Vaccination has been part of a holistic approach which has seen pneumonia rates plummet at Rerrick Park Farm, Dumfries.
Around 10 years ago, the McDowall family invested in a high welfare, greenfield site dairy to allow them to expand to the current 1,200-cow herd.
However, it took Katrina McDowall several years to convince father, Fergus to improve the youngstock rearing facilities.
Miss McDowall says: “For the number we have, we needed a dedicated shed. You need enough space to rest pens and not mix ages.
And also a dedicated shed for the right airflow for calves.” In the old set-up, calves were housed in the ‘spare old shed’.
Calves were in the same air space as dry cows, which increased infection risk, while the sheer number of animals coming through did not allow pens to be rested.
As a result, the farm was treating about 15% of calves for pneumonia. “Any type of pneumonia is bad enough. It’s a check and it effects my weight gains.
When you’re trying to achieve 800g a day, you can’t afford any check,” says Miss McDowall.
“We had repeat cases of pneumonia in heifers when they calved and in later lactation.
We could often track that back to them having pneumonia as a calf.” As soon as calves moved into the purpose-built shed, pneumonia treatment rates dropped to 8%.
This was also thanks to greater ‘attention to detail’, including increasing CMR rates from 660g per calf per day to 900g. In winter, calf coats were also put on calves at birth.
However, the main thing was the ability to steam clean and disinfect pens between calves, thanks to increased space.
The team continued to feed four litres of quality, fresh colostrum within an hour of birth.
In a drive to further reduce pneumonia levels, vet Jimmy More, of The Galloway Vet Group, advised vaccinating calves against pneumonia.
As calves were going down with the disease at around two weeks old, using Bovilis INtranasal RSP Live was deemed the best option as this can be administered from one-weekof-age.
Following vaccination, pneumonia treatment rates dropped even further to 2%.
Average calf growth rates have subsequently increased from 700g a day to 800g a day.
Miss McDowall adds: “In general, the dairy industry is trying to reduce antibiotic use.
If I can get a fit, healthy animal that means less drug use – that’s my aim.
And it means my calf rearer and I can spend our time rearing calves. It’s the worst part of the job looking after sick animals.”
Creating a healthy, stressfree environment is essential to stop M. haemolytica bacteria from multiplying and causing long-term lung damage. M. haemolytica is a normal bacteria which lives in the respiratory tract in low numbers.
However, if the respiratory tract is compromised, for example from a dusty environment or stress, this bacteria can multiply and create toxins which go into the lungs and body, causing illness and death. APHA reported a peak in M. haemolytica cases in March 2020.
This could have been caused by a sudden fluctuation in temperature as the weather changed from cold to hot – leading to calf stress.
As spring calvers are likely to have more stock on the ground at this time, stress from high stocking rates could also have been an influencer.
To prevent issues, Dr Baxter-Smith advises vaccinating youngstock at winter housing and ensuring young calves are vaccinated as early as possible after birth.
Good hygiene, plenty of colostrum and keeping calves in smaller groups is also helpful.
"You need enough space to rest pens and not mix ages. And also a dedicated shed for the right airflow for calves."
Those coughing, sick calves you treat for pneumonia are just the tip of the iceberg, according to a calf lung ultrasound trial which identified much higher levels of subclinical disease below the surface.
As part of the trial, the lungs of 400, fourto six-week-old calves on six Scottish farms were scanned.
Lung consolidation on the ultrasound was used to detect damage.
Vet Jimmy More, of The Galloway Vet Group, says the results indicated a lot of subclinical disease.
“We found 2% was the treatment level for pneumonia, but, including those treated, we were seeing 15-17% with lung consolidation.
So those treated animals were the tip of the iceberg,” he explains.
Following the initial scan, the farms introduced a number of management changes.
As a result, when a similar age group of calves were ultrasound scanned six months later, there was an average reduction in lung consolidation of 4%.
The management changes implemented included:
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