Posted by Administrator on June 25 2009 15:20

Authored By: Dr. Paul Rapnicki
University of Minnesota

Veterinary challenges

One of the challenges dairy veterinarians are running into related to drug use on our dairies is we're managing some conflicting priorities on how the drugs are use. We provide sick cow care, disease prevention and other traditional production medicine services to our clients. We are dealing with food animals because milk and dairy beef is a food product and we have to be careful to prevent residues in the food.

There are also economic pressures of the veterinarians to earn a living in their practices related to drug use and drug sales. In addition clients are applying economic pressures from the different ways they want to try to access prescription drugs for their operations. These economic pressures get into some pretty interesting meetings with practitioners and everyone has an opinion because it's hitting everyone close to home.

We train veterinary students to take care of sick cows. They need to be hands on to gain the needed experience. A lot of dairy operations temp their fresh cows every morning, sometimes they even check for urine ketones, and traditional production medicine and the system we have in place talks about managing the herd and preventing diseases. That is making the individual cow decision to treat the cows.

On most farms the technical job of identifying the sick cows and delivering the protocols is not being done by the veterinarian. Those technical jobs are being taken over by on-farm personnel so the veterinarians have moved up a level and are now responsible for the training to make sure those people are doing things correctly. That can be a challenge because those people who are doing the treatments often haven't had the pharmacology or the science background to really know what each of these medications are capable of doing.

PMO and NCIMS

The Pasteurized Milk Ordinance (PMO) is a public health document that protects the safety of the milk supply. It regulates the interstate shipment of milk between states. Appendix N is the part of the PMO that details what the legal requirements are for testing every tanker load of milk. In the late 1980s the PMO incorporated testing every tanker load of milk for beta lactam antibiotics. The last fiscal year report (Oct 05 – Sept 06), the total bulk milk pickup tankers, there were about 3.5 million tests with 1,300 positives, so the percent positive was 0.038%. There is a very aggressive screening program for beta lactam antibiotics and very few of the tankers are actually testing positive.

Even 10 years ago when the national milk drug residue database began reporting, they were still only having 1/10th of a percent of tanker loads positive. This program has been successful for the dairy industry to look hard for beta lactam antibiotics and keep them from entering into the food chain.

The reason beta lactams were chosen, is when the FDA did surveys on-farm to find out what types of drugs were used, they found about 95% of the antibiotics were the beta lactam class.

The National Council on Interstate Milk Shipments (NCIMS) conference meets every other year and they actually evaluate and review the PMO and potentially propose changes. The FDA submitted a proposal at the 2005 NCIMS to form a committee to take a look at maybe requiring that raw milk be required to be tested for drug residues on a statistically-designed basis rather than just testing every tanker load for beta lactams. If you look at the percent positive, it's very small, and the dairy producer is bearing the cost of testing every tanker load with very few actually positive.

We know that other drugs are used on dairies besides beta lactams. The FDA is starting to see in some surveys there is a shift away from beta lactam use to tetracycline and sulfa-type drugs. Routine screening doesn't always pick that up so they want to evaluate what is the right way to prevent residues from getting into the food chain.

I'm on the committee representing the AVMA and AABP participating with regulators and the FDA and the industry people as far as what should the testing program be in the PMO. It's looking at what is the volume of drugs being used, toxicity of drugs and the FDA is very concerned about any potential public health risk factors. They will review beta lactam testing and then also other drugs which opens up the possibility to non-steroidals, other classes of antibiotics. It will all be evaluated and changes likely will be proposed. However, it's not going to happen this year at the conference. The committee has met a number of times over the last year. I believe it is coming that the testing programs will become more aggressive on the milk side.

We have the Milk and Dairy Beef Residue Prevention Protocol manual. A lot of state agencies require if a producer ships a contaminated load of milk that the PMO requires they go through some type of producer education so they don't incur additional residues. A lot of states have adopted this manual as being the HACCP-type document that identifies the critical control points for keeping the antibiotics from getting into the milk tank.

VCPR

One of the things that the residue prevention manual references is the importance of having a valid veterinary client patient relationship (VCPR). These are the key points to the VCRPR.

