Housing Ventilation and Calf Health
Dr. Clell V. Bagley, DVM
USU Extension Veterinarian
When enclosed housing is used for raising calves, proper ventilation becomes a critical consideration for calf health. The �weakest link� in the physical makeup of a calf is the digestive tract, but only for the first three weeks of life. After this first three weeks, once the gut has matured, the respiratory tract becomes the weakest link for the remainder of the life of most cattle. The availability of good quality air becomes a major factor for cattle health and level of production.
Because of climatic factors and weather challenges, there are locations where enclosed housing is protective and very helpful for cattle. However, much of the housing built for cattle is really designed more for the comfort of their human care-takers than for the well-being of the cattle. We tend to worry about keeping calves warm. It IS important, right after birth, to get the calf dried off and out of severe cold and wind. But, after that, even baby calves can tolerate very cold weather if they can stay dry, are shielded from the wind and have adequate, clean bedding. I recently observed some calves (3-5 months old) that were outside on a cold, windy day. They had only a good fence for a windbreak and lots of straw for bedding. I was shivering in a good coat and they were stretched out on their sides or lay chewing their cud, completely oblivious to the cold.
Enclosed housing provides protection from cold, precipitation and wind but it also severely decreases ventilation and the quality of air available to the calf for breathing. Electric fans are sometimes installed to improve air flow, but almost always these seem to be undersized and often do not provide proper ventilation. A further concern with the use of fans is that when the electricity is interrupted for some reason the lack of ventilation may become more serious and even deadly. At one time I was consulting with a large swine operation and had cautioned them about their fans and maintenance. The system finally broke down on a cold night in February and resulted in the death of half of the 500 pigs in the nursery. The only ones to survive were those on the sides near the fan openings where some fresh air could blow in from outside.
Time after time I see housing where the owner is trying to be kind to the calves and practice good husbandry - but actually is predisposing the calves to illness, resulting in death or long term reduced growth and production. The major problem in these cases is lack of ventilation. Both swine and poultry are raised in very enclosed housing. But, those producers have learned that they must provide ventilation and have also learned how to do it.
Ventilation problems relate to increased humidity, numbers of bacteria and viruses present in the air, dust particles and gases (such as ammonia, hydrogen sulfide, carbon dioxide and methane). Some gases are very irritating to the respiratory tract while others (such as methane) are non-toxic but may displace air so there is no oxygen for respiration. Some calves are kept in elevated crates, without bedding, and this is a good system in some ways. But, these calves will be more susceptible to drafts than if they were on the floor, bedded in straw. Some barns tend to be much colder than it is outside. This may be an advantage in the heat of summer, but may make them unusable in the winter.
Before you build new housing for your calves, carefully review the options available and those best suited for the local climate. Don�t make them more enclosed than is really needed for reasonable protection. Plan for adequate ventilation and minimize the dependence on electric fans.
Some enclosed buildings are much more easily ventilated than others, but all will require astute observation and trial and error to develop a ventilation management system that works. Changes in the number of animals present, outside temperature, precipitation and wind will all require adjustments in the mechanics of ventilation. If you (or especially visitors to your farm) notice moist, odorous air in the calf housing, changes are needed. Evaluate the current situation and adapt to correct the ventilation problem. If the illness and death losses are elevated, correct the ventilation problems before you begin �chasing bugs� for the cause of the problem. Some barns or buildings may require remodeling or renovation to enable adequate ventilation. For others it may only require opening some doors or windows at the required times and closing them at other times.
Similar ventilation concerns apply to older calves and adult cattle kept in enclosed housing. Poor ventilation can certainly lead to decreased production and increased disease in cattle of any age. Prevent it from being a problem for your animals.