BULL movements within the Australian Breeding Values list are not uncommon.
ABVs are an estimate of the genetic merit of an animal, so as the amount of information available about the animal increases so does its reliability.
Australian Dairy Herd Improvement Scheme group genetics learning package leader Michelle Axford said reliability indicated an ABV may change in the future.
"As a bull adds more information, reliability improves," she said.
"With more information the bull's ABV becomes a better estimate of its true genetic merit."
One of the factors that contributes to the reliability of an ABV is the "records in progress" or RIP%.
"Records in progress indicates the percentage of two year olds with three or less test days in their lactation," Ms Axford said.
"These cows have an incomplete lactation."
Ms Axford said a higher percentage of RIP% is more likely to affect a bull's breeding values - moving it up or down - if only a small number of progeny contribute to his breeding values.
She said ADHIS applies a minimum criteria for a bull's ABV to be published and it recommends farmers take a risk management approach by using a team of bulls with higher reliability.
"Through testing more daughters and collecting more data on those daughters (artificial breeding) companies can actively improve the reliability of young bulls tested," Ms Axford said.
