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Are you Part of the Residue Problem or Soultion?

Posted: December 14, 2010

Data regarding antibiotics in dairy products and meat has been monitored and of concern for many years, but recently government agencies, medical personnel, and consumers have place much more interest in this public health issue.

You may have noticed a number of articles in popular farm journals that address the issue of antibiotic residues and/or resistance.  Data regarding antibiotics in dairy products and meat has been monitored and of concern for many years, but recently government agencies, medical personnel, and consumers have placed much more interest in this public health issue. Why has this issue seemed to re-appear?

It is very likely that if progress is not made on the residue and resistance issue, in the near future, restrictive legislation may greatly limit the use and access livestock producers and veterinarians have to antibiotics.

The Food Safety Inspection Service (FSIS) recently released it most current data on residues. That report was from 2008 data. In that year, approximately 34.7 million cattle were harvested. Tests were positive in 0.0007% of bob veal calves, and 0.0004% of dairy cattle. While these numbers seem low, they are much much higher levels than found in steers, swine, special fed veal, or poultry. Of all the positive antibiotic residues from meat, dairy cattle contributed 66% of all the positives and bob veal calves contributed 24% of the positive tests. Dairy cattle account for approximately 28% of the total pounds of beef nationwide. Bob calves only contribute about 33% of the veal into market channels. Since both the market (cull) dairy cow and bob veal calf are essentially residue problems due to animals leaving dairy farms with volatile residues, much emphasis and finger pointing has been turned toward the dairy producer. The FDA and FSIS personnel are also being more aggressive in trace back to individual farms to identify repeat offenders with greater fines and restrictions. Some of the controversy is complicated by concerns from public health officials and some consumers regarding antibiotic resistance. 

The residue and resistance controversy tends to be different.  Most of the resistance issue is related to antibiotics in feed or water. Antibiotics administered in this way rarely are implicated as a residue problem. In this case, antibiotics are usually given on a herd or flock basis. Residues are more found after treatment of individual animals (or contaminated milk fed to bob veal calves).  In both cases the long-term damage to the image of dairy and livestock owners is related to the perception that cattle producers, as well as veterinarians, are not doing everything possible to use antibiotics judiciously and avoid residues. It is very likely that if progress is not made on the residue and resistance issue, in the near future, restrictive legislation may greatly limit the use and access livestock producers and veterinarians have to antibiotics. 

One reason that antibiotics residues appear to have increased in cull cattle over the last few years is related to the strategy now employed at most processing plants to target animals likely to be positive for residues. Federal inspectors now target for additional testing animal that upon inspection appear likely to have been treated, have blemishes, or may  be from a producer who had a history of previous positive tests. Further new tests have been developed to identify compounds that might not have been detected a few years ago. This is certainly the case for flunixin meglumine (Banamine ®, Intervet Schering-Plough; Millsboro, DE, USA). The use of flunixin meglumine has been promoted to improve animal well-being, and is a real aid for pain and fever. In this case, a good and effective product has been used more frequently and advocated. This product is labeled for IV use but is frequently given IM or SQ. Many veterinarians and producers were not aware that this product creates a tissue blemish and at a packing plant it is easy to predict where this or other products have been injected into animals. 

A few years ago there was no simple test to detect flunixin meglumine either in milk or meat. While withdrawal and with-holding times were advocated and published, on-farm tests would be negative and some producers likely were tempted to assume there was no residue. Cull cattle or milk could have been inadvertently marketed while positive. It is very important that producers follow the label instructions for all products and only deviate from the label instructions if they receive specific directions from their veterinarian. If products are used at levels higher than normal or in tissues or therapeutic conditions different  than those published on the label, withdrawal and withholding times must be extended.  

At this time, many interested regulatory agencies and consumer groups are looking over the shoulder of dairy and livestock producers, plus large animal veterinarians, and questioning how and why pharmaceutics are being used in farm animals. While on-farm food safety has been steadily improving, the risk of antibiotic residues is small, and the emergence of antibiotic resistance related to animal ag is low, we are not at zero and there is still room for improvement. Dairy producers have for many years taken pride in the quality of their products. For obvious reasons most of the emphasis has been placed on milk quality and safety. The dairy industry has a great track record here. In the case of cull cattle and bob veal calves, dairy producers need to realize that they are also responsible for the residues found in these meat animals. In most cases, dairy producers simply do/did not appreciate nor always attend to details regarding the meat animals leaving their farms. For many producers these animals are considered a by-product of the dairy. However, market (cull) cattle and bob veal calves contribute much more to the meat supply than most dairy producers realize.

With greater emphasis on careful antibiotic use, modest improvements in protocols and records, and attention to detail on withdrawal times, the dairy industry should be able to make progress in reducing their proportion of antibiotic residues. At this time, many producers in the other meat industries consider the dairy industry as the major culprit in the antibiotic residue problem. Proactive dairy producers should be part of the solution and help ensure all products that leave their farm are safe, free of residues, and of high quality.

Reference: FSIS, Audit Report, 2008

- Dr. David R. Wolfgang, Extension Veterinarian, Penn State Department of Veterinary and Biomedical Sciences