Breeding the Correct Cow for your System

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Published: Monday, 24 Feb 2025

Breeding the Correct Cow for your System - Milk Matters February 2025

Over the last decade, breeding has significantly improved milk solids production and herd fertility. While these advancements have positively impacted many herds, some farmers are now concerned about a reduction in overall milk volume. As a result, they are looking to breed more milk into their cows.

Genetics and management work hand in hand. While the right genetics are essential, effective management is what ultimately maximizes a cow’s potential. The genetics required for one herd may differ significantly from another, depending on the system in place. For example, an intensive grass-based system feeding half a tonne of meal annually differs greatly from a system using over 1.5 tonnes of meal in a total mixed ration (TMR) diet. Matching genetics to the production system is crucial for optimal results.

Should you be breeding for more milk?
Many farmers express a desire to breed for more milk, but genetics alone cannot overcome system limitations. It is essential to determine whether the herd has the capacity for increased milk yield. In lower-input herds, breeding for higher milk volume can have negative consequences. Increased milk production requires additional energy, and with limited energy in low input herds, cows may suffer from reduced body condition, higher disease incidence, lower fertility, and poorer survival rates.

Often, lower-than-expected milk volumes are linked to herd maturity. Herd expansions have led to an increase of replacements, resulting in a high percentage of first- and second-lactation cows. However, to fully realize genetic potential, cows need to remain in the herd longer.

First-lactation cows typically produce about 80% of the milk production of mature cows (lactation 3+)
Second-lactation cows reach about 91% of a mature cow’s milk production

Increasing the age of the herd by just bringing in sufficient number of replacements (i.e. increasing survival and fertility of cows) will improve the overall milk production of the herd. It is important to check milk performance of the different cohorts within the herd. It was identified in Munster Bovine milk recording, that in 20% of herds, first lactation cows produced less than 70% of the milk yield as the mature cows in the same herd. This is likely due to inadequate energy intake of the younger animals which can occur when feed space is limited or large herds where grass allocation is limited.

Selecting Cows and Sires for Your System

To maximize herd performance, breeding decisions should align with your system’s milk yield requirements. Data from the 2024 Munster Bovine milk recordings demonstrates a strong relationship between a cow’s genetic merit for milk yield and her actual production on the farm.

Table 1 shows the 305-day milk yield across different lactations for cows with varying genetic merits for milk kg. The trend is clear: selecting sires with higher genetic merit for milk kg results in increased milk volume in the herd.

Table 1: Average 305-Day Milk Yield by Genetic Merit for Milk kg

Milk recording results allow you to assess whether your herd is realizing its genetic potential. If your 305-day milk performance aligns with or exceeds expectations in Table 1 and you still want to increase yield, you can consider using sires with higher milk yield genetics.

However, if your herd is below these averages, genetics may not be the limiting factor. Instead, evaluate forage quality, concentrate feeding, and herd health to identify areas for improvement. In addition if cows are struggling in your system with poor body condition score, you should either aim to increase the energy in the diet or potentially consider breeding for lower volume cows.

Myth about negative milk kg bulls

A common concern among farmers is that using bulls with negative milk kg values will result in insufficient milk production. However, for many herd systems, maintaining milk volume below 6,500 kg can be beneficial, as it reduces input requirements and helps keep the herd within Band 2 for nitrates.

On average, mature cows with a genetic merit for milk kg between -100 and 0 produce between 6,123 and 6,473 kg of milk over 305 days. While this serves as a general benchmark, actual production can vary due to factors such as concentrate feeding, forage quality, and overall herd management.

Increasing milk solids within your system

Once you identify your target milk volume, your aim is to maximise the amount of solids within that milk volume for the system. Key trait to look at is Milk solids which is a combination of Fat and Protein solids. In Figure 1, it shows that there is a strong relationship between the genetic merit for solids and the actual amount of milk solids produced in herds. On average, Munster Bovine milk recording herds have genetic merit for milk solids of 15 kg for cows lactation 3+ which on average equates to 530 kg of milk solids at 305 days. Based on 2024, 305 day milk solids will change by 3kg for every 1 kg change in milk solids.

Figure 1. Average 305 day solids yield for cows in lactation 1, 2 and 3+ based on there genetic merit for solids

For example, if your herd average is 15kg and you use a team of bulls with a milk solids average of 30kg the resulting progeny will be 22.5 kg on average. These will be expect to produce 551kg of milks solids when mature cows.

Summary
Milk recording is essential for assessing herd performance and making informed breeding decisions. The ideal cow should match the energy availability in your system.

High-input systems can support cows with higher milk output due to sufficient energy availability.
Low-input systems should prioritize cows that maximize performance on limited energy, ensuring efficiency and sustainability.
Negative milk kg bulls will still produce enough volume for low to medium input systems farmers want to reduce concentrate input stay out of a higher banding for nitrates.
Milk solids drive profitability—regardless of the system, most herds are paid on an A+B-C basis, meaning increasing solids while maintaining milk yield boosts revenue and profit.