THE OFTEN promised and long awaited fertility index on UK dairy sire proofs is to be launched in this May”s proof run, along with a host of other changes.

These will include type and production evaluations and will cause changes to the PLI bull ranking order, warns Lucy Andrews, research and development manager at Holstein UK. “It will take effort to ensure everyone understands them.

” At the British Cattle Conference, she said the main differences included a new type merit formula for Holstein bulls. “This will put the focus on important traits for health and welfare traits, fertility and longevity.

” It would have dairy strength as a new trait, more emphasis on rump structure and less on feet and mammary traits, she explained.

But there would also be a base year change to type and production proofs and the introduction of Test Day Model evaluation of milk yields for Holsteins, Jerseys, Guernseys and Ayrshires.

This is already used in many other countries and should increase accuracy. But there have been some problems with its introduction. Nick Kirby of Inimex Genetics said in Italy one bull jumped from 150th to 10th in its ranking, but had, unfortunately, been slaughtered a few days before its owners found out.

Ms Andrews added that breeding companies must prepare for such events and that February”s proof run results would be run through the new model before May to give them an indication of changes.

Other new additions in May will be the introduction of persistency proofs and the fertility index for Holsteins and Friesians, which will be included in the PLI calculation. “This information is more accurate and has more depth than we have ever had before,” she said.

“Buying semen is an important decision. It takes a minute to put it in a cow and a lifetime to breed out problems.”