Most chopped straw used for bedding in Australia are based on cereal crops (barley and wheat), however some grass straw is also used. To be an effective litter material, it needs to be chopped and/or crushed prior to use to avoid severe matting and subsequent caking. Chopped straw is commonly used in southern states, particularly South Australia and Western Australia.
Due to its high risk of caking, chopped straw requires more maintenance and management to keep the litter dry and friable than other commonly used litters. While it is not a preferred litter, growers have established additional management practises to improve its effectiveness.
Characteristics
Lightweight; Medium particle size; Soft and compressible; Low thermal conductivity; Good absorbency when chopped to less than 20mm; Slower drying rates than shavings if not actively managed; Moderate to high friability if actively managed.
Some processor companies prefer wheat straw over barley straw for its perceived improved adsorptive qualities.
Contaminants and pests
More likely to attract pests during storage prior to use than wood-based (shavings, sawdust) products because any seeds will be attractive to rodents and wild birds. It is also naturally more susceptible to mould than other shavings. Quality control is required to ensure low moisture content during baling and that the product is covered/placed in a shed before use.
Has an increased risk of residual chemicals and pesticides if applied during cropping.
There is no evidence that it is more or less susceptible to litter beetle infestations than other bedding material.
Sourcing and pre-treatment
Straw is generally readily available in most states. There have been issues with reliable supply at a competitive price in recent years due to severe drought conditions, as there is not only a lack of overall supply, but growers face increased competition from livestock producers. In 2017, the price per cubic metre (m3) on-farm was $10–15, with these prices tripling in some areas in 2019.
Straw-based bedding materials require pre-treatment to reduce the particle lengths to less than 20mm. This is generally done by chopping and/or crushing bales of hay. Reducing the particle size improves its absorbency and reduces caking problems during the growing cycle.
Ventilation and moisture management
Even with chopping/crushing, straw-based litter will generally require more management to avoid caking issues than other commonly used litters. This will include regular scarifying/conditioning to release excess moisture and break up material on the surface that is beginning to cake. Some producers have found it beneficial to add a layer of sawdust over chopped straw to reduce caking problems, particularly in cooler, wet winters in southern Australia.
Caking and litter conditioning
Chopped straw is more susceptible to caking than other bedding materials and will require more diligent monitoring and conditioning/scarifying than shavings.
Provided that it is effectively chopped to reduce the particle size to less than 20mm and it has a low moisture content (<15% wet basis), producers have effectively used straw without excessive caking.
Litter re-use
Re-use with chopped straw has not been common in Australia, as most re-use has occurred in Queensland and New South Wales, where straw use is minimal. It has, however, been successfully re-used in the USA.
Spent litter management
Useful as a fertiliser under Australian conditions but will likely have more weed seed contamination than wood-based (shavings, sawdust) products. This, however, can be overcome with effective composting before application.
It is more desirable for use in energy generation than timber-based material using anaerobic digestion, as the straw will more readily digest than timber. The manure and straw components will also generate energy in combustion processes, provided moisture levels are low.
