Factors Contributing to Variation in Reported Milk Component Percentage in Holstein and Jersey Milk

Precision of milk fat, protein, and lactose determinations by Multi-Spec operators in the state DHIA laboratory was studied and milk fat values were compared with Babcock determinations and with pay plant reports. Also, day-to-day variation in milk component content was examined in sample herds of 24 Holstein and 24 Jersey cows for a 10-d period.