farmers with hook and eggs

There are times when animals on our farms need to be treated with some medication or other chemical and most of these treatments have a withholding time. These withholding times are the crucial periods after administering a medication when you can’t use meat, milk, eggs, or fibre from your animals.


What is a withholding time?

Withholding times are not just arbitrary rules; they serve a vital purpose. They are designed to ensure that any residues of medications used in your animals' treatment have sufficiently cleared from their system before their products enter the food chain. This helps to safeguard human health and maintain the integrity of your farm's products.

Antibiotics, anti-inflammatories, dips, and drenches all have specific withholding times and all are different, so it's very important to read the label and record somewhere when the animal/animals are treated and how long the withholding time is.

There have been instances where people have been caught out and had an animal rejected from the works because a chemical residue has been found in the meat.

One medication can have multiple withholding times. For example one for milk, one for meat, and one for fibre can all be different.


Common Medications 

Let's look at a few areas where you have to consider withholding times:


  • Tailing - Depending on the season, lambs may be sprayed with a treatment to prevent flystrike. If there are lambs going straight to the works at weaning, it is crucial that they are past the withholding time for whichever treatment has been used. Different breeds can also have different withholding times, generally, a merino-type breed will have a longer withholding time than a strong wool sheep.
  • Pink eye - Antibiotic powder is commonly used for pink eye and has a withholding time.
  • Shearing - If sheep have been dipped or sprayed for fly or lice, they must not be shorn until the withholding time has been passed. Wool contaminated by chemicals can ruin a whole clip. If you have wool that goes away to be blended with other wool of the same types to make up a bale, you don’t want to be responsible for that wool being rejected. There will also be a withholding time for their meat.
  • Footrot - If you have treated your animals for footrot and used an antibiotic spray, there will be a withholding time for this.  
  • Drenching - When drenching for worms with either an oral drench or a pour on the withholding time again needs to be noted, particularly if any are destined for the works. 
  • When treating chooks for worms or mites etc, there will be a period of time when the eggs produced can’t be used for human consumption.
  • Any medication given to an animal producing milk for human consumption - cows, goats, or sheep - will have a withholding time. During that time the milk will need to be disposed of and not consumed.  Generally, it is not a good idea to feed treated milk to your growing pigs, although people do. If you do then the pigs are also subject to the withholding time and cannot be eaten.


Other farm animals

It’s not just animals that are being produced to feed humans that have to have their withholding time monitored. Horses and donkeys that have been treated with antibiotics, anti-inflammatories or drench and who are subsequently euthanised cannot be used for pet food if they are still within the product's withholding times and they will need to be buried.

There has been concern recently around bobby calves being fed “red milk”. This is milk from cows that have mastitis or another disease and have been treated with antibiotics. The milk is then fed to the calves as it can’t go into the vat. If calves are sent away to the works after consuming this red milk, they may not be out of the withholding period.


Why are withholding times important?

The main reasons we need withholding times are:

Consuming products with medication residues can have adverse effects on human health, including allergic reactions, and can be a factor in antibiotic resistance.

Violating withholding periods can result in your animals or products being rejected in the market. If milk or fleece from an animal within the withholding period is mixed with others the entire lot may have to be destroyed.


What to do on your farm

  • Always read the withholding time when using a medication
  • Make a note when giving medication to the animal who received it and the date they’ll be out of the withholding time (or times, remember meat and milk may be different.)


Note: We’ve been looking at medications but there are also “natural” treatments, feed additives, and other animal health products that have withholding times. It is wrong to assume that if it isn’t a drug then it won’t have a withholding period.  Always check!

Withholding times for drugs are an important part of responsible farming. Knowing why they’re there and following the guidelines will help to maintain the health and well-being of your animals and the market value of any farm products.