiograph thorax if evidence of abdominal spread
What is the treatment for penile tumours?
- Local lesions with no invasion / spread
- Cryotherapy/ topical treatment with 5-fluorouracil
- or local excision/posthioplasty/partial phallectomy (depends on location and size)
- Non-invasive (S1 or 2 lesions)
- local excision/posthioplasty/partial phallectomy (depends on location and size)
- Extensive spread or invasive (S3 lesions)
- Partial phallectomy and sheath ablation/en bloc resection/palliative treatment or euthanasia
- Evidence of abdominal spread
- palliative treatment or euthanasia
NB Posthioplasty is surgery to the sheath
What is the purpose of penil reefing/posthioplasty?
- For treatment of kissing metastases of squamous cell carcinoma - Removes the preputial ring
- Primary lesions needs to be removed by local excision or amputation of penile tip
What is an Enblock resection?
Removal of the penis (and tumour) including some healthy tissue:
* Very invasive surgery with high risk of complications, but gives best prognosis in terms of recurrence (86-100% survival)
- Partial phallectomy has a reported success rate of 54–67% due to recurrence
What is coital exanthema?
What is the cause?
What is the treatment?
Is it contagious?
- Equine herpes virus 3
- Results in small vesicles on the penis and sheath
- Usually resolve spontaneously within a few weeks
- Stallion may be unwilling to mate at this time as painful
- May infect mares if active lesions present at the time of breeding
- Infected mares develop similar lesions but do not develop endometritis or abort
What does the papilloma virus cause in young stallions?
What is the treatment?
What are the concequences?
- Small, raised florid lesions on the penis
- Stallions rapidly develop immunity and the lesions are self-limiting
- No treatment is required
- At the time of infection breeding may be painful
- Monitor resolution as can progress to SCC
what are the key aspects of managing scrotal trauma?
Treat symptomatically but rapidly and use methods to aims to reduce scrotal temperature and risk of testicular degeneration from occurring
* Local treatment
* NSAIDs
* Systemic broad spectrum antibiotics
* If one side is severely affected it may be prudent to perform a unilateral castration
Significant problem as may lead to testicular degeneration
What is the risk with scrotal hernia?
How is diagnosis made?
- Inguinal hernia may become strangulated and become a surgical emergency
- Diagnosis likely to be made by ultrasound examination of scrotum or rectal palpation where distended intestinal loops may be detected at the inguinal ring
- Check colts presented for castration carefully - do not use open castration technique
How does testicular degeneration occur?
- Usually acquired secondary to thermal injury following previous injury or damage to the scrotum, testis, or ventral abdomen
- Including secondary to:
- Scrotal hernia
- Scrotal injury and dermatitis
- Testicular trauma and testicular haematoma
- Torsion of the spermatic cord
- Orchitis
- May develop secondary to some other inter-current disease such as testicular neoplasia
- Rarely following systemic disease, drug administration or toxin exposure
Why are systemic antibiotics used in the treatment of testicular haematoma?
since in some cases haematoma can be become infected (?haematogenously) resulting in testicular abscess
What occurs during torsion of the spermatic cord?
In a severe torsion what will occur?
What is the treatment?
rotation of the testis around its long axis
In severe torsion there is:
* Marked scrotal swelling
* Abdominal pain
* Clearly this is one of the DDs for acute scrotal swelling and similar to inguinal hernia may occur after recent exertion
* NB Less common than inguinal hernia
Prompt removal of the swollen testis is necessary to treat the condition and in attempt to prevent testicular degeneration in the remaining testicle
What is the most common cause of orchitis?
What can infective orchitis result from?
What is the treatment?
- The most common cause is local trauma
- There may or may not be infection, and the condition may be considered mixed inflammation / haematoma
- Infective orchitis may result from penetrating wound or occasionally from haematogenous spread
Viral orchitis may be caused by EVA - In all cases there is substantial swelling, local oedema and pain
Treatment should be aimed at controlling the primary cause and attempting to reduce the testicular temperature to prevent subsequent testicular degeneration- Unlateral castration may be considered
What are the signs of testicular tumour in the stalion?
How do you differentiate these from other diseases?
What is the treatment?
- Testicular tumours are rare and commonly unilateral therefore they usually cause unilateral enlargement
- Seminoma
- Lipoma
- Teratoma
- Sertoli cell tumour
- There may be reduced size of the contra-lateral testis
- Differentiate from abscess, haematoma etc on basis of slow increase size and using ultrasound
- Metastases are rare
- Treatment is castration
