The U.S. Food and Drug Administration (FDA) recently approved a new-generation feed antibiotic, Aquaflor (florfenicol) the first antimicrobial licensed for U.S. aquaculture in more than 20 years.
New classification
In keeping with FDAs new regulations for new therapeutics in food-animal species, the new product was licensed as a Veterinary Feed Directive drug, or VFD, which can be used only when there is a veterinary-client-patient relationship in accordance with FDA guidelines.
In the past, catfish growers have long utilized the free fish- and water-testing services of state universities and their extension services. Not all of these state-funded facilities have veterinarians readily available, however, thus leaving a void in the process for obtaining the paper work needed to obtain a VFD drug from the feed mill.
The problem is there arent many catfish veterinarians, per se, says Dr. Dick Endris, Aquaculture Research Program Manager for Schering-Plough Animal Health Corporation, the company that developed Aquaflor. Its sister product, Nuflor (florfenicol), has been used in beef and non-lactating dairy cattle in the United States since 1996. Although it contains the same active ingredient, Nuflor is not a VFD drug because it administered by injection, not through the feed.
In fact, only one feed antimicrobial has been approved as a VFD drug tilmicosin for swine. That designation has not been an obstacle because swine practitioners are readily available to producers. The catfish industry is hoping companion and large-animal veterinarians will help to fill the void so growers can establish working relationships and obtain the paperwork needed to use a VFD drug.
The new classification is not complicated, but it will be important for everyone to know and understand the rules governing the use of VFD drugs, says Endris.
Diagnostic Methods
The VFD process begins when a catfish producer contacts his veterinarian or diagnostic laboratory for an accurate diagnosis concerning his sick catfish.
Currently catfish growers rely heavily on AFS certified Pathologists and Diagnosticians for their catfish and pond health issues. Were well qualified and trained in the areas of fish health and pond management, stresses Bill Hemstreet, fish health specialist with the Alabama Fish Farm Center. However, many of us are not licensed veterinarians.
The veterinarians responsibility for VFD drugs begins with diagnosis and writing the VFD. It continues through delivery of the VFD to the feed mill and maintaining records of it for two years, says Dr. Patricia Gaunt, a veterinarian and associate professor, aquatic animal health, Mississippi State University College of Veterinary Medicine.
Meeting the Need
While Mississippi State University trains veterinarians in fish disease and health, it is a relatively new concept in catfish production.
Traditionally, water quality issues have played a larger role in fish production than disease diagnosis and treatments, points out Hemstreet, so there hasnt been a lot of interest in fish production and diagnostics from veterinarians.
Thats expected to change with the arrival of VFD drugs, many more of which are expected to be licensed for catfish and other aquatic species as part of FDAs efforts to streamline approvals for products targeting minor species.
Veterinary Feed Directive drugs are part of a new process that requires the involvement of a veterinarian, says Hugh Warren, executive vice president of the Catfish Farmers of America, which represents 87 percent of the catfish-producing waters.
With only a handful of catfish veterinarians throughout the Mississippi, Arkansas, Alabama and Louisiana, change is on the way. Only a licensed veterinarian can prescribe VFD drugs, notes Dr. Richard Sellers, American Feed Industry Association. The government regulations are clear on that point.
Veterinarians and the VFD
The VFD is a simple written statement issued by a licensed veterinarian in the course of the veterinarians professional practice that orders the use of a VFD drug in an animal feed. Pharmaceutical companies marketing such products make preprinted forms available at no charge.
This written statement authorizes the client to obtain and use the VFD drug in accordance with the directions for use approved by the FDA. A veterinarian may issue a VFD only if a valid veterinarian-client-patient relationship exists. The drug may not be used off label, however, and the feed mill must have the written VFD on file before medicated feed can be delivered to the catfish producer.
The need to obtain a written VFD may cause some initial inconvenience until enough veterinarians are trained at the local level to diagnose enteric septicemia (ESC) in catfish caused by the bacteria Edwardsiella ictaluri, notes Dr. Gaunt. I think this a minor issue, however, and I am confident that this will change quickly after the product is approved.
The FDA approval of this new VFD drug for catfish will open a new avenue of opportunities for other approvals. However, subsequent approvals depend on the success and proper use of the VFD process and the availability of veterinarians trained in the process.
Writing a VFD
In 1996, the Animal Drug Availability Act (ADAA) established the Veterinary Feed Directive (VFD) and created a new category of animal drug.
The following outlines VFDs:
- Animal drugs in feed were classified as over-the counter prior to the passage of the VFD.
- Prescription status for drugs was impractical for use in medicated feeds because many states regulations prohibit feed manufacturers from dispensing prescription drugs.
- Veterinary diagnosis and supervision is required for use of VFD medicated feeds.
- The VFD will not change the status of OTC drugs approved prior to 2000.
- A Veterinary Feed Directive order refers to a written authorization for use.
Following the diagnosis and determining the need for a VFD, the veterinarian must complete a VFD order that contains the following:
- Clients name, address, telephone number
- Identification and number of animals to be treated/fed the medicated feed including the species and location of the animals
- Date of treatment and date of prescribing the VFD drug
- Approved indications for use
- Name of the animal drug
- Level of animal drug in the feed and the amount of feed required to treat the animals
- Feeding instructions and withdrawal time
- Expiration date of the VFD order
- Number of refills (reorders)
- Veterinarians license number and name of state issuing the license
- The statement Extra-label use (i.e. use of this drug in a manner other than as provided for in the VFD drug approval) is strictly prohibited.
What is a VCP Relationship?
What exactly is the veterinarian-client-patient relationship needed to obtain an order for a new VFD drug? FDA offers the following guidelines:
- The veterinarian has assumed responsibility for making clinical judgments regarding the health of the animals and the need for medical treatment, and the client has agreed to follow the veterinarian's instructions.
- The veterinarian has sufficient knowledge of the animals to initiate at least a general or preliminary diagnosis of the medical condition of the animals. This means that the veterinarian has recently seen and is personally acquainted with the keeping and care of the animals by virtue of an examination of the animals or by medically appropriate and timely visits to the premises where the animals are kept.
- The veterinarian is readily available for follow-up evaluation, or has arranged for emergency coverage, in the event of adverse reactions or failure of the treatment regime.
