Submitted to: Journal of Dairy Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/8/2013
Publication Date: 4/1/2013
Citation: Hausler, K., Godden, S.M., Schneider, M.J., Lightfield, A.R., Bulthaus, M., Haines, D. 2013. Hot study: Investigating the risk for violative meat residues in bob veal calves fed colostrum from cows treated at dry-off with cephapirin benzathine. Journal of Dairy Science. 96(4):2349-2355. Interpretive Summary: The antibiotic cephapirin is approved by the U.S. FDA for intramammary infusion in cows during the dry off period. This pilot study investigated whether colostrum from such cephapirin treated cows, when fed to young bob veal calves, would lead to violative levels of cephapirin residues in veal tissues. Colostrum was collected from cows treated with cephapirin during dry off and fed to young bob veal calves, which were then sacrificed. Cephapirin residues were not found in the colostrum using either a CHARM II screening test, or by high performance liquid chromatographic analysis. Similarly, no cephapirin residues were detected in veal tissues using a KIS (trademark) screening test, or LC-MS/MS analysis. This work suggests that potential transfer of cephapirin from cows treated at dry off to calves via their colostrum may not be a significant source of cephapirin residues in veal tissues.
Technical Abstract: The objective was to complete a pilot study to investigate if violative meat residues are detected in very young bob veal calves that are fed first milking colostrum harvested from cows that were dry treated, on label, with cephapirin benzathine. First milking colostrum was collected from cows that were given intramammary treatment at dry off, on label, with cephapirin benzathine (ToMORROW®, Boehringer Ingelheim Vetmedica, Inc., St. Joseph, MO). Newborn bull calves meeting study inclusion criteria were removed from the dam shortly after birth and before suckling, and assigned to one of two trials. For the first trial, six treated calves were fed 3.8 L of fresh maternal colostrum and one control calf was fed 1.5 doses of a plasma-derived colostrum replacer (Secure Calf Colostrum Replacer®, VitaPlus Inc. Madison, WI) within 1 hour after birth. For the second trial, five treated calves were fed 3.8 L of fresh maternal colostrum and one control calf was fed 1.5 doses of Secure Calf Colostrum Replacer® within 1 hour after birth. All calves were humanely euthanized at either 24 hours of age Trial 1) or 48 hours of age (Trial 2) and tissues harvested for antimicrobial residue testing. Samples of maternal colostrum and colostrum replacer were also submitted for antimicrobial residue testing. All maternal colostrum and colostrum replacer samples fed to study calves tested negative for cephapirin benzathine residues, as determined using the CHARM II test as a screening test (Charm Sciences, Lawrence, MA) and HPLC as a confirmatory test. Similarly, frozen kidneys collected from all study calves tested negative for cephapirin benzathine residues as tested using both the KISTM assay (Charm Sciences, Lawrence, MA) and LC-MS/MS analysis. To conclude, in this pilot study, one 3.8 L feeding of first milking colostrum collected from cows given intramammary treatment with cephapirin benzathine at the time dry off, and on label, did not result in a violative meat residue in bob veal calves.