Getting ventilation right

Despite huge advances in technology in the last 15 years, stockmen and women still have the most influence in determining the success or failure of ventilation systems in piggeries, Hugh Crabtree, managing director of Berkshire-based Farmex told a meeting of the Pig Veterinary Society at  Newcastle Upon Tyne.

As an example, he showed the differences in energy use between four batches of pigs in a brand-new nursery house incorporating the latest building materials and ventilation systems.  "Real-time monitoring showed that energy use varied between 10.2 kWh per pig to 3.7 kWh per pig giving a range in annual costs from £12,546 to £4,706, while CO2 output ranged from 77 to 28.9 tonnes per year," he said.

Mr Crabtree also highlighted the fact that global warming means that a typical UK ambient temperature design range of -5ºC- 24ºC is steadily becoming outdated.  UK systems can operate across am ambient temperature range of -10ºC-14ºC but, as soon as it gets above 14ºC outside, systems will be out of control, unless facilities such as misters or evaporative cooling are used.

He also pointed out that, with rising energy costs, it would be reasonable to expect a revival in interest in ACNV (automatically controlled natural ventilation).  But when it comes to efficient, sustainable pork production, taking into account the pig's growth rate and feed conversion as well as low greenhouse gas emissions, a well-designed and monitored fan system holds sway.

"It is worth remembering that even in 2011, most pigs in the UK are finished in naturally-ventilated confinement systems and the majority of these are uncontrolled.  How much longer this can be sustained in a volatile commodities market, remains to be seen," he said.