Devon farm drives down pneumonia

Devon farm drives down pneumonia

When weigh data highlighted calves with pneumonia had weight gains below average and were affecting others in the group, the decision to vaccinate was an easy one for farmer Mark Glanvill.

Since he began vaccinating last December, no antibiotics have been used for respiratory disease on pre-weaned calves and average growth rates pre-weaning have risen to around 1kg/day. Calf manager, Jonathan Miles now routinely uses a weigh tape to track growth rates on batches of animals.

A recent Mole Valley Farmers’ survey of 540 farmers found pneumonia was one of the biggest health challenges faced by youngstock rearers and the main cause of antibiotic use. Vet Johanna Marsden of Molecare Farm Vets says designing a specific herd vaccination plan with a vet is one way farmers can boost calf health - something 79% of respondents wanted to do.

It was Johanna that suggested monitoring calf growth rates as a means of identifying the impact of pneumonia at Rydon Farm. With Mark aiming to rear plenty of quality heifers to cope with ongoing TB challenges and 24 months age at first calving in his sights, he was keen to get involved.

“We’re always keen to push on and it’s good to know where your strengths and weaknesses are. Plus pneumonia has always been a bit of a battle,” he says.
Pneumonia issues were historically linked to suboptimal calf sheds, which were solid brick, poorly ventilated and hard to clean. As a result, last year the Glanvill’s decided to build a purpose-built building for milk-fed calves (see graph).

Mark viewed the investment as vital, particularly considering he’d already recognised cows that had suffered from pneumonia as a calf did not perform as well in the herd. As the 290-cow dairy herd at Rydon Farm averages 11,500 litres per cow per year, milked through four robots, performance is paramount.

 

The trial

A batch of 19 calves aged one day to 10 weeks old were assessed with a weigh tape in September and October last year. The first weights were compared to average birth weights of 40kg. The results showed excellent average daily liveweight gains (DLWG) of 0.86kg/day. This is supported by milk feeding rates of up to six litres a day, mixed at
150g/litre and an 18% pellet fed ad-lib.

However, four calves that had been treated for pneumonia were below average and were averaging around 0.7kg/day. Although this is a good rate of growth, it’s below the farm’s target and underlines the negative impact of disease on growth.

On the second recording, the four calves that had been treated for pneumonia were in the same pen and two of the other calves in that group also had DLWGs below the farm’s average. Johanna says this shows the hidden impact of subclinical disease.

“It’s as much about subclinical pneumonia as clinical,” she comments. “It can delay bulling weight by 30 days, which can delay the onset of first calving and often affects first lactation yields,” she explains.

Vaccination

Calf blood protein levels were good indicating adequate colostrum management. Blood tests from a sample of calves also showed exposure to Bovine Respiratory Syncytial Virus (BRSV), whilst most of the disease was happening around weaning. Consequently, Johanna advised giving an intranasal vaccine pre-weaning to deliver three months of protection.

This, combined with moving milk-fed calves into a new shed in October 2020 means no antibiotics have been used for pneumonia pre-weaning. The open sides and open ridge on the new shed, coupled with lower stocking rates have played a key role in reducing pneumonia risk.
Any pneumonia is now occurring in older calves, which correspond to animals moving back into the old brick buildings post-weaning. Consequently, the vaccination strategy has changed, so calves are vaccinated at 60 days old with a vaccine that provides six months of cover.

Johanna says the farm was already performing exceptionally well. However, an all-encompassing approach has helped raise performance further. “It’s a combination of the shed working well and vaccination that’s helped protect them. A vaccine is never the fix all, it’s something to add into a calf management programme,” she adds.

For more information, please speak to an in-store
Registered Animal Medicines Advisor (RAMA) or contact your farm vets.

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