Vet´s perspective

Nov 25, 2011
by WLJ

Drug residues: cause and effect

Reports distributed by USDA have demonstrated test results with carcass drug residues on many occasions. Not only are carcasses involved in an inspection, but the management and environment may be assessed for proper equipment, training and protocols.

So why do these residues occur? Multiple factors are associated with this process. Any pharmaceutical can be detected when used off label instructions or when withdrawal times are not adhered to.

First, and very commonly found in my experience, is the repeated change or inaccurate dosing of antibiotics. A commonly used drug like penicillin is often administered at doses twice that of labeling protocol. Animals that are treated with drugs at higher than recommended levels or given medications in an unprescribed method (subcutaneously versus intramuscular) can ultimately increase the slaughter hold withdraw time by weeks.

Another commonly used pharmaceutical is the pain medication flunixin meglumine or Banamine. This drug is labeled to be administered in the vein, but many times is alternatively given under the skin or deep in the muscle. These off-label methods can increase the withhold time to over a month versus four days when given in the vein.

The same condition is also true for cows marketed after being treated for mastitis, dry-treated cows that have recently aborted, intrauterine use of tetracycline boluses, and calves fed medicated milk replacers.

Sulfa-type drugs (sulfonamides) can be detected in residues when over-dosed or administered inappropriately into the muscle or under the skin.

The National Cattlemen’s Beef Association works in accordance with outline specifications related to judicious use of antimicrobials. Such rules include: avoiding use of antibiotics that are concur rently important in human medicine, using the narrowest spectrum of antibiotics possible for treatment, treating the fewest number of animals feasible, and limiting antibiotic use to treatment and prevention of disease—versus the intent to improve an animal’s performance.

Proper animal records and withhold protocols are key to preventing residues from being found on your facility. No meat sold in the U.S. is allowed to contain antibiotic residues that violate FDA standards, and these drugs have gone through a rigorous testing process before attaining FDA approval.

A recent finding, according to the Reuters Health Poll, stated that approximately 57 percent of Americans are concerned with the status of food safety; this has decreased from approximately 61 percent last year. Even with the outbreaks of food-associated disease related to produce earlier this year, meat supply is still the top concern to most Americans.

The Government Accountability Office also reported recently that there is currently not enough data to study links between antibiotic usage in food animals to antibiotic use in humans due to a lack of evidence necessary to analyze trends and relationships between use and resistance. Data was collected via USDA and the Department of Health and Human Services. Congress has continued to make attempts at restricting antibiotic use in food animals regardless of this statement.

Veterinarians and producers can access further information on common “mistakes” that often lead to meat residues by going online and viewing a presentation in accordance with Washington State University. The program can be accessed at www.; search for “farma-cology 101.” — Dr. Genevieve Grammer [Dr. Genevieve Grammer is a mixed-species veterinarian practicing in eastern Colorado. Please direct correspondence to drgi]