14 March 2025

Delivering a more fertile suckler herd

Regardless of your suckler production system, whether that be producing weanlings, selling stores or carrying all progeny to finish, having a herd of fertile suckler cows is a cornerstone.

However, making improvements to the fertility of the national suckler herd has proved a difficult nut to crack. Even with today’s record returns from the market place, suckler farmers need to remember that a fertile herd is the starting point to a profitable herd – without each cow producing a calf every year, the journey to profitability becomes that bit steeper. Calving your heifers down at 24 months of age is another proven route to improve suckler profitability, along with having positive impacts of greenhouse gas emissions.

But how can farmers improve these traits? One potential solution is to focus on the Replacement Index of the breeding females present within your herd, striving to breed up to a herd of 5-star cows on the Replacement Index.

To verify the role of the Replacement Index, and particularly 5-star cows, in delivering a more fertile suckler herd, the ICBF has recently completed an analysis of 145,000 females that calved for the first time in 2018 on Irish suckler farms.  Its key findings: 5-star cows calved younger, had fewer calving issues, produced more calves, had shorter calving intervals, and lived longer.

The analysis, summarised in table 1 below, compares the fertility and calving performance of 1-star and 5-star cows that calved for the first time in 2018. By only using animals that calved for the first time in 2018, the ICBF ensures that the cohort of animals in the analysis is consistent throughout the seven year period (2018-2024).

Table 1: Analysis of fertility and calving performance of 145,000 suckler females that calved for the first time in 2018. 

On the results, the ICBF explains: ‘The most notable result is that 5-star cows produced one extra calf over their lifetime. This extra calf adds revenue to the herd. For example, in a herd of 20 cows, 5-star cows would have produce an extra 21 calves over their lifetime. 5-star cows produced an average of 4.98 calves from 2018-2024 (20 x 4.98 = 99.6 calves). 1-star cows produced an average of 3.91 calves in the same period (20 x 3.91 = 78.2 calves). This increased output is due to calving at a younger age, having shorter calving intervals, and surviving longer.’

Key results for 5-star cows:

• Calved as a first-calver 2.7 months younger;
• Had 6.9% fewer difficult calvings as first-time calvers, and 4.2% over their lifetime;
• Produced 1.07 extra calves over their lifetime;
• Had a 36-day shorter average calving interval;
• 17% more were still alive on the farm in 2024.

For further benefits on using 5-star Replacement Index sires, please visit the ICBF website here.

Heavier carcasses and higher returns from 5-star sired animals

Another analysis undertaken by the ICBF has also highlighted the distinct advantages progeny from 5-star sires on the Terminal Index have over 1-star sires.

Based on suckler-bred steers finished in 2024 and encompassing more than 160,000 animals, the results of the analysis, available to view in table 1 below, show that animals sired by 5-star sires on the Terminal Index were 16 days younger at finish, produced 70kg heavier carcasses and graded 0.5 of a conformation score higher. All-in-all, this resulted in a €405 higher return at slaughter.

Table 1: 2024 Carcass Performance of suckler steers. Animals are ranked by sire across-breed Terminal Index rating

For further information on how the Terminal Index of the sire impacts the performance of progeny, please visit the ICBF’s website, where a breakdown of performance by breed type is available.