Evaluation of propane flaming for reducing bacterial counts in sand bedding.

An experiment was conducted on a commercial dairy farm to determine the effects of propane flaming on bacterial populations of common environmental mastitis pathogens in recycled sand bedding. One row of freestalls was flamed within 12 h after recycled bedding was added to stalls and then daily for the next 6 d. Bedding in a control row of freestalls was untreated. Stalls received the same treatment for 3 consecutive weeks. After 3 wk, bedding treatments were changed between rows in a switchback design. The daily movement of the 760°C propane-fueled flame at 3.2 km/h over the surface of recycled sand bedding in stalls had a positive effect by reducing mastitis pathogen loads at different depths of bedding in a pathogen-specific manner. The greatest reduction of mastitis pathogen populations by flaming was on the surface 25 mm of recycled sand. Reductions in bacterial counts in deeper layers were less consistent. Bacterial populations in both flamed and control sand bedding were lower on the surface 25 mm compared with sand at a depth of 50 to 75 mm. The effects of subsequent flaming of sand over a week also differed among pathogens. In general, mastitis pathogens were reduced the most on the day that recycled sand was added to stalls, and flaming was less effective as sand bedding was in stalls over a 6-d period. The use of propane flaming of recycled sand was shown to have potential as a practice to control mastitis pathogen populations in bedding. The greatest advantage afforded by flaming was on the surface of bedding, with inconsistent effects deeper in the stalls. Flaming was more effective in controlling bacterial populations in fresh recycled sand than in sand after several days use