3 bay polyhousePolytunnels or polyhouses have been used for housing sheep throughout the UK for around 40 years.  However, in more recent times they have also been widely adopted for housing other forms of livestock, most notably poultry, gamebirds and cattle.  Lancashire-based manufacturer Northern Polytunnels Ltd. have been at the forefront of the livestock polyhouse evolution.

 Martin Edwards, partner at R & D Gregory near Garstang, Lancashire installed two 850m² polyhouses in 2018 to supplement his existing traditional buildings.  Each polyhouse consists of two 9m wide outer bays and a 4.5m wide central bay.  The wider outer bays are used for calf pens, whilst the narrower central bay is used for access, handling and feeding.  Ventilation is provided through 1m high mesh sides positioned above 1.2m high concrete walls.  This is supplemented with belt-driven fans installed at one end which blow fresh air along poly ducting downwards in to the pens.  The addition of roof-mounted extractions fans exhausts stale air out through the roof, and can also be used to reduce any excess heat during the summer months.

Polyhouses are usually clad with white polythene covers, although heavy-duty PVC-coated fabric covers are also available.  White polythene allows 65-70% light transmission, providing a much welcome source of light and warmth, creating a dry, low-stress environment for livestock. The 30-35% shade value keeps the house cooler during sunny periods, making them the ideal year-round housing solution.  The influx of natural light, in particularly the sterilising effects of UV light, keeps bacteria, fungi, moulds and odours at minimum levels. Black or green polythene covers are occasionally used, but don't allow any natural light to enter the building, which takes away most of the environmental benefits of a polyhouse.

Cattle are homeothermic animals which need to maintain a constant body temperature around 38°C.  The lower critical temperature (LCT) is the temperature below which an animal must burn extra energy to keep warm (i.e. feed is channelled away from growth/production to keeping warm) hence the warmer winter temperature within a polyhouse will significantly reduce feed inputs. An abundance of natural daylight entering the polyhouse reduces the requirement for artificial lighting reducing power consumption, and the warmer, well-ventilated atmosphere allows floors and bedding to dry quicker, reducing bedding costs.

Martin currently rears around 2,000 calves a year as part of Dunbia's integrated calf scheme, taking them from around 2 weeks up to 16 weeks of age.  A further five polyhouse blocks are planned over the next couple of years which should see Martin's output more than double. "Good health and weight gain are what it's all about, but ultimately gross margins need to be optimised" says Nigel Carr, commercial director at Northern Polytunnels. Carr adds "The low cost of polyhouses, combined with the enhanced environment inside them makes polyhouses the ideal livestock housing solution in a modern, ever-changing agricultural world".