AgriSearch and the Agri-Food and Biosciences Institute (AFBI) have published a new calf housing design guide.

This is an outcome of the Optihouse project, which examined different aspects of calf house design on 66 farms across Northern Ireland.

The aspects of calf house design that were observed included hygiene of bedding and water, ventilation within calf houses, pen sizes and drainage.

The Optihouse project was carried out by AFBI and co-funded by AgriSearch and the Department of Agriculture, Environment and Rural Affairs (DAERA).

Calf housing

The project aimed to investigate the role of calf housing and environmental management in the delivery of high performance calf-rearing systems that protect animal health and welfare.

The quality of the environment that a calf encounters during the rearing period will have a significant impact on calf performance, health and welfare.

Good calf house design and management can improve herd productivity and ensure growth rate targets for calving at 24-months-of-age are achieved.

In addition, costs associated with poor performance can be reduced.

The booklet contains a number of general recommendations.


The principle requirements are to provide a clean, dry and well ventilated environment for calves, with a complete absence of draughts.

Ventilation is typically provided by the wind. The prevailing wind direction may occur for two-thirds of the year. But the wind comes from every point of the compass at some time during the year.

Fresh air delivery at pen level without a draught or increased air speed is a key target. A draught is an air speed above 0.2m/s.

The minimum area requirements for outlet in the roof and the inlets in the sidewalls are easy to calculate – a balanced design is most effective.

Many, or most, calf houses will benefit from positive pressure tube ventilation (PPTV) to ensure fresh air supply 24/7 basis.

Calf pen design

The calf house should have sufficient facilities for the maximum number of calves aged from birth to 14 days post-weaning expected at any time of the year, plus one empty pen.

Group size dictates optimum pen area at maximum body weight, and minimum pen width for feeding.

The number of pens should not include provision for older animals in the same airspace. This always increases the risk of disease spread.

Calves from birth until two-to three-weeks-old will be particularly cold during the winter months. Large volume buildings of concrete and steel are not supportive of good performance and health.

Modern calf systems are making greater use of plastics, insulation, and mineral fibre roof materials.

Hygiene and drainage

Hygiene is compromised by lack of time and space to clean individual pens effectively. So farmers should design pens to be easily cleaned.

Calf rearers should consider a calf kitchen area to make the preparation, delivery and cleaning of the feed system a safe and efficient routine process.

The dryness of a building relies on good drainage in the right locations, and effective ventilation.

Pen floors should have a minimum one in 60 slope for effective drainage after cleaning and an optimum of one in 20 slope for drainage under straw.

In addition, pens should slope towards a simple channel drain located immediately outside the pen front.