Bull Breeding Soundness Flashcards
What is the main aim with bull management?
- Reduce the risk of fertilisation failure in bulls
- Want to eliminate any problem bulls before they breed and contribute to subfertility of the herd
What are the components of a breeding soundness exam in bulls?
- Identification
- Clinical Exam
- Service testing
- Scrotal circumference
- Palpation of genitalia
- Semen Exam
What usually composes a beef breeding soundness exam?
- Palpating and looking for lesions of genitalia that affect service
- Locomotor problems
- Libido and ability to mate
- Possibly sperm-producing capacity
What usually composes a dairy breeding soundness exam?
- Palpating and looking for lesions of genitalia that affect service
- Palpating and looking for lesions of genitalia that don’t affect service
- Sperm-producing capacity
- Abnormal semen
What are beef farmers most concerned about with their bulls?
Whether the bull can serve ( service testing)
- Must be sound in limb and have high libido to seek out cows
What are dairy farmers most concerned about with their bulls?
Conception rates
- sperm characteristics
Usually buy bulls that have already been service tested, or bulls that are young with high libidos
- more likely to want a clinical exam, semen testing and BVD testing
- bulls usually only for non-AI cows and for serving 1st year calvers
- 1:25 to 1:40 ratio
What is tested for while the bull is in a bail?
- General inspection especially feet, legs and BCS
- Scrotal circumference
- Clinical exam of genitalia
What is tested for while the bull is in the yard?
- Behaviour, locomotor system
- Service test
- Semen Exam
- Final Assessments
What are the general proportions of outcomes of bull testing?
74% sound
19% unsound
5% uncertain (retest)
Why is it important to look at hocks and backs of bulls?
When mounting there is heaps of pressure on the hocks and back
- this gets progressively worse as the bulls age
e. g. poor hock conformation
e. g. spondylitis excess spinal bone growth- usually progressively worsens
What is temporary unsoundness?
Something that may get better
e.g. a foot abscess
What is permanent unsoundness?
Something that is:
- Incurable
- Will worsen with time
- Is congenital
- Is inherited
e. g. malconformed claws
What is important about the locomotor system in bulls?
It is usually associated with impaired mounting or service behaviour
What can be seen when bulls with spondylitis try to mate?
They mount the cow
They are slow to achieve intromission
They don’t / can’t thrust
What is important about lesions of the penis and prepuce in bulls?
It is usually associated with impaired mounting or service behaviour
Describe a rupture bulls penis…
Commonly occurs when bull mounts but doesn’t get the line up with the vagina correct
- When he thrusts he hits the back of the cow
- Huge pressure causes tunica albuginea to rupture and lose blood from the cavernous penis
- Blood pressure needed for erection can no longer be maintained
Describe abnormal venous drainage of the corpus cavernosum…
Bull is unable to get an erection
Small veins that drain the corpus cavernosum during development fail to occlude before puberty
- If they fail to occlude the corpus cavernosum is not blind-ending so pressure can’t be raised significantly for an erection to occur
Describe blockage of the longitudinal canals of the corpus cavernosum…
Bulls unable to achieve erection due to blockage of the common dorsal longitudinal canal near the base of the penis
Describe ventral ‘rainbow’ deviation of the penis…
- Associated with persistent frenulum
Describe spiral deviation of the penis…
- During ejaculation the bull displays spiralling of the tip of the penis
- Usually seen in bulls > 2yo
- Most common abnormality of the penis
- Treatment by slaughter
- Appear to mount normally but get only 10-20% cows pregnant
- Worsens with age and under pressure
Describe penile neoplasia: fibropappilomata
The only common tumour of the bovine penis
- multiple or singular
- pedunculated or sessile
Unsound for current breeding season
Must be careful (if removing) to avoid incising the urethra
Describe preputial trauma…
Damage or dessication to everted preputial mucosa
- may be oedema, inflammation, fibrosis and abscess formation
Describe Bovine herpesvirus affected penises…
Causes severe ulcerative balanoposthitis
- small necrotic foci develop into deep ulcers which can coalesce into large areas
What do farmers call bovine herpes virus penises?
Bull burn
