Jersey factors are used for Milking Shorthorns, and Holstein factors are used for additional breeds. Only Holstein factors are listed in Table 1. Others are available on request. Records are projected by adding to the cumulative yield an estimate of average daily production for the number of lactation days remaining to 305. Estimated average daily production remaining A and B are relatively straight forward and readily available for most cows.
C is more awkward to estimate.
Sample day and herd average factors for Holstein cattle in Virginia are in Table 1. Proper use of the above formula requires that the mathematical functions within parentheses be performed first. Next, perform multiplications before additions. Consider the example of a first lactation Holstein freshening in December in a 15,000 lb herd with 7,000 lbs of yield in 100 days and 55 lbs of milk on last test day. When days in milk exceed 155 days, the herd average is no longer used to project the record.