Keith Woodford: Composting Barns Require New Thinking.
• Solar-Powered Cow Barns: Self-Sufficient Energy Solutions
• Case Study: New Feed Pad Surface with flood wash for Jersey Girl Farm
• Case Study: Borries' Feed Pad in Waitaki
• Exclusive Interview: Greg from Entegra on Ridgeback Barn Designs
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Composting Barns Require New Thinking.
Article by Keith Woodford.
Composting barns require new thinking about managing the dairy system. It’s not just a case of sticking up a shed and then sitting back and watching additional milk and dollars flow.
Whenever I discuss composting barns with prospective farmers the first thing I want to know is why do they want a composting barn. How do they think it will make their farm more efficient and how will they measure this efficiency?
There are lots of valid reasons to build a composting barn. In Southland it might be to solve the problem of winter mud and associated animal welfare. In Canterbury the key driver might be the need to reduce nitrogen leaching and the cost of off-farm wintering. In much of the North Island, the primary objective might be to deal with summer feed shortages rather than winter issues.
For one South Island farmer I regularly visit, it is about achieving a low-cost system that is resilient to both environmental issues and milk-price downturns. He achieves this by wintering all stock on farm with the aid of a composting barn, hence having no off-farm wintering costs, and only needing to feed eight kg dry matter of silage per cow per day during winter. This is also a very labour efficient farm with a focus on worker welfare. On this farm, the weekend winter work day, or indeed any winter work day can be over by mid-day regardless of the weather. The cows can be observed 24/7 by camera from the dining room table.
Benefits can come from unexpected outcomes. For example, farmers and their cows love composting barns at calving time. I recall one barn where, at calving time, the farm worker said to me that it was like working on a hobby farm. Another farmer said to me that he had to reduce the work schedules because it took all the stress out of calving and the work hours were much less.
The value of compost as fertiliser also needs to be considered. There can be considerable savings, particularly in nitrogen, but also other elements.
The first thing to work out in relation to designing the barn itself is the cow stocking rate. Will the cows be in the barn 24/7 during winter or will they still be going out for say three or four hours of grazing except during exceptionally bad weather? Under what conditions will the cows use the barn at other times of the year? These are the questions that will determine the area of bedding per cow.
Not all composting barns are successful. There are multiple reasons for this, starting with flawed design. My estimate is that less than half the existing barns are working at an acceptable level. This is a big issue as a composting barn is a major investment.
When composting is working well then it all looks so easy. However, when things start to go wrong, then it is easy to miss the early warning signs.
The efficiency of moisture removal from the urine and dung deposited in the bedding is critical. Particularly in the South Island, I am impressed by the benefits of roll-up side curtains as a management tool to get
Agri expert: Keith Woodford
the chimney effect operating effectively. In the South Island I would never consider building a barn without these curtains.
Bedding can be sawdust, wood shavings, woodchip or any other vegetative material that is high in lignin.
Any plant that stands 2 metres or more in height is going to be high in lignin. Conversely, wheat and other short stemmed cereals will be low in lignin and the straw turn to mush rather than sweet-smelling compost.
Ideally, the temperature in the compost should be above 50 degrees C and the moisture level preferably no more than about 65%. Seventy percent is the moisture irrecoverable level at which problems quickly multiply.
I am particularly keen on Giant Miscanthus for bedding. This is a sterile pant that has to be reproduced vegetatively, and this can be somewhat of a hassle. However, I am convinced that Giant Miscanthus is going to become a key component of composting systems in New Zealand, with farmers typically growing their own Miscanthus, often on land that has low value.
Giant Miscanthus has been in New Zealand for more than ten years but it is only now that the growing and harvesting technologies are starting to be applied properly. Also, currently we only have one variety of Miscanthus available, and almost certainly this is not the best variety in many parts of New Zealand. Plans to get new varieties into New Zealand are under way.
Regardless of the specific type of bedding that is used, there is a very similar heating value when measured per tonne of dry matter. However, the heating value per cubic metre depends very much on the bulk density of the material. There is no value in paying for air.
