TEST DAY Model dairy sire evaluations have reduced the “Rip-Dip” effect, which caused proofs of bulls with flatter lactation curves to suffer once daughters started their second lactation.

Theo Meuwissen of the Nor<00AD>wegian University of Life Sciences said because standard lactation curves were used to predict second lactation yields, their results were pulled down when daughters began their second lactation.

Test Day Model evaluation, due for introduction in the UK shortly, stops this happening.