Bovine Andrology Flashcards
bull requirements for reproductive success
- physically sound and in good health
- functional reproductive system
- have strong libido and fertile spermatozoa
- free of venereal diseases
bull selection
- how many?
- bull to cow ratio 1:25
- what kind?
- age, breed, type
- buy virgin bulls
- at least 60 d before breeding season
- about 15 months of age should be ready to breed
- disease free
- allow time to adjust to ration
-
traits
- conformation, color, temperament, longevity, price
BSE of bull
-
identification and history
- identification of owner and bull
- history of bull
- physical examination
- reproductive examination
- collection and examination of semen (motility/morph)
physical exam of bull for BSE
- structural soundness
- BCS
- eyes
- feet/legs
- wounds, physical defects
- generalized disease
- rectal exam of internal genitalia
- accessory sex organs (prostate, seminal vesicles, ampulla, inguinal rings
- assessment of size, shape, consistency
- external genitalia
- scrotum, testes, spermatic cord, epididymides, penis/prepuce (sheath)
assessing accessory sex glands
-
palpating per rectum
- seminal vesicles (vesicular glands)= abnormalities here can lead to fertility issues
- ampulla
- prostate
- bulbourethral glands
accessory sex glands
- lobulated
- 2-3 fingers long
- width of index finger
- movable
- check for size, consistency
Structures of the bull reproductive anatomy that can lead to infertility
- scrotum
- penis
- testicle (seminiferous tubules)
- epidydimis
- seminal vesicles (lose lobulation, or one/both is larger than other )
- prepuce
seminal vesiculitis
- only frequently diagnosed disease of bovine accessory sex glands
- diagnosed by palpation per rectum and by precipitate and cells in semen
-
very pronounced seminal vesicles
- can’t discern lobulation
- sometimes adherence
- unsatisfactory to breed (usually)
etiology of seminal vesiculitis
- more common in bulls housed in groups
- A. pyogenes (most common)
- Brucella abortus
- H. somni, Mycobacterium sp.
abnormalities of penis and prepuce
- fibropapilloma
- persistent frenulum
- hematoma
- prolapsed prepuce
- skin separation
- laceration
fibropapilloma
-
warts and papillomas of penis are common in bulls of all ages
- more common in young bulls
- most mild cases clear after excision
- lidocaine then excision
- poxviruses
- unsatisfactory
corkscrew penis
- S shaped deviation
- unsatisfactory
penile hematoma
- break in tunica albuginea of penis with escape of blood from corpus cavernosum into surrounding tissues
- edema in front of testicles
- preputial prolapse usually follows
- unsatisfactory
prolapse of prepuce
- most common in Bos indicus breeds with pendulous prepuce
- injury to preputial tissue with edema
- sequel to hematoma of the penis
- congenital preputial abnormality
treatment of preputial prolapse
- surgical intervention
-
sling
- control edema, abx solvent
scrotal circumference
- scrotal circumference, testicular size, and sperm production are highly correlated in bulls up to 3 years of age
- most easily reproducible measurement for testicular mass (parenchyma) in the bull
- measurement of testicular mass reflects parenchymal mass (seminferous tubules) and sperm production
benefits of bull with large scrotal circumference
- earlier puberty in daughters and sons
- reduced probability that bulls suffering from testicular hypoplasia or degeneration will be mixed with breeding herd
- in litter-bearing animals
- sires selected for testicular growth produce daughters with more active ovaries
evaluation of sperm morphology
- standard microscopy of stained smears
- typically negative stain
what is minimum recommended threshold for progressive sperm motility?
30%
what is the minimum recommended threshold for sperm morphology to be considered normal?
70% normal spermatozoa
classification of breeding potential
- satisfactory
- equals or surpasses minimum threshold of scrotal circ (based on age), sperm motility, sperm morph
- unsatisfactory
- below one or more thresholds
- highly unlikely to ever improve
- include bulls which show genetic faults or irrevocable physical problems (infect dz) which would compromise breeding/fertility
- deferred
- bulls which do not fit into above categories (may benefit from retest)
- bulls which are substandard but have capability to improve
satisfactory
-
equals or surpasses the minimum thresholds
- scrotal circumference
- sperm motility
- sperm morphoogy
- does not show genetic, infectious or other problems or faults which could compromise breeding or fertility
unsatisfactory
-
below one or more thresholds
- highly unlikely to ever improve
- bulls which show genetic faults or irrevocable physical problems (including infectious disease) which would compromise breeding or fertility
deferred
- bulls which do not fit into satisfactory or unsatisfactory categories
- which may benefit from a retest
- bulls which are substandard but have the capability to improve
- suggested re-examination date
normal bull spermatozoa
wrinkled acrosome (sperm head abnormality)
pyriform head (left)
small or large sperm hear (right)
nuclear vacuoles (indicates issue with physiology/morph of head)
Diadim defect (head)
sperm midpiece/tail defects
-prox/distal droplet most common
midpiece/tail abnormalities
midpiece/tail defect
midpiece* abnormality
-caused by gossypol tox (cotton seed)–>impaired motility
Primary vs Secondary sperm abnormalities
- primary = involves head
- secondary= midpiece/tail
