High preliminary incubation (PI) counts could signal some problems with your milking-hygiene procedures. Dan Waldner, Oklahoma State University extension dairy specialist, offers these insights:


  • High PI counts are usually associated with failure to thoroughly clean and sanitize the milking system or to properly prep the cows.
  • PI counts can be affected by marginal cooling; that is, milk held at temperatures higher than 40 F.
  • Prolonged storage times may result in unacceptable PI counts because trouble-causing organisms are allowed to multiply.
  • Improper use of sanitizing products, or worn inflations and milk hoses, can contribute to the problem.