Today’s post is the last in a three-part series on veterinary medications on the farm. Since January, we’ve discussed injectable drugs and oral and topical products. Today, we’ll take a closer look at the vital information that’s on a drug’s label and the importance of withdrawal times.
What to Look For
The label of a drug should provide you with the following information:
- what animal species the drug is intended for
- what the drug is supposed to do
- doses to give and how frequently
- the concentration
- any warnings about the drug
Depending on the size of the product, there may be more than one label, such as the sticker directly on the bottle and also the box it came in. A leaflet/insert is sometimes in the box.
Not all information may be located directly on the bottle due to size limitations. Full drug information may only be on the leaflet or box.
When using a new product, don’t throw away the packaging before you’ve read all the pieces.
A Warning About Warnings
Not all drugs are intended for all farm animal species or age of animal. This is why it’s important to carefully observe any warnings on the label.
For example, copper-containing products should not be used in sheep. They are extremely sensitive to that mineral. Ionophores to treat coccidiosis in cattle such as monensin should never be given to horses, as they are fatal to equines.
Perhaps the most vital piece of information on a drug label for farm animals is the withdrawal time. A withdrawal time is for meat and/or milk. This period of time can range from zero to several weeks and represents the amount of time required for the animal to metabolize the drug so that no drug residues will be present in the meat/milk and consumed by a human.
A withdrawal time represents the period of time the farmer must wait before sending the animal to slaughter (or putting milk in the bulk tank) after being treated with the drug.
Let’s look at an example. Say you have a litter of growing hogs with a respiratory infection and they all need an antibiotic.Your veterinarian comes out, prescribes Drug X and says to give this drug once daily for five days and that it has a seven-day meat withdrawal time (sometimes called a slaughter withdrawal or hold time).
On Monday you start your hogs on Drug X. On Friday, the five-day drug regimen finishes.
Now, starting on Friday, you must hang onto your hogs for another seven days until they can go to slaughter, if your plan was to send them after they recovered from the infection. This same concept applies to a milk withdrawal time for dairy animals. No milk goes in the bulk tank until the withdrawal time has passed.
All animals that provide food for human consumption are subject to withdrawal times to protect the human consumer—even honey bees. Various mite treatments and the few antibiotics that are available for foul brood diseases all have withdrawal times for honey.
If in Doubt, Ask
Maybe the most important aspect about farm medication and withdrawal times is that if you ever have any questions, don’t hesitate to ask your veterinarian.
Use her as a resource, along with your local agricultural extension agent. That’s what they are there for.
Education is key in making safe, healthy decisions for the animals on your farm.