Mascol IV is back on top

THE HIGHLIGHTS

• Canadian-bred Goldwyn is the biggest riser – ranked third.

• British-bred Picston Shottle returns to the top 10 – ranked sixth.

• Newly-released British bull Cogent Desmond has debuted in the top 10 – ranked ninth.

• Comestar Export climbed nearly 20 places to 12th.

This follows a change announced at the beginning of July that Profitable Lifetime Index (PLI) scores would be revised in order to shift the focus towards achieving better dairy cow ‘fitness’.

Only 45 per cent of the new PLI score comes from production traits (£PIN – milk, fat and protein), with the other 55 per cent coming from fitness and longevity traits.

According to the figures, the top 25 bulls in the list are all capable of extending the lives of their daughters by, on average, at least a quarter of a lactation, as well as reducing somatic cell counts by 10 per cent – all within one generation.

Marco Winters, director of the MDC’s breeding+ genetic evaluation service, also said the results should be achievable without compromising fertility.

“As well as being good on longevity and somatic cell counts, the top 25 bulls score very highly for their ability to improve feet, legs and udders,” he said.

“And there’s no need to sacrifice production – on average they will still improve milk yield by some 500kg per lactation.”

Mr Winters said a team of scientists, industry specialists and dairy farmers had been working on overhauling the index for more than a year and the 55 per cent emphasis on ‘fitness’ traits was one of the highest in the world.

He said it would identify animals that would pass on good natural disease resistance and have the right conformation to promote longevity in their offspring.

“The application of this new PLI has produced considerable re-ranking within the top 100 Holstein bulls, with almost a third now ‘new entries’.

“Mascol has been reinstated as the number one bull with a PLI of over £250 – meaning his daughters will improve profitability by £250 over their lifetime (rather than the ‘lactation’ value used previously) thanks to their combination of traits.”

Mr Winters said Mascol’s combined ability to reduce somatic cell counts in his daughters by 27 per cent, increase lifespan by 60 days, improve feet, legs and udders, and deliver very good

all-round production traits made him stand out from the others.

“Another familiar name can be found in second place. O-Bee Manfred Justice holds on to his high ranking under the new PLI thanks to his good daughter fertility – one of the highest in currently available bulls.”