Fertility and the true cost of calving difficulty – an opportunity for native breeds

Sarah Dusgate and Rob Havard of Phepson Angus point to a way of ensuring that native breeds are relevant in the 21st century

Do you know the average calving interval for your herd? What age do you calve your heifers at? 

Did you know that fertility is key metric for profit in suckler herds, not growth or muscling?

We should target for an age at first calving of 24 months old and a calving interval of 365 days. Calving older heifers increases heifer rearing costs to unprofitable levels and reduces the number of productive cows you can run each year. Calving at 24 months old will also increase the number of calves per cow across her lifetime on your farm. A tighter calving pattern means lower labour costs and a more consistently aged calf cohort.

2019 BCMS data for beef cattle in Wales has revealed an average calving interval of 426.1 days and average age at first calving of almost 34 months old. Both figures have increased on 2018 data. So, what is causing poor fertility in herds and why is this figure getting worse?

The successful birth of a huge calf, often requiring assistance of ropes or a jack may leave you with pound signs in your eyes at the sight of a 50+kg live calf, but what is the true cost of this. Can we really call it a ‘successful’ birth if without farmer assistance the calf would have probably died? Is it successful if the calf has to be tubed with colostrum and milk because it can’t stand quickly because of a traumatic birth? Is it successful if the dam requires anti-inflammatories or steroid injections to correct her after a difficult calving?

In nature these calves simply wouldn’t survive.

The following table with data from AHDB shows the impact of assisting cows to calve in subsequent breeding season:


Calving History

Subsequent breeding season success rate

No assistance


Assisted by stockperson


Assisted by vet





Assistance by farmer has a huge negative impact on the ability of that cow to get back in calf. Every day that cow goes over the 365 day calving interval target is a loss of profit to your business.

If we take the 2019 calving interval average from Wales of 426 days, which is 61 days over the target range, we can estimate the loss of production as 365/61=5.98.

That means a herd hitting the target of 365 day average calving interval will get an extra calf per cow every 6 years on the farm vs the average herd in Wales.

Cows consistently hitting that tight calving interval will reduce your calving period. Calves will be more uniform across their weights and labour is reduced at this busiest period in the farming calendar, ultimately reducing production costs. Calving seasons of 3 months and more mean your youngest calves will be 90 days behind your oldest, often over 100kgs behind already.  Aiming for increased growth rate will likely reduce the maternal traits and extend your calving period and as we can see, the benefits of rearing slightly heavier calves are often outweighed by the time it takes to get them there when your calving block is so much longer.

When does a beef heifer become profitable? Rearing heifers can be costly to the farm business. Age at first calving and cow longevity can have a big impact on the number of replacements you need to raise. Reducing calving difficulties and eliminating the need for assistance will increase cow longevity in the herd.

A case study at Kemerton Red Poll Herd:

Below is a picture of one of our pedigree Red Poll cows, Kemerton Ulricha. She is 16 years old and she has her newborn Red Poll heifer calf at foot – this is her 14th calf.   

All of her calvings have been unassisted and her calving interval is 366.4 days.

 She calved inside before being turned out on Bredon Hill when her calf was 48 hours old. Ulricha has a very tidy udder, especially for such an old cow, excellent length from hook to pin and good feet and leg structure. She is a profitable cow.

She was in good condition at calving. You can see from the photo below that she is coping really well in her 14th lactation and has continued to put on condition now turned out. She had one of the smallest heifer calves born this year, with a birth weight of just 30kg and she calved just over 60% of the way through our calving period.

In previous years she has had Red Poll calves with birth weights in the high 30kg/low 40kgs, and she has had Charolais cross calves with birth weights of low to mid 40kgs. 

 She has consistently been one of the first 25% of cows to calve in the herd up until this year, so maybe the low birth weight and slightly later calving in the herd is a sign that Ulricha might be starting to ease off. But for now, she sure seems to enjoy her job! 

 Considering all of this, it seems to me that this gives our native cattle breeds a real opportunity. They are never going to compete with continental breeds on the EUROP grid but they can run rings around them as profitable suckler cows if they are managed to their strengths. Too often you see breeders of native cattle taking the breed away from the natural advantages they have to chase a game they will never win. A ruthless selection on productive longevity would go a long way to ensuring our native breeds are still relevant far into the 21st Century. Forget about the weigh scales and focus on FERTILITY!