EACH index ’ s formula has been adjusted to reflect changing economic conditions and the ongoing needs of dairy processors and farmers . Most notable financial changes are in feed , labour and replacement costs , as well as in the value of cull cows since the last update in 2018 .

The changes result from consultation across the industry , which is undertaken routinely by AHDB , working with market specialists and through the Genetics Advisory Forum ( GAF ). Stakeholders in the forum include farmers , breeding companies , vets , milk processors , the RSPCA , milk recording organisations and breed societies . These participants collectively review the genetic progress dairy breeds are making , the long-term market outlook for inputs and output , and they fine-tune the three economic indexes as the need arises .

£ PLI , £ ACI and £ SCI

The indexes were last updated in 2018 and before that , in 2014 . Each continues to be formulated to suit a manufacturing contract , reflecting both an industry shift in this direction and some value in producing components , even in liquid markets .

Feed Advantage

To address the rising significance of feed cost , Feed Advantage ( FAdv ) will also be added to £ PLI . A combination of Maintenance Index and a genomic prediction of feed efficiency , FAdv was developed from extensive trials over many decades measuring actual feed intake in relation to a cow ’ s size and milk production .

Currently only available for the Holstein breed , which took part in these trials , all other dairy breeds will continue to use the Maintenance Index which acts as a proxy and is based on a prediction of feed efficiency based on the size of the cow . Maintenance will also continue to be used in the across-breed indexes , £ ACI and £ SCI , for all breeds .

Digital dermatitis

Another change to all three indexes and all breeds is the inclusion of the genetic evaluation for Digital Dermatitis ( DD ). This follows ongoing work at the University of Liverpool which showed the AHDB genomic evaluation for DD was very effective in predicting the odds of a cow having DD . As a result , DD will now be included alongside Lameness Advantage ( LAdv ), which was introduced in 2018 . By using both LAdv and DD Indexes in

harmony , more rapid genetic benefits can be achieved to help tackle lameness , as they offer distinct and different benefits .

£ SCI only

For the £ SCI only , additional changes will be made with the April proof run . This will see bulls whose daughters are heavier penalised more severely for spring block calving , grazing based systems . This move has been driven by feedback from farmers running grazing systems , many of whom place a higher value – over and above purely the additional maintenance feed cost – on the lack of soil damage and ease of management smaller cows can bring .

Marco Winters , AHDB head of animal genetics , says cattle breeding is a longterm business and the economic model which sits behind the changes considers the outlook five to 10 years ahead .

“ At the time of the 2022 update , we see more volatility in the market for inputs than on previous occasions ,” he says . “ However , we don ’ t know how sustained current prices will be , so we have to base our decisions on longer term projections , but will continue to carry out regular reviews and may have to make adjustment if circumstances dictate .”

Marco Winters

He also remarks that the relative emphasis between production , health and efficiency has not significantly changed in any of the indexes , such that each continues in its previous direction of travel for each type of farming system . This places around two-thirds of the value of each index on health and efficiency and one third on production .

The £ PLI is tailored for year-round calving herds and is a within-breed index ; the £ ACI is an across-breed index , designed for autumn block calving herds producing much of their milk during the winter months ; and the £ SCI has been formulated specifically for herds with a heavy reliance on grazed grass which calve in a tight block in spring , and can also compare animals across breeds .