Respiratory diseases are most common in calves during the post-wean period and they can have long-term effects.
Why it matters: Respiratory diseases are extremely common on dairy farms, although they are simple to prevent. They can have lasting effects on cattle up to their first lactation.
Dr. Dave Renaud presented ways to prevent respiratory diseases at the recent 2019 Smart Calf Rearing Conference.
Aside from the immediate issues these diseases cause, there are long term effects as well.
“We can have reduced growth in the pre-wean period or post-wean period, we can have substantial reduction in the first lactation milk production — almost a 550 kilogram reduction,” says Renaud.
As well, newer studies are showing respiratory diseases can reduce reproductive performance in the animals.
When looking to identify animals with respiratory disease Renaud likes to venture from the Wisconsin scoring chart and use a simple yes or no scoring chart asking the following questions.
- Does the affected animal have eye discharge?
- Does the affected animal have nasal discharge?
- Does the affected animal have droopy ears?
- Is the affected animal coughing?
- Does the affected animal have difficulty breathing?
- Does the affected animal have a high temperature?
These questions cover the important aspects of disease identification – nasal discharge and droopy ears – while removing subjectivity from the scoring.
“That’s important because if you have multiple people that are looking for calves with disease, it’s just a yes or no answer.”
Preventing respiratory disease is centered around the calf housing environment — bedding, stocking density and ventilation.
Calves can be affected “especially moving into the winter time or having (cool, wet mornings) where calves are outside of their thermoneutral zone of 15 to 25 degrees Celsius.”
It’s critical these calves have good bedding for nesting and avoiding drafts.
When reviewing the nesting scores, it’s ideal the legs of the calves are covered with straw — a nesting score of three.
When looking at stocking density, it’s important to ensure your barn is set up for the number of animals which it is housing.
“It can lead to some substantial challenges. It’s important when doing new builds to ask ‘how many calves am I going to have in here in the future, maybe in 10, or 15 years — to make sure that you can fit it to the right capacity?’”
Next is ventilation
The purpose of ventilation is to deliver air into the facility with no drafts.
It’s advised producers have fresh air entering the facility frequently – about four air changes happening every hour.
“One way which can work really well is using positive pressure tube systems, which can deliver the air really gently, so you’re not drafting the calf — especially in the winter months.”
Vaccinations can be quite complicated.
The calf is given some protection from respiratory disease within the first three weeks of life from maternal antibodies found within colostrum.
“The challenge with that is that they decline over time, but the calf’s immune system isn’t really ready to take on the full effect or the full load of dealing with fighting off disease,” said Renaud.
This creates a window of opportunity for infection and where intranasal vaccines come into play.
These vaccines are injected within the nostril providing immediate protection. As well, they are not subjective to the presence of internal antibodies, working well with a shorter duration of nine weeks.
A study completed by the University of Guelph found a 36 per cent drop in lung consolidation when using intranasal vaccines.
Unfortunately, injectable vaccines are not useful in calves within the early stages of life with the presence of high levels of maternal antibodies.
“If we inject a vaccine into a calf, the antigens which are produced will bind and neutralize the effectiveness of that vaccine, preventing an effective immune response.”
Renaud also advises use of anti-inflammatory drugs to help with the pain that pneumonia or respiratory diseases can cause.
“Research shows that it’s reduced the level of the rectal temperature that’s happening and also reduces the level of lung consolidation.”
Pneumonia is a common disease. Prevention is key with proper housing environments and early identification is critical to reduce the long term impacts. With providing the proper therapy with antibodies and anti-inflammatories, farmers can reduce the instances of respiratory diseases on their farms.