Storing colostrum in the fridge or freezer gives flexibility to the colostrum feeding program.
According to the National Animal Health Monitoring System (NAHMS, USDA, 2014), 49 percent of dairy operations are storing colostrum in the fridge or freezer. Storing colostrum gives flexibility to the colostrum feeding program in having colostrum accessible in the event that the dam does not have enough or it’s of low quality, bloody, or the dam will not be milked within two hours of giving birth.
Where to store?
Colostrum can be stored in the fridge or the freezer. According to NAHMS, of the producers storing colostrum, 21 percent are storing it in the fridge while 73 percent are using the freezer. Storing colostrum in the freezer gives longer shelf-life, however it will take longer to thaw and warm to body temperature. In addition, the process of freezing and thawing destroys white blood cells, or leukocytes. There is evidence that white blood cells are beneficial to calves, however not much is known about how important the role of white blood cells is in colostrum. A benefit to freezing colostrum is that Bovine Leukemia Virus is stored in the white blood cells and is effectively inactivated by freezing and thawing colostrum. It is not recommended to store colostrum in a “frost-free” freezer because of freeze-thaw cycles that could damage colostral antibodies.
How long to store
While not everyone is in agreement on the maximum time to store frozen colostrum, it is generally agreed upon that colostrum can be stored up to six months without damage to antibodies. How long colostrum will stay good in the refrigerator depends on the cleanliness of your colostrum and storage equipment. In general, two to three days is the longest Michigan State University Extension recommends storing colostrum in the refrigerator.
High-bacteria colostrum needs to be used sooner and very clean colostrum can be kept longer. Using a preservative, such as potassium sorbate, will stop bacterial growth and extend the length of time colostrum can be stored, up to seven days. Food grade potassium sorbate is very affordable and can be purchased online and mixed on-farm. Many vet clinics offer the pre-mixed product to farms, saving the hassle of mixing and ensuring it stays fresh.
Cleanliness is key
Whichever way you chose to store colostrum, the basic principles of cleanliness still apply. Milk cows using clean equipment, and store colostrum in clean, single serve containers that you can write the date and quality on. If freezing colostrum, it is a good idea to use bags with a label of date and quality, that will stack neatly, and the increased surface area of the bag will rapidly cool and thaw the colostrum. Freezing will stop bacterial growth however it will not decrease the bacterial counts that are already present when put into the freezer. Consider pre-chilling the colostrum in an ice bath before placing in the fridge or freezer. Pre-chilling will rapidly cool the colostrum, preventing the refrigerator from warming and causing harm to other colostrum or vaccines stored in the fridge.
In conclusion, storing colostrum in the fridge or freezer provides you with flexibility to ensure that a newborn calf has high quality colostrum available within two hours of birth. The refrigerator can store colostrum for a few days, while the freezer can effectively store colostrum up to six months. The advantages of storing colostrum in the refrigerator or freezer, or some combination of both is to ensure there is always colostrum available on your farm.