Effect of an Insecticide Controlled-Release Bolus on a Milk Antibiotic Residue Test

¹ Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610 and American Cyanamid Company, 2175 Ten Eyck Avenue, Cazenovia, NY 13035

Following the use of diflubenzuron controlled-release insecticide boluses in a dairy herd, there was a concern that post-calving cows were testing positive on a milk antibiotic residue test for more milkings than they had prior to the use of diflubenzuron. A field trial was conducted to examine for possible effects of diflubenzuron milk residues on the milk antibiotic residue test, Delvotest-P®. Data of 24 cows in the treatment group and 29 cows in the control group were analyzed. There was no significant difference in the number of milkings after calving in which the milk tested positive on the milk antibiotic residue test between the treatment (2.75 ± .94) and control (2.97 ± 1.05) groups when cows in all lactations were analyzed or when analyzed by lactation (1, 2, and 23). It was concluded that the use of diflubenzuron boluses had no effect on the milk antibiotic residue test.

Key Words: diflubenzuron • insecticide • controlled-release bolus • milk antibiotic test

Submitted on February 5, 1990
Accepted on August 1, 1990