The following information was presented at the National Mastitis Council Annual Meeting in January 2013. Click here to visit NMC online. To assert that dairy farming is a rapidly changing business in today’s world is an understatement. Not only is technology driving change on the farm at a never-before-seen pace, it is driving change with cooperatives, processors, retailers and consumers alike. None of us can afford to do business in the same manner we did in the past. This particularly applies to animal agriculture.

Concerns over animal well-being resonate in the public sector. Food safety is continually monitored by processors, buyers and regulatory agencies.

Consumers, driven by the easy access of information on the Internet and social media sites, are asking more questions and demanding more answers about nutrition, health and food in general.

As these discussions become more frequent, producers will begin to feel the push for better and safer food. At the center of many consumer discussions about food we hear words like pesticides, hormones and antibiotics.

The following article talks about risk factors for uses of specific drugs and behaviors when using those drugs. Most of the information in this section comes directly from the National Milk Producers Federation Milk and Dairy Beef Residue Prevention Manual.

However, I do feel compelled to make a couple of disclaimers. The mention of specific drugs or trade names does not imply an endorsement or condemnation of their use in dairy cattle.

The suitability of particular drugs for certain applications is part of a valid veterinarian/client/patient relationship and is the sole responsibility of your veterinarian.

Examples of products and risk factors for residues

• Flunixin meglumine: Using flunixin meglumine in an unapproved route of administration, such as intramuscular or subcutaneous, may result in unintended residues. This drug is only approved for intravenous administration. Using another administration method results in extended withdrawals.

• Ceftiofur: This drug is used in a variety of applications. Some are administered intramammary, some intramuscularly and one is to be injected only at the base of the ear. In addition, meat withdrawal times for one of these applications have recently changed.

Directions for use for each type must be reviewed and followed. Using withhold times for one product when using another may result in residues. Producers must keep accurate records of product given.

• Enrofloxacin and danofloxacin: Extra-label use of enrofloxacin and danofloxacin in food animals is prohibited. They are only labeled for non-lactating dairy replacement animals and beef animals for pneumonia. Any other use is illegal.

• Florfenicol: Florfenicol has a sustained release, and as a result, has a longer withdrawal time than some other commonly used drugs. It is not approved for dairy cattle over 20 months old. The labeled meat withdrawal is 38 days.

• Tilmicosin: Tilmicosin is another drug that has extended withdrawal times. It is not approved for dairy cattle over 20 months old. The labeled meat withdrawal is 42 days.

• Gentamicin: Use of gentamicin also results in extended withdrawal times. Because of the extended withdrawal time, its use is discouraged by American Veterinary Medical Association , the American Association of Bovine Practitioners and the Academy of Veterinary Consultants .

Gentamicin use in lactating dairy cows intramammary is not recommended. The Food Animal Residue Avoidance Database (FARAD) recommends not less than a two-year withdrawal and therefore, the use of this drug should not be considered.

• Neomycin: Risks for neomycin residues include not following withdrawal times as listed on labels, feeding neomycin-medicated milk replacer to calves to be processed for veal and using oral neomycin products in an extra-label fashion.

• Penicillin: Penicillin residues and extended withdrawal times are fostered by increasing the dose, frequency or duration of administration without an extended withdrawal period.

Residues can also occur from using the drug in an unapproved route of administration – i.e., subcutaneous or intramammary and by giving more than 10 cc per injection site.

Penicillin use at levels beyond label directions, commonly one cc per 100 pounds of bodyweight, must be prescribed and extra-labeled by a veterinarian.

• Sulfas: Using any sulfonamide product not labeled for lactating dairy cows is illegal. Using a higher dose or increase in frequency of administration will result in extended withdrawal times.

Extended withdrawal times also result from using a sustained-release product instead of using a daily product. Sustained-release products are not legal for use in lactating dairy cattle.

