|CALVO, MICHELLE - University Of California
|GERRY, A - University Of California
|McGarvey, Jeffery - Jeff
|MITLOEHNER, FRANK - University Of California
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/17/2009
Publication Date: N/A
Interpretive Summary: The production of house flies at commercial dairies affects both animal welfare and neighbor relations. Calf bedding mixed with excreta, spilled milk and grain, and water promotes optimal conditions for bacterial and immature fly (larval) development, often resulting in high adult fly abundance near calf-rearing facilities. The present study demonstrated that an antimicrobial acidifier, sodium bisulfate (SBS), was an effective tool in decreasing the survival of fly larvae and the bacteria they feed on when applied to calf bedding. Application of SBS to calf bedding in the field should reduce adult fly populations originating from calf hutch environments.
Technical Abstract: Environmental stressors, such as high fly density, can impact calf well-being. Sodium bisulfate (SBS) is an acidifier that reduces the pH of flooring and bedding, creating a medium that neither bacteria nor immature flies (also known as larvae or maggots) can thrive in. Two experiments were conducted to investigate the application of SBS to a mixture of rice hull calf bedding and calf slurry (BED) to reduce house fly (Musca domestica L.) larval density and the abundance of bacteria. In Exp. 1, dish pans containing 1 L of BED and 3,000 house fly eggs were treated with SBS at a concentration of either 0, 8.9, 17.7, and 26.5 g of SBS/0.05 m2 of BED (CON, LOW, MED, HIGH, respectively), with each SBS concentration applied to 4 individual pans (16 pans total). Reapplication of the same SBS concentrations in each pan occurred 3 times/wk throughout the 23 d trial. Larval house fly survival was significantly reduced in all pans with SBS relative to CON pans, with lowest survival rates in the MED and HIGH pans (99% and 100% reduction). The mean pH for each treatment was inversely related to the SBS concentration. In Exp. 2, pans containing 1 L of BED and 3,000 house fly eggs were treated with either 0g SBS (CON), 8.9 g SBS/0.05 m2 BED with 3 times/wk reapplication of the acidifier (SB3x), or 8.9 g SBS/0.05 m2 BED applied only once at 48 hr before the end of the 8 d trial (SB48). Larval house fly survival and bacterial concentrations were reduced in the SB3x (90% larval reduction and 68% bacterial reduction) treatment relative to the CON. Mean pH was also reduced in SB3x pans relative to CON or SB48 pans. Overall, acidification of calf BED using the acidifier SBS resulted in a reduction of bacteria and house fly larval survival. This form of fly control might be expected to reduce adult fly production and therefore fly-related stress in calves.