Paybacks on bandwidth ventilation control

Bandwidth ventilation is with us and, if properly programmed so as to cover the likely environmental and management variations of growing pigs through to slaughter, gives automatic 24/7 cover, needing hardly any attention, bar occasional supervision.

Changing over to bandwidth from the existing manually set ventilation and temperature control system isn’t cheap, and with two clients making the change I persuaded one of them to delay a full changeover by keeping one unaltered house of 12 pens to run concurrently with another identical piggery converted to bandwidth – food, numbers and weights were the same. There are reports of improved performance from a move to bandwidth, but I was curious to see what the paybacks might be, if any.

I used meat per tonne of feed (MTF) as the final arbiter because it encompasses FCR, any food wasted, daily gain, dressing percentage and casualties. Moreover, MTF can be compared to MTFs from other options so as to achieve a cost-benefit comparison – the highest MTF figure being the best – providing it’s practicable and feasible for existing farm conditions in each case.

The table below gives the figures from our little trial, and shows comparative performance between conventional hand-set controls and a bandwidth system in pigs nursery to slaughter weight. The figures were produced from 12 pens of 15 pigs in identical houses.

Manual adjustment

Bandwidth system

FCR 33-105kg



Daily gain (g)



MTF * (kg)



Coughing index **



*MTF – saleable meat per tonne of food used.
**Coughing index – stockman’s assessment of the amount of coughing noticed.

In this case the bandwidth control of ventilation provided 9.1kg more saleable meat for each tonne of food fed. This was worth 12.74 euros at the prices of the time, which is equivalent to reducing the cost of the growers’ feed by the same amount per tonne (another reason why MTF is such a good figure to use). This was equivalent to 2.19 euros/pig.

From this, it’s simplicity itself to calculate a payback. The amortised changeover cost was in the region of 3.00 eros/pig, and relating this to the benefit of €2.19/pig, the payback was about 16 months for one batch of growers.

Less coughing
The staff noticed fewer coughs in the bandwidth pigs, and their own tallies showed it to be four times less. As they said, quite noticeable. We discussed why? My only suggestion is that bandwidth programming takes care of the nightime hours – which in this case were lengthy as it was a winter trial. When hand-setting, even adjusted at the end of the dayshift, it could make the atmosphere over the reclining pigs stuffy some of the time between, say, 11pm and 6am. An interesting area for more detailed research.

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About The Author

John Gadd, who has spent 60 years' involvement in pig production, has had more than 2,800 articles about pigs published and has written three best-selling pig textbooks. With hands-on experience that includes managing a grow-out herd at 1,800ft in Banffshire, Scotland, and 20 years in the allied industries with Boots' Farm Department, RHM Agriculture and Taymix, he set up his own international pig management consultancy in the mid 1980s and has now visited more than 3,000 pig units in 33 countries as a pig management adviser. (Photo courtesy Bournemouth Daily Echo)