Improving Air Movement For the Summer Months

We often think of ventilation as a key issue in the summer. But according to Brian Holmes, University of Wisconsin-Madison Biological Systems Engineering professor, ventilation is a key concern for calves year-round.

Holmes said that’s because we must first understand that ventilation is defined as air exchange; fresh air from outside replaces contaminated air inside. This is essential to preventing respiratory problems in calves.

The next step is providing air movement to keep calves cool and reduce heat stress during the summer months. Holmes provided the following tips when looking at ventilation and air movement in your calf facilities.

Calf barns
Holmes said you can choose from two different types of ventilation systems in your barns:  natural and mechanical. In a natural system, you take advantage of the wind by building barns perpendicular to prevailing winds. Ten-foot side wall openings are preferred and you should make sure no other buildings or features are acting as wind blocks. Holmes prefers naturally ventilated buildings simply because they require little management.

However, your farm layout or existing facilities may not allow you to rely on natural ventilation alone. That’s when you install fans for mechanical ventilation supplementation. A new positive pressure tube system has proven effective at improving the air quality in individual pens where natural ventilation is not completely effective in maintaining calf health.

Where natural ventilation has no hope of working, the most common form of mechanical ventilation is a negative pressure system in which fans blow air out from the building and inlets bring in fresh air from the outside. Holmes said it’s fairly common to overlook the inlets. He said producers should make sure inlets have a large enough capacity to handle adequate air flow in the summer months.

Individual pens in calf barns
When using individual pens in your calf barn, Holmes said it’s important to leave both ends of the pens open and use solid partitions between calves to encourage air movement along the pen but avoid facial contact between animals. Therefore, the airflow should run parallel to the pens so that air is moving through the open ends. Paired with evaporative cooling systems, Holmes said we’re starting to see these cross ventilation systems move into the Midwest for cow freestall barns. They can also be adapted for calf barns.

Calf hutches
Because of their design, Holmes said calf hutches are great for controlling heat stress in calves because the animals have a choice of whether they want to be inside or outside. He said some new hutch designs even equip hutches with their own ventilation systems. You may also consider raising the hutches a few inches off the ground with blocks to allow for airflow under the hutch.

Cost-saving strategies
Installing ventilation systems in your calf facilities can quickly become an expensive project. Homes said it’s important to cover a few of the basics before making that investment.

• Watch out for translucent hutches or greenhouse barns. These facilities trap the sun’s heat inside similar to the way your car collects heat when left outside on a hot summer day. Use shade cloths to reduce the solar gain in these hutches and barns.
• Look at your bedding. Long dry straw is a great insulator and traps too much heat in the summertime. Consider using sand, sawdust or chopped straw instead.
• Think about the whole system. Adding one big circulating fan doesn’t count as ventilation. Rather, think about the entire air exchange process as well as the air velocity moving past the animals. What are your goals for ventilation?  What are the opportunities or limitations of your current facilities?  Make sure you have answers to these questions when planning your ventilation.

Once you have a firm grasp of all of these items, it’s time to look at the ventilation tools you can use. Holmes recommends you talk with capable ventilation experts about your needs. You may locate local experts by contacting a university extension agent or Vita Plus representative to learn more about specific ventilation strategies on your operation.