The New-Old Bedding Dilemma
Posted: June 11, 2009
Dairy producers have been very challenged recently to find consistent and economical sources of suitable bedding material for dairy cattle. The debate of organic vs. inorganic bedding and which has better udder health has gone on for some time. Many organic and inorganic bedding options have been tried and can be used successfully. In general, many organic bedding options can work but producers need to focus on keeping them dry and frequent cleaning. Inorganic bedding materials almost always start out lower in bacterial counts and generally they support lower bacterial populations. Under the right circumstances and with the proper management, a long long list of products can be used successfully on the dairy farm.
For various management, manure handling, and economic reasons the use of manure solids has re-emerged as a bedding product on dairy farms. Manure solids are a new-old bedding option. Dried manure solids have been used successfully for decades. The key here has been dried solids. Currently bio-digesters, composting facilities, and manure separators are generating manure solids that are being used on dairy farms. There are some challenges using these products and maintaining udder health; however, if managed properly they can be used successfully.
There is strong correlation between mastitis, Somatic Cell Counts (SCC) and teat end exposure to bacteria as reflected by bacteria counts on the teat skin. Bacteria counts in bedding that exceed 1 million colony forming units per gram are likely to lead to increased cases of mastitis. Bedding counts for clean fresh sawdust are often in the low thousands to tens of thousand range prior to application to cow beds. Conversely recycled manure or dried manure solids may have hundreds of thousand of bacteria in them prior to adding them to stall beds. The key issue is time under the cow, moisture content, and number of times stalls are scraped. Any organic material will generate very high bacteria counts if the bacteria are supplied with sufficient moisture and warmth. This is still in contrast with inorganic bedding materials which tend to stay lower in bacterial counts until they become contaminated.
Sawdust and shavings vs. manure solids or recycled manure or composted manure can act very similar in the level of bacterial exposure to the teat skin. If used properly they can be used successfully if mis-managed they can lead to significant increases in mastitis. Fresh wood products tend to have more energy to support bacteria growth long term, but usually are drier and have lower counts initially. Recycled manure or dried manure solids tend to have less energy to support bacterial growth but frequently are much higher in initial bacterial counts. In both cases some general rules can be applied.
1. The hygiene score of the upper hind leg and udder are positively correlated with SCC and mastitis. That is simply, if the cow bed is clean and bedding is dry such that no manure, bedding, or wet staining of the hind leg or udder is visible when the cow rises from the stall, you are probably doing an acceptable job of stall maintenance. No secret here, clean and dry is better.
2. The drier you can keep the bedding the better. Covered sheds vs. a tarp is a preferred method of storing stockpiled bedding materials. Very dry or manure solids that have been heated via a composting process, will start out at lower counts.
3. The rear one third of the stall should be scrapped several times per day and fresh bedding added to that portion of the stall. It is better to add new bedding and not simply rake bedding back from the front of the stall.
4. Long particle length or fluffy materials will support slower bacterial growth and reduce bacterial exposure of the teat skin.
5. In some cases bedding additives may influence bacterial counts for short periods of time. They do not replace frequent stall cleaning and daily stall maintenance. Manure solids or recycled products tend to be close to a neutral pH when initially added to stalls. Here lime or other alkalinizing products may increase the pH to such high levels that for the first day or two bacteria counts are inhibited. Conversely some fresh sawdust products actually have a slightly acidic initial pH; here acidifying products have been shown to lower counts for the first couple of days. In either case adding the wrong product can bring the pH closer to neutral and may actually encourage more bacterial growth Additives should never be viewed as replacing frequent and adequate stall maintenance or sufficient bedding depth.
If readers are interested in having their bedding cultured, this can be done by contacting the laboratory of Dr. Bhushan Jayarao, 814-863-2160. To achieve some meaningful numbers a few basic guidelines need to be followed for sampling and shipment, otherwise counts will be meaningless.
Readers are also encouraged to contact members of the Ag and Biological Engineering Department for specific questions on stall design and manure handling systems at 814-8635-7792.
References for further reading.
- Hogan, J.S. and K.L. Smith, Bacterial counts associated with sawdust and
recycled manure bedding treated with commercial additives, Ohio State Extension
Special Circular 169-99
- Reneau, J.K. et al., Association between hygiene scores and somatic cells
scores in dairy cattle, JAVMA 2005, Vol. 227, No. 8, pp 1297-1301
- Reneau, J.K., Bedding and Bacteria, University of Minnesota Dairy Initiatives Newsletter, 2001, Vol. 10, Issue
- Zdanowicz, M., et al., Bacterial populations on teat ends of dairy cows housed in free stalls and bedded with either sand or sawdust, JDS 2004, Vol. 87, No. 6, pp 1694-1701
David Wolfgang, Penn State Extension Veterinarian