DairyCo

Ventilation in livestock buildings

Housing and ventilation

Much research work has been done in recent times to study the extent and effects of bad ventilation in livestock buildings. Many variables exist in appraising ventilation levels buildings from farm-to-farm, but techniques exist both to measure the effectiveness of ventilation in current buildings - and suggest practical means of improvement - as well as to predict how well as yet unconstructed buildings are likely to perform.

The important of good ventilation is well-understood in promoting good health in housed livestock, with a particular emphasis on respiratory illness. Attention to stocking densities within livestock buildings is of prime importance due to the effects of confining animals more intensively in environments where pathogens can multiply and colonise more easily.

Bad ventilation can also be factorial in the spread of mastitis principally because condensation can contribute to increased humidity levels and help to support a variety of pathogens responsible for environmental mastitis. The ideal humidity level for dairy livestock buildings is around 70%, but in wet winter conditions it can easily reach 85%. There is increasing awareness too about how dairy cows are affected by heat stress in warmer weather, particularly as more herds are housed year-round.

General tips for improving the standard of ventilation in farm buildings include:

• Installing efficient roof apex ventilation. Many existing roof apex outlets in older sheds may be too small to provide an adequate gap for stale air to escape. Some may have no effective ridge ventilation at all.
• Leaving strategically-placed gaps between the roof sheets in new livestock buildings, allowing warm stale air to escape, or cutting slots in the ridges of roof sheets in current buildings to achieve a similar aim.
• Using spaced vertical boarding in place of solid walls or wall sheeting to enhance ventilation.
• Paying close attention to stocking levels within farm buildings.
• Employing good bedding management in loose-housed yards and cubicle housing.
• Avoiding large, wide-span buildings with a large internal surface area, or multi-span housing that may be difficult to ventilate adequately.
• Ensuring good drainage in loose-housed straw yards or effective slurry management in cubicle sheds.

Good ventilation, while removing stale air and replacing it with fresh air should not allow draughts at cow level. At bedding level they can blow fresh bedding from cubicle surfaces and can cause chills, particularly around the cows' udders, which can be factorial in new cases of mastitis.