Residue Roulette

November 21, 2015 02:24 PM
Residue Roulette

There’s no question antibiotic usage—and residues—are coming under increasing scrutiny by consumers and government agencies.

This past year, the Food and Drug Administration (FDA) released the results of a 2012 study that found just 0.7% of raw milk samples from nearly 2,000 farms had violative residues. While the agency deemed the U.S. milk supply “safe,” it noted that all 16 positive samples were from drugs that are not approved for use in lactating dairy cattle. Consequently, none have established tolerance or safety levels.

Antibiotic residues in meat are also of concern. While the violation rate in dairy cows is very low, 0.03%, it is 20 times higher than in beef cows (0.0015%) and 400 times higher than fed cattle (0.00006%).

“The FDA is convinced residue risk drops dramatically when veterinarians work with farmers to develop treatment protocols and supervise their execution,” says Gary Neubauer, Zoetis, senior manager dairy technical services.

“FDA is also convinced all of these residues are the result of extra-label drug use or
using over-the-counter or prescription drugs without veterinary supervision,” he adds.

The three keys to preventing residues are pretty simple:

  •  Read and know label directions.
  •  Follow the label directions.
  •  Observe the labeled milk and meat withholds.

To get a better understanding of how farmers are using antibiotics, Zoetis conducted a study in 2012, 2013 and 2015. It used its veterinary student interns to visit farms to observe what drugs were on dairy farms and how they were labeled and used.


In the Midwest, the interns visited 72 dairy farms in Illinois, Iowa, Minnesota, South Dakota and Wisconsin. Average herd size was about 900 cows, but ranged from less than 100 to more than 3,000.
The results were eye-opening. Herds with fewer than 500 cows were the least likely to have written protocols for drug use. Less than 20% had protocols for mastitis treatment, and less than 10% had protocols for treating metritis, lameness or pneumonia.

Larger herds fared better. But even there, only 40% of herds with more than 500 cows had protocols for mastitis, metritis and pneumonia, and only 25% had protocols for lameness.

Then, the interns looked at whether the protocols were actually followed. Only 40% of the herds with fewer than 500 cows that had protocols were following them. The results were better for the larger herds: Roughly two-thirds were following their written protocols.

But here’s the kicker: The study found many dairies were using unapproved drugs. Only 52% of the herds with fewer than 500 cows were only using drugs approved for lactating dairy cows. Just 73% of 500 to 1,000 cow dairies were only using approved drugs for lactating cows, and only 42% of herds with more than 1,000 cows were only using approved drugs for lactating cows.

As a group, 20% of dairies were using mastitis treatment protocols that would be considered illegal by FDA standards, 20% were using risky extra-label pneumonia treatments and nearly 60% were treating metritis with an antibiotic not labeled for that use.

One bit of good news is that about 80% of all farmers were marking treated cows. But if drugs were not labeled for a specific use, it is difficult, if not impossible, to know what the withholding period for milk or meat sales should be.

So why weren’t protocols being followed? Here’s what the interns found:

  • Protocols are not regularly updated to include new treatment strategies or remove old treatments.
  • Changes in management and people treating the cows were not accompanied by protocol changes to reflect the new members of the management team.
  • Generic protocols are written by the veterinarian and do not involve the dairy farmer to determine the best treatment strategies for each dairy.
  • Protocols are only written for times when the regular sick pen worker is not available. The sick pen worker does not follow the same protocols.
  • Dairies are using illegal drugs, dose, duration or frequency, and therefore, the veterinarian and dairy management team will not include those treatments in written protocols. 


Back to news



Spell Check

Brian D Friesen
Sellersville, PA
11/24/2015 05:35 AM

  How can you write this, "Antibiotic residues in meat are also of concern. While the violation rate in dairy cows is very low, 0.03%, it is 20 times higher than in beef cows (0.0015%) and 400 times higher than fed cattle (0.00006%)." ? And then the next day in your column write "Also startling: “From all classes of cattle, dairy animals accounted for 75% of the inspector-generated KIS (kidney inhibition swab) test positives and 75% of laboratory-confirmed positive tests,” says Katie Mrdutt, a veterinarian and outreach specialist with the Wisconsin Veterinary Medical Association (WVMA)." The dairyman needs to hear the truth. Don't tell him his violation rate is low. Tell the dairyman he is the most reckless meat producer in the supply chain.


Corn College TV Education Series


Get nearly 8 hours of educational video with Farm Journal's top agronomists. Produced in the field and neatly organized by topic, from spring prep to post-harvest. Order now!


Market Data provided by
Brought to you by Beyer