Pasteurisation – is it time to consider?

What is pasteurisation?  It is a process whereby milk is heated to a certain temperature for a certain period of time thus killing bacteria and viruses. There are two types of pasteurisation:

  1. High Temp Heat Treatment (HTHT) or “flash” pasteurisation which works on a continuous flow process. It is short and quick, heating milk to 73°C for 30 seconds or so, and it may be useful for treating waste milk (red or penicillin milk) that can then be fed to calves. The process has no effect on the antibiotics in the milk, but by nature this milk is heavily laden with bacteria and so killing that bacteria is beneficial to calves. It is important to note that colostrum cannot be run through an HTHT system.
  2. Low Temp Heat Treatment (LTHT), batch or colostrum pasteurisers, where in order to kill off the bacteria or viruses that may be in colostrum, milk is heated to 60°C for 60 minutes. The time and temperature are critical. Studies have shown that, at 60°C for 60 minutes, even the difficult Johne’s bacteria are destroyed, and the temperature of 60°C ensures that the all-important immunoglobulins or antibodies that the new-born calf requires to get it through the first month of life are not destroyed.

Batch pasteurisation has a two-fold effect. Firstly, killing the bacteria is great for the calf’s health because it is well documented how most Johne’s transmission occurs around birth and that colostrum is a common vehicle of transmission. Secondly, bacteria in the colostrum actually compete with the antibodies for absorption across the small intestine during that all-important first 12 hours of life. So, batch pasteurising your colostrum actually helps to improve passive transfer or the uptake of antibodies in the newborn calf. This flows on to healthier calves and less disease in the rearing process. It further flows on to cows that may produce more milk in their first two years of life (as shown in a study published in the Journal of Dairy Science). This study showed how calves fed pasteurised colostrum experienced higher levels of passive transfer which then flowed on to healthier calves, not only in the rearing process but also in the production of  more milk in the first two lactations. This is the way of the future.

Before jumping on in to buy a batch pasteuriser though, how well are your calves achieving passive transfer? Your Vetlife veterinarian can check the process by running some simple cost-effective tests on your calves before they are a week old to ascertain if good passive transfer has occurred. If the first step is not being achieved, then considering pasteurisation is not for you, but it may be a wake-up call to try and do things better. Some steps to consider:

  1. Are you testing your colostrum with a Brix Refractometer and separating it into high and low batches to ensure that only the highest quality (>22%) is being fed to your new-born calves?
  2. Are you ensuring your calves get a minimum of 2 litres (3 is better) of this gold colostrum, preferably before 6-8 hours of life?

If you answered `no` to one or both of the above, then talk to your Vetlife veterinarian to discuss options for testing the effectiveness of passive transfer of your calves and, of course, whether pasteurisation is right for you. It certainly is right for your calves.

Ivan Holloway