How to Choose the Right Bull for Your Dairy Herd

Choosing the right bull for your dairy herd is one of the most important decisions you can make for the future performance and profitability of your farm. Every breeding decision has a long-term impact on milk production, fertility, health, longevity, and overall herd efficiency.

With hundreds of AI bulls available, it can feel overwhelming to know which genetics will truly benefit your herd. However, by focusing on the right traits and understanding your herd’s goals, you can make breeding decisions that improve performance for years to come.

This guide explains the key factors dairy farmers should consider when selecting bulls for their breeding programme.

Start With Your Herd Goals

Before selecting any bull, the first step is to understand what you want to improve in your herd. Every herd has different priorities depending on the farming system. For example:

• Grass-based systems may prioritise:

  • Fertility

  • Longevity

  • Moderate milk production

  • Strong health traits

• Higher-input systems may focus on:

  • Milk yield

  • Milk solids

  • Udder quality

  • Production efficiency

Rather than chasing extreme production figures, the most successful breeding programmes focus on balanced genetics that suit the farm system.

Focus on Fertility and Longevity

Fertility is one of the most important traits in modern dairy breeding.

Poor fertility leads to:

• Longer calving intervals

• Higher culling rates

• Increased replacement costs

• Lost milk production

Selecting bulls with strong fertility indexes helps build cows that get back in calf quickly and remain productive in the herd for longer.

Longevity is closely linked to fertility and health. Cows that stay in the herd for multiple lactations are far more profitable than animals that leave early due to health or fertility problems.

Breeds such as Norwegian Red and Montbéliarde are increasingly popular in crossbreeding programmes because they bring improvements in fertility, health, and durability.

Look Beyond Milk Yield

For many years, breeding decisions were heavily focused on increasing milk yield. While production remains important, focusing solely on yield can lead to problems such as:

• Reduced fertility

• Poorer health

• Higher maintenance costs

• Shorter herd life

Instead, modern breeding strategies focus on lifetime profitability rather than maximum production.

Milk solids (fat and protein) are often more valuable than simply increasing litres, particularly with current milk pricing structures.

Use Genetic Indexes to Compare Bulls

Genetic indexes help farmers compare bulls based on predicted performance in key traits.

These indexes combine multiple factors such as:

• Production

• Fertility

• Health traits

• Longevity

• Calving ease

Using genetic indexes allows farmers to make more informed breeding decisions rather than relying on individual traits alone.

However, it is still important to consider how those genetics will perform within your own herd and farming system.

Consider Calving Ease

Calving difficulty can lead to:

• Increased veterinary costs

• Lower calf survival

• Reduced fertility in the cow

• More labour during calving

Choosing bulls with good calving ease traits is particularly important for:

• Heifers

• Smaller-framed cows

• Herds aiming to reduce intervention at calving

Balancing calving ease with growth and production traits helps maintain a smooth calving pattern across the herd.

Think Long-Term

A breeding decision made today will affect your herd for the next 5–10 years.

That’s why the best breeding programmes focus on:

• Long-term herd improvement

• Balanced traits

• Consistent breeding strategy

Working with an independent genetics advisor can help farmers create a breeding plan tailored to their herd’s needs, ensuring the right bulls are used on the right cows.

Final Thoughts

Selecting the right bull is about far more than chasing the highest production figures. The most profitable dairy herds are built on cows that combine:

• Strong fertility

• Good health

• Efficient milk production

• Long productive lives

By focusing on balanced genetics and breeding decisions that suit your farming system, you can build a herd that performs reliably and sustainably for years to come.

If you’d like help developing a breeding strategy or selecting bulls suited to your herd, JMC Genetics provides independent advice to help farmers maximise the value of their genetics.