Bedding might seem like a small detail in the bigger picture of dairy infrastructure, but in a composting barn, it’s the engine that keeps everything working. Get it right, and the barn stays dry, warm, and easy to manage. Get it wrong, and the system struggles to compost efficiently – turning into mud and a mess you’d rather not have to clean up.
At Aztech Buildings, we’ve trialled and refined bedding systems for more than two decades. While there are several materials farmers can use, we continue to favour woodchip because it strikes the best balance between comfort, composting performance, and long-term value.
TABLE OF CONTENTS:
Why Bedding Matters
Woodchip: The Balanced Performer
Sawdust: High Absorption, Higher Maintenance
Sand Bedding
Matching Bedding to the Barn
Can Different Bedding Materials Be Mixed?
FAQs
Why Bedding Matters
Composting barns rely on a living process. Beneath the herd, a mix of carbon-rich bedding and nitrogen from manure creates an aerobic environment where microbes convert waste into heat and compost. That heat – often around 55 °C – evaporates moisture, kills bacteria, and provides a dry, cushioned surface for cows to rest on.
The choice of bedding affects every stage of that process. It determines how much air can circulate through the pack, how moisture is absorbed and released, and how well the compost maintains its structure over time. In other words, it’s not just what your cows lie on – it’s what keeps the whole bedding functioning.
Woodchip: The Balanced Performer
Woodchip remains Aztech’s go-to bedding material for most composting barns across New Zealand. Its coarse, open structure allows air to move freely through the bedding, helping microbes do their job and preventing compaction under hooves.
It’s also a durable option, especially in high-traffic areas like feeding areas or entry points, where finer materials can quickly mat down. Over time, woodchip breaks down slowly, maintaining the structure of the compost while providing a steady carbon source.
The result is a bedding surface that feels firm yet springy underfoot, drains well, and stays aerated – ideal conditions for cows and compost alike.
We also like that woodchip is readily available through local timber and arborist waste streams, keeping input costs reasonable and reducing transport miles. Where available, screened chip of mixed particle sizes tends to perform best: fine enough for comfort, coarse enough for airflow.
Sawdust: High Absorption, Higher Maintenance
Sawdust and fine wood shavings can also be used in composting barns, often as a secondary or blended bedding material. They’re soft, easy for cows to lie on, and quick to absorb moisture. That makes them particularly good for calving areas or barns with excellent ventilation.
However, sawdust needs careful management. Its small particle size can reduce airflow through the compost pack, and if moisture levels climb too high, it can start to compact. Without regular turning, the bedding can shift from aerobic (healthy) to anaerobic (smelly and wet) surprisingly fast.
Many farmers find success combining sawdust with coarser chips – the sawdust improves comfort, while the woodchip maintains the structure underneath.
Sand Bedding
Sand bedding is widely recognised for its comfort and hygiene benefits in dairy farming. Sand is widely used in freestall barns for these very reasons in conjunction with daily maintenance and dedicated manure-handling equipment.
Its non-absorbent nature helps keep the surface dry, reducing bacterial growth and improving udder health.
However, while sand has clear advantages for cow comfort, it’s not suitable for composting barns. Sand contains no carbon, so it can’t support the microbial activity that drives the composting process. Instead of breaking down, it accumulates - becoming heavy, cold and difficult to manage. It also increases wear on machinery and removes the “living” biological function that keeps a composting pack warm, dry, and self-aerating.
Matching Bedding to the Barn
No two farms are identical, and the best bedding often depends on climate, management style. In cooler, wetter regions, coarser materials like woodchip help maintain airflow and prevent matting. In drier or warmer climates, a finer surface layer of sawdust can improve comfort without sacrificing performance.
Can different bedding materials be mixed?
Blending coarse chip and fine sawdust often gives the best results — structure for airflow, softness for comfort.
Frequently Asked Questions
How Much Management Is Required?
Most farmers aerate their bedding once a day when using the barn. Bedding is typically topped up once or twice a year. The key is consistency, the more routine the turning, the better the compost performs.
How deep should the bedding be?
Most Aztech composting barns start with 600-800 mm of bedding. The compost pack naturally settles over time as it breaks down.
Can different bedding materials be mixed?
Yes. Many farmers blend woodchip and sawdust to combine structure and softness. The goal is always airflow, moisture control, and comfort.
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