Stallion BSE Flashcards
1
Q
What is the purpose Breeding Soundness Exam (stallion)?
A
- Estimates a stallion’s reproductive potential, which is the current ability of a stallion to impregnate a mare, resulting in the birth of a normal foal
- Estimate the number of mares the stallion can breed
- Fertile vs Subfertile vs Infertile stallions Determined by:
- Quality and Quantity of spermtozoa
- Libido and mating ability
- Physical defects or lesions
- Venereal infectious diseases
- Heritable defects
2
Q
When should a BSE be performed?
A
- At the beginning of each breeding season
- determine breeding book size
- monitor semen changes and fertility over time
- Pre-purchase exam
- Pre-insurance exam
- If lowered Infertility is suspected
3
Q
What information is needed to estimate a stallion’s present fertility
A
- Reproductive history
- Physical examination
- Heritable defects
- Infectious and Venereal diseases
- Evaluation of external genitalia
- Evaluation of internal genitalia
- Bacterial cultures
- Sexual behavior/Libido
- Collection of semen
4
Q
What information is part of the reproductive history of a stallion
A
- Signalment (name, breed, age)
- Vaccination and deworming history
- EVA status or vaccination
- Travel and show information
- History of fever or infections
- Illnesses and lameness
- How many mares he bred last year
- Current medications
- Pregnancy rate
- When was he last collected or bred
- How is he managed reproductively
- How are the mares managed reproductively
- Previous BSE findings
- If artificial insemination is used how is the semen processed
- Tasing and breeding behavior
5
Q
What is part of the general physical exam for stallions?
A
- Verify identification of the stallion
- Body condition
- Conformation
- Examination of body systems
- Lameness/Back pain
- Neurological function
- Heritable conditions
- Observe the stallion in hand and on the mare or phantom for signs of discomfort
- Stallions that dismount prematurely may do so because of joint or back pain
- Stallions in pain may become disinterested in breeding
6
Q
What are some heritable conditions that are undesirable for a stallion to pass on?
A
- Cryptorchidism
- Parrot Mouth
- Cervical Stenotic Myelopathy
7
Q
What is being looked for for when examining the penis of a stallion?
A
- Lacerations/Trauma
- Squamous Cell Carcinoma
- Papilloma
- Melanoma
- Equine coital exanthema
- EHV-3
- Habronemiasis
- Balanitis
8
Q
How is the scrotum of stallions evaluated during a breeding soundness exam? (what parameters)
A
- Palpation of the scrotum
- Skin thickness or irregularities in the scrotum
- Ensure both testicles are present
- Descend 30 days before to 10 days after parturition
- Mobility
- Size (width, length, height)
- Tone/Texture/Symmetry
- Position
- Cranial to caudal with the head of the epididymis cranially and the tail caudally
- Ultrasound of the scrotum
- Size (length, width, height)
- Testicular parenchyma
- Epididymids
- Spermatic cords
- Scrotal contents
- Size and Volume:
- varies (Bread, season, age, repro status)
- Daily Sperm Output (DSO)
- highly correlated with:
- Testicular weight in Stallions
- 16-18 million sperm per gram of testicular tissue
- Length, width, and height
- Stallions total scrotal width
- ≥ 8 cm at 2-3yrs
- Testicular weight in Stallions
- highly correlated with:
9
Q
What is expected DSO?
A
- Reference point to determine number of mares/day that could be bred
- Compare Expected DSO to Actual DSO to determine spermatogenic efficiency
- Based on the total testicular volume:
- 0.523 x length x width x height = Testicular Volume
- Total testicular volume = Right TV + Left TV
- Expected DSO (billions of sperm) = 0.024 x TTV - 1.26 (or 0.76)
10
Q
What is actual DSO?
A
- Total number of sperm a stallion can ejaculate 1 day after depletion of extra-gonadal reserves (tail of the epididymis)
- Collect the stallion daily for 5-7 days
- Total spermatozoa is at a constant for 3 days in a row
11
Q
What is Estimated DSO?
A
- Collect stallion 2x one hour apart
- Second collection is used as the estimated DSO
- Generally same volume and motility as first collection
- Generally 60% concentration of total sperm count as first collection
12
Q
What does Actual/Estimated DSO vs Expected DSO tell you about the stallion?
A
- Determines if spermatogenesis is occurring as efficient as expected
- Early indication of testicular dysfunction
- Testicles are of normal size, but spermatogenesis is reduced
13
Q
How is the internal genitalia evaluated? What should be evaluated?
A
- How:
- Rectal palpation
- Ultrasound
- What:
- Bulbourethral glands
- pre-spermatic fluid
- Amount of fluid increased by teasing
- Watery, cleans the urethra
- Ampulla, Prostate gland
- Sperm rich fluid
- Milky, contains most spermatozoa
- Vesicular Glands
- Clear gel
- Washes out remaining sperm from the urethra
- Bulbourethral glands
14
Q
What bacterial cultures should be done on stallion genitalia?
A
- Aerobic culture:
- Shaft of the penis
- Urethra fossa
- Pre-ejaculate urethra
- Post-ejaculate urethra
- Transport media
- Stuart
- Amies w/charcoal for CEM
- Normal stallion - Mixed growth
- Proteus spp
- Staphylococcus spp
- E. coli
- Streptococcus s
15
Q
What bacteria found in culture would cause a stallion to fail their BSE?