A VCPR exists when all of the following conditions have been met:

• The veterinarian has assumed responsibility for making clinical judgments regarding the health of the animal(s) and the need for medical treatment, and the client has agreed to follow the veterinarians instructions.
• The veterinarian has sufficient knowledge of the animal(s) to initiate at least a general or preliminary diagnosis of the medical condition of the animal(s).
  • This means that the veterinarian has recently seen and is personally acquainted with the keeping and care of the animal(s) by virtue of an examination of the animal(s), or by medically appropriate and timely visits to the premises where the animal(s) are kept.
• The veterinarian is readily available
  • or has arranged for emergency coverage, for follow-up evaluation in the event of adverse reactions or the failure of the treatment regimen.

This is the definition that AMDUCA, state practice acts, the AVMA and the PMO refer to. But like anything that is listed in the law, it is a little subject to interpretation. That is where a big part of my last 7-8 years working with practitioners has been -- when have we actually met these conditions?

Have those conditions been met for a valid VPCR? I get two different answers from two different parts of the room. If you are a veterinarian, how do you answer this question if you are accused of not having a VCPR with a client you are supplying drugs to versus if you look at a dairy in your area and you want to accuse another veterinarian of not having a valid VCRP? This is where having a fairly vague definition in the law starts to create a lot of controversy and heated discussion on what truly constitutes a valid VCPR. Your examining boards use the AVMA definition, but when there is a problem it needs to be more specific. You sort of get the answer "we knows it when we sees its".

When you are accused of not having a valid VCPR, it's a difficult spot to be in. Most people really don't think about this until the issue comes up. We are not dealing with this proactively, it's usually in response to a residue violation or a dairy producer is procuring drugs from several states away from a route truck or internet pharmacies, etc.

Economic pressures

This leads us into economic pressures facing dairies today. For dairies, economics revolve around how much milk is going into the tank. Dairy farms are production systems that produce pounds of milk. As much milk as you produce, you can sell to coops. The downside is you can't tell them what the price will be. Individual producers are rewarded for shipping volumes of milk. The economic pressures come from putting milk in the tank because a lot of milk means low milk prices overall.

Related to drug use, there have been dual roles for veterinarians. One is specifying and overseeing the use of prescription and extra label drugs as mandated in the law. It's also a necessary and appropriate role for the veterinary profession and that's the prescribing role. The medical decision of what drugs should the producer have access to.

The second role has been in the distribution channel and this has been a major source of practice revenue. It's still important to a lot of practices for a cash flow standpoint, but maybe not from a profitability standpoint. We're seeing this role get separated from the medical decisions of which drugs go on to dairies.

When BST came out in 1994, Monsanto proved that Fed Ex can find every dairy farm. There are different ways for the drugs to get out to the farm than just the veterinary truck. It's important to separate these two issues, prescribing and distribution.

Establishing a VCRP is part of the prescribing role. One of the things in the Minnesota Best Practices that we wanted to do was help provide some tangible guidance for practitioners who wanted to do a better job of verifying to an agency that yes, they do have a valid VCPR.

What we created are five data-capture forms that can be downloaded by veterinarians for use. There is an increasing need for written documentation. Our idea was to take forms and put them in pdfs or Word documents so that people can download and edit as needed.

We have five forms. One is a basic herd form. As we started to think about the concept of the VCPR and saying the veterinarian has it for the whole dairy automatically is not what often happens in the field. On the dairy a lot of times veterinarians are there for purely reproductive purposes. They are very familiar with the repro programs and those drugs. The potential is that the youngstock are kept in a different area, or even on a different location. The VCPR doesn't automatically apply to the young stock if all you do every two weeks is work with the reproductive program.

What Minnesota Best Practices has done is broken the VCPR down into a reproductive VCPR, a young stock VCPR, a mastitis VCPR because mastitis is far and away the largest reason we using antimicrobials on an operation, and then other clinical diseases VCPR area.

A traditional veterinary practice probably has all four VCPR areas covered as long as they collect information and have sufficient knowledge in those four areas. But it's entirely possible for these dairies today to have VCPRs with multiple veterinarians. They may have a milk quality expert that has a mastitis VCPR and another who is the reproductive guy with the reproductive VCPR. They each do the prescribing in part for the drugs used in that program.

When you are establishing a VCPR with a client, the veterinarian, based on his or her medical judgment regarding the health of the animal(s) and the need for medical treatment, specifies appropriate use of drugs under his/her VCPR.

