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Colostrum - why calves need it and what to do with the excess

Since Molly had her calf, Monty, in early April, I've had plenty of opportunity to observe colostrum and I am finding it quite fascinating.  Like all mammals, when a cow first has her calf, she produces colostrum to feed her calf, rather than true milk.  Colostrum is more yellow/orange than milk (although Molly's had been slightly different to Bella's, so I assume every cow is different) and much thicker than milk.  It reminds me of a thin pouring custard.  Over the days following the birth, the colostrum gets gradually thinner and whiter, and eventually becomes milk, this is called transitional milk.

Why does a calf need colostrum?
It is essential that the calf has its dose of colostrum very soon after birth.  The calf is born with no antibodies in its blood, and colostrum is its first source of antibodies, as well as providing nutrients and stimulating the bowels to expel myconium.  The calf gets most benefit from the antibodies in the first 6 hours, as it is able to absorb the antibodies through its stomach wall and into its blood.  After the stomach wall tightens, the antibodies are digested instead, which can still stimulate the immune system, but is not as effective.  As the stomach wall is more open during this time, it is best that the calf receives colostrum to coat the stomach lining before it has the opportunity to accidentally eat anything else, like manure or soil, which could cause an infection to pass into the blood instead (see more here).  Many commercial dairy farmers stomach tube calves as soon as they are born, to ensure that they receive colostrum as early as possible.  They also milk colostrum from multiple cows, test for antibodies and use the best colostrum from their herd.

Molly with her newborn Monty
What to do with excess colostrum
Dairy cows produce far more milk than their calves can use, so we needed to milk Molly after the first day, both to prevent her getting mastitis and to stimulate continued high milk flow, even though we don't have much use for the colostrum ourselves.  Several of my cheese-making books specifically state that colostrum should not be used for cheese-making, as if its is some kind of dangerous substance, however there are many traditional recipes using colostrum and it is sold as a supplement.  I'm not sure whether it has any special health properties or not!  We were not keen on drinking it anyway!  Apparently is has a salty, bitter taste.

We froze the first few days of colostrum, until we ran out of old milk bottles, and we tipped the excess down the sink (terrible waste, I know, we need pigs!!).  The frozen colostrum will be useful if we have an orphan calf that needs colostrum.  We gave Monty frozen colostrum when Molly wouldn't let him nurse at first, so it can be very useful to have some stored, to ensure that the calf receives colostrum as soon as possible.  The colostrum does not necessarily need to come from the calf's mother, colostrum from your own property or a nearby property is ideal, as the cow is likely to have the antibodies that the calf will need in the local environment.

Can't have a post about colostrum without a cute pic of Monty
How to get colostrum for a calf
If you ever need colostrum, you might be able to get it from a dairy farmer, they will usually have one or two cows producing some colostrum (definitely in spring, but in Australia dairy cows are calving all  year round), and if you ever have excess colostrum, its a good idea to freeze some, you never know when you will need it.  You can also buy dried colostrum powder.  The problem is that you will usually need it in a hurry, so it will pay to be prepared   If you have no acccess to real colostrum and need to make an artificial colostrum for a newborn calf, you can try the following recipe, but it will not have the antibodies that the calf needs and the calf will require extra attention until its old enough to form its own antibodies.

It is not true that a calf who doesn't receive colostrum will never thrive, all calves eventually make their own antibodies.  In fact, the antibodies received in colostrum are naturally diluted and metabolised as the calf grows (see here). The calf will just be more susceptible to infection in its first few weeks and months compared to calves that received colostrum.

Artificial colostrum substitute
1 egg beaten
300 ml water
2 ml (½ teaspoon) castor oil
600 ml whole milk

When does the real milk start?
In a commercial dairy, the farmer usually discards the first two days of colostrum (giving it to calves or pigs if they are smart), and after that the milk just goes in the vat with the rest of the herd.  But it took a week for Molly's milk to be white enough to be considered "normal".  It gradually changed from orange, to yellow, to white, and for several days, after the milk had settled in the fridge, there was a pink line between the milk and cream.  We assumed that this was blood (as the antibodies are transferred in blood).  The pink line became smaller and smaller each day until it disappeared from the milk altogether.  I couldn't find much on the internet about the pink line, apart from this forum discussion.

Monitoring for mastitis
When the cow first calves her udder is very swollen and she is full of colostrum and then transitional milk.  She is at high risk of developing mastitis due to all the stress of the new calf and new milking regime, so it is very important that she is milked twice a day and fed plenty of dolomite (for the calcium).  She will make more milk for the calf (who doesn't need much when its small), so don't worry about taking as much as you can.  When Bella had mastitis, we could tell because it took longer than normal for her milk to drain through our filter.  We also used a mastitis test kit.  Draining time is the main factor that we use to regularly monitor for mastitis, and then the test kit if we suspect a problem.

Colostrum references
Solar Family Farm
The Family Cow Handbook: A Guide to Keeping a Milk Cow
Savacaf - Preserving the Value of Natural Maternal Colostrum
APHIS - A guide to colostrum and colostrum management for dairy calves
Agromedia - Colostrum and The Newborn Calf

Would you, or have you, eaten colostrum?  Why? Why not?  Did you realise how important it was for a newborn calf to consume colostrum?

You might also be interested in my series on getting started with homestead dairy


  1. Sorry but I'm thinking baby humans here as well as cows. Colostrum is just amazing! Isn't nature incredible! If we ever decide to try again with milking a cow I will be devouring your blog. When we gave it a go last time, I hadn't given it half the research that you have done. I tend to throw myself into something and work out the pitfalls as I go. You have done a great job of researching everything every time you take on a new venture.

    1. Thanks Linda, the research is usually "on the run", but at least I know more for the next calf now.

  2. This is wonderful info for anyone interested in dairy animals! I'm tucking this away in my brain for future use. :) Thanks for sharing on The Creative HomeAcre Hop! Happy Mother's day to Molly! Join us for the new hop today, if you have time :)

  3. Thanks for following my blog. Dropped in to check out yours can’t wait to look through all of it. I love this artificial colostrum subsitute we don’t need it often but it seems when we do need colostrum it is when the stores are closed or we have to make a hurried trip to town to get some.


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