When calves are born, their immune systems aren't developed and they must absorb antibodies from colostrum until their own immune system becomes functional. The immune compounds in colostrum are essential to prime that non-developed immune system and protect them against disease in their first few weeks of life.
Gold colostrum is the very first milking after a cow has calved - it is energydense and contains defence molecules that provide immunity to the calves and bioactive molecules that are important to the development of their organs and growth. When a calf gets enough good quality colostrum in its first hours it is known as 'successful transfer immunity', while the reverse is called 'failure of passive transfer'. Calves that don't get enough good quality colostrum are at greater risk of disease and at twice the risk of dying compared to calves that get enough colostrum.
So how do you ensure your calves get all the good quality colostrum they need to give them the best possible start?
The simplest way is to focus on the three Q's of colostrum:
1. Quickly
Once a calf is born there is a 24-hour maximum window to get that good quality colostrum into them. This is for two reasons - the first is the calf's ability to absorb antibodies declines and after around 24 hours they won't get any antibody transfer from the colostrum, and the second is once the cow has calved the antibody levels in the milk start to rapidly decline as she is no longer producing colostrum. That is why it is important to milk freshly calved cows and feed the newborn calves good quality colostrum as soon as possible - the sooner you can do this, the better chance they have of good health.
2. Quantity
It is recommended that you feed calves four to six litres of colostrum within their first 12 hours of life. However because a calf can only hold about 1.5 to 2 litres in its abomasum (fourth stomach), two feeds within the first 12 hours is the target. Calves should be ideally fed 2 litres of gold colostrum as soon as possible, followed by another 2 litres later in the day. Since there is so much natural variation among cows, by bringing in the freshly calved cows twice a day you can also be sure you're getting the best quality colostrum out of them.
3. Quality
Not all colostrum is the same so determining the best quality is important and can be done by using a Brix refractometer. Brix refractometers are inexpensive and simple to use, and provide assurance that calves are receiving the best quality colostrum possible. Pooling colostrum together and storing it in the same container is common practice in New Zealand - while this helps provide a broader range of antibodies for calves to ingest, there is a risk of mixing high quality colostrum with colostrum that isn't quite as good and diluting the overall quality. If you are going to pool your gold colostrum, it is recommended you make sure it is going in with a Brix reading of at least 22%.
For more calf rearing tips head to nzfarmsource.co.nz/calving.