Advice for designing new calf sheds and improving existing buildings was offered by Ray Foy from Teemore Engineering at a calf rearing event last week.

Getting moisture out of calf sheds was highlighted as a key priority, with Foy pointing that it will lead to a healthier environment for calves and will also reduce bedding costs.

“A slope of one in 20 will drain bedded floors. When you see it, it seems like quite a lot, but we have found it is needed to allow urine to drain out,” he said at the event in Coleraine.

After that, channels are needed at the front of calf pens to collect and remove urine and soiled water from the shed.

“Small channels will get rid of urine faster, but they block more easily. The width of channels depends on labour and how often someone will be in the shed to spot a blockage,” Foy said.

Another consideration is how to make the best use of natural ventilation to help lower humidity levels and push stale air out of sheds.

The problem in calf sheds is that calves are too small to create a “stack effect” where heat generated by livestock causes the air rise and move out of shed outlets.

Foy said two rows of staggered boards along the back and gable walls, known as Yorkshire boarding, is the best option for creating natural ventilation in calf sheds.

He said it allows fresh air to flow into sheds slowly, so it should prevent draughts developing. Air then flows out through an open ridge on the shed roof in a chimney effect.

However, Foy said mechanical ventilation should also be considered as “an insurance policy” for calm days when there is no natural air flow.

A positive pressure tube is a popular choice for calf houses as it allows a uniform flow of air into the building but does not lead to cold air blowing on top of calves.

“We want calves evenly distributed in the pen when they are laying down. It means there are no hot spots or cold spots,” Foy said.

He explained that calves feel cold when the temperature goes below 14 degrees Celsius and this can negatively affect their immune system and liveweight gain.

Putting jackets on calves and placing heat lamps in pens are two common ways to prevent cold stress in calves.

Maintaining adequate levels of bedding is also crucial for minimising cold stress, as well as maintaining hygiene in calf pens.

Hygiene was highlighted as a key factor in calf rearing, with Foy recommending that sheds are laid out to allow both feeding equipment and pens to be cleaned and disinfected easily.

He said sheds should ideally be designed so that pens can be cleaned and washed out individually, rather than having to wait until the entire row of pens is due for cleaning.