Bedding - on the surface, it seems quite a straightforward subject: if a farmer is going to put cows in a housing facility they need to provide something to make the cows' resting time comfortable and to soak up the manure.
However, once one digs below the surface it gets a bit messy and there are many things that need to be considered.
So step back off the bedding pack and have a look at the purpose of bedding, what materials are used, and the types of bedding systems.
Purpose of bedding
There are three main purposes for bedding: To provide a comfortable, soft lying surface for the cows. To absorb moisture. To assist with hygiene in the cow housing facility by minimising bacterial growth.
Bedding also helps with providing traction on the housing surface allowing cows to safely move about the facility.
Lactating cows spend 10-12 hours per day lying, but they are picky about their lying surface.
If cows do not like the bedding surface or do not feel they have enough space to lie down comfortably, they will reduce the amount of time they spend lying, which can lead to reduced milk production and health issues such as lameness.
The ideal bedding provides ample cushioning, has a dry surface so cows are kept clean and provides enough grip so they can stand up and lie down confidently.
Bedding materials Organic material options for bedding include straw, sawdust, woodchips, rice hulls, shredded paper and composted manure solids. Inorganic options include sand, crushed limestone and man-made materials such as rubber, plastic and other products.
The base for bedded areas in any cow housing facility can be compressed earth, clay, gravel or concrete. It may also include a mat, which can be made of hard rubber or plastic, carpeting materials, or other compressed products. The housing base alone, with or without a mat, does not provide sufficient cushioning for cows to lie on for any length of time.
There are several bedding systems commonly used for dairy cattle in Australia, and the system used depends on the type of housing facility.
Freestall bedding systems. In a freestall facility, bedding will usually be a deep bed system or a mattress-based system. For a deep bed system, bedding material is placed in each stall on the housing base to a depth of at least 15 centimetres (25cm for sand). Soiled or wet patches of bedding need to be removed daily and the bedding surface thoroughly raked or 'groomed'.
Holes need to be filled in to ensure cows can use the stalls safely and the bed needs to be levelled so the effective lying area in the stall is not reduced by bedding banking up at the edges. Additional bedding material is added as required to maintain adequate depth. The frequency of complete replacement varies with the material.
Mattresses for free stalls consist of a tough fabric material, such as heavyweight polypropylene, that is stuffed with a filling such as shredded rubber, water or gel. A mattress is fitted in each stall and then top-dressed with additional bedding material to absorb moisture. Soiled top-dress bedding material needs to be removed daily and replaced with new material. Mattresses also need to be scraped or hosed off regularly.
Bedding systems for loose housing. In a loose housing facility, the bedding is usually operated as a deep litter (straw yard) system or a compost pack. Large amounts of bedding are required. While deep litter and compost pack systems can look similar, the management principles are quite different between them.
In a deep litter bedding system, a large amount of organic bedding material is placed on the housing base and is then continuously topped up to maintain a clean, comfortable surface. A deep litter system acts as a manure storage with the entire bedding material scraped out and replaced only once or twice a year.
In a compost pack system, the aim is to use the natural composting process in situ to maintain a comfortable bedded area. The combination of carbon from the bedding material, nitrogen from the manure and urine, and the right moisture level and aeration results in microbial breakdown of organic matter, i.e. composting, in the bottom 10-20cm of the pack.
The biological activity of the composting process generates heat, which helps dry the upper portion of the bedding pack.
The bedded pack requires aerating two or three times a day to maintain the composting activity and refresh the bedding surface. Fresh bedding is added to the pack when it becomes too wet.
Particular attention needs to be paid to cow density and ventilation in the housing so moisture levels do not get too high. A compost pack may operate for several years until it is removed and replaced.
Composted manure as bedding. The use of composted manure (also known as dried or recycled manure solids) as a bedding surface has been gaining popularity as it is a relatively cheap product, and in plentiful supply. Manure is separated from the effluent stream, composted and then spread into the housing area. It is important to be clear that composted manure bedding is not the same as a compost pack bedding system.
So there you have it. More options than a stroll through a Forty Winks store really. But regardless of housing system and bedding choice, the goal is always to make sure cows have somewhere clean, dry and comfortable to lie down.D
Contact: Dr Sarah Chaplin, phone 0439 275 896, email email@example.com.
*Dr Sarah Chaplin is a development specialist animal performance with Agriculture Victoria and Dr Yvette Williams is a research scientist ù dairy nutrition with Agriculture Victoria.