Ireland’s dairy industry prides itself on producing safe and nutritious food products which are sold around the world. The dairy industry has an exemplary record on food safety and maintaining this is vital to protect existing markets but also for gaining access to new markets.

The importance of this cannot be overstated. With milk output expanding, Irish dairy processors are working hard to secure new markets for their produce, which in turn is creating opportunities for Irish farmers to expand production.

Everyone has a part to play in food safety. Here, we outline some of the key considerations farmers should make this spring.

The biggest risk is around antibiotic residues in milk. With the removal of quotas, many farmers have shortened the dry period this year and this is a cause for concern as it means there is a higher chance of mishaps due to the incorrect use of dry cow therapy/tubes.

The big thing to remember with dry cow therapy is that there are two withdrawal periods. The first withdrawal period concerns the activity period of the drug. This varies greatly from product to product, with a range from 28 to 54 days for some commonly used dry cow tubes.

So if a cow happens to calve within the withdrawal period, her milk cannot be sent to the bulk tank until after the withdrawal period has elapsed.

The next withdrawal period is based on time after calving. Most dry cow tubes have a withdrawal period of 96 hours (eight milkings) after calving but again, there is a range of withdrawal periods between commonly used dry cow tubes of between 84 and 156 hours.

So the key piece of advice is to only use a dry cow tube that is suited to the expected length of the dry period and also to adhere to withdrawal times after calving. At a minimum, cows should get eight weeks dry and heifers should get ten weeks dry, but for one reason or another that does not always happen – for example, if drying off is delayed or if a cow calves earlier than expected.

This is where good records come in to play. By law, dry-off dates and the products used should be recorded for each cow. Before the milk from any cow enters the bulk tank, at least eight milking should have elapsed and her records should be checked to ensure that she has calved outside of the withdrawal period.

The penalties for supplying milk with antibiotic residues are severe. Each tanker of milk entering a processing site in Ireland is required to be tested for antibiotics before the milk is offloaded. When a tanker tests positive, the samples from each farm that supplied the tanker are tested for antibiotics. The offending farmer is then charged for the contaminated load and the Department of Agriculture is informed. Most processors also issue a penalty for the month’s milk supply.

To avoid a mishap, many farmers are now purchasing antibiotic test kits to test individual cows before their milk enters the bulk tank and also to test the bulk tank before collection. The kits cost around €200 to €300 and are available nationwide. Best advice if you are in doubt about antibiotic residues in your milk is to contact your milk quality adviser immediately and get the bulk tank tested before it is collected.

Transition milk

More farmers are now using selective dry cow therapy at drying off, that is, only treating high cell count cows with antibiotics. There is a belief out there that milk from cows that were not given dry cow tubes can be sent to the bulk tank sooner than milk from cows that have been treated with antibiotics.

A number of processors have been in touch to say that this is not the case and request that milk from at least the first eight milkings after calving be discarded before milk is supplied for human consumption.

There appear to be two main issues with processing milk within eight milkings after calving. The first is colostrum residues in milk and the negative effects this has on processing, and the second is to do with residues from teat sealer.

Really, colostrum is only the first milking after calving. Milk from the second to eighth milking should be called transition milk, as the milk transitions from colostrum to normal milk. While colostrum is a wonderful feed for new-born calves, it is a headache for processors to deal with, particularly if the milk is being dried into powders.

As farmers will be aware, colostrum milk has a different texture to ordinary milk – it is sticky and it is harder to clean off surfaces and equipment. Milk with colostrum residues causes problems for processors as it reduces the processability of the milk, restricting the products that can be made.

It also causes increased downtime in plants as it leads to fouling of the equipment and it takes longer to clean. It tends to burn on to the surface of heaters and pasteurisers, blocks tubes in evaporators and leads to stickier powders and increased product rejection, which all leads to increased processing costs.

Residues from cows treated with teat sealer are a big concern for cheese makers. Speckles from teat sealer cause a black spot in the cheese, which means that the cheese has to be rejected. So even where no antibiotics have been used, the processors are still requesting that the first eight milkings are discarded or fed to calves.

Practical steps can help to alleviate the problem, such as making sure that the teat sealer is only infused into the teat and not the udder and also ensuring that teat sealer is fully stripped out by hand at the first milking. The machine should not be used to strip out the teat sealer.

Chlorine

Trichloromethane (TCM) residues in milk are caused by incorrect cleaning of milking machines. Problems occur when the chlorine in the detergent/sterilisers comes in contact with and binds to milk. It is caused by inadequate rinsing of the plant or too much chlorine being used in the wash.

A Teagasc survey found that most of the TCM problems are caused by using too much detergent in the milking machine and bulk tank and by using products with high chlorine levels in the detergent/steriliser. Only detergent/sterilisers with less than 3.5% chlorine should be used.

Because TCM levels can be detected in all milk products, and because they cannot be removed during processing, it is up to farmers to ensure that they are using the right products in the right way. Take the time now to review your own machine washing procedure and consult with your milk quality adviser about the best approach, not forgetting that the quantity of water used in the final rinse is essential.

Also, don’t forget about the bulk tank, most of the issues with TCMs relate to the bulk tank wash.

  • Check withdrawal periods on dry cow tubes and only supply milk from cows that are free of antibiotic residues.
  • If in doubt, get your bulk tank checked for antibiotic residues before collection.
  • Milk from the first eight milkings should not be supplied, even if the cow was not treated with antibiotics.
  • Incorrect use of detergent/sterlisers causes TCM residues which show up in milk products.