By Marianne Curtis
REVISION of the PIN formulae to place more emphasis on fat has brought a degree of reranking in the latest Holstein PLI proof run.
The new PIN formula sees a decrease in protein to fat ratio from 6:1 to 2.5:1 to reflect changes in milk pricing policy over recent times, explains Gordon Swanson of the Animal Data Centre.
"Quota prices have acted against high fat levels in the past, but a reduction in quota cost means a reduced protein to fat ratio is more appropriate in the PIN calculation."
The change brings some new names into the PLI top 10 including New Zealand bred bull Bagworth Z Keet offering 426kg milk, 34kg fat and 20.8kg protein. However, as well as a low production figure compared with other bulls in the top 10, this bull is also disadvantaged by a lack of type merit data. "This bull has no daughters in the UK and no Interbull proof for type," says Mr Swanson.
Ricecrest Marshall and Delta Webster retain high positions, ranked first and second on PLI, respectively. Genus bull Ricecrest Brett performs well in both PLI and the new TOP ranking, with a £95 PLI and 685 TOP score.
Holstein UKs TOP index is published for the first time this month, following its launch at this years Cattle Breeders Club Conference.
The TOP index places more emphasis on traits such as legs and feet, udder conformation and somatic cell counts (SCC) than existing indexes, with the aim of breeding more trouble-free cows. Trait weightings for TOP are 50% production, 40% type and 10% health and longevity.
Producers increasingly conscious of health traits, such as SCC, will be helped by this proof run through the introduction of Interbull evaluations for SCC. Until now, these have relied on conversions for Holstein bulls and there have been no SCC PTAs for foreign Ayrshire, Guernsey and Jersey bulls, says Mr Swanson.
"SCC has become an important management trait and these improved evaluations will enable breeders to make more informed selection decisions," he adds. *
Corgee, a daughter of Crichel Principal which ranks highly in both the latest PLI proof run and new Holstein TOP index.
TOP £PLI £PIN Supplier Price
Olmo Prelude Tugolo 822 64 64 Semen World £22
Crichel Principal 820 91 88 Cogent £18
Etazon Lord Lily 775 73 70 Genus £25
Genus Jayson 765 63 65 Genus £21
Maughlin Storm 722 44 39 Semex £80
Shoremar James 707 58 61 Semex £22
Cogent Lucky 696 64 59 Cogent £17
Ricecrest Brett 685 95 95 Genus £16
Southland Marker 677 53 53 Genus £25
Genus Carling 674 74 79 Genus £12
Source: Holstein UK.
£PLI £PIN Type merit TOP Supplier Price
Ricecrest Marshall 96 87 1.7 837 Alta £35
Delta Webster 95 86 1.8 827 Avoncroft £25
Ricecrest Brett 95 95 0.6 685 Genus £16
Elite Mountain Donor 93 90 -0.2 594 Semen World £15
Eastland Festival 93 96 -0.2 599 Avoncroft £17
Crichel Principal 91 88 1.9 820 Cogent £18
Sikkema-Star Magma 91 82 1.8 793 Semen World £36
Bagworth Z Keet 90 90 – 325 LIS £14
McCloe-Pond Trent 88 90 1 767 Avoncroft £32
Lorak 88 91 1.3 715 Supersire £25
Source: Animal Data Centre.