Unlike a human baby which is born with antibodies passed on through the placenta, a new born calf arrives without such protection and relies entirely on colostrum to receive those crucial antibodies.
It’s probably the most vital stage in a calf’s life, which means it’s critical to ensure it receives clean colostrum in good time. Flooding a new born calf with dirty colostrum could damage it for life because harmful bacteria prevent antibodies from being absorbed and that can leave you with a calf which is far more susceptible to disease than it should be. If you find yourself with calves with bacterial scour in the first few days of life you need to ask yourself some stern questions about your colostrum hygiene.
‘Hygienic colostrum’ is easier said than done! On dairy farms we work in an environment full of bacteria and during the harvesting, collection, storage and feeding of colostrum there are plenty of opportunities for bacteria to invade and cause problems. Most importantly we have to recognise that colostrum and milk products are the ideal medium for bacteria to live and multiply. It’s also an ideal warm temperature as it comes out of the cow, just right to promote multiplication.
Getting things right is easier said than done, but when we look at the figures it becomes obvious why it’s vital: fresh colostrum left for just two hours at room temperature can develop a bacterial count as high as 230 million cfu/ml* – when the target level we should be aiming for is a mere 100,000 cfu/ml!
In a recent trial some colostrum that was deemed to be ‘fresh’ (see above) was actually found to contain 3,600,000 cfu/ml, which is a bacterial soup! This is because the bacterial count can double every 20 minutes at room temperature.
That certainly gives things some perspective and what it tells us is that everything we do from the point of milking the cow to the point when it goes into the calf’s mouth has to be done quickly and efficiently, taking care to keep everything clean, thereby reducing the time and environment in which bacteria can breed.
The good news? It can be done!
Because there are so many opportunities for the colostrum to begin rapidly adding up its bacterial count and because time is crucial, it makes a tremendous difference if you have everything prepared before you collect it.
Here’s a plan:
- Wash and sanitise the cow’s teats then dry. Strip to remove teat sealant. Wear clean gloves and keep them clean.
- Make sure the collection bucket has been thoroughly washed with dairy circulation cleaner and scrubbed if necessary. Hypochlorite alone won’t work, colostrum is very fatty, so a detergent/steriliser works best, then rinse with water.
- Make sure the oral calf feeder is dedicated to newborn calves, use a separate one for sick calves. Clean with hot water and circulation cleaner. The same applies to any calf feeding bottles and teats.
- Make sure any colostrum storage bags or vessels are clean and ready to fill with a clean funnel.
- Milk the cow and test the colostrum with a colostrometer or refractometer.
- If the colostrum is good enough (green), or 20 + on the Brix scale, feed immediately, but any remaining colostrum should be cooled rapidly and stored.
There’s a trick to getting colostrum down to the correct temperature and doing so quickly.
A good method is dropping a (clean) jerry can full of ice into the bucket of warm colostrum and there’s even an ideal ration of ice to colostrum to achieve that, which is 4:1 i.e. 20 litres of colostrum cooled by a five litre ice block.
You’re aiming for 4℃ and once you’ve achieved that, adding a preservative such as potassium sorbate or MilkMate™ will drop the pH and prevent bacterial build-up for a few days.
It’s worth pointing out though that these products don’t kill bacteria, they simply restrict their growth, so they’re not a shortcut – if you start with dirty colostrum, it won’t make it clean.
Put a lid on the bucket of your cooled colostrum to keep dirt out and it will keep in a fridge for up to a week as long as you’ve followed all of the hygiene precautions.
Freezing and defrosting colostrum
If you have good colostrum that you want to keep for future use it can be frozen. How you do this is important, as is the way it is thawed.
The Store & Thaw system, sold by Wynnstay Agricultural Supplies, provides an affordable method with all of the components you need to carry out freezing and thawing successfully.
When freezing you should separate it into small quantities in Store & Thaw bags which can be frozen flat to create a thin sheet of ice. This allows it to thaw more quickly than it would in big blocks.
It will keep in its frozen state for up to a year but when it does come out of the freezer it still has to be handled carefully. If you’ve stored two litres at a time in the traditionally popular pop bottle or ice cream container it can take a couple of hours to thaw, giving the bacteria a long incubation time. This means you could be drenching the calf with freshly brewed E Coli!
The key is to thaw quickly and feed quickly to limit the bugs’ breeding.
Defrosting must take place below 50°C to avoid cooking the antibodies. It must be defrosted quickly in warm water, or slowly overnight in a fridge. Frozen colostrum will float in water, so if you can keep the colostrum submerged, it will thaw more quickly. e.g. in a specially designed tank such as the Store & Thaw.
The type of bag can make a big difference too (see below). If the bag is thick in the centre it will take much longer to thaw. The graph shows 3.5L colostrum from the same cow, thawing in the same bath, at the same time. The thin one took 32 minutes to reach 40°C and the thicker one took 65 minutes.
Is Pasteurisation an option?
Pasteurisation can play a role, but it’s important to note that it is not the same thing as sterilisation. Heat treating colostrum at 60°C for 60 minutes will kill off many pathogens, but not the ones which enjoy a higher temperature, so some will remain and could cause problems later. There is some evidence that calves fed Pasteurised colostrum absorb antibodies more efficiently, but it has to be clean to start with!
What have we learned?
Colostrum is crucial to newborn calves and if it is to do its job to maximum effect and give you a robust animal it has to be handled carefully.
The key points are:
- Only harvest healthy colostrum from healthy cows.
- Feed the calf quickly, or cool and freeze the excess quickly.
- Pasteurise if you wish to create a cleaner product for better passive transfer, but don’t rely on pasteurisation to clean up a dirty sample.
- Defrost frozen stores quickly before the bugs get a chance to multiply.
- Feed ‘on time’ in the first 6 hours after birth – Job done!
If you’re unsure about the level of contamination you are getting and the immune status of your calves, it’s worth asking your vet to blood sample the calves and send some colostrum away for bacteriology. That way you will know what you’re working with and, following these guidelines, be able to work on improvements if they’re needed.
Store & Thaw is available to buy from Wynnstay. Contact us for prices.
Steve Brown – Ruminant Feeds Product Manager, Wynnstay
* colony-forming unit (CFU or cfu) is a measure of viable bacterial or fungal cells. CFU measures only viable cells. For convenience the results are given as CFU/mL (colony-forming units per milliliter) for liquids, and CFU/g (colony-forming units per gram) for solids.