Male infertility and breeding soundness exam Flashcards
What history questions would you ask when investigating male infertility?
- Has he ever been used successfully? How long ago?
- How old is he?
- How many females has he been with and when?
- Were they in good breeding condition?
- Did females breed successfully with other males or A.I.?
- Is he home-bred or bought/hired in? When?
- Has he had febrile disease or treatment recently?
What should you include in your clinical exam when investigating male infertility?
Physical ailment may result in sub-fertility and infertility. Injury or disease may cause an infertility which appears as a subfertility if it affects the male part way through a breeding cycle.
* Whole animal clinical exam not just the reproductive system
* Observe from a distance – lameness, posture, demeanour
* TPR and BCS
* Teeth to check age/alignment
* Eyes check for cataracts
* Brisket – check for sores – will not mount with sore brisket
* Legs check range of movement and any indication of pain in legs as well as feet
Why is BCS important for fertility?
- Bulls and rams that are in BCS 2 or less should be deemed unsatisfactory in this section as they are unlikely to be able to perform adequately during an intensive breeding period
- Bulls and rams that are obese (>4) may suffer from poor semen quality due to deposition of fat in the scrotum leading to thermo-regulation problems
What limb conditions can affect fertility?
Post-legged
* increased risk of lameness due to hock, stifle or hip joint pathology and young bulls showing this conformation should be avoided.
Puffy hocks
* Swollen hocks due to excessive synovial fluid are not uncommon in intensively reared young bulls less than 2 years old.
* Distension of the hock joint may be caused by osteochondrosis which if mild may not be causing any lameness. Progression to osteochondritis dissecans (OCD) is possible in some bulls so bulls with swollen hocks and lameness are not suitable for breeding
What should you include in your reproductive tract exam? How could each part be affected?
Scrotum
* Scrotal shape: straight sided, normal (pendulous), wedge-shaped
* Testis should move easily within the scrotum, if not then adhesions are indicators of previous infection and inflammation
- scrotal circumference is highly correlated to paired testes weight, daily sperm production and semen quality (>33cm in rams and >30cm in ram lambs)
Could see:
* Orchitis (firm/painful), NB. Brucella Ovis in rams is notifiable and causes orchitis as primary symptom
* Dermatitis: Chorioptic mange common cause of scrotal dermatitis in rams
Testicles
Could see
* Hypoplasia – bilateral or unilateral. Congenital can be due to abnormality of blood supply (Belgian Blue bulls)
* Hard and possibly small due to post-traumatic scarring or fibrosis/calcification with age
* Soft due to tubular atrophy (including non-breeding season)
* Absent – cryptorchid
* Rotated – stallion. Not significant.
* Enlarged – neoplasia, especially older dogs
* ULTRASOUND can help diagnosis
Epididymis
Could see
* Lumpy, esp. ascending infection (mainly ram-epididymitis), blockage (spermatocoele)
* Floppy, small, possibly displaced caudally
* Absence (segmental aplasia of mesonephric duct)
* Don’t just measure; palpate!
Prepuce
Could see
* Penile rupture/haematoma
* Preputial laceration/avulsion
* Prolapse of prepuce
* Urolithiasisis – crystals on preapical hair
* Absent musculature in bulls/Too tight musculature can prevent intromission – hard to palpate
* Phimosis (can’t get out) and paraphimosis (can’t get back)
* Infectious balanitis
* Trauma and foreign bodies
Penis
Could see
* Corkscrew penis in bulls
* Trauma – all species, but especially stallion
* Rupture at the sigmoid flexure – ruminants
* Papillomas and other tumours – sometimes self-cure; can often be ligated in bulls; Squamous cell carcinoma at urethral orifice in stallions, fibroblastic sarcoids on penile/preputial skin.
* Persistent frenulum
* ‘Pizzle rot’ – Rams - Corynebacterium renale: grows in the alkaline environment caused by the high urinary urea content of rams on high protein diets (posthitis)
Accessory sex glands
Examination
* Digital in Ram
* Rectal in bull/stallion
* Ultrasound
Conditions
* Seminal vesiculitis – typically yearling bulls; can become refractory to treatment; diagnose & treat early.
* Tulathromycin weekly for 6 weeks; (licensed in cattle, but not for this use – what does that mean for cascade?)
