We know that calves aren’t born with immunoglobulins, which are critical for their health. Immunoglobulins are supplied by the cow via colostrum, or first milk, and timing is critical as the new born calf has less than a 24 hour window to ingest these molecules through the lining of their gut before that window closes. The amount of colostrum intake is also critical for the passive immunity and long term health and productivity of a new born calf.
During his presentation at the 2020 Ohio Beef Cow/Calf Workshop and excerpted in the 2 minute video below, Dr. Francis Fluharty further explains why a calf must receive adequate colostrum within the first 24 hours of life.