Bull Fertility

Question 1

How can you definite a fertile bull?

Answer 1

Gets 60% of healthy, cycling females pregnant in the 1st 3w

Gets 90% of them pregnant in the 9 week breeding period

Question 2

What should be the conception rate of a normal fertile bull?

Answer 2

60%

Question 3

What should you examine during a bull breeding soundness exam? 1. General clinical examination

Answer 3

General clinical exam

• condition score 3 or 3.5 ideal
• check locomotion - lameness and back pain will reduce mounting
• conformation - unusual conformation predisposes to lameness
• ocular assessment - need to be able to see
• teeth - ocular or undershot jaw - heritable

Question 4

What should you examine during a bull breeding soundness exam? 2. Reproductive tract examination

Answer 4

Scrotal circumfernce
Testicles and associated structures
Penis and prepuce
Accessory sex glands - rectal palpation of prostate and seminal vesicles, rule out seminal vesiculitis

Question 5

What should you examine during a bull breeding soundness exam? 3. Semen evaluation

Answer 5

Gross motility
Linear progressive motility
Morphology
White blood cells

Question 6

What is the most commonly used method of semen collection?

Answer 6

Electro-ejaculation

• poor volume and concentration
• welfare issue

Question 7

What should you evaluate in semen?

Answer 7

Gross motility - grade 3 or above is acceptable (1-5)
Linear gross motility - how many move progressively
Morphology - make a smear - more than 70% normal
Make a smear to assess for WBCs - stain with methylene blue
- seminal vesiculitis

Question 8

How can you libido test a bull?

Answer 8

Put it in will a female in oestrus

Should serve her within 20mins, ideally within 10

Question 9

How does a penile haematoma present?

Answer 9

Swelling
Abscess and adhesion formation
Poor px

Question 10

How can you treat penile haematoma?

Answer 10

Likely to recurr - cull

Cold hose for 4 days, then 3 weeks of warm hosing and massage
Antibiotics and NSAIDs to prevent abscessation

Surgery to remove blood clot if medical management fails

Question 11

How does a penile papilloma present and what should you do about it?

Answer 11

Young bulls
Interferes with service
May spontaneously regress, but if not
Surgical removal is indicated

Question 12

How should you treat a persistent frenulum?

Answer 12

Surgical removal

Don’t use for breeding - heritable

Question 13

How long will it take for the sperm count to recover after a disease?

Answer 13

60 days

Question 14

Where are the seminal vesicles located?

Answer 14

Either side of midline on rectal examination

Question 15

What are some venereal disease spread by the bull?

Answer 15

Campylobacter foetus venerealis
Trichomonas foetus
BHV1

Question 16

What are the signs of trichomonas foetus in a herd?

Answer 16

Bulls are a symptomatic carriers
Prolonged return to service interval
Poor fertility in cows
Abortion in first 2-4m

Question 17

How is campylobacter foetus venereallis spread?

Answer 17

Bull is persistently infected - epididymal crypts

Question 18

What are the clinical signs of campylobacter foetus venereallis?

Answer 18

Seen in naive heifers

Endometritis after first service
Failure to conceive
Late embryonic death and irregular return to service
Abortion at 4-5 months of gestation

Question 19

How can my you treat Bulls for campylobacter?

Answer 19

Wise to cull - persistently infected

Can try long term streptomycin or preputial washes with pen/strep

Question 20

How can you control campylobacter in a herd?

Answer 20

Use AI for at least two years
Separate infected from non-infected herds
Use a virgin bull
Vaccination - autogenous

Question 21

What should a farmer consider when reading a Bulls proof?

Answer 21

1. Production traits - milk yield, protein and fat
2. Profitable lifetime index - fertility, SCC, udder conformation, locomotion, lifespan
3. Conformation traits - eg udder and pelvic conformation
4. Management fitness traits
   - calving ease
   - production life
   - lifespan
   - fertility index
   - maternal calving ease
   - direct calving ease
   - total performance index

Question 22

What are the advantages of AI?

Answer 22

Can use better Bulls
More compact calving period
Disease control - campylobacter
Safer as you don't have to keep a bull
No bull costs
Heat detection devices can be used