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Bacteria Counts in Sawdust Bedding
Dairy Pipeline: December 1997
by
G. M. Jones
Extension Dairy Scientist, Milk Quality and Milking Management
Virginia Tech
Drs. Joe Hogan and Larry Smith, Ohio State University's OARDC at Wooster, followed the change in bacteria counts when fresh sawdust was used as bedding in tie stalls. Bedding was changed every 7 days. In one-third of the stalls, the back one-third of the sawdust was replaced daily. In another one-third of stalls, 1 kg (2.2 lb) of hydrated lime was spread over the back one-third of the stall on the day that new bedding was added. Neither daily replacement nor addition of lime was as advantageous as changing sawdust every 7 days. The lime reduced the bacteria count on the day it was added but its "ability to alter bacteria counts was diminshed within 48 hours." Bacteria on teats were counted, but there was no effect of lime on coliforms or streptococci, the usual causes of environmental mastitis. The only effect of lime was a significant reduction in bacteria counts on day 1. As for daily removal of manure from the back third of the tie stalls, the advantage was minimal and only on day 0. The bedding increased in moisture content, comparable to the other two treatments and the organic matter in the bedding became a source of nutrients to the bacteria and daily removal had little effect on bacteria found on teat skin. In other presentations, I have heard these scientists recommend sand over sawdust, shavings or straw because of diminished environmental mastitis (coliforms and streptococci).