It is no secret that colostrum provides the antibodies a calf needs to build immunity. The antibodies, specifically called immunoglobulins in colostrum, are absorbed in the calf’s small intestine in the first few hours of life. After the first four hours of life, the absorption of immunoglobulins decreases. Therefore, it is important that newborn calves receive colostrum within four hours of birth.
In many cases, high quality colostrum is frozen for use when calves are born. The quality of the colostrum is measured when it is fresh, placed into a bag for freezing and then labeled with the quality of the colostrum and the date the colostrum was produced. High quality colostrum is measured using a Brix refractometer and should read 22% or greater. Anything less than 22% is lower quality and does not help the calf build up immunity. The quality of colostrum is equally, if not more important, as providing the calf colostrum in the first few hours of life.
It is a common practice, when a calf is born to remove frozen colostrum from the freezer to thaw in hot water and then continue to perform newborn calf cares. The water temperature to thaw the colostrum should be between 120° F and 140° F (49-60° C). Water temperature above 140° F (60° C) is inactivating the immunoglobulins in the colostrum, thus decreasing the amount of immunoglobulins absorbed in the small intestine. When we test the quality of colostrum, we measure the amount of total immunoglobulins. We do not have instruments to measure the amount of active and inactive immunoglobulins. Immunoglobulins may be deactivated if the water temperature gets too hot, which is why we do not recommend a water temperature above 140° F (60° C) for thawing.
Typically, water heaters are set to produce water of 170 -180° F (77-82° C). If we would thaw colostrum with water from a water heater and then measure the quality of the colostrum, the quality will measure the same as when it was fresh, but the amount of active immunoglobulins will be decreased. Therefore, the quality of the colostrum has decreased and calves are not receiving the antibodies they need for immunity. If you are using water from a hot water heater, fill a 5 gallon bucket about 1/3 full with hot water and mark that line on the inside of the bucket. Stick a thermometer in the water and begin adding cold water until the temperature is between 120° F and 140° F (49-60° C). When the water temperature is in that range, make another mark on the inside of the bucket. The first mark shows how much hot water to put in the bucket first, and the second mark shows how much cold water to add to ensure a safe temperature to thaw colostrum. A good rule of thumb is if the water is too hot for you to stick your hand into, it is too hot to thaw colostrum.
As the newest calf is born and you prepare newborn calf cares, keep in mind these three reminders.
1) Feed high quality colostrum (22% Brix or greater) within four hours of birth.
2) The water temperature to thaw colostrum should be between 120-140° F (49-60° C).
3) Measuring colostrum quality measures the total amount of immunoglobulins; the number of inactive immunoglobulins increases as the colostrum becomes too hot thus reducing colostrum quality fed to the calf.