Reproductive Disorders in the Stallion Flashcards
1
Q
Which stallions should be selected for breeding?
A
- 75% pregnancy rate during one breeding season if can do 40 mares with natural cover and 120-140 mares with AI
- Eliminate stallions with genetic defects
- Alert owner about potential unsatisfactory breeders
2
Q
Breeding soundness exam in stallions
A
- PE
- Testing (hereditary disorders and infectious disease)
- Testicular palpation and measurements
- Penis exam
- Semen collection and evaluation
- Testicular measurements
3
Q
Semen collection and evaluation method
A
- 2 ejaculates one hour apart
- Total # of spermatozoa/ejaculate
4
Q
What is the number of normal, progressively motile spermatozoa that we should get?
A
- At least 1 billion in the second ejaculate
5
Q
Testicular measurements
A
- Total scrotal width
- Length, height, and width
- Volume
6
Q
Common complaints in breeding stallions
A
- Visible abnormalities (cryptorchidism, penile lesions)
- Behavioral problems (poor libido or aggression and self-mutilation
- Impotentia coeundi
- Impotentia generandi (ejaculation failure, abnormal ejaculates with regards to color, concentration, viability, or morphology)
- Emergencies
7
Q
When should both testes be in the scrotum?
A
- At birth
8
Q
What is cryptorchidism?
A
- Incomplete descending of testicles at birth
9
Q
Risk factors for cryptorchidism?
A
- Breed predisposition
10
Q
Treatment of cryptorchidism
A
- Improve testicular descent?
- hCG
- GnRH
- Not effective
- Best recommendation is castration
11
Q
Breeding cryptorchids
A
- Eliminated from breeding in several countries (not in the US)
12
Q
How to differentiate between a cryptorchid and gelding with stallion behavior?
A
- Testosterone before and after hCG
- Estrogen
- Anti-Mullerian hormone
- Transabdominal or transrectal ultrasonography
13
Q
Will AMH be higher in a cryptorchid or a gelding with stallion behavior?
A
- In a true cryptorchid or stallion
14
Q
Transabdominal or transrectal ultrasonography suggestive of cryptorchid
A
- Normal development of accessory sex glands
- Presence of intra-abdominal testis
15
Q
Categories of things that cause balanitis or balnoposthitis
A
- Viral
- Smegma accumulation (bacterial/fungal)
- Parasitic
16
Q
Viral cause of balanitis
A
- EHV-3 or coital exanthema
17
Q
What causes smegma accumulation in general?
A
- Bacterial/fungal complications
18
Q
When are parasitic infections of the penis most likely?
A
- Summer (summer sores with Habronema larvae)
19
Q
Diagnosis of parasitic causes of balanitis?
A
- Biopsy and clinical presentation
20
Q
Treatment of parasitic balanitis?
A
- Topical
21
Q
Prevention of parasitic balanitis?
A
- Fly control, hygiene, ivermectins
22
Q
What are most tumors of the penis?
A
- Squamous cell carcinomas (75%)
- Also melanomas
- Cutaneous lymphoma and sarcoids less commonly
23
Q
Diagnosis of neoplasia of the penis
A
- History
- Lesions
- Histopathology
24
Q
Treatment of SCC in the penis
A
- Early on 5-FU and cisplatin
25
Treatment of melanoma of the penis
- Vaccines?
26
Surgical repair of tumors of the penis?
- Reefing or phallectomy
27
What are most common causes of paralysis of the penis?
- Mostly neurologic diseases
- Damage to sacral nerves
- Infectious disease
- Phenothiazine based tranquilizers (propionyl promazine)
- Exhaustion
- Starvation
- Trauma
28
Infectious diseases that can cause paralysis of the penis
- EHV-1
- Rabies
- Streptococcal purpura hemorrhagic
29
Symptoms of penile paralysis
- Flaccid penis, edema, excoriation
30
Treatment of penile paralysis
- Medical/physical management
| - Phallectomy and urethrostomy if too late
31
Poor libido definition
- No response to a mare in estrus after a period of 10 minutes
- Don't vocalize or have Flehmen response or erection
- No secondary behaviors
32
Male donkey libidinous behavior in general
- Takes longer
33
Causes of poor libido in stallions?
