When planning to build new calf housing we often focus on important factors such as capital expenditure, available space, what will be easiest to get planning approval for and how close can we get it to other buildings for convenience.
However, to maximise ongoing calf health and performance (and minimise ongoing costs) there are other really important variables to consider.
Which way does the wind (normally) blow?
For most of our clients the wind direction is normally from the south west. When thinking about new cattle housing it can be very helpful to look at Met Office data regarding wind direction near to where you are. The picture on the right is an example of a wind rose easily obtainable from the internet.
In this case the wind often comes from the west as well as the south west. This knowledge could allow plans to orientate a new building with the long side across the prevailing wind direction to maximise the ventilation opportunity. It also shows that there are considerable amounts of time when strong winds come from the north east (probably in February) and so protection from this direction is needed (a mono pitch building with the open side pointed north east would probably not be appropriate in an exposed position).
Calves also need to be upwind of adult cow housing to minimise the potential for respiratory pathogen spread.
How tall does it need to be?
Sheds that are as low as possible (to eaves height) are the most conducive to calf health, as smaller air volumes in the shed can then be more easily ventilated.
The temptation is often to build the opposite – a really tall shed that tractors can get in. It might be more cost effective in the long run to build shorter sheds and direct the money saved on building materials into smaller machinery for bedding etc.
How big does the floor area need to be?
What is the maximum number of calves that you will need to house at any one time? Take this number and add a spare pen for contingency/isolation/cleaning etc. The amount of space you then assign to each calf will directly impact calf health and performance. Absolute minimum space per calf on milk is 1.5m2 but there will be significant benefits to providing 2.5-3m2 or more.
What does the floor need to be?
Concrete with a 1:20 slope down towards a drain, either outside the front or outside the back of the pens. Beware of chalk/rubble bases that will harbour crypto eggs despite cleaning.
What group sizes should I plan for?
We often see the best health outcomes in calves on milk in groups of at least four animals but less than 10. However this will depend on other risk factors. It will probably be uneconomical to have these sort of group sizes with automatic feeders so careful thought needs to be put into minimising other risk factors when using these systems.
How else can I minimise the spread of disease?
Solid barriers between groups to prevent nose-nose contact will help from the start and are also likely to make the environment more cleanable.
A well designed positive pressure ventilation system (fans and ducts) should be a prerequisite for new calf sheds.
If you are thinking about a new building to house your calves then please give us a call. We can help you through the design process including consideration of all the above factors and
a lot more.