Stallion repro physiology, BSE and issues Flashcards
1
Q
When should the tested be decended?
A
2 weeks postpartum
2
Q
When does a stallion reach puberty?
A
12-24 months
3
Q
When does a stallion reach maximum reproductive capability?
A
4 years old
4
Q
Is reproductive function affected by season?
A
Yes
In winter everything decreases
5
Q
Where will you find the ‘bean’?
A
In the urethral sinus or diverticulum
6
Q
When is the most amount of sperm during ejaculation?
A
The first 3 jets
7
Q
How can you recognise ejaculation in the stallion?
A
Cessation of thrusting
Flagging tail
Palpation of urethral pulses
On dismount they enter a refractory state where they become disinterested
8
Q
In the stallion what does GnRH do?
A
Stimulates pituitary to release FSH and LH
9
Q
What does FSH do in the stallion?
A
Causes sertoli cells to release androgen binding protein
10
Q
What does LH do in the stallion?
A
acts on Leydig cells to release testosterone
11
Q
What does the sertoli cells convert testosterone to?
A
dihydrotestosterone and oestrogen
12
Q
What cells produce inhibin?
A
Sertoli cells
13
Q
What 2 hormones exert a negative feedback effect on the hypothalamus?
A
Testosterone
Oestrogen
14
Q
What 2 things have a negative effect on GnRH secretion?
A
Melatonin
Opioids
15
Q
How long does spermatogenesis take?
A
Full cycle is 2 months
16
Q
When should you do a BSE?
A
Before onset of breeding season to detect problems and mating load
If subfertility/infertility suspected
Abnormal sexual behaviour
Disease or injury may have affected the reproductive system
Before sale
Before semen is preserved for AI
17
Q
Describe the steps of a full BSE on a stallion?
A
History and identification
General physical examination
Collect blood samples for testing EVA or EIA
Swabs
Evaluate breeding behaviour and libido
Examine scrotal contents - length, width, height, total
Examine internal accessory glands and inguinal rings per rectum
Collect 2 semen ejaculates an hour apart
Semen evaluation with longevity testing
18
Q
What 5 swabs should you do as part of a BSE?
A
Pre-wash penile shaft Pre-wash fossa glandis Pre-wash prepucial fold Post-wash urethra Post-ejaculate urethra
19
Q
What should you use to wash a stallion’s penis before taking swabs/samples?
A
Warm water only and dry with paper towels
-NOT chlorhex, iodine or disinfectants
20
Q
When collecting 2 ejaculates an hour apart, how many progressively motile and morphologically normal sperm should there be?
A
Over 1 billion
21
Q
When collecting 2 ejaculates an hour apart, what 4 criteria should they meet to pass?
A
Volume of both similar
Total sperm of the 1st is double that of the 2nd
pH should be stable or slightly increase
Motility should be stable or increase
22
Q
What things do you look at for semen evaluation?
A
Sperm concentration pH Culture it Percentage of total and progressively motile sperm Percentage of identified abnormalities Cytology Longevity in extender 1:1 Total number of sperm
23
Q
What is the minimum normal total scrotal width?
A
80 mm
24
Q
What is a DSO?
A
The total number of sperm that a stallion can ejaculate per day after depletion of epidiymal sperm reserves
25
What does a DSO allow you to estimate?
The number of mares a stallion can breed daily
26
How do you determine the DSO?
Ejaculate stallion daily for 10 days
OR
twice daily for 5-7 days
27
What 2 ways can you estimate a stallion's breeding potential for a season?
Testicular volume
DSO
-If DSO is lower than expected volume then need to determine cause
28
What does alkaline phosphatase concentration in seminal plasma tell you ?
If none present then no ejaculation has occurred
| However if it is high and there is no sperm, then there is a problem occurring
29
What are some ancillary tests that are available in stallions?
```
Alkaline phosphatase concentrations
Computer assisted sperm analysis
Urethral endoscopy
Chromosome analysis
Testicular biopsy
Endocrinological testing
Sperm chromatin structure assay
Anti-sperm antibodies
etc. etc. etc. blah blah blah
```
30
Would you expect a higher concentration of FSH in a gelding or a stallion, and why?
