Several studies have indicated additional benefits of early weaning may be increased calf feed efficiency and improved quality grade. A 1999 ISU study by Loy, et al. found no difference in feed efficiency, but did find that early weaning and placing calves on a higher grain diet improves marbling at slaughter. However, results of studies at ISU and elsewhere show that results are best when calves are weaned between 90 to 120 days of age. No matter what age the calves, it is best if they have been eating grain for at least 10 days. You should also provide water in the creep area, so calves get used to drinking from a tank.
Many veterinarians prefer to use a killed vaccine on small calves.
You should worm and revaccinate calves on the day they are weaned. Once you have weaned small calves, starter feed should be increased gradually and you should feed highly palatable long stem hay until 90-100 days of age. Consumption of starter feed should be 4-5 lbs. Calf starter is necessary in the diet to provide adequate nutrition, disease resistance and to replace milk. Understanding the daily nutritional needs of a 90-120 day old calf is the basis of a successful early weaning program.