|Mitloehner, F - TEXAS TECH UNIVERSITY|
|Mcglone, J - TEXAS TECH UNIVERSITY|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 20, 1999
Publication Date: N/A
Technical Abstract: The objective of this study was to reduce the dust generation in a commercial feedlot by understanding and managing dust-generating behaviors of feeder cattle. It was hypothesized, that through changes in feeding management practices, cattle activity patterns that result in high quantities of dust may be redirected towards feeding and ruminating behavior which generate significantly less dust. Treatments were either th (1) conventional feeding at sunrise, 10 AM and noon (CON) or (2) feeding at sunrise, noon, and just before sunset (ALT). Behavior of 1,123 steers in 4 pens at a commercial feedlot was recorded. Dust data loggers (DustTrak, TSI, MN) measured particulate matter counts particle size 2.5 um. Ambient temperature, humidity, wind speed and direction, precipitation, air pressure and solar radiation were measured with a weather station (Gempler, Austria). Regression analysis determined that weather parameters explained only 18% of the variation in dust levels (R*2=0.18, P<.001). High dust levels were observed around sunset. When cattle were ALT they were engaged in dust-generating behaviors 20.6% of the time compared to 69.0% in the control pens (P<.01). Unlike CON steers, steers fed at sunset ate, were waiting to eat or ruminated (8% VS. 32.6%, P<.01) during the sunset period. This change in behaviors had a positive effect on the dust levels. Over a period of 10 days, the 24-hr dust average in ALT pens was 0.044 mg/m*3 vs. 0.61 mg/m*3 for CON. Changing the feeding regime of cattle to ALT redirected the cattle away from dust-generating behaviors thereby reducing aerial dust concentrations below EPA allowable limits.