Traditionally we have done that with clients verbally and have communicated how to treat mastitis, RP and metritis. This is not going to be sufficient if it's challenged. At some point you need to have a record of verbal communications with your client. As production animal agriculture has moved to be more transparent with what we do with animals, there is an increasing pressure to be able to document what we do.

When you give your protocols, you can't just say you have communicated to the client. You have to have written evidence of those protocols.

There is a pamphlet put out by the FDA in response to judicious use of antimicrobials. It's targeted for dairy producers. They talk about the importance for the producer to do a proper job. They use the term "diagnosing" sick animals. But the producers are actually recognizing the symptoms of metritis or mastitis rather than using the term diagnosing. On my part the term "diagnose" implies what we do as veterinarians.

Working with producers

Producers are very good at recognizing the common conditions, especially if they are trained by the veterinarian and understand what are the clinical signs and which protocol to use. It's my experience working with farms with protocols they all work better if the farm spends enough time getting the correct diagnosis. If every cow with a high temperature has fever of unknown origin or "Naxcel deficiency," protocols don't work well. You need to come down to "what is the condition affecting the cow."

Even the FDA is promoting this idea of developing written protocols for producers to help guide them in the proper judicious use of drugs on dairies.

In addition to the veterinarian assuming responsibility for how drugs are being used on the farm, the client has to agree to follow their instructions. Again, probably having that verbal agreement is not enough. You need to document that in writing. On our Best Practices forms, at the end we have a place for both the veterinarian and the producer to sign. This step formalizes this relationship we'll have about how these regulated drugs will be used on the animals.

Clarifying these instructions is problematic when the client has the ability to buy some of these products over the counter. We had a discussion with an FDA regulator and asked what if one of my clients buys a bottle of penicillin and they thought they heard from someone else who repeated that it's good to give 100cc penicillin in the quarter and you don't have to hold the milk and then the client used the OTC drug this way. It is clearly an extra label use of the drug. This scenario is that it is NOT the veterinarian who told the client to do this extra-label use and the client is acting on his own initiative.

When that causes a residue violation, the regulator walks onto that farm thinking the veterinarian is responsible because that is your client and you need to know what your client is doing regarding drug use on the farm. AMDUCA says it is illegal to use drugs extra-label without a veterinarian's supervision. The FDA has clearly stated they will hold everyone responsible in the production chain by omission or commission when a violative residue occurs.

This formalization of what the protocols are when you are communicating to your clients, that the clients agree to follow your instructions when they go extra label is very important when we have these types of circumstances. To the FDA it's illegal for the dairy producer to do extra label drug use without a veterinarian. This is why we are encouraging veterinarians to have these discussions. This is the spirit of the VCPR, to have these discussions with your clients so all of this is out in the open.

On our website you can edit the VCPR forms we have created. We wanted to start to give practitioners a starting point to decide with their level of comfort what do we need to be capturing to have that documentation in case anyone ever accuses us of not having a VCPR with our clients.

The last part is the prescribing veterinarian/practice is readily available for follow up in case of adverse reactions or failure of the therapeutic protocol. There is a great deal of controversy about what this means. If you are going to prescribe, can you be prescribing for a farm that is two states away or that you are at once per month? A lot of veterinarians don't like to be relegated to just sick cow work and someone else is doing the "cream of the crop" work, but that's the controversy. Part of what happens in practice is how you position yourself with the client and the type of services you are going to offer to them.

In summary, we need to have a system in place that allows the prescribing veterinarian/practice to monitor the amount of use of the prescribed drug, to assure that the rate of use is reasonable and consistent with the intent under the prescription. The reality is that very few practices can do this today. It would require both a budget projection of use and a record of actual use for comparison.

Where are we today?

If the future really involves these verifications of a valid VCPR and having written treatment protocols, where are we today within the industry?
There have been a couple of recent surveys. The 2007 Penn Dairy Survey was posted on AABP in March. They put the survey on AABP-L and had 99 veterinarians respond.

I picked out a couple of the questions. One was how many dairies do each of the veterinarians serve? Some practices serve more than 400 dairies.

