What you need to know when building a new calf shed
Most calf sheds now require PPTV for adequate ventilation. File Picture.
Calves should not share airspace with older animals, due to the risk of disease spreading from the older cattle, and poor calf housing has an important role to play in disease outbreaks.
A stand-alone calf house is preferable to a lean-to or an extension of an existing shed, with the back of the calf house perpendicular to the prevailing wind.
For a building to ventilate well, it must efficiently exchange stale air from inside for fresh air from the outside.
Fresh air comes in through the sidewalls (inlet), with spaces divided evenly along both sidewalls of the long axis of the shed and moves outwards through roof openings (inlet area should be double the outlet area).
The sidewalls of calf sheds should be solid up to a height of 1.5m (that is, above calf level) to avoid draughts.
Yorkshire boarding is recommended above these side walls.
This provides an inlet for fresh air, while also protecting against wind and rain.Â
It comprises two rows of boards with gaps between them.
The size of young calves mean they produce inadequate warm air in the shed to create a current that will push the stale air towards the roof.
Thus relying on this type of air exchange in calf sheds, especially on calm days, can be problematic.
It is now recognised that most calf sheds require positive pressure tube ventilation (PPTV) to ventilate calf sheds adequately, as this is the most dependable way to provide fresh air without draughts.
These are tubes that run along the long axis of the shed and are attached to a fan, which actively blows fresh air along the tube, evenly distributing it through the shed (according to individual shed requirements).
To increase the shed temperature, ventilation should not be compromised by blocking air inlets or stopping PPTV fans.
Instead, bedding and feed allowance should be increased, and special breathable calf jackets that are washed between calves, may be used to help calves maintain body temperature.
Ventilation is also impacted by the pitch of the roof which should be between 15° and 22°.
Building design, pen size and drainage The size of a new shed will depend on the maximum number of calves it may need to hold.Â
The shed and its surfaces must be easy to clean (wooden surfaces not recommended).
The shed must include enough space for:
• Effective cleaning (important in year-round calving systems, as pens should be empty for at least 48 hours between calves).
• Adequate sized passages for machinery to clean pens.
• Feed and water troughs.
• Food storage and preparation areas.
• Separate isolation area for sick calves.
Drinkers and feed troughs should be positioned at the front of each pen for ease of observation and cleaning.
(See animalhealthireland.ie for more detail on space and trough requirements for feed and water and shed lighting requirements.)
Group size is often dictated by the feeding system to be used, and groups of not more than 12 calves are recommended, although automatic feeding systems generally require group sizes larger than this to make use of the feeder.
The legal space requirement for calves over 150kg is 1.5 square metres per calf.
Moveable solid partitions (1.2m high) dividing larger pens may offer more flexibility if future conversion to an automatic system is a possibility.
The floor should slope towards a drainage channel at the front of the pen, with a gradient of 1 in 20, and drainage channels need a gradient of 1 in 60.
A wide, flushable drain is preferable, and drains should flow to a collection tank outside the calf house.
Automatic feeders may be placed on a raised concrete plinth with a channel drain around the perimeter to collect waste from the feeder.
- Michelle McGrath, CalfCare Technical Working Group, Animal Health Ireland.Â