- Learning problems in young stallions or stallions retired from performance
34
Aggressive behavior signs in stallions
- Flank biting (abdomen, flank or hind limb while kicking and/or striking out, vocalizing in sharp squeals or barking grunts
35
Rule outs for aggressive behavior signs in stallions
- Painful conditions
| - Behavioral problems
36
Management of aggressive behavior in stallions
- Address pain
- Physical device treatments to reduce self-mutilation (like cones)
- Provide motivation for a substitute behavior or strong distraction
- Diet change
- Odor masking preparations
- Medications
37
What diet for aggressive stallions?
- Only grass
38
Medications for aggressive stallions?
- Long-acting tranquilizers may work (fluphenazine)
- TCAs: imipramine, clomipramine
- Nutritional supplementation with L-tryptophan (serotonin precursor)
- Progesterone treatment
39
Risks of progesterone treatment in stallions when treating aggressive behavior
- Affects fertility long-term and testicular size
40
Impotentia coeundi problems
- Mounting problems
| - Erection failure
41
Causes of erection failure?
- Complicated
- Look for painful lesions on the glans penis
- Abnormal vasculature
- Penile deviation
42
Abnormal vasculature causes of erection failure
- Compromised blood flow to the cavernosum body
43
Penile deviation from Stallion rings
- I guess it's a thing
44
Diagnosis of causes of erection failure
- History
- PE
- Neurologic examination
- Contrast rads
- Penile ultrasound
45
Impotentia generandi
- Ejaculatory disorders
46
What's included in ejaculatory disorders?
- Ejaculatory failure
- Incomplete ejaculation
- Retrograde ejaculation (rare)
- Premature ejaculation (rare)
- Urospermia
- Spermastasis (occluded or plugged ampullae)
- Poor semen quality (Azoospermia/oligozoospermia, teratozoospermia
47
Azoospermia
- No sperm
48
Oligozoospermia
- few sperm
49
Teratozoospermia
- Deformed sperm
50
Plan to work up ejaculatory disorders
1. Complete physical examination
2. Lameness and musculoskeletal examination
3. Complete repro exam
4. Use different collection methods
5. Natural cover
6. Videotape all sessions for review
7. Use aids to facilitate ejaculation
8. Attempt ex-copula induction of ejaculation
51
Aids to facilitate ejaculation
- Enhance sexual arousal (prolonged teasing, breeding chedule for maximum arousal, use mount mare in natural estrus, stable mount mare, minimal distraction in breeding shed, positive reinforcement)
- remove or reduce cause of pain or discomfort
- Increase stimulation of the penis by hot compress
- Enhance sexual arousal
- Lower ejaculatory threshold
- Induce ejaculation
52
Drugs to enhance sexual arousal
- GnRH, Diazepam
53
Drugs to lower ejaculatory threshold
- Imipramine
54
Drugs to induce ejaculation (ex-copula)
- Detomidine
- Imipramine
- Xylazine
- Imipramine + xylazine
55
Usual protocol for ex-copula induction of ejaculation
- Imipramine 2 hours before with xylazine 2 hours after that
- Ejaculation within 1-15 minutes
56
Volume and concentration with ex-copula ejaculation
- Volume decreased with high concentration
57
Management of true ejaculation failure?
- 100 mg imipramine 2 hours before collection
| - Hot towels
58
How do we know if the horse has ejaculated or not?
- Pelvic thrust right before ejaculation
| - Flag the tail after ejaculation
59
What % of ejaculatory disorders due to musculoskeletal system?
- ~50%
60
Examples of musculoskeletal disorders that can lead to ejaculatory problems
- Osteoarthritis
- Neurologic diseases
- Sore back
- Rhabdomyolysis
- Laminitis
- Aorto-iliac thrombosis
61
Management of stallions with musculoskeletal disease
- Control pain
- Enhance sexual arousal
- Ex-copula ejaculation
- Accommodate for musculoskeletal deficiencies
- One mount rule
62
What is the one mount rule?
