Producing a safe and wholesome food supply
No one worried about antibiotics in milk until in the 1970s when cheese makers found it inhibited the work of cheese starters.
The issue of public health is relatively new. It wasn't until the 1980s that consumers became concerned about the possibility of antibiotics in milk or meat, particularly for those individuals who are severely allergic to antibiotics.
More recently some people are concerned about the potential of the development or transmission of resistant bacteria to humans.
Dr. Ellen Hooker, DVM, Wisconsin Department of Agriculture, Trade and Consumer Protection, says farmers and veterinarians are working together to manage potential hazards.
They have the goal of producing a safe and wholesome food supply, protecting public health and preserving antibiotics for use by future generations.
She points to research indicating that there is only a very small fraction of a percent of times that milk tests positive of the presence of antibiotics in milk shipped but she said the public wants "zero."
She also points out that testing today is much more sensitive and can detect the most minute traces of anything. Where tests used to be able to detect parts per thousand they now can detect parts per billion and even trillion.
Scientists have said the risk to humans is negligible due to on-farm antibiotic use. There are numerous peer-reviewed scientific assessments that have failed to demonstrate any detectable risk treatment failure in humans caused by on-farm antibiotic use in animals.
Failure to prevent or treat illness causes unnecessary animal suffering and death. Further animals with residual effects of illness are more likely to cause human food-borne disease.
Every farm with animals is both a maternity hospital and a day care. Animals need medicines at times, just like children do. This becomes a moral and ethical issue with farmers deciding at what point they deny treatment?
Antibiotics for animals are needed because illnesses can move quickly through populations and livestock cannot "stay home" when they are sick.
Dr. Hooker described sampling in slaughter plants. She said there are two types of sampling: scheduled random sampling of carcasses, both dairy steers and beef steers; inspector generated sampling, based on the inspector's professional judgment.
An inspector will choose to inspect an animal where there is swollen liver or kidneys, a bad foot that can affect the long-term carcass quality, droopiness of the animal, or a limping cow.
She adds, "When the hide is pulled down, if there are lift marks on the hips, injection or IV marks, the inspector knows someone has done something with her."
Regarding calves, she said in the past there were frequent violations with formula-fed veal but now there are hardly any.
When inspectors check for residues in meat or milk, penicillin is the biggest concern because it can produce life-threatening allergic reaction in some people, with serious nerve damage, severe inflammation of the colon, swelling of the lips, tongue or face, bleeding or diarrhea.
When residues are found in either milk or meat, violators get a letter followed by a visit from the district veterinarian. She said that is why it is very important that farmers keep good records so if they get a visit from the district veterinarian they are able to show what treatment the animal had and the date of the treatment.
In rare cases antibiotics have been administered after the animal leaves the farm and if a farmer has good records, he may be able to get off the hook for the violation.
WHY RESIDUES OCCUR
Dr. Hooker says usually residues occur because of failure to record properly, mis-identification of the antibiotic, communication between the person administering it and the person making the decision to ship the animal, or lack of adequate training.
She says most dairy farms occasionally use antibiotics. Usage of antibiotics is also strongly linked to herd size with larger herds using them more often.
On dairy farms 86 percent of antibiotic treatments are associated with treatment or prevention of mastitis. She said most problems come in with extra-label administration of drugs.
Extra label is any administration of a product that does not exactly follow the label indications and dosage. This can be by using a different dosage, different frequency, different route, different animal and different disease.
She says, "Extra label drug use is permitted only under the supervision of a veterinarian and only allowed for FDA approved animal and human drugs. It is not allowed for non-approved compounds including botanicals. It is allowed only for therapeutic purposes and not for production use. It cannot be a given as a feed additive and it is not permitted if it results in a violative food residue."
She points out that sometimes the problem comes in because the use of the extra label drug may mean that it takes longer than the listed withdrawal period to get out of the system.
Another concern is the definition of lactating cow. According to the FDA dairy cattle 20 months of age or older, regardless of whether they are milking or not, are considered lactating cows. Too often a dairy farmer believes if a cow isn't milking it is not a lactating cow and therefore it is okay to administer certain drugs.
This especially becomes a problem with the administration of sulfa drugs that cannot be used for adult dairy cattle, even by the veterinarian.
She said, "The only sulfonamide available for use in dairy cattle older than 20 months of age is sulfadimethoxine (SDM). In adult dairy cattle this drug may only be used on-label. Administering higher doses or sustained release SDM products is prohibited."
When it comes to organic farms and the use of botanicals and natural products, she said it is not regulated but that doesn't mean the consumer would not be allergic to residues of these natural products.
When it comes to drug residues she stresses the importance of maintaining a strong relationship with the veterinarian and make sure that the veterinarian is involved in animal health decisions. Provide good animal health care through surveillance and diagnosis and then discuss and agree on treatment protocols.
"Ideally have written decisions," she says. "Decide and limit who is allowed to treat the cows and provide training."
Identify all animals using permanent identification tags and keep temporary (cow side) and permanent cow records. Double check those records and maintain a history of cull cows.
She concludes, "When you ship several cows at a time, record the cow number and the number the trucker puts on her back so if there is a problem who will know which cow it was and you can producer her record."
She adds, "Every farm must also have records on every calf that is born, including bull calves. If a mistake is made or the middle man does something to trigger a concern, you need to show what you did with that calf."