The proportion of practices and herd sizes was initiated by the New Bolton Center out of Pennsylvania. The herd sizes were in the 60-300 cow range, though there were about 15% of practices that served over 1,000 cows.

One of the questions they asked was in the last six months, how often has the veterinarian performed a number of different services. If you look at the traditional role and the number of times in the last six months the veterinarians were doing preg checks, it was greater than 30. It reinforces that a lot of times on the dairy it relates to something about the reproduction program. Writing treatment protocols and vaccine protocols were not near as frequent as the technical work of reproductive programs even though all of these services are important to have in place.

The other survey that I came across was done by Pfizer. It was a sampling of almost 400 dairy farms with more than 200 cows. It was designed to learn about the dairies' behavior regarding injectable antibiotics.

There is interesting information in that that tells us as dairy veterinarians where we are at regarding drug use on those farms. They broke the areas into the Southeast, West, Midwest and Northeast to summarize the results. This gives a national look at how injectable antimicrobials are used.

One question was: how often do you maintain written protocols for treating your dairy cattle with injectable antibiotics? Overall less than half of the farms maintained written protocols for treatment. The Midwest is the highest with only 54% of the farms always having written treatment protocols.

Another question asked: how often do you formally review and update injectable antibiotic treatment protocols? Six months was the median time frame for formally reviewing and updating injectable antibiotic treatment protocols. But, 35% of the respondents reported that they review and update records every three months or often.

How frequently does your dairy operation keep complete written records of dairy cattle treated with injectable antibiotics? Forty-two percent of the farms don't keep complete written records, in spite of the fact that within the PMO is the legal requirement to keep records when you use drugs, not just antibiotics, on your animals. If you treat animals, to avoid residues you need to identify animals, the treatment records need to capture the identity of the animals, date of the treatment, drug administered, dose, milk and meat withhold times also need to be recorded, and then those records maintained. In the PMO it even talks about some drugs have prolonged residues in the milk for 45 days or 18-24 months on slaughter, so the PMO requires producers to keep the treatment records for a minimum of two years. The survey shows about 40% of them don't maintain treatment records. This is a problem.

How many different individuals on your dairy operation administer injectable antibiotic treatments? The study showed it was pretty common to have more than one person involved in delivery, injections into the cows which means training and written protocols are important so that everyone is clearly directed on what they are supposed to do.

How often is the prescribed course of therapy completed when treating pneumonia? Sixty percent of the time producers said they always follow the complete course of therapy, and 90% do the protocols most of the time.

Some diseases have less compliance. For the question: how often is the prescribed course of therapy completed when treating metritis? The numbers drop down to less than half of the farms. According to this survey compliance to the directions of using the drugs isn't always the greatest.

How routinely do you seek your veterinarian's advice before administering injectable antibiotics to your dairy cattle? Less than one-third of the farms said they always or most of the time seek their veterinarian's advice.

Overall, this study found a significant number of producers do not have complete treatment records and nearly half of the producers surveyed reported being less than fully compliant with antibiotic therapy even though bacterial infections such as pneumonia and metritis have the potential to cause significant economic loss; most dairy producers did not seek a veterinarian's advice before administering injectable antibiotics. Records really protect the producer, and unfortunately many farms lack good records.

So the future is stormy. Veterinarians provide services to dairy operations. As a service organization, dairy veterinarians trying to provide services to these operations need to change the types of services we offer producers.

Implementing protocols

It's easy to like the concept of treatment protocols. How do we overcome the challenges of implementation? They take time and effort to write. There is protocol drift on the farm. Herdsmen can be very creative with their "farmacology". Protocols require routine updating because there are new drugs or new labels. Medications must be available when needed. If you are in the sick pen and given a protocol for metritis but none of that drug is available, how can you expect to be compliant? We need to make sure if we strategically decided to use drugs on those operations, they are available. So, how do we go about appropriate prescribing amounts so there is medication there when needed?

Some of the solution to the drug issues facing dairy veterinarians is vehicles to help establish and document to outside people you do have a VCPR with your client and get your client involved in a formalization of this process of treating animals. The Wisconsin VMA has some tools available through their organization and other state VMAs are working on similar things. I had a conversation with Dr. Dave Rhoda of Wisconsin about making sure that other state organizations know what MVMA and WVMA are doing so that not everyone is feeling like they have to reinvent the wheel and we can share resources.

