Compost Bedded Pack Structures
Compost bedded pack structures can provide many benefits for dairy farmers in dryer and warmer climates. The strengths, limitations and keys to success of these structures are summarised below.
- Compost bedded pack structures are flexible in their use if they appropriately designed and managed to support higher levels of cow comfort and include appropriate space allocation for a hospital herd, breeding and calving.
- The structures have the potential to mitigate risks to high-producing herds from seasonal weather variability and long-term changes in climate systems.
- There is a low capital outlay and maintenance costs, although they present new management challenges, such as staff training and changes in labour use.
- In some cases, these structures can allow for better pasture use and dry matter production.
- There is a range of low-cost options available. Many of these facilities have used plastic greenhouse-type structures for the shelter rather than solid sheds.
- Larger herds can become difficult to accommodate if using compost bedded packs.
- Excellent management of mastitis is required. The cows should be properly prepared and teat preparations applied after milking.
- Poorly ventilated structures resulting in high bed moisture content can increase the risk of environmental mastitis in humid conditions.
- Bedding materials can fluctuate in price through changes in availability.
- Summer storms in warmer months with higher than normal rainfall can wet the bedding.
Keys to success
- Make sure staff are well-trained in identifying issues and understanding the processes of bedded structures, such as monitoring moisture and bedded pack tilling, along with any required extra steps in milking management, teat preparation and spraying.
- Reduce water/mud splashing on return to feed bunk to reduce mastitis or compost bedding contamination. Keeping cows standing for one hour following milking is advisable.
In recent years, composted bedding packs as a loafing area surface have become more common on Australian dairy farms.
The basis for these shelters is the use of bedding that can promote the composting of cow manure into the bedding of the shed. This is achieved by using a deep bedding which can be aerated on a daily basis.
Why build a compost bedded pack structure?
The decision to build or modify a bedded pack structure may be in response to changes in farming systems, such as feeding rations, paddock rotations or a bigger herd. Decisions on the design and maintenance of a bedded pack structure should consider the potential impact of heat stress impacts from the composting process.
Compost bedded pack structures can be a significant investment of time and money. However, from a heat stress management perspective, a compost shed will be able to handle high levels of animal traffic better than a few shaded paddocks over the summer.
Many farmers use sacrifice paddocks over summer which have some shade. These paddocks are used until mastitis levels start to increase, then another paddock is found. A compost barn is an alternative to sacrifice paddocks.
Application in humid climates
It is still unclear how effective compost bedding pack systems will be in hot humid areas of Australia, such as coastal Queensland, especially if using dry manure solids as compost bedding. It is important the bedding pack does not get too wet, as this will kill the composting bacteria. This is a challenge in humid climates.
A recent investigation into the experiences of 11 Australian dairy farmers showed heat stress issues had decreased on most of the compost bedding pack shelter farms visited. However, some farms have cows that are still experiencing some heat stress (in Victoria and Queensland) and some farmers are considering using fans in hot periods (Chamberlain, 2018).
It remains unclear if the heat generated from microbial activity causes more heat stress when cows are lying down. However, it is assumed some heat transfer will occur from the pack to the cow when the cow is lying down. This could possibly add to heat stress or the willingness of cows to lay down during periods of high temperatures.
For a broader look at the benefits of compost pack structures, limitations and design considerations, visit the Dairy Infrastructure website.