Ongoing improvements to the way in which genetic indexes are calculated has produced a slight re-ranking of bulls in the newly published August proofs (published August 19, 2008). But the top three bulls from the previous proof run can still be found in the first four positions of this new ranking.
An O-Bee Manfred Justice daughter
Test Day Model – the method used for the calculation of genetic indexes
– is being refined all of the time,” explains Marco Winters, director of
DairyCo breeding+ who publish the figures. “On this occasion, a
substantial increase in available computing power has enabled us to include all
fourth and fifth lactation information for bull daughters and ancestors into
the calculation – that’s 20 million extra lactations.
with other improvements in accuracy – stemming from better adjustments
for environmental effects such as season and age group – we now have more
accurate figures than ever before.”
result of the changes is a small average reduction of -0.05 percent fat and 13
points PLI (Profitable Lifetime Index) amongst Holstein bulls, although some
bulls have inevitably bucked this trend.
first bull to do so is the remarkable O-Bee
Manfred Justice, a bull which continues to impress and now takes his most
commanding lead ever with a massive 265 PLI points.
first newcomer to the top 10 – moving up from number 13 last April - is
the second-placed Laudan, another
second crop bull and the first of two Lukas sons to feature in the top 10.
two and three from the last proof run – Mascol and Wizzard - now
rank in third and fourth positions with minimal changes to their figures, while
fifth position is taken by Leif, the
second Lukas son. The proof of this older second-crop bull confirms him as a
fitness specialist with outstanding cell count, lifespan and daughter fertility
ranking of the UK progeny tested bulls is Huddlestone
Spooky - bred out of a full sister to Mascol and with a PLI of 190.
noteworthy bulls in the top 20 and all with an impressive 175 PLI points or
more are the daughter fertility specialists Delta Peridot (Fertility Index +5.1) and Klassic Merrill Lynch (FI +7.0).
top daughter lifespan transmitters are Ramos and Gibor with Lifespan Indexes of
+0.8 and +0.7 lactations respectively. And finally the top Type Merit
bulls in the top 20 are Picston Shottle – now with almost 5,000 daughters contributing to his UK proof –
who maintains an excellent Type Merit of +3.5; and Braedale Goldwyn, at a comparable +3.4.
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