Higher in a gelding
| There is no negative feedback
31
Should oestrone sulphate concentrations be high or low in mature stallions?
Should be high
32
On endocrinology testing in a stallion with progressive testicular disease, what do you expect to see?
```
High FSH
Low oestrogen
Low inhibin
Declining testosterone
Rising LH
```
33
How should you collect a sample for endocrinology testing?
Blood sample
Every 30 minutes
For 6 hours
34
What can a hCG stimulation test tell you?
hCG stimulates testosterone and E2
| Low concentrations will occur in infertile stallions
35
How can you diagnose a cryptorchid stallion?
By looking for a positive biomaker for testicular tissue
- Basal and post stimulation testosterone
- Oestrone sulphate
- Anti-Mullerian hormone (From sertoli cells)
36
If trying to diagnose cryptorchidism in a stallion under 3 years old, what test should you do?
Anti-Mullerian hormone
- However not available in Australia
- Oestrone sulphate and testosterone may be low
37
List some factors which may contribute to a stallion's sperm count being lower than expected?
```
Age - Under 3 years old
Total scrotal width
Frequency of ejaculation -every 2nd day ideal
Sexual behaviour
Drugs - testosterone drugs bad
Testicular injury/disease
Pituitary dysfunction - affect gonadotrophin secretion
Collection difficulty
Season
```
38
What are the 4 broad ways that can cause sexual behaviour to be compromised in a stallion?
Reduced libido
Erectile dysfunction
Ejaculatory dysfunction
Physical problems, or issues in incoordination
39
What are some psychological issues that may reduce stallion libido?
Previous stallion handling - discipline, aversion to a particular handler
Unreceptive or hostile mares
Overused as a teaser
Preference for different mares
Unstable collection dummy, or wrong height
Change of environment
40
What are some steps that can be implemented to improve libido in a stallion?
Eliminate any causative factors - pain, disease, certain people
Behaviour modification - positive reinforcement
If using AV, increase stimulation after finding preference for liner and temperature
Expose to receptive mares
Develop ritualized breeding routine
Retain conditioned stimuli known to asist in arousal
Reduce distractions in breeding area
Reduce mating load if needed
41
What are 3 causes of stallion impotence?
Penile paralysis
Desensitisation
Fibrosis of corpus cavanosum
42
What are some causes of ejaculatory dysfunction?
Incomplete intromission
Inadequate pelvic thrusts
High threshold to ejaculate
Neurological lesion
43
What drugs do you administer for chemical ejaculation?
Imipramine orally
2 hours later xylazine IV
Wait 5-25 minutes
44
What are some physical and coordination factors that may affect a stallion's reproductive performance?
```
Fatigue
Poor condition
Obesity
Physical trauma - kicks, stallion rings, priapism, paraphimosis
Current lesions on penis
Musculoskeletal disease
Penile deviation preventing intromission
```
45
If a stallion has decreased libido, should you administer testosterone?
No
It may have negative feedback effects, decreasing LH and spermatogenesis
-Use hCG or GnRH
46
What is paraphimosis?
Inability to retract penis into prepuce
| -Usually due to prepucial oedema or secondary to trauma or systemic disease
47
What condition in stallions can administration of acepromazine induce?
Paraphimosis
| -Nerve damage
48
How do you treat paraphimosis?
```
NSAIDs
+/- Opioids
Hydrotherapy - cold hosing
Return penis to prepuce
Purse string suture prepuce to reduce oedema
Support wrap
+/- catheter if indicated
Mild exercise if appropriate
Topical or systemic antibiotics
Tetanus prophylaxis
Isolate from mares
If severe unilateral testicular trauma, unilateral castration
```
49
What is priapism?
Persistent erection without sexual arousal
| -Detumescence of engorged corpus cavernousm penis fails because of altered arterial or venous flow
50
What drug type can cause priapism?