- Find proper handling to achieve ejaculation with a single mount
63
Azoospermia causes
- Complete testicular degeneration
- Orchitis
- Testicular hypoplasia
- Epididymal blockage (bilateral)
64
Causes of oligozoospermia
- Testicular degeneration
- Incomplete ejaculation (sperm accumulator)
- Retrograde ejaculation
65
Factors for testicular degeneration causing azoospermia or oligozoospermia
- Age
- Anabolic steroids
- Altrenogest
- Testicular trauma/infections
- Fever
66
Clinical findings suggestive of testicular degeneration
- Small testes/asymmetry
- Increase spheroids in ejaculate
- increased sperm abnormalities
- Low motility
67
Prognosis of testicular degeneration
- Poor
| - Irreversible
68
Alkaline phosphatase in diagnosing epididymal blockage***
- <100 IU/L epididymal and testicular secretions not present
- 100-1000IU/L you should re-evaluate
- Basically measuring the contributions from the testicle and epididymis
69
Causes of epididymal blockage
- Bilateral segmental aplasia
- Epididymal hypoplasia
- Both in theory would have low Alkaline phosphatase
70
Plugged ampullae syndrome typical history
- 12 year old QH
- Normal collection and shipping 4 seasons
- This season low volume and high concentration
- Low motility
- No physical abnormalities
- First semen collection was ejaculate gel only
- Second ejaculate very thick, high concentration semen
71
Typical history with ejaculation failure
- 8 year old QH bred successfully for 1 season
- Present season covered 9 mares but no pregnancies
- erection, mounting, and intromission normal
- No ejaculation
72
Diagnosis of sperm agglutination/accumulation or plugged ampullae syndrome
- Very high concentration
- Presence of epithelial cells
- Clumping
- Transrectal ultrasound shows enlarged ampullae of the vas deferens
73
Treatment of plugged or occluded ampullae
- Ampullae massage
- Oxytocin or PGF2alpha before breeding (smooth muscle contraction before ejaculation)
- Frequent ejaculation (1-2 times per day for 10 days)
74
Where can the blood in hemospermia come from?
- Surface of the penis
- Urethra
- Internal genitalia (seminal vesiculitis)
75
What is the most common source of hemospermia?
- Urethra (either urethritis caused by Strep, E. coli, or P. aeruginosa; or urethral rents
76
Where can blood come from with the urethra?
- Urethritis
| - urethral rents (most common)
77
Things to evaluate with hemospermia?
- Timing of blood discharge
- Quantity
- Transrectal ultrasonography to determine if there are any abnormalities
78
Diagnosis of hemospermia?
- Clinical evaluation
- Transrectal ultrasonography
- Endoscopic evaluation of the urethra and accessory sex glands
79
Where do they look during a urethroscopy for a source of hemospermia?
- Urethra at the level of the ischial arch or slightly cranial
- This is where urethral defects or rents are generally located
80
Treatment for hemospermia*
- Antimicrobials
- Sexual rest***
- Urinary antiseptics
- Sub-ischial urethrotomy
- Management during breeding season
81
Management of hemospermia during the breeding season (less ideal but okay)
- Fractionated ejaculate
- Collect into an extender
- Chemical ejaculation? (probably don't do that!)
82
Urospermia causes
- Cauda equina neuritis
- EHV-1
- Sorghum and Sudan grass
- Severe pain
- Urolithiasis
- Generalized neoplasia
83
Clinical signs of urospermia?
- Large volume ejaculate
- Change in color
- Urine odor
- Sediment
- Poor motility
84
Diagnosis of urospermia
- Evident (odor, color)
- Azostix
- Determination of creatinine (>2 g/dL)
- Urea (>30 mg/dL)
85
Primary causes of urospermia?
- Severe neurologic disorder or severe pain
86
What is the pathophysiologic cause of urospermia?
- Lack of the detrusor muscles doing their job during erection
- They should normally contract
87
Treatment of urospermia
- Furosemide IV
- Catheterization of the bladder and imipramine
- No improvement with furosemide or imipramine in 3 cases
- Management
- Flavoxate hydrochloride
- Bethanochol chloride
88
Management of urospermia
- Fractionation of ejaculate, washing
89
What does flavoxate hydrochloride do?
- Bladder wall relaxation primarily
| - Often hit or miss
90
What does bethanechol chloride do primarilY?
