Dairy Cow Residue Risk

We were involved with a herd pinkeye outbreak in lactating dairy cows.  To prevent cows from losing eyes, we decided to treat the eyes of 3 cows with a subconjunctival injection of Penicillin and dexamethasone.  As a precaution, we tested the milk, but thinking it would be negative, the milk went into the bulk tank.  All 3 cows, injected with just 1.5cc PenG had a positive test.  To make matters worse, that 4.5cc PenG actually caused a positive bulk tank.  The test was sensitive but we took no chances and dumped the tank.   

This herd took zero chances when it came to a potentially violative milk residue problem.  Unfortunately, other herds are not as careful.  There could be a lack of communication between the client and veterinarian.  Treatment regimens are not recorded.  Labels are not read carefully, or treated cows are not properly identified.  Therefore, we need to have “The Talk,” a blunt discussion about drug residues. 

In short, selling adulterated milk or meat that possess drug residues is illegal.  In 2007, the top antibiotic residues in milk were in order, Beta-Lactams (penicillin, ampicillin, amoxicillin, cephapirin, ceftiofur, cloxacillin, etc), Sulfa-drugs, Tetracyclines, Neomycin, Macrolides (erythromycin, Micotil, Draxxin).  The top 2 dairy meat residues are Penicillin and Flunixin meglumine, better known as Banamine.  We will use an eye-opening discussion on Flunixin to help illustrate how using a drug in an extra-label fashion can lead to violative residues. 

Flunixin meglumine (Banamine, Vedagesic, etc)  is a non-steroidal anti-inflammatory drug  approved for use in dairy cattle to control fever associated with bovine respiratory disease and fever and inflammation associated with endotoxemia.  Flunixin is to be administered by slow intravenous (IV) injection only.  According to the label, when administered IV and at approved dosages, slaughter withhold is 4 days after the last dose.  Milk withhold is 36 hours after the last dose.  Flunixin is not approved for use in dry dairy cows and calves processed as veal.  No withhold has been established for pre-ruminating calves. 

The majority of readers have used Flunixin in an extra-label manner.  Most frequently, Flunixin has been administered intramuscularly (IM) or subcutaneously (SQ) which is an extra-label use of Flunixin.  As you can see by the picture provided by Dee Griffen, DVM, University of Nebraska, when injected SQ or IM, Flunixin causes a serious tissue reaction that likely causes more pain than what it was intended to prevent. 

Have you ever seen a cow that has been tail-docked by Flunixin a couple of weeks after a failed tail vein injection?  To make matters worse, SQ and IM dosing takes longer for Flunixin to remove from the tissues when compared to IV administration.  Consequently, the slaughter withhold becomes longer.  So, for many years, culling decisions for SQ/IM injection of Flunixin were based incorrectly on the recommended and approved IV slaughter withhold of 4 days.  The Food Animal Residue Avoidance Databank (FARAD) recommends slaughter withholds of 30 days for a single IM injection of Flunixin and 60 days for multiple IM Flunixin injections.  Understanding the facts, we strongly recommend IV administration only.

Unfortunately, the flunixin example is only one of many stories that we could discuss on residue avoidance.  The following section will outline recommendations that will reduce residue risk. 

What can you do to reduce residue risk?

In response to residue concerns, the American Veterinary Medical Association (AVMA) and National Milk Producers Federation (NMPF) has established the 10-Point Milk and Dairy Beef Quality Assurance Program. 

Focus on herd health management (nutrition, reproduction, cow comfort, milk quality, vaccinations).  Common Sense:  When you prevent disease, you use less drugs.  For example, herds that have a lower somatic cell count, treat less mastitis cases.

Establish a valid vet-client-patient relationship (VCPR).  Which means, you and your vet need to communicate– talk. listen, and ASK QUESTIONS!  Routine herd health programs and consultation prevent disease and lead to early diagnosis and treatment.  If drugs are to be used in an extra-label manner, use only under the guidance of your veterinarian.

Use only Food and Drug Administration (FDA) approved over-the-counter and prescription drugs under the guidance of your veterinarian.

Make sure all drugs for use on dairy cattle are properly labeled according to state and federal regulations. 

Store all drugs properly.  The manufacturers’ label will have storage instructions on optimal storage temperatures.  Storage outside the temperature range could change the integrity of the product, increasing residue risk.

Administer all drugs according  to the label dose and route of administration—Intravenous (IV), Intramuscular (IM), Subcutaneous (SQ), Intramammary (IMM), Intranasal (IN).  If you are dosing more than 10 cc, administer only 10 cc per injection site to allow adequate distribution and less tissue damage.  Use the smallest needle allowable to avoid excessive tissue trauma.  Then properly identify treated cows using leg bands or tape, paint, ear tags, etc.

Maintain and use proper treatment records on all treated cows.  Treatment records should include cow identification number, disease being treated, name of drug(s) being used to treat the disease, dose, route of administration, and withholds of drug(s), date treatment was initiated, date treatment ended, milk withhold duration and date milk can be placed back in the bulktank, and date when slaughter withhold expires. 

Use drug residue screening tests.  Strict adherence to labeled dosing, routes of administration, and withholds will significantly reduce residue risk.  However, you may run into that rare circumstance where a compromised patient does not follow the rules.  Additionally, extra-label use of a drug requires a residue test before selling milk or marketing the cow.  Several tests exist for on-farm or clinic use.  Many farms use Snap or Delvo tests to analyze individual milk samples before addition to bulk tank or the bulk tank milk before every pick-up.  All high risk cull cows should have a urine residue test before shipping.  Charm or Premitest offers broadspectrum analysis of drug urine residues.

Implement an employee education program to avoid marketing adulterated milk and meat.  Establish written treatment and drug-use protocols specific to every situation and specific to your dairy.  Protocols should address the management challenges and strengths and weaknesses of your employees which are unique to every dairy.  Limit the number of individuals permitted to treat cows allowing greater accountability, supervision, and better record keeping. 

Continuously strive for improvement by reviewing your quality assurance program annually with your veterinarian.  Protocol drift may occur over time, new treatment regimens could be defined, or new herd health management concepts that further prevent disease could be identified and implemented. 

Many areas of residue risk exist.  By working with your veterinarian to implement a Milk and Dairy Beef Quality Assurance Program, residue risk can be significantly reduced.