WHEN cows are calving indoors and calves spend the first few weeks of their lives housed there can be problems. The common causes of pneumonia are virus's bacteria, while lungworm is to blame in older calves at pasture. The common viruses I isolate are RSV, PI3, IBR and usually I see secondary bacterial infections compounding the problem.
I would always assess the calves' immunity, look for the agent causing the problem and then carefully assess housing. More strategic control can be achieved by getting or ascertaining the cause of the pneumonia quickly by nasal swabbing .
I'd like to focus on the importance of housing in contributing to pneumonia problems in calves. Where I see herd issues with pneumonia it usually is where ventilation or housing is the main problem.
Obviously you will have infectious agents causing the problem, but we will see much more severe clinical signs and more rapid spread where there is poor housing.
Vaccination for viral pneumonia can play a huge part in controlling disease but will only work best if husbandry is correct as well. Vaccination alone works well if calf housing/nutrition is not contributing to the problem.
It doesn't have to mean building new sheds but maybe altering existing housing set up to reduce the exposure or stress that may be on calves.
Where you have poor ventilation and build up of ammonia and gases in your sheds, this can lead to big problems around respiratory disease.
Equally, there can be disastrous consequences if you have draughts and cold winds blowing in on calves.
Stress on stock should also be controlled and managed when debudding and castrating calves.
Where your shed is located in relation to prevailing winds can play a role in how well ventilated your shed is. So when considering any new constructions get advice and plan the building carefully.
Good ventilation, fresh air, calf comfort and avoiding draughts are the key factors to keep in mind.
Where existing sheds are poorly ventilated I have seen mechanical ventilation used to good effect, with fans etc. In naturally ventilated sheds adequate air change should be provided by wind force and stack effect.
It is so important that at calf level there is no draughts, they are warm but also there is plenty fresh air.
Some important figures when assessing housing:
• Height at eaves should be at least 4m;
• The inlet area should be twice the size of outlet area (top ridge) to allow fresh air to move through the shed;
• Outlet area should be 0.04 square metres per calf and up to 0.1 metre squared for cows. For example, 25 calves and 25 cows should have 3.6 metres squared of outlet space;
• Height between inlet and outlet should be greater than 1.5m;
• Avoid high stocking densities and ensure access to fresh clean water.