A
- Pseudomonas aeruginosa
- Klebsiella pneumoniae
- Taylorella equigenitalis (CEM)
- Heavy growth of a single organism
16
Q
What is the purpose of semen collection in a BSE?
A
Assess libido and mating ability
17
Q
What methods are there for collecting semen from a stallion?
A
- Artificial vagina
- jump mare
- phantom
- Standing collection
- Pharmacologically induced
- Condom
- Manual stimulaiton
18
Q
What are the requirements for an artificial vagina for a stallion?
A
- Colorado and Missouri types
- Pressure and Temperature are important!
- Inner temperature 45-48C
- Clean, free of soap residue
- +/- Disposable polyethylene liners
- Filter to remove debris and gel
- Non-spermicidal lubricant
19
Q
How is semen evaluated for a BSE? parameters? tests?
A
- Gross evaluation
- volume
- Aspect
- Color
- Biochemical tests
- Urine contamination
- True ejaculation
- Microscopic evaluation
- sperm motility
- sperm morphology
- sperm concentration
- Total sperm = volume x concentration
- Total Progressively Motile Morphologically Normal Sperm
- Represents events that have occurred approximately 2 months ago
- spermatogenesis: 55-57 days
- Maturation and epididymal transport: 9 days
20
Q
What should semen look like on gross evaluation?
A
- Color: White
- Yellow = urine contamination
- Red = blood contamination
- Aspect: crude assessment of concentration
- Milky
- Watery
21
Q
What Biological tests are run on semen? expected results?
A
- Urea Nitrogen
- assess for urine contamination
- >30mg/dL indicated rine
- Azostix (like a pH stick)
- lower limit of sensitivity is 39 mg/dL
- Slight contamination may result in false negative or weak positive
- Creatinine
- assess for urine contamination
- > 2mg/dL indicates urine
- Alkaline phosphatase
- produced by epididymis
- >1,000 U/L indicates full ejaculation
- pH
- Normal 7.2-7.7
- Abnormally high pH
- Urine or soap contamination
- Inflammatory lesion of the genital tract
- Osmolarity
- Normal 336 (+/- 10.5) mOsm
22
Q
What is the desired motility of stallion sperm?
A
- >60% progressively motile sperm
23
Q
How does a Hemacytometer work to count sperm?
A
- Dilute semen 1:100
- 10 ul of raw semen to 990 ul formalin solution or water
- Carefully load hemacytometer (don’t overflow!)
- All 25 large squares can be counted or a counting pattern using fewer squares
- Count 5 squares and multiply by 5
- Count both sides of the hemacytometer and take the average
- Concentration (millions/ml) = Mean # x 10,000 x dilution factor
24
Q
How is sperm morphology assessed?
A
- Eosin-nigrosin stain
- Phase contrast
- 100x oil immersion
- Count 100 cells
- >60% morphologically normal
- <5% abnormalities of acrosome and midpiece
- Routine examination
- Testicular degeneration
- Orchitis
- Epididymitis
- Sort sperm into following categories:
- Normal
- Abnormal head
- Detached head
- Abnormal/broken neck
- Abnormal midpiece
- Rroximal droplet
- Distal droplet
- coiled tial
- Kinked tail
25
Q
How is Total progressively motile sperm calculated? Total progressively motile morphologically normal sperm?
A
- TPMS = TS x PMS%
- TPMMNS = TS x PMS% x MNS%
26
Q
what is the longevity of sperm motility?
A
- Stimulate survival of sperm in mare’s reproductive tract
- Evaluate periodically until progressive motility <10%
- Longevity is poor if progressive motility <10%
- <6hrs in raw semen sample
- <24 hours in extended semen sample
- Prepare insemination dose and evaluate at 24-48 hours to monitor stallion’s ability to be cooled and transported
27
Q
What are the requirements for a stallion to be considered “Satisfactory” on BSE?
A
- Should have normal libido and 2 scrotal testes
- Should have total scrotal width ≥8cm
- Should be free of undesirable, potentially heritable defects, behavioral disorders, or transmissible diseases
- Should not have physical traits that interfere with mating, semen quality or sperm output
- Should ejaculate 1 billion progressively motile morphologically normal spermatozoa in second of 2 ejaculations collected 1hr apart after 1wk of sexual rest
- Be able to impregnate 75% of a full book of mares in ≤2 normal estrous cycles with fresh semen
- Full book = 40 mares by natural cover OR 120 mares by AI
28
Q
How does a stallion earn a “questionable and Unsatisfactory Breeder” score on BSE?
A
- Failure to pass 1 or 2 parameters
- Slight changes = Questionable
- Severe changes = Unsatisfactory
- Stallions can be re-evaluated ≥60days from the initial BSE
- may differentiate temporary changes from permanent changes
- Stallions ≤4yrs should be re-evaluated due to sexual immaturity
- Proven stallions with questionable or unsatisfactory status are not always retired from breeding
- Findings used to develop management decisions to maximize reproductive efficiency
