The choice of bedding system and the type of bedding materials used in cow housing facilities will have a substantial impact on the management, and even design, of that facility.
Dairy farmers who are planning a new development of a house facility should consider bedding before they start to build, not after.
Bedding choices are driven by several different factors: Materials readily accessible in the required amounts and at a suitable cost. Information and recommendations provided by local consultants and salespeople. Local climatic conditions and expected variations in weather. The bedding systems and materials that have been traditionally used in the industry. The operator's skills to manage the bedding system. The farm's ability to handle the bedding waste.
As observed in the first article in this series , whether dairy cows are housed in a freestall barn or kept in some form of loose housing, the purpose of providing bedding is to create a comfortable lying surface that encourages cows to lie down, and to keep the cows clean and healthy.
If the lying surface is not comfortable, cows may spend less time lying down or have a more disturbed pattern of lying behaviour. Shorter lying times in housed systems have been associated with lameness, while cows that spend more time standing in slurry are also at risk of other foot conditions such as slurry heel. Apart from the obvious welfare issue of lameness itself, lame cows produce less and are harder to get in-calf.
Dirty cows and a soiled bedding surface are risk factors for clinical and subclinical mastitis. Every dairy farmer knows that these reduce milk quality and have direct, and avoidable, impacts on milk income.
A bedding depth that is inadequate or bedding that has been allowed to compact can increase the presence of skin injuries on the cows, particularly on the knees or hocks. Skin injuries can range from small areas of hair loss to open wounds, infection and joint swellings.
The bedding systems used for freestall barns are usually deep-bed or mattress-based systems. For loose housing barns, a deep-litter system can be used, and compost pack systems are becoming popular. In each of these bedding systems a range of different bedding materials can be used successfully.
When choosing a bedding system and type of bedding material, it is important to consider how the bedding will be managed on a daily basis, what interaction it will have with the effluent-management system, and how the waste bedding will be handled once removed from the housing. Every bedding material type has its own costs, benefits and management challenges.
The local climate will also need to be considered. Compost pack systems rely on careful management of heat and moisture in the compost pack, particularly in dry, wet, hot or humid conditions. In areas where heat stress needs to be managed, thought needs to be given to how the cooling system will interact with the bedding. For example, use of a water spray or evaporative cooling will increase moisture levels whereas cooling fans do not rely on water. Sand bedding will conduct heat away from cows whereas some forms of compost bedding will generate heat.
A local supply will be needed that can be affordably and easily accessed. A farmer doesn't want to design a bedding system around a bedding material that is only available sporadically or where the price varies markedly.
Here are some general comments about different bedding types:
Sand is often considered the gold standard for deep bedding in freestall barns. Sand is inorganic, so bacteria is less likely to grow in the bedding, assisting with mastitis control, and generally a deep sand bedded freestall can be comfortable (provided the design and dimensions of the freestalls are suitable). Sand can, however, be hard to handle in some effluent systems, and may be hard to source in some areas of the country. A well-planned and designed freestall barn and effluent management system can allow sand bedding to be efficiently recovered and re-used.
Organic materials, such as sawdust, straw, woodchips, wood shavings, shredded paper, dried manure, bark, seed hulls (e.g. rice, almond, etc.), can be used effectively for deep bedding. Dried sawdust and wood chip is usually preferred over green wood sources, as the dried bedding can absorb more moisture than the green bedding. Dusty bedding can lead to eye and respiratory problems and, of course, it is important to avoid any materials that may be toxic when ingested. Used organic bedding material can also be dried and re-used or composted following a specific standard and then re-used.
Mattresses or rubber matting can be used in freestall barns to provide a cushioned lying surface in each stall, but they need absorptive bedding added on top to soak up moisture and keep the cows clean. Some research shows that mattresses are associated with a higher incidence of lameness than sand bedding. Waterbeds are another synthetic option that also need an absorptive layer but have been reported to help cows manage heat stress.
Straw has traditionally been used in deep-litter bedding systems. It performs well as a bedding material provided moisture levels at the bedding surface can be kept low. Less severe hoof disorders and reduced wear have been reported for deep-litter bedding systems compared with freestall barns, although different hoof disorders may be more prevalent. Very large amounts of straw are required: 7-18 kilograms per cow per day has been recommended, which equates to about 1 tonne per day per 100 cows.
Many different organic materials can be used for a compost pack system, provided they maintain a coarse particle size, don't clump together or compact excessively, and can be tilled easily. They also need to be readily absorbent. Care needs to be taken with some wood types as they have antimicrobial properties that reduce the effectiveness of the composting process, and some have the potential to cause diseases such as laminitis.
Although less bedding overall is required in a compost pack system, compared with deep litter systems, it takes a lot of skill and attention to maintain the compost
Farmers need to make sure that they make an informed choice and end up with a bedding that suits their farm and their management, and that keeps their cows clean, comfortable and healthy.D
Contact: Dr Sarah Chaplin, phone 0439 275 896, email email@example.com.
*Dr Sarah Chaplin is Agriculture Victoria's development specialist (animal performance) and Dr Yvette Williams is an Agriculture Victoria research scientist (dairy nutrition).