- Improves coordination of hte bladder sphincter and detrusor function
- Often hit or miss
91
Urospermia clinical case
- 24 year old QH
- Bred successfully for several seasons
- Shipped semen all dead
- Normal erection
- Abnormal mount and thrusting
- Abnormal gait
92
Other management practices of urospermia
- Can give Bute to make comfortable before collection
| - COuld use imipramine to lower the threshold
93
Signs of seminal vesiculitis
- Infertility (with or without normal breeding behavior)
- Poor quality sperm
- Straining and posturing after breeding
94
Semen findings in seminal vesiculitis
- Inflammatory cells in ejaculate +/- microscopic hemospermia
- Bacteria: Pseudomonas aeruginosa, Klebsiella pneumoniae, Strep spp, Staph spp, Proteus spp
95
Causes of seminal vesiculitis
- Urethritis
- Cystitis
- Iatrogenic (endoscopy)
96
Diagnosis of seminal vesiculitis
- Culture with catheterizaition and massage
| - Needs referral for scope
97
Treatment of seminal vesiculitis
- direct flushing
- Antibiotic infusion
- Systemic antibiotics
- NSAIDs
98
Management of seminal vesiculitis
- Minimum contamination breeding (especially in TBs)
| - AI (direct collection into the extender; fractionate ejaculate)
99
Common emergencies in the breeding stallion
- Penile/preputial trauma
- Persistent erection
- Sudden scrotal enlargement
100
General considerations with emergencies in the breeding stallion
- Careful evaluation (VERY painful)
- Sedation and referral
- Make sure the horse is able to urinate
101
What is the first thing you need to check with a stallion with penile trauma?
- Make sure he can urinate
| - Evaluate the tissue
102
How long does it take to determine viability of penile tissue in a stallion?
- Usually takes a couple of days
103
Treatment and therapy for penile injury
- Protect the wound
- Ointments like lanolin plus antibiotics (Petercillin)
- Can do hydrotherapy (when the size has reduced a bit)
- Can do a 500 mL plastic bottle and cut off the bottom to put the penis inside with holes in the bottom to drain the urine
- Then a suspensory system so that the penis can't go out again until the retractor penis is functional
- Walking, hydrotherapy
- NSAIDs for the first 3 days
- Watching, exercise, and local therapy is important
- Sexual rest
104
Rudimentary mammary glands in horses - which breeds?
- Donkeys and draft horses
105
What are three things that contribute to penile paralysis or prolapse that is very severe?
- Trauma
- Penile frostbite
- Severe malnutrition
106
What is priapism?
- Persistent erection
107
Drug causes of priapism?
- Phenothiazine derivatives and reserpine
| - General anesthsia
108
Non-drug causes of priapism
- Inflammatory spinal cord lesions
- Trauma
- Purpura hemorrhagica
- Generalized malignant neoplasia
109
What is the fundamental underlying cause of priapism?
- Failure of sympathetic stimulation necessary for detumescence
- Increased CO2 tension and increased viscosity of the stagnant blood leading to venous occlusion
- Urinary difficulty or blockage leads to more metabolic compromise
110
Treatment of priapism
- Reduction of penile tumescence (manual massage and lubrication in conjunction with cold hydrotherapy or ice water baths)
- Suspension of the penis with a bandage or a sling
- Slow IV administration of the anticholinergic agent benztropine mesylate
- Systemic diuretics, corticosteroids
- Diphenhydramine and terbutaline
111
How can diphenhydramine or terbutaline help with priapism?
- Diphenhydramine has anticholinergic activity
| - Terbutaline is a beta-2 adrenergic receptor agonist and tocolytic
112
After what time does manual massage and drug administration not help much with priapism resolution?
- Past 12 hours
113
Post op surgical treatment for priapism
- Local (DMSO)
- Systemic anti-inflammatory therapy and antimicrobials
- Bladder lavage and placement of an indwelling catheter may be necessary for 2-3 days
- Bethanechol may enhance bladder function
114
Surgical treatment for priapism
- Flush sluggish blood from the corpus cavernous penis
- Coagulated blood flushed with heparinized saline
- Surgical shunt between the CCP and corpus spongiosum penis
- This is typically a referral
115
What should you do if a stallion isn't urinating?
- Catheterize and refer
116
Outcome of surgical treatment of priapism?**
- Lose ability to have a normal erection
- If kept as stallions, there are other options in addition to ex copula
- They may ejaculate inside the vagina instead of the uterus
117
Approach to examination of testicular enlargement?
- History (may be difficult in pasture bred horses)
- PE
- CBC/Chem
- Test for EIA, EVA, Dourine
- Palpation (external and per rectum
- U/S
118
Which infectious diseases should you screen for with testicular or scrotal enlargement?
- EIA, EVA, Dourine
119
How emergent is acute scortal or testicular enlargement?
