Ken Nordlund and his colleagues at the University of Wisconsin School of Veterinary Medicine have developed the “ideal Wisconsin calf pen concept” based on their research, which shows that a poorly designed pen can create an unhealthy microenvironment inside a naturally ventilated calf barn. The Wisconsin calf pen concept outlines seven criteria for healthy pens.
- Provide 32 square feet per calf, with a 6-inch layer of bedding to cushion against physical injuries and to insulate the pen surface. Clean, dry bedding will help calves maintain a clean, dry hair coat that provides further insulation.
- Use solid panels that are 4-feet tall between calves. Solid pen walls reduce nose-to-nose contact that can spread disease and minimize drafts on calves.
- Extend side walls 12 inches past the front of the pen to further reduce contact between calves.
- Construct open front and rear panels to promote ventilation and good air quality in the pen. If pens are placed back-to-back, leave at least one foot between them to reduce contact between calves.
- Limit the solid part of the back wall to a maximum height of 18 inches to help keep bedding in place without limiting ventilation.
- Provide two holes in the front panel for feed and water access. Forcing calves to use separate openings reduces the amount of milk and water dribbled into grain and grain dribbled into water, wasting less grain and improving intake of both grain and water. Place bucket rails so feed is 12 to 16 inches above the pen floor; this helps calves find feed and water quickly.
- Keep drafts down with bedding, not hovers, during cold weather. Hovers placed on the back third of a pen eliminate ventilation and increase counts of airborne bacteria in the pen. Provide deep-straw bedding and use calf blankets instead.