Pigs are grazing on lush green pastures at a Norfolk farm which is testing how grass cover can boost their health and productivity - while helping the environment.
The animals are more often seen outdoors on bare ground which can become a dustbowl in summer and a muddy quagmire in winter.
But LSB Pigs has planted grass mixes across two farms near Fakenham in a trial to assess the impact on pig performance and pollution reduction.
About 1,000 sows are enjoying their new surroundings on 110 acres of land at East Rudham, which has all been sown with grass, while another 550 sows are on 50 acres of grass at Weasenham.
The trial partners say the animals are fitter and more content, while the soil is holding onto nutrients, minimising phosphate and nitrate losses through surface run-off and leaching to groundwater.
LSB Pigs unit manager Rob McGregor said: "These are grazing animals at the end of the day. People forget that.
"Compared to what we were doing, which was just bare earth, this is a massive step forward.
"The pigs are very content. They spend a lot more time out exploring, whereas if it was bare earth they would be in the hut. They are fitter as well. So by having a fitter sow, of course it is going to help her when she comes to give birth and look after a litter.
"Nutritionally they are getting nothing at all from the grass. They are still getting fed exactly the same levels of feed, so it is just about contentment, fibre and gut-fill. The fibre is improving their gut health.
"There's another thing we've become aware of - we always knew the sows ate some of their bedding but we never realised how much. Now they have got as much grass as they want to eat, there is so much less straw needing to be put in the huts. Straw can become scarce and very expensive, so that's another positive."
Mr McGregor said the ground temperature had also been measured at seven degrees cooler than bare earth, which reduces heat stress that can be a particular problem for the boars.
Rob Battersby, LSB Pigs' managing partner, said there were benefits for farm workers too.
"It is also a better working environment for the staff," he said. "Walking across this grass compared to walking across a slushy, muddy old field in the winter, or all the dust in the summer - it is far kinder, not just for the pigs, but for us too."
Ed Bramham-Jones, director of farming and land management at Norfolk Rivers Trust, said the trial will test how the grass is keeping nutrients in the soil, rather than running into watercourses.
"For us, there are lots of benefits in putting pigs onto grass leys," he said. "One is that the roots are holding the soil together physically and it means any rainwater landing on here will infiltrate better, which is helping with soil compaction and soil health in general.
"We have also been looking at ways to reduce the nutrients, things like nitrates, leaching into groundwater. By having a living grass ley here, it is holding on to those nutrients, and you can see from the lush grass growth here it is taking those nutrients up really well.
"That is a real benefit, because we don't want those nutrients leaving the field and leaching into groundwater or, with the patterns we are seeing of intense rainfall, running off fields into the rivers."
Although other pig producers have explored grass leys for pigs, this trial has found a new way of splitting each paddock into three, with the central section including the housing and drinking water used constantly, and two equal-sized areas of grass either side used alternately, with a fence line moved every few weeks to give the grass enough time to recover and regrow.
The trial is the result of collaboration between pig producers, their landlords and organisations including the Agriculture and Horticulture Development Board (AHDB), Norfolk Rivers Trust, Anglian Water, Catchment Sensitive Farming (CSF), the Environment Agency and Kings Crops.
“By bringing everyone together, great progress has been made in basic soil management and effective ways to minimise run-off,” said AHDB knowledge exchange manager Andrew Palmer.
“We have also focused on cultivating good working relationships between producers and their landlords, which is crucial.
"The grass cover trial is the next exciting step forward, to understand more about how proactive management to protect the soil can be mutually beneficial to pig production, water quality, the arable rotation and biodiversity."
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