How rumen boluses can help manage suckler cow fertility

A Welsh beef farm has lifted the rate of conception at first service in its heifers by 10% since using bolus technology to aid heat detection.

Rumen boluses are more usually associated with heat detection in dairy herds, but Farming Connect demonstration farmers Llion and Siân Jones are monitoring their performance and relevance in a beef herd.

The pair, who farm at Moelogan Fawr, near Llanrwst, Conwy, had previously synchronised maiden heifers for artificial insemination (AI) using controlled internal drug release (CIDR) protocols. In 2019, this worked out at £29.51 a heifer in vet costs.

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They were keen to use a more natural approach to service, but wanted one that wouldn’t rely on lengthy observation periods.

Trialling the boluses

Boluses that detect changes in activity and inner body temperature associated with oestrus were administered orally into the rumens of 39 yearling Stabiliser heifers ahead of the 2020 breeding period.

The device collects data on the animal’s temperature and movement and transmits it to a base station. From there it is uploaded to a cloud system for the farmer to access.

The boluses were administered on 14 April and began capturing valuable data on the heifers’ cycles ahead of visual monitoring from 1 June.

“This was the most important thing for us, to be able to pick up on their cycle before we started observing them.

“It is the reason why we were able to AI so many in their first cycle,’’ says Mrs Jones.

“Because genetics and estimated breeding values [EBVs] are such an important part of what we do, it also meant that we could turn the heifers that weren’t cycling in with the bull straight away so that we would only breed replacements from our most fertile animals.’’

Peak activity data captured by the bolus was used to identify each heifer’s insemination window to allow Mr Jones to AI at the most appropriate time in her cycle.

Results

At pregnancy scanning in October, 95% were confirmed as being in-calf; of these, 68% conceived at the first AI service, compared with 58% in 2019.

A further 5% conceived after the second and 21% following service with a sweeper bull.

Vet Iwan Parry, who is providing veterinary input into the project, describes this as a positive result.

It is often difficult to detect heat visually in young heifers and this can lead to an extended calving pattern and additional veterinary costs for fertility and health treatments, he explains.

“Heifer fertility and the length of calving period are vitally important to herd profitability and, in that respect, use of the bolus has been a success,’’ says Mr Parry, of Milfeddygon Dolgellau Cyf, Dolgellau.

Overall, 80% of the heifers calved in the first six weeks of the calving period.

Across the herd, the calving period reduced from 11 weeks to nine in 2021.

Costs and benefits

Vet costs associated with the breeding period fell to £6.64 a heifer in 2020, a saving of about £23 an animal on the previous year.

This saving must, however, be balanced against the upfront cost of the boluses: as well as a set-up price of £4,000 for the base station, solar unit, installation and support, the boluses cost £30 each and there is an associated annual maintenance fee of £3 a cow.

The Joneses admit they didn’t make any labour savings in this first year of using the bolus.

Siân and Llion Jones © Debbie James

This was because, as the technology was new to them and they weren’t completely confident of its reliability, they used visual observation, too.

“Observing the heifers was a big part of the monitoring because we didn’t know if we could trust the technology,’’ says Mr Jones.

Reliability

Comparison of bolus data and the observation records showed that they matched up 79% of the time.

While the bolus failed to detect 11% of heats, visual observation alone would have missed 8%.

The bolus also has the capability of monitoring calving and health events and is the reason why they chose this system over collars.

Alerts were sent to their mobile phones eight to 36 hours before a heifer was due to calf.

The results showed a 58% reliability of heifers calving within that 36-hour period, while the remainder calved outside that window.

In 4% of cases, the bolus didn’t pick up on imminent calvings.

Verdict

Mr Parry says the project at Moelogan Fawr was a new opportunity to show that heat detection technology can work effectively in suckler herds, but adds: “It is up to the economists to decide if it is cost-effective or not.’’

The Joneses calculate that the technology could pay for itself within three years from a reduced empty rate and improvements to the herd’s EBVs and genetics as a result of an increase in the percentage of the heifers that stand to AI.

One of the challenges of the bolus technology is that it has been designed for dairy herds, and animals need to be near the base station twice a day for data to be gathered.

In a dairy situation, this would be next to the milking parlour; with suckler cows, it needs to be in the field.

To overcome this, they used a solar energy unit to power a mobile base station mounted on a trailer in paddocks close to the handling area where they AI their cattle.

“This was the biggest issue – we had to put a mineral bucket next to the trailer to acquire the data,’’ says Mr Jones.

Their base station has a 30m range, but for newer models, it is more than 100m.