Phenothiazine-derivative tranqualisers
| -Acetylpromazine
51
What is the end result if priapism isn't treated?
Impotence
| -Loss of erectile function and sensitivity
52
What are 2 DDx for priapism?
Penile paralysis
| Penile trauma
53
What are 2 drugs that are used to treat priapism?
Cholinergic blocker - Benztropine mesylate
Sympathomimetic - 1% Phenylephrine HCl directly into CCP
- If this fails irrigate using 12G needles into CCP
- Chronic case- anastamose the CCP to the CSP
54
What is phimosis?
Inability of stallion to protrude its penis completely from prepuce
55
Should you be concerned if you see a foal with phimosis?
No - it is normal in foals
56
What can phimosis lead to?
Urination within prepucial cavity
| Get inflammation and secondary infection
57
How do you treat phimosis?
Surgically
| -Enlarge the prepucial orifice
58
How do you treat squamous cell carcinoma of the penis and/or prepuce?
```
Surgical debridement
Cryosurgery
Small lesions - Topical treatment with fluorouracil
Reefing operation
Radiation therapy
Phallectomy - salvage procedure
```
59
What are some clinical signs of cutaneous habronemiasis?
```
Localised swelling
Prepucial oedema
Haemospermia
Superficial ulceration
Granuloma formation which can look like SCC
```
60
How do you diagnose and treat cutaneous habronemiasis?
Diagnose by biopsy or response to treatment
Treatment
-Ivermectin
-If required may need surgical excision or amputation of urethral process
61
What is the causative agent of equine coital exanthema?
Equine Herpes Virus 3
62
How do you diagnose EHV-3 in stallions?
Biopsy
Serology
PCR
63
How do you treat equine coital exanthema in stallions?
Sexual rest until lesions healed
Strict hygiene procedure to avoid mechanical transmission
Antibiotic ointment to reduce any secondary bacterial infection
64
If a stallion has been infected with EHV-3 before, can it happen again?
Yes
| Immunity is temporary
65
List some DD's for scrotal oedema or swelling of the spermatic cord in a stallion? (Hint there's 9)
```
Trauma/wound
Varicocoele
Hydrocoele
Haematocoele
Torsion of the spermatic cord
Inguinal hernia
Neoplasia
Insect bite
Orchitis/epididymitis
```
66
What is a varicocoele?
Dilation and tortuosity of the veins of the pampiniform plexus and draining of the cremaster muscle
-Causes a unilateral enlargement that is not painful
67
How do you treat a varicocoele?
Usually don't need to
Only treat if there is sperm quality affected
May then need unilateral removal of cord and testicle
68
What is a hydrocoele?
Serous fluid accumulation between the visceral and parietal layers of the vaginal tunic
69
What are the 3 causes of a hydrocoele?
Idiopathic - During hot weather and resolves when it cools
Aberrant migration of strongyle larvae
Peritonitis or orchitis
70
What are the clinical signs of a hydrocoele?
Unilateral or bilateral enlargement
May develop acutely or over time
usually painless
71
What two types of fluid can accumulate in a hydrocoele, and how do you differentiate?
Transudate or an exudate
Transudate - Hypoechoic on US, aspirate clear fluid
Exudate - Hyperechoic on US, aspirate cloudy fluid
72
How do you treat a hydrocoele?
Find and treat underlying cause
Hydrotherapy
Exercise
NSAIDs
May disappear over time
If unilateral hydrocoele with transudate, may need unilateral castration to prevent temperature induced degeneration of unaffected testicle
If inflammatory fluid - treat the primary infection with appropriate antibiotics
73
What is a haematocoele, and what causes it?
Accumulation of haemorrhagic fluid within the vaginal cavity
Caused by trauma to the scrotum, rupture of tunica albuginea, haemoperitoneum
74
What are the clinical signs of a haematocoele?
If from trauma will be painful
Swelling of scrotum
US - Signs of haematoma formation - hyperechoic fluid with fibrin tags
75
How do you treat a haematocoele?
