New Dairy Fitness Index Scores Well For Longevity

UK - The UK’s new focus on achieving better dairy cow ‘fitness’ through breeding has passed its first big test with the issue today (13 August) of a list of bulls radically re-ranked by their revised Profitable Lifetime Index (PLI) scores.

14 August 2007

4 minute read

Europe

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% – all within one generation. Director of the MDC’s breeding+ genetic evaluation service Marco Winters also confirms that these 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 says. “Plus there’s no need to sacrifice production; on average they will still improve milk yield by some 500kgs per lactation.”

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“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,”

Marco Winters

Mr Winters explains that a team of scientists, industry specialists and dairy farmers have been working on overhauling the index for more than a year, and finally announced the results last month. The resulting new PLI has a 55% emphasis on ‘fitness’ traits – among the highest in the world – so identifies animals which pass on good natural disease resistance and have the right conformation to promote longevity in their offspring.

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

“Mascol has been reinstated as the No 1 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 explains that Mascol’s combined ability to reduce somatic cell counts in his daughters by 27%, increase lifespan by 60 days, improve feet, legs and udders, and deliver very good all-round production traits makes 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.”

The biggest riser in the new top 10 thanks to the new PLI weightings can be found in third spot. Canadian-bred Goldwyn makes his debut with a PLI of £222. As breed leader for ‘type’ he is already a familiar name to many and under the new system he is given due credit for this. However, this bull also manages to impress on somatic cell counts and lifespan traits as well as good daughter fertility. Well-known British star Picston Shottle makes a welcome return to the top 10; his combined ability to reduce somatic cells counts, increase daughter longevity, and improve feet, legs and mammary without significantly affecting fertility is unrivalled among the other bulls in the top 10.

Finally, newly-released British bull Cogent Desmond comes straight in at No 9 with a PLI of £204, thanks to superb production, and the ability to reduce somatic cell counts and increase daughter lifespan by 0.1 lactations.

Mr Winters says that not only Holsteins have received this new treatment – other breeds having the new PLI applied are Friesian, Jersey and Jersey Island, Guernsey, Shorthorn and Ayrshire, although the change in rankings in these has not been so extreme. “Due to smaller population sizes, the breed leaders tend to be further ahead of the pack and we have seen most of these maintain their standings,” he says.

“It is important to recognise the importance of keeping all breeds on the most up to date system of ranking. However, producers must not compare sires between breeds – just within them – as each breed uses its own genetic base.”

For further information on the new PLI lists please visit www.mdc.org.uk and click on breeding+. The Holstein sire list includes Holstein UK (HUK) Type Merit values and the company marketing each bull. Every effort has been made to make sure that lists published by MDC and HUK are the same.

The published information includes top PLI lists for bulls with UK progeny tests and international proofs as well as top cow and herd lists. All breeding+ information has also been sent to breed societies and milk recording organisations.