If purchasing bedding per tonne, then knowledge of dry matter content is also essential. Woodchip and sawdust from freshly harvested timber can be 50% water, and one does not want to pay for this. Also, much of the heating value inherent in the bedding material can be used up in getting rid of this initial water.
One of the advantages of Miscanthus is that the dry matter, when correctly harvested at the correct time, is likely to be over 85% and perhaps close to 90%. Accordingly, it heats up very quickly.
One of the problems with composting-barn developments in New Zealand is that the formal R&D organisations have been very slow to come to the party. Hence, most of the knowledge acquisition has been led by farmers working by trial and error and then sharing their knowledge.
One of the challenges we have been seeing in some North Island situations, where the barn is used for lactating cows, is for E coli mastitis to become a major issue. There will be solutions to prevent E coli from becoming a limiting factor, but we are not quite there yet. What we do know is a high level of discipline is needed to ensure the compost stays above 50 degrees C for prolonged periods and ensuring the fermentation is always aerobic. E coli loves the cooler non-aerobic compost sometimes found at depth in the compost.
Growing miscanthus can offer further benefits
Solar Panels on Cow Barns: Is SelfSufficient Energy Possible on NZ Dairy Farms?
As the world grapples with climate change and rising energy costs, New Zealand's dairy industry faces a unique opportunity. What if our dairy farms could generate their own electricity, right from the rooftops of their cow barns? It's an idea that's beginning to take off overseas and could soon make waves here in New Zealand.
Learning from Overseas
A progressive dairy farmer in southern Pennsylvania, USA, provides an inspiring example. Eric Weaver, from the 10th Generation Dairyman YouTube channel, recently installed 324 solar panels on the south side of his barn roof, creating a 175-kilowatt system. Featuring 550-watt panels, the setup aims to power the entire farm and even produce a surplus.
Initially sceptical, Eric was impressed by the financial viability of the project. "Ithoughtsolarwassomething thatonlyworkedifsubsidisedbythegovernment," he said. However, after accounting for tax credits and rebates, he found that the panels would pay for themselves within four years. Even during the short, sun-deprived days of winter, the panels performed admirably, hinting at the potential for year-round energy generation.
Harnessing the Sun: Eric Weaver's Pennsylvania dairy barn, equipped with 324 solar panels, generates 175 kilowatts of power.
The system has produced the expected amount of electricity through the first two months, despite it being winter. Eric is optimistic about the panels' performance in the sunnier months of May, June, and July. "It'sgreattohavethesepanels producingalltheelectricityweneed,especiallyduringthe summer whenwe run thefans,"he noted.
Local Efforts and Hurdles
While the American example is promising, how feasible is this for New Zealand dairy farms? Currently, there are no widely known instances of Kiwi barns sporting solar panels. However, local companies are exploring renewable energy solutions for the agricultural sector.
Peter Saunders from Solagri, a Canterbury based energy company, highlights the potential benefits. "Dairyisabig marketwithalargeandpredictableloadprofile.Whilethere aretimingissueswithwhentheymilk,incomparisonto whenthesolarpanelsaremakingpower, thereareplenty ofthingsthatcan betime-shiftedtobetteruse thesolar energy, suchas effluentpumps,"Saunders explains.
Crunching the Numbers
In the US, financial incentives were crucial. Tax credits and power company rebates significantly reduced the payback period. For New Zealand farmers, a similar approach could unlock the potential of solar power. Collaboration between the government and industry bodies to create attractive financial packages could spur a surge in solar energy projects on farms.
Peter Saunders notes that industry conditions are also in favour of solar power becoming a major feature on NZ dairy farms. "Theongoingincreaseindemandfor electricityandlimitedgenerationgrowthintheshort termarelikelytocontinuepushingelectricitypricesup. Thiswillmakesolarlooklikea more attractiveoption, particularlygiventhedownwardpricepressure ofpanels atthemoment."
