Increasing environmental legislation may be a burden on many outdoor pig units, but making simple management changes could overcome some key problems.
Reducing nutrient leaching and soil erosion associated with keeping pigs outdoors, as well as help preventing excess destruction to ground cover, could all limit the chances of falling foul of legislation, Sandra Edwards of the University of Newcastle told visitors to the Pig and Poultry Fair, Stoneleigh.
“Keeping pigs on under sown or autumn sown grass compared to stubbles has shown to have a greater persistence of cover and root structure, helping minimise soil erosion and possible leaching,” said Prof Edwards .
Work on the Ecopig project, funded by DEFRA, has shown that pigs develop toilet areas, so certain areas become more polluted than others with greater areas of soil erosion.
“The project is testing whether muck can be better distributed by moving huts and fences, as sows have been shown to dung as a way of marking territory.”
Diet is also important in reducing pollution, she added.
“Formulating diets to reduce total nitrogen and phosphorus excretions are already possible, but precision feeding is a better method of matching diets to sows’ needs, as well as preventing excess excretion.
“By offering less protein in older sow diets and feeding more energy based feedstuffs in winter, nitrogen excretions in urine will be lower.”
Work has also shown soil nitrogen is high in feeding areas, which she told visitors was as a result of waste feed when scattering rather than feeding in troughs.