Effects of Changes in Fed Antibiotics

We are now well over halfway through 2017. This also means we are several months into the new Veterinary Feed Directive (VFD) and the new procedures and protocols that must be used when feeding approved antibiotics to dairy animals. More specifically, this applies to the feeding of antibiotics that previously did not require a veterinary prescription for use. At this time, the fed medications of concern include those mentioned in Table 1.

The medications on this list may not all be routinely used in dairy health management, but is does provide a list of medications whose use has been directly affected by the new VFD.

Refresher

Remember, the purpose of the new VFD was multifold. First, many consumers, doctors and scientists believe the apparent microbial resistance to many antibiotics developed because the food animal and poultry industry routinely overfed various antibiotics as a means of growth promotion. In other words, by routinely feeding antibiotics as a means of reducing or eliminating the challenge posed to the animal by various micro-organisms (pathogenic or otherwise), improved growth and feed efficiency can be recognized. But since this practice does not eliminate all of these organisms, many experts believe this has resulted in more resistant “bugs” that can subsequently infect humans and that are not affected by human antibiotics, many of which are the same or at least in the same drug families as the antibiotics fed to animals. All this said, there has been a desire to eliminate this practice as much as is feasible.

Second, there is a perceived need to improve the veterinarian-client relationship. This, hopefully, gives the veterinarian a greater degree of oversight of how specific fed medications are administered to their clients’ animals. The belief is with this improved relationship and oversight, medications will be fed more according to the prescription and veterinarian’s directions. This may or may not be the case. Finally, the focus was also on using these fed medications for more specific, therapeutic purposes when a specific medical indication had been diagnosed.

The general effect of the new VFD ruling has been to complicate and create more paperwork and record-keeping for the dairyman. Secondly, now the dairy manager is supposed to have a specific reason for the use of (for example) CTC in newly weaned heifers. If the manager now wants to use CTC (or another fed medication) simply as insurance in these types of cattle, he has to contact his vet; technically, the vet is supposed to come to the farm and look at the heifers in person and render a diagnosis for the specific med fed for a specific rate. This obviously generates fees the producer must pay that were not required previously (farm calls, diagnosis, etc.), thus production expenses increase to some degree. Third, there is now a paper trail that needs to be maintained with copies of the prescription to be kept on file by the vet, the producer and the medicated feed manufacturer.

So what are the results?

There are essentially three responses to this new system I have seen working with clients.

  1. Some producers feel the medications are a critical part of their program and have jumped through the necessary hoops to continue their use, albeit in a modified form since these products are not supposed to be used sub therapeutically for performance improvement.
  2. Some producers are approaching the new regulations more skeptically and are “testing the waters” to determine if the program revisions will work for them or not. If they do, more than likely they will adapt and continue the use of needed medications. If not, then they will look for other options.
  3. Finally, some producers will simply stop the use of fed medications and will look for other options. This has happened to a significant degree already—and no doubt the med companies are feeling the pinch somewhat. On the other hand, this situation is accelerating a scenario the feed and food animal production industries have been discussing for some time—the removal (totally or in part) of fed antibiotics for routine, production—enhancing use. While the VFD has not eliminated the use of antibiotics, it has limited their use and has made that use more onerous.

As a result, for some time these industries have been searching for alternatives—non-antibiotic means of enhancing immune system function, binding and elimination of pathogens, manipulation of rumen function (although feeding of ionophores such as Rumensin, Bovatec, etc., have not been affected by this program), etc. Quite a number of additives and products have been identified as having some positive effect on the health and performance of the animal. These include yeast and yeast cell wall components, various direct-fed microbials, essential oils (plant extracts), mycotoxin binders, enzyme sources, etc. In many cases, the initial effect is to act as a stress reducer. Stress is well known to suppress immune performance, so steps that can reduce stress in the animal will support health and overall animal performance.

There are an unlimited number of combinations of products/additives that may work synergistically in the animal to improve animal health and performance and potentially reduce or eliminate the need for certain fed medications. Also, these efforts include management applications on the part of the dairy to reduce stress and the potential for pathogenic challenge on the farm in general. This will require some extensive evaluation of protocols and practices that are a negative influence on health and performance.

Conclusions

So, overall, we know several things: The VFD is here to stay. It works for some producers but not as well for others. If it is like any other governmental regulation, you can be assured it will grow and expand. In an effort to remove the farm from these issues, producers, their nutritionists and vets will continually search for effective, non-fed antibiotic alternatives. This will extend not only to the feeding program but to overall management in general. The hidden benefit to this all is like so many other changes over history; it will serve to improve the management and operation of the farm. This, without a doubt, benefits the dairy producer and the industry.

TABLE 1 Drug transitioning from OTC1 to VFD2 status
Established drug name Examples of proprietary drug names
chlortetracycline (CTC) Aureomycin, CLTC, CTC, Chloratet, Chlorachel, ChlorMax, Chlortetracycline, Deracin, Inchlor, Pennchlor, Pfichlor
chlortetracycline/sulfamethazine* Aureo S, Aureomix S, Pennchlor S
chlortetracycline/sulfamethazine/penicillin* Aureomix 500, Chlorachel/pficlor SP, Pennchlor SP, ChlorMax SP
hygromycin B Hygromix
lincomycin Lincomix
oxytetracycline (OTC) TM, OXTC, Oxytetracycline, Pennox, Terramycin
oxytetracycline/neomycin* Neo-Oxy, Neo-Terramycin
penicillin Penicillin, Penicillin G Procaine
sulfadimethoxine/ormetroprim* Rofenaid, Romet
tylosin Tylan, Tylosin, Tylovet
tylosin/sulfamethazine* Tylan Sulfa G, Tylan Plus Sulfa G, Tylosin Plus Sulfamethazine
virginiamycin Stafac, Virginiamycin, V-Max

1Over the counter

2Adapted from: https://www.fda.gov/AnimalVeterinary/DevelopmentApprovalProcess/ucm482107.htm, “Drugs Transitioning from Over-the-Counter (OTC) to Veterinary Feed Directive (VFD) Status.”

*Fixed ratio, combination drug

 

Source: Stephen Blezinger, progressivediary.com

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