Farm Horizons, April 2014
Calf barn ventilation: How’s your system doing?
By Starrla Cray
Farmers have a lot to consider when it comes to calf barn ventilation.
“There is no single ideal design. There are trade-offs,” said Kevin Janni, professor and extension engineer at the University of Minnesota.
Janni encourages producers to ask these questions: How many animals are inside? How old are they? What is the outdoor temperature?
“In order to be effective, each part of a ventilating system needs to be sized correctly, work properly, and adjust as temperature and conditions change,” Janni noted at the Carver County Dairy Expo in Norwood Young America Feb. 17.
Preventing respiratory diseases
Ventilation is vital for calf health. According to an article in Bovine Veterinarian, improper airflow can lead to pneumonia and respiratory diseases, especially in cold weather.
The barn shouldn’t be drafty, and air should be uniformly circulated to remove ammonia and airborne pathogens.
“If you’ve got a leaky barn, it’s going to be hard to ventilate it well,” Janni said.
Solid pen walls can reduce draft, but they also can create pockets of poorly ventilated areas.
One way to minimize calves’ heat loss in cold barns is through clean, dry bedding.
“Bedding is important,” Janni said. He noted that in cold weather, calves’ urine and spilled water isn’t able to evaporate well, so there needs to be enough bedding to absorb it.
According to Janni, the minimum ventilating rate in the winter for one calf age 3 to 13 months is 20 cubic feet per minute. In the summer, the rate per calf should be 130 cubic feet per minute.
Trying a tube system
For farmers considering a new ventilation system, Janni advised choosing an experienced company for the design work.
Tube systems, which have been around for decades, are gaining renewed popularity. When using tubes to distribute fresh outdoor air, design considerations include tube diameter, length, mounting height, number of holes and rows of holes, hole size, and spacing.
“Multiple tubes, each with their own inlet fan, can be installed to provide the minimum airflow rate needed in barns with many calves and older calves,” Janni noted.
Utilizing exhaust fans
Tube systems must use a continuously running exhaust fan to maintain neutral pressure conditions.
Despite extra cost, the use of multiple fans is encouraged, because ideal ventilation rates change depending on temperature.
A 40-foot-by-70-foot barn with 65 calves, for example, could have a ventilating rate of 1,170 cubic feet per minute in cold weather. The same barn in hot weather could have a ventilating rate of 7,670 cubic feet per minute.
The age of the calves is also taken into consideration. In the previous example, 26 of the calves were between 0 and 2 months of age, while 39 of them were ages 3 to 13 months. Four exhaust fans were used, to match all four seasons.
For more information about calf ventilation systems, contact Janni at firstname.lastname@example.org.