The most important thing you can do as a cow/calf producer is to make sure all calves receive adequate colostrum promptly. Making sure all newborn calves get adequate colostrum is critical to their future health and colostrum must be ingested as soon after birth as possible. Although calves can absorb some colostrum up to 24 hours after birth, the ability to absorb colostrum greatly decreases every hour until no absorption occurs at 24 hours.
Passive antibodies received from colostrum is the only protection calves get against infectious agents. Mark Johnson at drovers.com says that colostrum also has the biochemicals transferrin and lactoferrin which bind iron and restrict bacterial growth, helping to decrease bacterial infections.
If you find a calf and are not sure if the calf has nursed, it is a good idea to feed the calf colostrum as you may miss the absorption window by waiting until the calf nurses. It is important to have several doses of colostrum or colostrum replacer on hand as you prepare for calving season unless you can get the cow to a chute and milk her out which is difficult in most beef cattle situations.
Colostrum must be kept frozen to protect the large protein molecules that make up the various immunoglobulins. Storing one-quart doses in a gallon freezer bag works well. Lay the bags flat in the freezer and thaw them in a 122ﹾ F water bath for about an hour. Do not thaw in a microwave or at higher temperatures because the immunoglobulins will be destroyed.