Bomaz AltaTopshot has retained his number one position in the Profitable Lifetime Index (£PLI), published by AHDB Dairy – surviving the upset of a base change to the evaluation system.

The five-yearly base change means the national average is recalculated in the UK and reset to zero. This means all other genetic index figures change in their difference from breed average – although the order in the rankings remains the same.

Carried out with the April, 2020, index run, for which the average has been reset to reflect the average genetic merit of cows born in 2015. This has pulled down almost all genetic index figures for all dairy breeds – but for Holsteins, the overall decline in £PLI is £142, meaning each bull’s £PLI declines by this amount purely due to the base change.

This is designed to ensure genetic index figures don’t keep getting higher and higher, moving so far away from the original average it becomes hard to see where a bull stands in relation to the UK’s national herd.

That said, with a PLI of £708, Topshot reaffirmed his transmission of high weights of milk and protein – Predicted Transmitting Abilities (PTAs) of 985kg and 33.4kg, respectively – alongside excellent lameness advantage (+3) and good udder health (SCC -21, Mastitis -3).

Graduating into second place from further down the genomic list was Westcoast Guarantee (Boastful) which has an impressive PLI of £694. This is both a general indication of the genetic credentials of the newest generation of daughter-proven bulls and a specific reflection of this bull’s transmission of superb udder health (SCC -22, Mast -4) and fertility (Fertility Index +13.4), said AHDB.

After that comes the leading improver of daughter lifespan (LS +176 days) View-Home Littlerock, which daughters also boast low costs of maintenance (-19), and Seagull-Bay SR Stardust, both bulls changing little since last time with PLIs of £677 and £674, respectively.

Taking a jump in the table from 16th to fifth place was Hoanster Zanzibar, with 163 more UK daughters now contributing to his figures and earning him a 99% reliable production PTA and a PLI of £673. He affirmed his transmission of excellent calf survival (CS +3.2), udder health (SCC -19, Mast -3) and fertility (FI +15.2).

At £650, super-high production bull, AOT Silver Helix is little changed in sixth position, while seventh ranking Seagull-Bay Jo Dancer (PLI £641) moves up from 14th place. Both bulls offer high milk quality.

Both Pine-Tree Verona (PLI £639) and Cookiecutter Harper (PLI £637) move from just outside the top 20 into eighth and ninth position and are followed by three bulls which tie for 10th position, with PLIs of £617.

Welcome Silver Griff makes improvements in daughter fertility (FI +9.6), ABS Achiever continues to excel for percentage fat (+0.26%) and Progenesis Unicorn is a newcomer, rising spectacularly from the genomic ranking.

The lowest milk volume bull in the top 10, Unicorn transmits improvements to most health traits including SCC (-20), lifespan (+131 days), daughter fertility (+14), TB resistance (+2.3) and calf survival, which at +3.7 is the highest in the top 10.

Commenting on the daughter-proven ranking, Marco Winters, head of genetics for AHDB Dairy, said: “Some producers have turned to the exclusive use of young genomic sires but for those who prefer the higher reliability of bulls which have milking daughters, this list gives them plenty of opportunity to improve their herds.

“In particular, there are many proven sires in both the top 10 and further down this £PLI list which offer the chance of making substantial gains in daughter health and fertility. Since this is advocated on so many levels – from an economic, animal welfare and a sustainability perspective – I would strongly urge producers to shortlist their bulls on £PLI and then look at the components of health as well as production in detail.”

 

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