MDBP key components

At key component to us if veterinarians are going to take control over drug use is the veterinarian visits a herd every six months as a best practice goal, and he or she completes a minimum database of information pertaining to on-farm practices.

From the VCPR the veterinarian develops the specific protocol for how drugs are used, then can create a drug budget based on written protocols. These would be valid for six months and be specific to each dairy.

It's very important to note that the DBP-recommended process is only one way to potentially achieve a valid VCPR with a dairy. It is certainly not the only way. The more I have learned about it I think it's good that the legal definition is vague and it allows people to be creative rather that being prescriptive and telling you the exact steps to get a valid VCPR. They would miss the spirit of the law. We need to recognize that many methods for establishing valid VCPRs exist and new ones will be invented.

Drug budgeting

I want to go through a case example of how we could go through the drug budget on a dairy. We'll take this example of a dairy that has 500 milking cows. Only four diseases occur on this dairy: foot rot at 10%, clinical mastitis (mild clinical mastitis 15%, severe clinical mastitis 3%) and pneumonia (5%). Let's go through how we would budget drugs for this dairy given that these are the conditions they are going to need to treat.

The first thing we do is create protocol frames or descriptions of the conditions that cows will need drugs for. For this dairy it's foot rot, pneumonia, clinical mastitis, a hot case of mastitis and routine dry cow treatment that is part of the mastitis control program. These describe the conditions the cows may get that require some drug use.

We have to choose a drug to treat that condition. We need to determine the total therapy amounts. For example, when cows are dried off they get one dry tube per quarter and a cow is only dried off once per year. So four times every cow that goes through dry off and that will calculate the total amount of drug use for that indication. If you treat a cow with metritis with Excenel, the dose is 25cc given subQ once per day, so if she is on that therapy three days is 75cc. So you decide which drugs are appropriate for using in those conditions, then determine the total amount of drug that is used every time an animal goes through that protocol.

When you do a therapy, it has to have an indication, route, dosage, frequency, duration and milk and meat withhold times. When you use FDA-approved therapies, this information is provided to you as a part of the approval process. If you want to go extralabel and you change an indication or route or dosage, you still need to fill in each of these sections and then calculate the amount of drug that is going to be used.

So for this dairy, we might end up the dry cow therapy which is intramammary dry cow tubes. The foot rot option one could be Excenel, option two could be Oxytet. Mild mastitis could be treated in the quarter with ceftiofur or hetacin-K. Severe mastitis could be treated in the quarter and since those cows are at high risk of becoming bacteremic we treat her systemically with Excenel. We give her flunixin IV for toxic mastitis and treat her with hypertonic saline. So this protocol for severe mastitis is a little more complicated than just routine dry cow therapy.

For pneumonia we have a lot of approved antibiotics so on this dairy we'll give them three different choices and maybe they'll pick one as a first choice, second choice, etc.

Then we drop these treatments into our frame and break it down whether it's local, systemic, supportive or other. A dry cow treatment would be dry treatment, local IMM therapy, there is no systemic therapy or supportive therapy and in "protocol comments" you could put in external teat sealants or post-dip or whatever is appropriate.

After graduation from Michigan State University in 1986, Dr. Paul Rapnicki practiced for 12 years at the Kiel Veterinary Clinic in northeast Wisconsin. In practice, became actively involved in organized veterinary medicine at the local (NEWVMA), state (WVMA) and national (AVMA) levels.

Dr. Rapnicki joined the University of Minnesota College of Veterinary Medicine in 1998 as a clinical professor in dairy production medicine. He earned an MBA in Agriculture from the University of Guelph in 2002.

Dr. Rapnicki is currently director of the Center for Dairy Health, Management, and Food Quality in the College of Veterinary Medicine at the University of Minnesota. Rapnicki's duties include teaching DVM students, veterinary extension/outreach programs, applied research with milking equipment, applied research in transition cow management, monitoring dairy reproductive programs, and dairy treatment protocols/prescription drug use.

Rapnicki is a member of the AVMA Animal Agriculture Liaison Committee and since 1999 has served as the appointed AVMA and AABP liaison to the National Conference of Interstate Milk Shipments. In 2004 he was appointed chair of the MVMA Food Animal Pharmaceutical Committee.