Ventilation defects could be affecting pig performance
Over the last few months, the hot temperatures have meant ventilation systems running at maximum capacity, as we enter the autumn-winter period it is a good time to re-assess how effectively your ventilation system is operating, especially when it’s running at lower capacity. Michael McKeon tells us more.
When visiting different pig units, several common ventilation issues/defects keep cropping-up. This is, in no particular order, my ‘Top 5 Vent Defects’ list.
Dung under side-wall vents
Many pig buildings use a cross-ventilation design, whereby air enters the room through side wall vents and exhausts through a centre chimney. In this situation the side walls should be the warmest part of the pen where pigs lie, and the pigs should dung beside the centre passageway near the drinker & feeders. However, on many farms the pigs are dunging underneath the side vents, which indicates that the cold air is falling here. Pigs will therefore either lie here and be cold, which will increase the risk of scour and impact feed conversion efficiency (FCE) or else they will lie elsewhere with an increased risk of tail biting. Neither situation will help your pig performance!
Cobwebs
Cobwebs in your pig house are a sign of poor airflow. When air enters through the side vents it should follow the curve of the ceiling before falling into the centre of the room as air speed slows. If your ceiling has cobwebs it indicates that air is not flowing at speed in this area or else the air is being obstructed by a roof support etc. Either of these scenario’s indicates that the air movement is insufficient and therefore you have pockets of dead air in the house. This will lead to hots spots of temperature or ammonia build-up.
Huddled against pen division
If pigs are huddled against the pen sides/divisions, it indicates that the room air speed is too high. This is especially important for younger pigs (piglets/weaners) as they have very little hair or body fat so the fast-moving air will cause a ‘wind-chill’ effect, leading to scour or respiratory issues. This issue can be caused by; vents being stuck and not opening fully, too large a fan for the size of the room or the room temperature being set too low. Pigs do not like fast moving air so it should be avoided at all costs, the only exception is in very hot conditions.
Roaring fans
Frequently when entering a pig room you can hear the fan ‘roaring’ at 100%. This can correctly occur in mid-summer, but often in relatively mild conditions it can be heard. If it is incorrectly operating at maximum capacity over days or even weeks then not-alone will it be using expensive electricity, but it will also reduce the fans lifespan. Some of the main causes of this occurring are; vents stuck and not opening fully, fans size is too small for number of pigs/pig weight in room, the temperature sensor has a build-up of dirt and is not reading accurate room temperature, the room temperature is set too low.
Square lying
Pigs like to have a specific designated lying are in a pen. If the ventilation in a room/pen is incorrect then cold/fast air may fall on their lying area, so the pigs will move to lying against all four walls of the pen i.e. ‘square lying’. Similar to humans who get bad sleep, this will lead to chronically stressed pigs over time resulting in greater activity and aggression in the pen. This in-turn can lead to reduced growth rates and higher levels of tail biting and lameness.
Next time you are entering the pig house, do not switch on the main lights. Instead sneak into the house and walk quietly down the passways and observe where the pigs are lying, and what the ventilation system is doing, vents open/closed, fan speed, air movement. The pigs lying position will tell you if the ventilation is working correctly! Once you have walked the house then switch on the main lights and carry-out the rest of the daily checks.
If the ventilation isn’t working correctly it isn’t good for the pigs or your pocket!