* Meloxicam by injection alternate days for first 2 weeks.
What are infectious causes of male infertility in cows and sheep?
Anything resulting in pyrexia
Cows
Viral - IBR, BVD, EBL, Bluetongue
Bacterial
* Campylobacter, Brucella, TB, Lepto, Johne’s, Mycoplasma, Ureaplasma
* Protozoal
* Trichomonas
Sheep
* Viral - Bluetongue and possible Schmallenberg.
* Bacterial - Brucella ovis (notifiable), possible Johne’s, Mycoplasma, Ureaplasma
Any febrile condition or treatment with cortisone is likely to result in reduced semen quality 4-6 weeks after fever/treatment.
How can you collect semen?
- Artificial vagina – Ruminants, stallions, boars
- Digital manipulation – Boars
- Electro-ejaculation – Most common method in Rams and Bulls
What tests must be done for domestic use of semen within the UK? What is the quarantine length for international distribution of semen?
bTB, Brucella and EBL tests are required by law
All semen must be frozen and is subject to 28-day quarantine period before distribution internationally
What should you include in your microscopic examination of semen?
Need
- Warm stage – essential to avoid cold shock to sperm
- Warm slides
Gross examination, Volume , Concentration, Abnormalities, Morphology
What should ram semen look like under the microscope?
- Volume = 0.5-2.5ml relate to ram age, size and breed, testicle size
- Colour = Concentration + Contamination
- white – yellow = normal.
- brownish = blood,
- greenish = Pseudomonas aeruginosa,
- clots or mucus = pus and inflammation.
- Density = 2500 – 5000 million sperm/ml (use of EEJ can result in a sample more dilute than would have been collected with AV)
- Motility = 70 – 95 %
What is the semen motility scale? How is gross motility measured? How is it different to progressive motility?
Gross motility
* Gross motility is assessed by placing a 5-10mm drop of the fresh semen sample on a clean warmed slide and examining under low power brightfield magnification.
* Gross motility is scored subjectively on a five point scale with the following descriptors.
* Gross motility depends on three factors: concentration, % progressively motile sperm and speed of progression of sperm.
Progressive motility
* After gross motility has been scored, a small drop (2-4mm) of semen is placed on a clean warm slide and covered with a warmed cover slip.
* Examination under x 200 - x400 magnification will allow an estimation of % progressive forward motility
* The standard required to pass the semen examination section of the BCVA PBE certificate is a progressive motility of > 60% .
How do you assess sperm morphology? What might you see?
- To make a smear, a small 5-6 mm drop of eosin-nigrosin stain is placed at one end of a warm, frosted-end slide and using a fine dropper or insulin syringe a small drop of semen is mixed with the stain.
- After a short period the smear is made by pulling the drop of stain/semen along the slide with the edge of another slide
- Morphology counts must be done under x1000 oil immersion magnification either with stained slides and brightfield microscopy or using fresh, wet (formol saline killed) preparations and phase contrast microscopy
Abnormalities
- proximal cytoplasmic droplets - sign of disturbed epididymal or testicular function
- detached heads - can be a sign of abstinence
- distal midpiece reflex/bent tails - sperm maturation gone wrong
- severely coiled tails/dag defect - due to midpiece developmental abnormalities
- distal cytoplasmic droplets - indicates abnormality of seminal fluids or ejaculation
- nuclear vacuoles
When is a semen sample deemed satisfactory?
Satisfactory if:
* Progressive motility of >60%
* Normal sperm morphology count of >70%
* Absence of significant numbers of foreign cells such as leucocytes
What is possible pathogenesis of abnormal sperm production?
- Stress - pain, hunger, cold
- Heat - obesity, scrotal abnormality, climate, fever
- Season - photoperiod, nutrition, temperature
- Hereditary - sperm defects, testes size
- Puberty - resembles disturbed spermatogenesis
- Toxicity - zearalenone (mycotoxin), bacterial toxins
- Nutritional - a deficiency of any of: protein, vitamin A, Se
What can have an effect on testosterone? How does that affect sperm production?
Sperm production:
* Testosterone dependent
Testosterone is reduced by:
* Stress
* Cortisol
* Dexamethasone
* Exogenous oestrogen
