The volume of colostrum at the first milking after calving may have a bigger influence on colostrum quality than age of the dam, contends Jud Heinrichs, professor of dairy science at PennStateUniversity. If a cow produces more than 15 pounds or 1.5 gallons of colostrum at the first milking after calving, the colostrum may have lower immunoglobulin G (IgG) levels, he says.

Here are some other dam-related factors that can influence the IgG content of colostrum:

  • The dam’s immune status.
  • Length of the dry period. A three- to four-week dry period is necessary for maximum IgG concentration.
  • Leaking milk before calving. Avoid feeding colostrum from cows that leaked prior to calving.