How does your herd fertility measure up

Date published: 4 August 2025

CAFRE, Senior Beef and Sheep Adviser, Rachel Megarrell states: “Fertility and getting live calves on the ground has always been fundamental in any suckler operation. A cow’s primary job on farm is to get in-calf and then rear that calf. Not only that, but fertility now plays a critical role in payments to cow enterprises and therefore should be at the forefront of farmers’ minds.” Therefore, it is important to:

1.          Have a clear concept of what herd fertility is.

2.          Understand how it should be measured.

3.          Understand how your own herd measures up.

Without having any data available it becomes impossible to manage. There are several metrics that can be used to measure fertility in suckler herds and sometimes there can be confusion due to the misunderstanding of terms. So, what do they mean?

Herd calving index is the average calving interval of all cows in a herd at any given time, expressed in days.

Calving interval is the number of days from calf to calf and ideally this should be 365 days. Remember though that you could cull your way out of a poor calving index. however, be mindful that this will result in a significantly higher replacement rate, therefore don’t rely on calving interval alone as a measure of fertility.

Replacement rate – think about your herd replacement rate.  Is it 15% or is it 30%?  If it is too high, what is the reason why?  Are there too many barren cows each year?  Remember to pay close attention during the mating period for repeats.

Reappearance rate is a measure that takes both calving interval and culling rate into account. If a cow has a calf in one year, she reappears in the herd register again when she calves again the following year. Ideally 75% of the herd should have reappeared by 390 days.

Calving spread – the period between the first and last calf being born. Ideally this should be less than 12 weeks.

A herd fertility report will provide you with information in relation to the metrics outlined above and will include an overall herd calving index for that year alongside an individual calving interval for each cow that calved in the herd.

The report itself is easy to follow and can help you to identify those animals that require further scrutiny. It is based on a simple traffic light system as follows.

Green – cows calved 390 days or less.

Amber – cows calved between 391 and 450 days.

Red – cows calved 451 days or more.

In any given herd there will be a range in calving intervals. However, you need to remember the targets that are associated with the Suckler Cow Scheme and work towards as many calving events qualifying for payment as possible. Remember to be eligible in year one of the scheme cows must calve within 415 days of their previous calving event. This target is reduced incrementally to 385 days in year four.

Putting the targets into context

If you choose to breed 50 cows this year how many would you expect to see in calf?

To scan 48/50 = 95%+ would be excellent, 45/50 = 90% which is very good and 43/50 would be 85% which is probably closer to the average performance on herds out there. Industry targets will tell us to aim to wean 90% of what you choose to breed, thus highlighting the need for excellent fertility from the start!

A good starting point is to understand the fertility of your own herd and how to improve it. Working with your CAFRE Adviser offers a range of benefits from tailored advice and guidance on new technologies to support this.

CAFRE Suckler Cow Fertility Themed Groups are still open for application. Participation in a Group can help increase the number of calving events achieving the annual Suckler Cow Scheme targets.

To make an application to the Suckler Cow Fertility Themed Groups, visit the CAFRE website or for more information contact your local CAFRE Adviser. Scheme applications close on Friday 15 August 2025.