Hygiene - Keeping Bacteria at bay

The health of any animal relies on the balance between an internal immune system and the external challenges of viruses and bacteria.

Bacteria simply need moisture, energy and temperature (2 degrees +) to replicate. It is not surprising that they thrive in most situations. When assessing calf-rearing systems, we find moisture, energy and temperature associated with most environments and related jobs. When we look to reduce bacterial counts or bacterial load on equipment or milk, it is sensible to try to eliminate one or more of their breeding requirements. Bacterial numbers in warm colostrum can double every 20 minutes.

When Marc Boelhauve spoke at the European Calf Conference in Berlin earlier this year, he presented data from a colostrum study, showing that 85% of colostrum samples which were tested for quality were deemed “good.” But out of the calves fed this good colostrum, only 14.5% of them had sufficient uptake of immunoglobulins (IgG). Calves were fed sufficient quantity soon after birth, so the conclusion largely pointed towards the handling and hygiene of the colostrum after collection.

IOWA state university study (2011) found that on average, colostrum is moved between buckets/bottles 2.5 times and 42% of farms transferred it over 3 times before feeding. But each time the colostrum is moved to a new container it poses a risk of gathering more bacteria. Half of the specimens were held for over 60 minutes before storage or feeding and refrigerated samples were found to have 10 times more bacteria than those from a fresh cow.

• Thorough bucket & equipment cleaning is a basic, yet major aspect of reducing bacteria. Providing the udder is well cleaned before milking the fresh cow, milk should be practically sterile so it is only the buckets and equipment we expose it to afterwards, that may contaminate it.
• Dump buckets washed out and stored with the lid sealed on creates an “incubator” effect providing a moist, warm environment (perfect for bacterial replication). Washing out the buckets and pipes thoroughly and allowing them to dry upside down over a drainable surface is recommended. Buckets stacked up like this to drain can hold moisture and the ones touching the floor can pick up bacteria on the lip of the bucket which calves are likely to suck. A more appropriate way to store buckets would be on a rail, set up to allow each bucket to be able to drain fully, without too much contact with anything else. Unfortunately, we will never eliminate every pathogen in an environment. However, the more it is reduced, the lower the risk is of it causing harm to calves.
• Having a foot dip (including a product such as KILCO Virophor) at the entrance to the calf shed is recommended. But please remember you can’t disinfect organic matter, so boots must be visibly clean before the foot dip is able to disinfect them.
• Wearing disposable gloves when feeding calves is recommended. It gives the opportunity to take gloves off and put on a new pair, especially if you have been helping one calf to learn to drink, or dealing with a sick animal. Also, our hands are always covered in bacteria, so it eliminates the calves contracting anything from us.
• Pasteurisation is a good tool to use to reduce the bacterial numbers in colostrum; although we accept the process will damage some of the important immunoglobulins. It is recommended to be performed at 60 degrees for 60 minutes and the equipment used for this must be very accurate and regularly serviced to ensure it is providing the constant temperature required. Dr Rick Dumm (2019) reported that if pasteurisation was carried out at 62 degrees (only 2 degrees higher) it can cause damage to up to 30% of the immunoglobulins, which would significantly reduce the quality of colostrum.
• The Store & Thaw (S&T) by Pyon is a very cost-effective way to pasteurise batches of colostrum. S&T can also be used as a water bath to thaw frozen colostrum quickly (within 15 mins). Thawing colostrum over long periods of time gives ample opportunity for bacterial replication due to parts of the milk being warm, allowing bacterial replication. Similarly, cooling colostrum slowly provides a breeding ground. Even in the fridge, a bucket of colostrum can take as long as 8 hours to cool through to the middle. Having bottles of frozen water/ice packs ready to put into the bucket can speed up this process.

1. Not removing all organic matter – disinfectant is not able to penetrate the surface, which needs cleaning if covered with organic matter.
2. The incorrect product being used – It is essential to know what you are trying to remove from the environment/equipment and to use a product which has been tested for that purpose.
3. Inaccurate dilution rate – a weaker than recommended dilution rate, or using the correct dilution but applying to a wet surface.
4. Not allowing enough drying time – time is often limited but allowing a shed to dry removes the moisture that bacteria require to multiply. If there is not enough time to allow it to dry, or there is poor ventilation so it can’t dry – try using a drying lime e.g Minstral, which also disinfects.
5. Not giving disinfectant enough kill time – most products have a “kill time” stated on the packaging. If you do not give the product this time, you cannot be sure it will have worked to its full potential.
6. Storing equipment incorrectly after disinfection – if the equipment is stored in a place that is likely to contain bacteria, it will become re-infected and when it is used again, it will be assumed to be “clean” but will be introducing bacteria to the milk/water it has contact with.

• KILCO Virophor 2.8% - foot dip – mix at 2% dilution rate – change every 2-3 days, or daily if soiling occurs
• KILCO Autosan Blue – alkaline cleaner, useful for buckets, automatic machines and equipment. 0.5% dilution in hot water or 1% in cold water
• Wynnsan Actigel – a foam detergent, helps lift the organic material and biofilm – a dilution rate of 3%. Can be used through pressure washers.
• KILCO Cyclex - For specific coccidial / cryptosporidial challenge apply a 3% v/v dilution, via a spray or foaming device, at a rate of 0.3L per square metre to cover all surfaces in the building as appropriate. Allow a contact time of 4h.