- ALWAYs an emergency
120
Things to look out for with acute scrotal enlargement?
- History of breeding trauma
| - Exercise history
121
Main differentials for acute scrotal enlargement?
- Spermatic cord torsion
- Testicular hemorrhage/rupture of albuginea
- Inguinal or scrotal hernia
- Orchitis
122
What should you check if a stallion is colicking for no apparent reason?
- Check the scrotum and penis
123
Best management to preserve fertility in acute scrotal enlargement
- Unilateral castration
| - Semen cryopreservation when possible
124
Presentation of spermatic cord torsion
- may be asymptomatic (<180° torsion)
| - SEVERE colic with increased degree of torsion
125
Timing of spermatic cord torsion
- May happen after mating
126
Diagnosis of spermatic cord torsion?
- Palpation and ultrasonography of the scrotum and its content AFTER sedation
127
Treatment of spermatic cord torsion
- Unilateral castration
| - Orchiopexy
128
Prognosis for fertility with spermatic cord torsion
- Good following hemicastration if no complications
129
PE for a horse with spermatic cord torsion
- L testicle soft and freely movable within the scrotum
- R testicle enlarged, extremely firm, close to the body wall, and not freely movable within the scrotum
- Tail of the epididymis palpated caudally
- Right spermatic cord revealed a torsion of 360°
130
Appearance on ultrasound of a testicle with torsion
- Pampiniform plexus revealed decreased blood flow with thickening in the wall of the testicular artery
- Edema
131
Testicular hemorrhage clinical signs
- VERY painful
| - May have hind leg lameness and progressive colic and pain
132
History with testicular hemorrhage
- history of trauma
| - Usually extremely painful
133
Diagnosis of testicular hemorrhage
- Ultrasound where you lose the contour of the testicle and echotecture
- Fluid is abnormal
- Albuginea rupture with trauma during breeding
134
Treatment for testicular hemorrhage
- Unilateral castration
135
When does inguinal or scrotal hernia usually occur?
- Following exercise, breeding, or trauma
136
Clinical signs of inguinal or scrotal hernia
- Variable
| - Sudden enlargement of the scrotum usually
137
Diagnosis of inguinal or scrotal hernia
- Ultrasonography
138
Treatment of inguinal or scrotal hernia
- Unilateral castration
| - Possible other surgery if there is something like small intestinal entrapment
139
Indirect herniation
- Herniation into the vaginal tunic
140
Direct herniation
- Results from a body wall defect
141
Common etiology of orchitis
- Streptococcus equi or Salmonella abortus equi
142
Treatment of acute orchitis
- Cold water hydrotherapy
- Systemic antibiotics
- Unilateral castration
143
What commonly causes chronic cases of orchitis?
- Equine viral arteritis or migrating larvae of Strongylus edentatus
144
Scrotal abscess treatment
- Drain and lavage with weak betadine for several days
- If outside the testicle, you can just manage like that
- Antibiotics too
145
Varicocele
- Dilation and increased tortuosity of the pampiniform plexus (most common), spermatic and cremasteric veins
- May see dilation of the central vein
- May be linked to a variation in elasticitiy
146
Treatment for varicocele
- Won't usually respond to treatment so may need to unilaterally castrate
147
Hydrocele
- Accumulation of fluid in the vaginal cavity (usually peritoneal)
148
When is hydrocele seen?
- Hot summer months and humidity
149
Treatment of hydrocele
- Must differentiate from pyocele
| - With sustained enlargement, stallions may lose fertility early, so he doesn't let it go for too long
150
Appearance of hydrocele
- Testicle surrounded by anechoic fluid, possible snowy as epithelial cells slough off
151
Scrotal neoplasias
- Sarcoid (well-identified)
- Melanomas (gray horses)
- Cutaneous lymphosarcoma
152
Diagnosis of scrotal neoplasia
- FNA or biopsy
153
Most common testicular neoplasia?
- Seminoma
154
Clinical signs of seminoma
- Sudden enlargement of one testicle, soft, fluctuant, possible metastasis
- Doesn't grow quickly
155
Diagnosis of testicular neoplasia like seminoma
- Look at with ultrasound
- Palpate inguinal lymph node
- Palpate spermatic cord for metastasis
156
Treatment of seminoma
- Castration including as much of the spermatic cord as possible
157
Where can seminomas metastasize?
- Liver possibly
