Bovine Andrology

Question 1

bull requirements for reproductive success

Answer 1

• physically sound and in good health
• functional reproductive system
• have strong libido and fertile spermatozoa
• free of venereal diseases

Question 2

bull selection

Answer 2

• 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

Question 3

BSE of bull

Answer 3

• identification and history
  
  • identification of owner and bull
  • history of bull
• physical examination
• reproductive examination
• collection and examination of semen (motility/morph)

Question 4

physical exam of bull for BSE

Answer 4

• 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)

Question 5

assessing accessory sex glands

Answer 5

• palpating per rectum
  
  • seminal vesicles (vesicular glands)= abnormalities here can lead to fertility issues
  • ampulla
  • prostate
  • bulbourethral glands

Question 6

accessory sex glands

Answer 6

• lobulated
• 2-3 fingers long
• width of index finger
• movable
• check for size, consistency

Question 7

Structures of the bull reproductive anatomy that can lead to infertility

Answer 7

• scrotum
• penis
• testicle (seminiferous tubules)
• epidydimis
• seminal vesicles (lose lobulation, or one/both is larger than other )
• prepuce

Question 8

seminal vesiculitis

Answer 8

• 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)

Question 9

etiology of seminal vesiculitis

Answer 9

• more common in bulls housed in groups
  
  • A. pyogenes (most common)
  • Brucella abortus
  • H. somni, Mycobacterium sp.

Question 10

abnormalities of penis and prepuce

Answer 10

• fibropapilloma
• persistent frenulum
• hematoma
• prolapsed prepuce
• skin separation
• laceration

Question 11

fibropapilloma

Answer 11

• 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

Question 12

corkscrew penis

Answer 12

• S shaped deviation
• unsatisfactory

Question 13

penile hematoma

Answer 13

• 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

Question 14

prolapse of prepuce

Answer 14

• most common in Bos indicus breeds with pendulous prepuce
• injury to preputial tissue with edema
• sequel to hematoma of the penis
• congenital preputial abnormality

Question 15

treatment of preputial prolapse

Answer 15

• surgical intervention
• sling
  
  • control edema, abx solvent

Question 16

scrotal circumference

Answer 16

• 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

Question 17

benefits of bull with large scrotal circumference

Answer 17

• 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

Question 18

evaluation of sperm morphology

Answer 18

• standard microscopy of stained smears
• typically negative stain

Question 19

what is minimum recommended threshold for progressive sperm motility?

Answer 19

30%

Question 20

what is the minimum recommended threshold for sperm morphology to be considered normal?

Answer 20

70% normal spermatozoa

Question 21

classification of breeding potential

Answer 21

• 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

Question 22

satisfactory

Answer 22

• 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

Question 23

unsatisfactory

Answer 23

• 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

Question 24

deferred

Answer 24

• 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

Question 25

Answer 25

normal bull spermatozoa

Question 26

Answer 26

wrinkled acrosome (sperm head abnormality)

Question 27

Answer 27

pyriform head (left)

small or large sperm hear (right)

Question 28

Answer 28

nuclear vacuoles (indicates issue with physiology/morph of head)

Question 29

Answer 29

Diadim defect (head)

Question 30

Answer 30

sperm midpiece/tail defects

-prox/distal droplet most common

Question 32

Answer 32

midpiece/tail abnormalities

Question 33

Answer 33

midpiece/tail defect

Question 34

Answer 34

midpiece* abnormality

-caused by gossypol tox (cotton seed)–>impaired motility

Question 35

Primary vs Secondary sperm abnormalities

Answer 35

• primary = involves head
• secondary= midpiece/tail