Beyond financial savings, the benefits are clear. Generating their own electricity allows farmers to achieve energy independence, shielding themselves from volatile power prices. Additionally, reducing carbon footprints aligns with global sustainability goals, enhancing the green credentials of our dairy industry.
Solagri has installed solar panels at five New Zealand dairy farms, with a further two installations underway. These efforts demonstrate the adaptability of solar energy in agriculture, suggesting it's not a question of if, but when, we'll see wider adoption in New Zealand.
However, there are unique challenges here in Aotearoa. Factors like our distinct environmental conditions, regulatory landscape, and upfront investment costs need careful consideration. Roof orientation and sunlight availability are crucial for maximizing efficiency. Moreover, farmers will need support from government incentives to make the financials stack up. Saunders also points out a practical hurdle: "Findingexperienced professionalinstallersisasignificantchallenge."
The Road Ahead
Imagine New Zealand barns glistening with solar panels, harnessing the power of our abundant sunshine. It's a vision that could revolutionize our farming landscape, making energy independence a reality.
While the journey towards self-sufficient energy on New Zealand dairy farms is just beginning, the potential is enormous. With overseas success stories and growing local interest, it's an exciting time for innovation in our agricultural sector.
The question now is whether New Zealand farmers are ready to embrace this solar revolution. It will take a willingness to innovate, invest, and envision a future where our farms are not just producers of milk, but also generators of clean, renewable energy. The opportunity is there – it's up to us to seize it.
Solagri Energy CEO Peter Saunders with business partner Hamish Hutton.
Eric Weaver 10th Generation Dairyman
New Feed / Wintering Pad Surface with Flood Wash for Jersey Girl
Jersey Girl Farm, located near Winton, recently upgraded its infrastructure by installing a new feed pad surface with a flood wash system. This initiative aimed to improve the operational efficiency on the farm and lift cow comfort. NumatAGRI recently visited the farm to find out how the new system is performing.
Project Scope and Objectives
The primary objective of the project was to create a system that ensured cow comfort by providing a dry and clean environment while also being practical and user-friendly for the farmers.
Key Components and Features of the System Conversion
Bart Geypen, the Construction Manager, explained, "Thissetuphasa calculatedgradient.Eachbarnis26 meterswideandgetsflushedwith60,000litresof greenwashwaterinunderfiveminutes."
• Siesta Rubber Bedding: Used for the wintering setup, providing a softer and more comfortable surface for cows to lay on continuously.
• Sloped Gradient: Each barn,measuring 26 meters wide,was designed with a slope to facilitate the flood wash system.
• Greenwash Water System: Utilizes 60,000 litres of water to clean each barn in under five minutes.
• Flood Wash System: Includes two interconnected storage tanks of 30,000 litres each. The tanks release water through a main pipe with risers every 300mm, creating a wave that cleans the area.
• Effluent Management: Captured at the end of the barns, the effluent is stored in a 160,000-liter sump and pumped back to the main effluent setup for reuse.
Cows enjoy the New Feed / Wintering Pad: 24h / 7days a week from May right through June and July.
Outcomes and Performance
The new system has significantly improved cow comfort, keeping them dry and clean. The farm now uses the flood wash system three times a day, saving approximately five hours of labour daily compared to the previous year. Bart emphasized the financial benefits, stating, "The combinationofsavingsinmulch,labour,andtractor runningcostsgivesthissetupa muchgreaterROI."
Feedback from Jersey Girl Farm Team
The feedback has been overwhelmingly positive. The team reports that the cows are comfortable, dry, and clean, and the flood wash system is simple enough to allow staff to handle daily tasks efficiently. "Theinitialfeedbackhasbeen amazing,"Bart shared. "Cowsarecomfy,dry,andclean.It’s savingthemfivehoursoflabouradaycomparedtolastyear inthecompostingbarn."
Advice for Other Farmers
Bart advises other farmers to consider the ROI, factoring in labour, tractor, mulch, and feed savings. He emphasizes the importance of maintaining the greenwash system efficiently and performing flood washes at least once a day to avoid build-up. "Doinga ROIconsideringlabour, tractor,mulch,feedsaved,etc.,mightshowhow affordableitreallyis,"he recommended.
Customer Case Study: Borries' Feed Pad in Waitaki
The Borrie’s Dairy Farm, owned by the dedicated and innovative duo Michelle and Rogan Borrie, is one of the three dairy farms they manage in the Lower Waitaki Plains. Their operation features an expansive milking operation with approximately 2,500 cows during winter. Recognizing the need for change and the impact of weather on their farming practices, they decided to undertake an ambitious project – the construction of a new feed pad on their 500-cow dairy farm.
Identifying a Need
“Obviouslythingsmove forwardandforenvironmental reasons we decidedtoputa feedpadon this500-cowdairy farm,”Michelle noted, emphasizing their commitment to both animal welfare and environmental sustainability. Their decision was precipitated by challenging winters characterized by heavy rainfall that turned the farm into a muddy mess, causing difficulty in managing cows and pasture. In pursuit of a more effective and efficient system, the couple toured several farms to study existing feed pad designs.
Designing the Feed Pad
From their explorative tours, the Borries identified features they liked and aspects they wished to avoid in their own design. “Wesaw ones weliked,buta lotofthemhad woodchipswherewethinkwoodchipsaregettingharder togetanddearer,”said Rogan, explaining their decision to opt for a rubber matting option instead. The rubber matting had a higher upfront cost but promised longevity and costeffectiveness in the long run.
The Role of NumatAGRI Construction
Their project was taken on by NumatAGRI’s construction division. “Aftertalkingtothem,they werevery keentocome on boardandwerevery enthusiasticandwantedtocome andbuilditfor us.So,wethought,well,whynot?Andwe’revery happywiththeresults,”Michelle added. NumatAGRI’s willingness to participate and dedication to the project was a driving force behind the successful implementation of the feed pad.
The cows spend 24h / 7days a week starting in May through June and July on the feed / wintering pad.
Using the Feed Pad
The newly constructed feed pad has been a gamechanger. Cows are fed 3 to 4 kilograms of maize and grass silage on the feed pad and then guided to the milking shed. Rogan valued simplicity in the design to avoid potential breakdowns. “There’sascraper forthe tractorandmotorbikeanda wheelpushertopushthe silagein.Thesharemilker’sgotasilagewagon tofeed thesilageout.So,there’sno mixerwagons. There’s nothingreallytobreakdown,” Rogan explained. They plan to keep the cows on the feed pad 24/7 during winter, feeding them maize and grass silage.
Reflection and Future Plans
Michelle appreciated the smooth working relationship they had with NumatAGRI, as the project execution was seamless with no unexpected hurdles. “I’veworkedwith a lotofbuildingagenciesandstuffwithlotsofthings happeningon farmconstantly.WithNumatAgri,this wasjustverysmooth,”she commented. The couple is waiting to evaluate the full effectiveness of the feed pad design through a complete winter cycle. If it proves successful, they plan to replicate the design on their other two dairy farms, accommodating 600 and 1,100 cows respectively.
Open Day Highlights at Borries' Feed Pad.
The Borries' Feed Pad Open Day provided valuable insights into the farm's new feed pad surface. Rogan, from the Borries' farm team, shared their journey and the benefits they've seen since implementation.
The farm, which grazes 485 cows and winters just over 500, faced challenges with their previous setup due to harsh weather conditions. This led to uncomfortable, wet conditions for the cows. The new feed pad surface has significantly improved cow comfort. Within a week, the cows adapted, finding their favourite spots on the mats.
Operational Benefits:
• Enhanced monitoring of cows, especially those close to calving.
• Simple cleaning process saves significant labour time.
• Daily routine involves pushing leftover feed to the concrete nib wall and feeding out, improving efficiency.
Technical Aspects:
• Siesta mats provide a soft, comfortable surface.
• Optimal drainage slope keeps the area clean and dry.
• Cleaning with water maintains hygiene.
Feedback has been overwhelmingly positive. The new system has not only improved cow comfort but also operational efficiency, reducing labour and enhancing overall farm management. Rogan emphasized the system's simplicity, allowing staff to manage daily tasks effectively.
The event concluded with a Q&A session, highlighting the successful implementation of the new feed pad surface at Borries' farm. The Open Day offered practical advice for dairy farmers facing similar challenges.
Check out the full case study with video interview: numatagri.co.nz/case-studies/borries
Revolutionizing Dairy Barn Design: An Interview with Greg McCalman from Entegra
In an engaging conversation, Greg McCalman from Entegra shared the story behind the innovative Ridgeback barn design, a structure that could be a game-changer for New Zealand dairy farmers seeking to house cows in barns.
The Birth of Ridgeback Barns
The Ridgeback barn design began as a solution to a unique challenge faced by one of Entegra's clients. The farm needed a wide barn, but local regulations imposed a height restriction. Traditional roof pitches would have made the barn far too tall, and using multiple gables to reduce height wouldn't provide adequate ventilation. So, Greg and his team sought an unconventional solution.
"Weweredealingwithaheightrestrictionof15metersfor a widebarn,"Greg explains. "Atraditional18to22-degree roofpitchwouldhavemadethebarnabout25meters high.Weconsideredusingthreegables,butthatwouldn't ventilateproperly.So,we hadtogetcreative."
To solve this, they turned to the field of aviation for ideas. "Wethoughtaboutairflowandhowairmoves aroundanairplanewing,"Greg continues. "Thisledus to designa barnthatpromotesefficientventilationwithout exceedingheightlimits."
Harnessing Natural Airflow
A standout feature of the Ridgeback barn is its ability to harness natural airflow, maintaining a comfortable environment for dairy cows. Greg elaborates on the design’s ability to harness natural airflow: "Theroofshape createsachimneyeffect,wherehotairrisesquickly, drawingincoolerairfromthesides.Thisnaturalairflow significantlyreducesheatstressoncows,makingthebarn feelalmostair-conditioned,even on thehottestdays."
The Ridgeback barn excels in promoting airflow, essential for cow comfort and health. Traditional barns often fail to provide adequate ventilation, especially during still, hot weather. The Ridgeback's unique curved roof ensures continuous airflow, enhancing the barn's cooling efficiency by 20% more than traditional gable roofs.
Adapting to Cooler, Wetter Climates
One of the critical advantages of the Ridgeback barn design is its suitability for cooler, wetter climates, which are common in some parts of New Zealand "Inplaces withhighhumidityandfrequentrainfall,maintaininga dryandcomfortableenvironmentforcows iscrucial.The Ridgebackbarn'sdesignfacilitatesexcellentventilation, helpingtokeeptheinteriordryandreducingissues relatedtodampconditions," Greg explains.
Benefits for Dairy Farmers
For dairy farmers, the benefits of the Ridgeback barn are clear. The improved airflow reduces heat stress, crucial for maintaining milk production during hot weather. Additionally, the design helps control environmental factors that can lead to mastitis, promoting better overall health and productivity in dairy cows.
Practical Insights for Farmers
Greg emphasizes the importance of understanding each farm's unique needs. "Thebiggestchallengeisidentifying theprimarygoalsforthebarn.Whetherit'skeepingcows on farmoverwinter,orliftingoverallmilkproduction,or pre-emptingfutureregulation,eachfarmhas specificrequirements.”
The Bottom Line
Entegra's Ridgeback barn design offers an innovative solution for dairy farmers looking to enhance cow comfort and productivity. By drawing inspiration from aviation, Greg McCalman and his team have created a structure that provides 20% better airflow than traditional gable roofs, which is beneficial for cow health and composting systems.
For more information and detailed case studies, visit NumatAGRI's website to explore how the Ridgeback barn can transform your dairy farming practices. numatagri.co.nz/construction
