How to Select the Right Bull for Your Herd
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How to Select the Right Bull for Your Herd
By Dr Duncan Houston
The wrong bull does not just cost one season. It sets your herd back for years.
In practice, bull selection is one of the most underestimated decisions in cattle operations. A bull contributes half the genetics of every calf, but more importantly, he determines fertility, calving outcomes, and long-term herd direction.
The mistake most producers make is focusing too heavily on appearance or sale hype, and not enough on function and fertility.
This guide will help you understand what actually matters when selecting a bull, how to assess risk, and how to make a decision that improves your herd, not just fills a gap.
Quick Answer
The best bull is structurally sound, fertile on examination, genetically suited to your herd goals, and physically capable of working in your environment. Selection should prioritise fertility and function first, then genetics, then appearance. A bull that cannot breed effectively will cost far more than any performance advantage on paper.
Decision Snapshot
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Structurally sound, passes BSE, fits herd goals → strong candidate
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Good genetics but no BSE or structural concerns → moderate risk
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Poor mobility, temperament, or condition → avoid
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Unknown fertility status → high risk purchase
What Actually Matters Most in Bull Selection
There are four core areas that determine whether a bull will perform:
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Structural soundness
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Fertility and breeding soundness
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Genetic merit and performance data
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Fitness, temperament, and environment fit
What vets actually worry about
Not how impressive a bull looks in the yard, but whether he:
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can physically breed
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produces viable semen
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lasts multiple seasons
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fits the production system
Structural Soundness and Conformation
Structure determines whether a bull can work, not just how he looks.
Key areas to assess:
Feet and legs
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Straight, strong limbs
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Correct hoof shape
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No signs of lameness or instability
Movement
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Free, fluid movement
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Able to cover ground without stiffness
Topline and back
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Straight and strong
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Indicates muscling and support
Hindquarters
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Well-developed muscle
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Important for breeding ability and carcass traits
What matters most
If a bull cannot move well, he cannot breed effectively, regardless of genetics.
Breeding Soundness Exam (BSE)
A BSE is one of the most important steps and is often overlooked.
A proper BSE includes:
Reproductive exam
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Testes, epididymis, penis, sheath
Scrotal circumference
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Linked to fertility and earlier puberty in offspring
Semen evaluation
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Motility
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Morphology
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Concentration
General health check
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Eyes, mouth, body condition, mobility
The key principle
A bull without a current BSE is a risk.
What vets actually see
In practice, subfertile bulls are more common than expected, and the cost of discovering this during breeding season is significant.
Genetics and Performance Data
Genetics determine long-term herd improvement.
Key tools:
Expected Progeny Differences (EPDs)
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Birth weight
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Calving ease
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Growth rates
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Carcass traits
Accuracy values
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Higher accuracy means more reliable predictions
Actual performance data
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Growth records
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Health history
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Fertility outcomes
What matters most
Genetics should match your production goals, not just be “high performing” in general.
Fitness, Condition, and Temperament
A bull must be physically and behaviourally capable of doing the job.
Key factors:
Body condition
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Ideal BCS 5 to 6 out of 9
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Too thin reduces fertility
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Too fat reduces mobility
Mobility
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Must move easily and cover pasture
Temperament
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Calm and manageable
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Not aggressive or unpredictable
What vets actually worry about
Temperament issues and poor mobility are major causes of early culling.
Matching the Bull to Your System
A good bull in the wrong system becomes a poor investment.
Consider:
Environment
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Climate adaptability
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Breed suitability
Feeding system
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Match frame size to available nutrition
Calving management
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Choose calving ease bulls where labour is limited
Real-world insight
The best bull is not the best animal in the sale.
It is the best fit for your system.
Severity Framework: Risk of a Poor Bull Choice
Low Risk
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Passed BSE
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Structurally sound
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Matches herd goals
→ High confidence purchase
Moderate Risk
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Good genetics but limited fertility data
→ Requires careful monitoring
High Risk
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No BSE
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Structural or mobility concerns
→ Likely performance issues
Critical
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Known fertility or soundness issues
→ Avoid entirely
How Bull Performance Plays Out Over Time
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Early season → active breeding behaviour
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Mid season → sustained fertility and coverage
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Late season → fatigue or performance drop if not fit
What matters
A bull must maintain performance across the entire breeding period, not just start strong.
When Should You Be Concerned?
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Low pregnancy rates
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Uneven calving spread
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Bull showing lameness or fatigue
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Reduced mating activity
These are signs the bull may not be performing.
What To Do Before Buying a Bull
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Inspect structure and movement carefully
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Confirm a recent BSE
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Review genetic data and EPDs
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Assess body condition and temperament
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Match the bull to your production system
Do not:
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Buy without a BSE
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Ignore mobility issues
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Over-prioritise appearance
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Choose genetics that do not fit your system
The rule to remember
Fertility first, function second, genetics third.
Common Mistakes
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Buying on appearance alone
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Skipping fertility testing
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Ignoring feet and leg issues
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Choosing bulls too large for the feed system
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Not matching genetics to herd goals
Prevention: Setting Your Breeding Program Up Properly
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Perform BSEs before every breeding season
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Monitor bull condition regularly
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Rotate bulls if needed
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Track pregnancy rates and outcomes
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Replace underperforming bulls early
FAQs
How important is a BSE?
Essential. It confirms fertility beyond appearance.
Can a bull look healthy but be infertile?
Yes. This is more common than many expect.
Should I prioritise genetics or fertility?
Fertility always comes first.
How often should bulls be tested?
At least annually before breeding.
What is the biggest mistake in bull selection?
Ignoring structural and fertility issues.
Final Thoughts
Bull selection is one of the highest-impact decisions in cattle production.
A good bull improves fertility, consistency, and herd genetics. A poor bull quietly reduces performance and profitability.
The key is not choosing the most impressive animal, but the most functional and reliable one.
If you want help reviewing a bull, interpreting BSE results, or matching genetics to your herd goals, ASK A VET™ can support your decision with practical, real-world guidance.