A protein produced by cells after they have been exposed to a virus. Interferon prevents the virus from reproducing within the infected cells and can also induce resistance to the virus in other cells.
Calves can be ready for weaning by 3 to 4 weeks of age; however, in Penn State studies calves weaned at 3 weeks required extra attention. The increased time and labor required to get these calves eating starter suggest that waiting until 4 weeks of age would be prudent.
Weaning age can have a large impact on calf raising costs. Dairy calves are ready to be weaned when they eat 1.5 to 2 lbs of calf starter for 3 consecutive days.