Wintering barns deliver environmental and animal welfare benefits for Canterbury farmers

Winter crop grazing brings environmental risks that are impossible to fully neutralise – whether by nitrate leaching on light soils or surface runoff on rolling paddocks, some contaminants will sooner or later end up in the local waterbodies.

However, there are a range of types of wintering infrastructure that farmers can use instead of winter crop grazing that manage and mitigate the difficulties of keeping stock well fed when the grass isn’t growing.

These include:

• composting barns
• herd homes
• feed pads
• loafing barns.

Canterbury’s cold – and often damp – winter climate means that when done well, the use of wintering infrastructure can be a great tool to get through a tricky time on the farm.

Canterbury farmers share their wintering strategies

Two Canterbury farmers employing different wintering strategies using infrastructure generously shared their experiences with us.

John Faulkner: A composting barn in North Canterbury

Hurunui farmer John Faulkner – who is also an Environment Canterbury councillor – is entering his first winter using a composting barn.  

Inspired by Waikato farmers Tony and Fran Allcock, Faulkner constructed a composting barn with deep bedding of 900 mm poplar wood chip, which is stirred frequently to mix in urine and dung, aerate the compost, and prevent compaction.  

Faulkner said he chose to invest in a composting barn to make necessary nutrient loss reductions without compromising on his farm’s productivity by lowering his stocking rate. 

“I want to have higher productivity out of the unit that I’ve got. Most documentation talks about a 10 per cent increase in production from having a barn, and we’re anticipating that here, so that’s a benefit to the farm and the economy.” 

Because cows burn so much energy keeping warm outside in winter, Faulkner says that the warmth of a composting barn means less feed is required.  

“We will reduce our winter grazing feed from 16kg per cow out on the paddock, down to nine or ten in the barn,” says John Faulkner.

The environmental benefits Faulkner expects to see: 

• Better soil structure: The barn has facilitated the transition from intensive winter grazing of fodder beet and kale crops and enabled a longer rotation period on support blocks, allowing soil structure to better recover.
• Improved water quality: A reduction in crop grazing will improve water quality through lower nutrient losses to ground and waterways.
• Faster pasture recovery: Having the cows off the pasture during wet periods reduces pugging and protects the soil structure and pasture health. With less soil damage, pasture recovery is quicker.
• Reduced nitrogen loss: By wintering the cows in the barn and reducing urine and dung on the paddocks during the highest-risk time of year, Overseer modelling indicates a 72 per cent reduction in nitrogen from the support block and nine per cent reduction from the dairy platform.
• Less fertiliser: The captured nutrients in the compost bedding material will be used in the cropping system for maize. Applying this back to the farm will reduce the need for synthetic fertiliser, with the potential to completely replace fertiliser on the support block.

Gary Michael: Herd Homes in Selwyn

Hororata farmer Gary Michael is entering his second winter with his dairy herd housed in three barns. He says he has already seen his cows’ health improve and expects his investment to pay off faster than anticipated.

In 2023 Michael started work on three 12.5 x 93m herd homes with plastics roofs and slatted rubber floors for effluent to drain into concrete bunkers below. Last winter he used all three for the first time.

“Cow comfort and cow health have improved,” he said. “I’ve noticed the cows are a lot quieter and so much easier at calving time.”

Michael claims the barns have enhanced efficiency across the farm through greater feed utilisation with zero wastage.

“We’re only feeding them about 9-10 kilos of dry matter, instead of 12-15 kilos when we had them on kale paddocks.”

By capturing cow effluent in the bunkers below the herd homes and spreading it on pasture and maize paddocks in summertime, Michael says he has reduced his fertiliser usage.

With a large reduction in feed and fertiliser spend, Michael’s looking forward to his investment paying off even sooner than expected.

“We thought it would be seven years, but I think these barns are going to pay us back within five,” says Gary Michael.

The environmental benefits of Gary’s herd homes:

• An option in wet weather: The barns provide greater flexibility in adverse weather and flood events to keep cows off the wet ground, reduce nutrient leaching and protect against soil compaction.
• Improved pasture health: Less soil damage increases long-term pasture health and makes resowing easier.
• No nutrient loss: Nutrient leaching is eliminated when cows are in the barns as  all effluent is captured and stored in bunkers.
• Effluent becomes an asset: The contained effluent is evenly distributed onto pasture in summertime when conditions are optimal and leaching risk is minimal.
• Lower fertiliser cost: Reusing the effluent in place of synthetic fertiliser greatly reduces the reliance on external inputs.

Is a wintering barn right for your farm?

Both John Faulkner and Gary Michael say it’s important to do a complete farm system analysis to identify the key drivers of why a barn is going to be built, and to determine which type of winter infrastructure is best suited to each individual site.

Wintering barns resources: