Dairy Consultant Dr. Sue Macky answers FAQs about dairy cow Composting Barns

Q1 What is a composting barn for cows?

Understanding Composting Barns: Composting barns are designed to allow cows to freely move around in a large, bedded area where composting of organic material takes place, providing a comfortable environment and effluent management system that can be later used as fertiliser.

Q2 What material is suitable for composting?

Suitable Materials for Composting: Materials such as wood shavings, sawdust, sand or other organic materials are suitable for composting bedding.

Q3 What's the composting barn process?

Composting Process: A composting barn provides the ideal environment for raw material to turn into compost through a natural biological process, storing carbon and using nitrogen to evapourate moisture. 

Q4 Depth of compost bedding, how deep to aerate, how to get oxygen into the bedding?

Bedding Depth and Aeration: Proper aeration is essential for composting efficiency and cow comfort, requiring specific depths and methods to ensure oxygen reaches the bedding.

Q5 Should the composting process be started before I put cows into the barn?

Starting the Composting Process: It's beneficial to start the composting process before introducing cows to the barn to manage the bedding properly.

Q6 What's the recommended frequency of tilling a composting barn?

Frequency of Tilling: Regular tilling of composting bedding is recommended to maintain optimal conditions and manage pathogens like E. coli

Q7 How to maximise lifespan of composting barn bedding?

Bedding Lifespan: Maximizing the lifespan of bedding through proper management techniques ensures cost-effectiveness and cow comfort.

Q8 What is the correct temperature of composting barn bedding?

Bedding Temperature: Monitoring and maintaining the correct temperature in composting barn bedding is crucial for microbial activity and cow comfort.

Q9 How does a lying-down cow produce more milk than a cow standing up and what is the impact on feed conversion efficiency and milk production?

Impact on Milk Production: Comfortable cows lying down more often can produce more milk and improve feed conversion efficiency. 

Q10 What is the optimum lying time for a cow per day? and what is the impact on milk production if this changes?

Lying Time and Milk Production: Optimal lying time per day directly correlates with milk production; changes in lying behaviour can affect milk yields. 

Q11 How will a composting barn impact feed conversion efficiency? How to feed my cows well enough?

Feed Conversion Efficiency: Composting barns can positively impact feed conversion efficiency through improved cow comfort and management practices. 

Q12 Will a cow barn cure all my problems? How to reduce farmer stress in crappy weather?

Managing Farmer Stress: Composting barns can mitigate stress during adverse weather, enhancing overall farm management and efficiency. 

Q13 Is a cow barn a magic fix? Do I need to get other parts of my farm system right as well?

Integrated Farming Systems: While beneficial, composting barns are not a standalone solution; integrating with other farm practices is essential for holistic farm management. 

Q14 Should I build the cheapest roof over my cows?

Choosing the Right Roof: Dr. Macky advises against simply opting for the cheapest roof over your cows. A well-designed roof plays a crucial role in maintaining optimal conditions within the composting barn.

Q15 Do cows really breathe out up to 30L of hot water vapour per day and what is the impact on roofs over cows?

Management of Moisture: Cows can exhale up to 30 liters of hot water vapor daily, impacting the barn's roof and necessitating proper ventilation and roofing design. 

Q16 What temperature is optimum in the cow barn? Is it true, uncomfortably cold for humans is comfy for cows?

Optimum Temperature: Cows prefer temperatures that may seem cold to humans, emphasizing the need for barns designed with animal comfort in mind to maximise com comfort and milk production.

Q17 What is the common problem with cow barn building design in NZ? (roof pitch too flat, eaves too low, space per cow, wrong type of roof, green house roofs are plants)

Common Building Design Issues: Challenges in roof pitch, eave height, and overall space per cow can affect barn functionality and cow comfort.

Q18 What is the optimum cow mob size in paddock and in cow barns and understanding the social behaviour of cows?

Cow Mob Size: Understanding social behaviour is crucial; optimal mob sizes in both paddock and barn settings can enhance welfare and productivity. 

Q19 What is the minimum and optimum area/ m2 per cow for composting barns?

Space Requirements: Dr. Macky discusses the minimum and optimum area per cow, essential for promoting cow health and welfare. 

Q20 What is the optimum feed-face or space per cow when feeding? And importance of feed rail location?

Feed Space and Rail Location: Optimal feed-face space per cow and proper feed rail location are critical for efficient feeding and cow welfare. 

Q21 Does heat from composting kill pathogenic bugs? E. Coli in compost barn vs in-paddock?

Heat from Composting: The heat generated by composting helps eliminate pathogens like E. coli more effectively than in traditional paddock environments. 

Q22 What are the environmental impacts of composting barns? How to improve carbon footprint considering greenhouse gases, leaching nitrogen and N-loss?

Environmental Impact: Addressing greenhouse gas emissions and nitrogen leaching through improved barn design and management practices is crucial. 

Q23 How does 'Cartref Jerseys' prevent mastitis in a composting barn? And how often to replace the bedding?

Preventing Mastitis: Case studies like 'Cartref Jerseys' showcase successful strategies for mastitis prevention through bedding management.