Pneumonia was calling last weekend- How to prevent mid housing season

On-call is unfortunately part and parcel of mixed practice this example of the collaboration of practices can help to recruit and retain vets going forward.

One of my ambitions as the president of Veterinary Ireland is to support a new working group, investigating how working conditions can improve in Ireland, including learning from other vets from around the world.

A weekend on call

My phone was pretty quiet on Sunday until of course I sat down with my first cup of coffee, the call was to a weanling with severe pneumonia. The weanling was part of a group of amount 20 weanlings that were housed in the last 10 days and my colleague had been out to treat another weanling the day before.

On examination the weanling exhibited visible respiratory distress, “a draw” as I like to call it upon auscultation, she had a temperature of over 40 degrees Celsius and was generally very lethargic.

The second call of the day came in about two hours later. While I enjoyed a nice cup of coffee, a running theme of weanlings with pneumonia was emerging. This time it was three animals out of a group of 25 weanlings that were housed three weeks ago. 

They made their way up the crush slow and steady, each animal reading a higher temperature than the previous and they all had a clear nasal discharge. The odd cough was also elicited from the weanlings during the exam; they were very lethargic and sedate a little different to their normal demeanour. The harsh lung sounds were very clearly evident when I applied my stethoscope and the respiratory rate was increased from a normal average of 30 to over 50 breaths per minute.

In both cases, the animals were treated with non-steroidal anti-inflammatories and antibiotics and a worming history was taken in which all animals had already been dosed. Both farms had implemented a pre-housing dose approach with a persistent Macrocyclic lactone (ML) pour, which can be given four weeks before housing to ensure lungs are clear of lungworm.

Link with lungworm

Lungworm infection predisposes the lungs to viral and bacterial infection due to the damage it can cause to the lung tissue and local immune defences.

If farmers have not dosed weanlings for lungworm at housing, discuss with your vet the best option for your farm that now may include fluke cover as the year goes on, especially as the recently released department’s fluke forecast anticipates higher levels of infection this year across the country.

At home, we used to always get cases of pneumonia in our weanlings every year, so vaccination has changed this completely for us. My dad was sceptical about vaccinating before housing always suggesting ways to improve the shed’s ventilation and yes, while this helps the overall situation, our shed unfortunately is not built for the purpose of storing weanlings. 

The combination of improving airflow in the shed, reducing stressors and the introduction of a dead RSV, P13 and Mannheimia haemolytic (formally Pasteurella) vaccine has reduced our caseload to zero in the last couple of years. I had previously taken Nasal-Pharyngeal swaps to diagnose the cause of pneumonia, and RSV returned on 4/6 swaps so I was confident I was choosing the most appropriate vaccine.

This particular two-dose dead vaccine needs to be administered, if possible, six weeks before housing to get the maximum benefit. It is probably not the best choice for most farms at this stage in the year however it is a protocol to discuss with your vet for next year. 

At this time of year, a live RSV/PI3 intra-nasal could be a good alternative to reduce the incidence of pneumonia this year, however, it is important not to vaccinate already sick animals and to administer as directed on the datasheet. It can take up to a week for a full immune response to launch using these live IN vaccines with an immunity duration, of approximately three months with a single dose. IBR vaccination should also be considered including the booster dose that follows on from a summer dose of IBR live.

When it comes to the environment in the shed, space for feeding, water intake and lying down is essential. For weanlings, a stocking rate is dependent on the weight of the animal, for example, a 280kg weanling on slats will require from 2-2.5m2 of space and slightly more when on straw beds. Stocking rate recommendations are all listed on the Teagasc website which is a great resource to use when housing animals.

Feed space is essential to reduce stress levels, 30-40cm per animal for forage-only feeding that increases to 50-60cm per animal when feeding ration. Water access should not be overlooked, with one small drinker per 10 animals optimal - just make sure they are cleaned regularly.

When it comes to sheds, the trusty measuring tape is your friend, don’t estimate. Then you can work out, if there is sufficient outlet space for the stale air to escape (approx 0.1m2 per animal) and ensure the inlet space is double the outlet (approx 0.2m2).

If the inlet is insufficient, perhaps sheeting can be removed or pushed out from the wall using wooden stands to create more inlet space. The outlet can include an opening in the roof as weanlings should elicit a stack effect due to heat produced from rumination that pushes the stale air up and out. 

A raised ridge can help to prevent rainfall from entering the shed and also to create a positive pressure effect that will suck the air out of the shed more effectively. Fresh air is, in fact, the cheapest form of disinfectant available to us, it can help to deactivate viruses and reduce the burden in the shed.

Pneumonia is a complex disease issue, there are a lot of factors that influence its prevalence on the farm. Talk to your vet today about both vaccine protocols and environmental improvements that can be implemented on your farm.