Hydrotherapy every 2 hours
Systemic antibiotics
Anti-inflammatories
Surgical drainage and evacuation of haematoma, repair any torn tissues
Unilateral orchiectomy may be indicated to prevent increased temperature affecting other testicle
76
Why do you need to surgically repair a haematocoele instead of just leaving it to drain itself?
Usually caused by some sort of trauma so there will be damage
This means that there is risk of development of antisperm antibodies
77
What are some clinical signs of a 360 degree spermatic cord torsion?
Signs of colic and unilateral scrotal swelling
- Can be chronic, intermittent or cause discomfort during sexual activity and reluctance to ejaculate
- Medical emergency, unilateral castrate
78
What are some clinical signs of orchitis or epididymitis?
Localised swelling, oedema and pain
May show reduced libido
May see inflammatory cells in the ejaculate and abnormal sperm
79
What are the two broad aetiologies for testicular degeneration?
Thermal injury
-Local inflammation, systemic disease
Previous injury and infection
-Of the scrotum, testes, epididymis, spermatic cord, hydrocoele, haematoma, haematocoele, idiopathic
80
What are the clinical signs for testicular degeneration?
Decrease in semen quality and concentration over time
Testes may initially be soft, later become firm
On US see evidence of fibrosis and calcification - Increased echogenic pattern or focal hyperechoic areas
Decreased Leydig cell number causes reduced concentrations of testosterone and reduced response to hCG stimulation test
81
How do you diagnose testicular degeneration?
```
Endocrinological tests
Palpation
Ultrasonography
Semen evaluation
Testicular biopsy
```
82
How do you treat testicular degeneration?
Treat underlying cause if present
No specific treatment once permanent changes have occurred
Reduce mating load
Inseminate fertile mares at optimal time
Can try ICSI or GIFT
83
What is the most common type of testicular neoplasm?
Seminoma
84
If you are presented a stallion for BSE with testicular hypoplasia, should you breed from him?
```
No
Likely hereditary
Can also be infertile
Also need to check if karyotype is normal
Can't treat it
```
85
When do you most commonly see a blockage of the ampullae?
Start of breeding season
86
How do you treat a blocked ampullae?
Rectal massage of ampullae
Oxytocin to stimulate smooth muscle
Frequent ejaculation
-Good prognosis
87
What will the sperm look like in a stallion with blocked ampullae?
Still get ejaculation
Large number dead sperm - Over 20 billion
High percent with detached heads
88
What are clinical signs of seminal vesiculitis?
```
Pus in semen
Haemospermia
Decreased pregnancy rates
Neutrophils in semen
Rectal palpation and US show enlarged seminal vesicles which are painful
```
89
How do you treat seminal vesiculitis?
Culture and sensitivity to find appropriate antibiotic that can penetrate seminal vesicles
Endoscopic lavage and infusion of antibiotics directly
Enrofloxacin usually pretty good broad spectrum
Long-term antibiotics
90
If you have a stallion with a bacterial infection in his reproductive tract, can you still breed for him?
Yes
-Incubate semen in extender with antibiotic for 30 minutes before service
Or infuse extender with antibiotic into uterus before natural service
91
List some venerally transmitted conditions by stallions?
```
Pseudomonas
Klebsiella
Strep. zooepidemicus
Taylorella equigenitalis - Contagious equine metritis
Equine viral arteritis
EHV-3
Dourine - Africa
```
92
What are some causes of haemospermia?
```
Lacerations of glans penis, urethral process, urethral rent
Bacterial urethritis
Seminal vesiculitis
Habronemiasis
Neoplasia
Epididymitis
EHV 3
```
93
Why is urospermia bad?
Decreases motility and longevity of semen
94
What signs indicate urospermia?
Urine odour and watery semen
| Semen creatinine over 2.0mg/dL and urea over 30mg/dL
95
How can you treat urospermia?
Encourage urination before collection
Only get sperm rich fraction during ejaculation
Bladder catheterisation and lavage before collection
Use alpha adrenergic agonist to increase tone in neck of bladder
Collect with semen extender preplaced in collection vessel to dilute urine