Prohibited extra-label drugs
The following drugs, families of drugs and substances are prohibited for extra-label animal and human drug uses in food-producing animals: chloramphenicol, clenbuterol, diethylstilbestrol (DES), dimetridazolez, ipronidazole, other nitroimidazoles, furazolidone, nitrofurazone, sulfonamide drugs in lactating dairy cattle (except approved uses of sulfadimethoxine, sulfabromomethazine and sulfaethoxypridazine), fluroquinolones, glycopeptides and phenylbutazone in female dairy cattle 20 months old.

Non-approved drugs
The following drugs are not approved for use in any species of food-producing animals: chloramphenicol, clenbuterol, colloidal silver, diethylstilbesterol (DES), dimetridazole, estradiol cypionate (ECP), glycopeptides (vancomycin), furazolidone, ipronidazole, nitrofurans (nitrofurazone paste or furazone aerosol spray) and other nitroimidazoles (metromidiazole).

Other drugs may be extra-labeled for use in dairy cattle if a valid veterinary/client/patient relationship is in place and the extra-label drug use guidelines are followed.

Flow charts are available to assist veterinarians in making decisions surrounding the appropriate use of extra-label drugs. See a copy of the Milk and Dairy Residue Avoidance Manual for details.

Where do we stand today?
Each year, nearly three million adult dairy cull cows are slaughtered for beef. Of that amount, a very small percentage actually test positive for a residue.

Over the past few years, USDA has made several changes in its residue screening program including implementation of the KIS test and increasing the number of tests conducted on dairy cull cows.

In spite of these changes, the number of tissue residues in dairy cull cows has decreased from 1,017 in fiscal year 2007 to 453 in fiscal year 2011 – a 55 percent reduction.

Only seven of the nearly 52,000 licensed dairy farms are listed on the USDA/APHIS “Residue Repeat Violator List.” Antibiotic residues in milk continue to decline. Data from 1996 to present shows a steady downward trend.

There were 3,530 loads of milk positive for beta-lactam drugs in 1996; this was a rate of 0.104 percent of all loads. In 2011, that number decreased to 671 loads – a rate of 0.021 percent.

Facilitating continued change
As we look back at the consumer concerns, antibiotic history, risk factors for residues and progress we’ve made, it becomes very apparent that there was an antibiotic residue problem of some magnitude within the dairy industry.

Fortunately, concerned producers have stepped up to the plate and put into place protocols, standard operating procedures and records to help minimize the risks of residues on their farms and across the industry.

Although producers will always do the bulk of the work needed to drive residue occurrences even lower, they certainly can use the help of industry professionals to achieve their goals. What tools are available for producers, veterinarians and dairy professionals to move this effort forward?

The National Dairy Farm Program: Farmers Assuring Responsible Management (FARM) offers a free download of the Milk and Dairy Beef Drug Residue Prevention Manual.

The manual is a concise review of judicious use of antibiotics in dairy animals and is a quick resource to review those antibiotics approved for dairy animals and can also be used as an educational tool and resource for farm managers as they develop their on-farm best management practices necessary to avoid milk and meat residues. Click here to learn more about this program.

The Wisconsin Veterinary Medical Association (WVMA) has also developed a program to aid member veterinarians and their clients in avoiding drug residues. Their producer message is relatively simple and straight to the point. The message centers on the word “trust.”

Talk with your veterinarian to set up and review treatment protocols annually. Record health treatments. Understand and follow label directions. Stop treating the incurable. Take on disease prevention as your top priority. Click here to learn more about WVMA’s program.

By following these simple steps producers can reduce the risks of residues in milk or meat and gain consumer trust in their products. PD

Michael O’Brien is the director of procurement at Foremost Farms USA Cooperative in Baraboo, Wisconsin.

References omitted due to space but are available upon request. Click here to email an editor.

—Excerpts from 2013 National Mastitis Council Annual Meeting proceedings

Michael O'Brien
Director of Procurement
Foremost Farms USA Cooperative