Ventilation

Good air quality leads to healthy animals and a productive animal facility. The goal of ventilation is to provide adequate fresh air that is free from dust and drafts. The air should be reasonably free from pollutants such as ammonia, carbon dioxide and air–borne pathogens.

Moisture accumulates and humidity rises when animals are confined without adequate ventilation, so proper air distribution is essential. In totally enclosed buildings, the preferred relative humidity range is 55 – 75 per cent. In ventilated buildings, a baffled slot along the wall opposite the fan, a baffled inlet in the ceiling over the alley, or a tube intake system will keep cold air off the calves and keep the barn relatively draft free. It is very important to ensure that naturally ventilated barns are exposed to summer winds, have adjustable sidewall openings and a ridge opening at the top to ventilate.

In the summer, cross ventilation through windows can be sufficient. If natural cross ventilation is not possible, then a total air exchange every two minutes through a mechanized system of fans is recommended.

For proper winter ventilation, mix cold intake air with heated air before moving the air into calf–rearing areas. Air inlets should be properly positioned and air supply matched to fan capacity. Thermostats should be used for automatic control of exhaust fans.

Correctly determining ventilation system characteristics will result in a properly controlled environment. This includes speed of air passing through the fans and pressure differences inside and outside the building. Airflow visualization is a useful tool to evaluate a ventilation system’s air distribution. The services of an agricultural engineer could be used to determine the efficiency of your ventilation system.

Ventilation rates for veal calves
Source: OMAFRA fact sheet 2006

Calf weight kg (lb.) Minimum cfm*/calf Maximum cfm*/calf
45 (100) 10 40
70 (155) 15 60
120 (265) 26 105
170 (375) 38 150
250 (550) 55 220
300 (660) 66 265
*cfm = cubic feet per minute

Minimum and maximum rates apply to winter and summer conditions, respectively. In controlled environments, temperatures may vary between 10°C–20°C (50°F–68°F), depending on the age and weight of the calves. Aim to change the room air between 4 times per hour and 0.5-1 time per minute. 55-75 percent is ideal.

Natural Ventilation

It is very important to make sure that naturally ventilated barns are exposed to summer winds, have adjustable sidewall openings and a ridge opening at the top to ventilate.

As calves grow, their space requirements increase from 2.2 m2 to 3.5 m2 (24 ft2-38 ft2) per calf. As with any barn design, calves must be kept clean, dry and well bedded.

Ventilation Rates and Housing
Practical Considerations for Ventilating Calf Barns in Winter by Ken Nordlund, DVM
Housing Factors to Optimize Respiratory Health of Calves in Naturally Ventilated Calf Barns in Winter by Ken Nordlund, DVM
Positive Pressure Air Tube Ventilation for Calf Housing

 

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