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Wy do a breeding soundness exam (BSE)?
- Studies have found that fertility in bulls is 10 times more important than carcass quality and 5 times more important than rate of gain
- One disastrous breeding season can be financially devastating
- Delayed conception can be costly:
- For every heat cycle (21 days) in a breeding season that a cow does not get bred, it can mean a loss of 50-60 pounds of calf weaning weight (at current market value that could mean $70-80 lost per head)
- It’s estimated that 1 in 5 bulls is sub-fertile
- Ideally bulls should be tested before the beginning of the breeding season
Three Requirements for Fertility
- Good libido
- Physical soundness
- Good semen quality
Libido (sex drive)
- Can be difficult to test—requires good observation by the producer
- Older, dominant bulls can suppress libido in young bulls
- Yearling bulls need time to develop their natural instincts
- Controlled tests are possible but complicated and time consuming to run
General Physical Soundness
- Good conformation required (feet, legs and back especially)
- Poor confirmation in both males and females can be passed on to offspring
- Good vision is vital (free of cancer-eye and pinkeye)
- Also important are attitude, general appearance, body condition and fecal characteristics
Reproductive Physical Soundness
- Scrotal evaluation/circumference
- Penis and erection ability
- Rectal exam
Scrotal Evaluation
- Palpation:
- Testes should be freely moveable
- Spermatic cords easily identified
- Epidydimi of similar size and consistency
- Free of abscesses, wounds, etc.
- Circumference:
- Indicator of testicular weight, which correlates with daily sperm production
- Increased scrotal circumference leads to younger onset of puberty in both male and female offspring
- Feeding too high of an energy ration (too much grain) causes smaller scrotal circumference and testicular degeneration
- Acceptable scrotal circumferences:
- <15 months of age = 30 cm.
- 15-18 months of age = 31 cm
- 18-21 months of age = 32 cm
- 21-24 months of age = 33 cm
- >24 months of age = 34 cm
Penis and Erection Ability
- During collection, the penis should be evaluated for injuries, abscess, scar tissue or deviations
- A bull that cannot achieve an erection may have obvious fertility problems
Rectal Exam
- Feel for abnormalities in the accessory sex glands (bulbourethral, prostate and vesicular) and inguinal rings
- Massage of sex glands can help with sample collection
Semen Quality
- Classified as very good, good, fair or poor
- Semen density and volume
- Sperm motility (gross and individual)
- Minimum for passing: >30% gross mobility (fair rating)
- Sperm morphology (minimum for passing: >70% normal)
4 classifications of a breeding soundness exam:
- Satisfactory: meets minimum requirements for physical soundness and semen quality
- Questionable: will likely impregnate cows but at a sub-optimal level or could pass-on undesirable traits to offspring
- Decision Deferred: usually pre-pubertal bulls with poor semen quality (expected to improve with time)
- Unsatisfactory: poor fertility with poor prognosis for improvement
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