Great variation is seen in this year’s spring Holstein genomic index, with Mr Rubicon Agronaut the pick of eight sire bloodlines represented among AHDB Dairy’s top 10.
The highest rated for type merit in the top 10 at 2,53 points (published 4 April ), the chart topper boasts a very different back pedigree to many, consisting of Rubicon-cross Shotglass-cross Shamrock-cross KHW Goldwyn Aiko.
High milk components (+0.18% fat and +0.08% protein) and good daughter health and fertility give Agronaut a profitable lifetime index (PLI) of £793.
In second place is former number one sire Westcoast Perseus, Penmanship’s highest ranking son. High production, good milk solids and daughter health and fertility have continued and hit a profitable lifetime index of £784.
Perseus herdmate Westcoast Guarantee is third. He is from the British Columbia-based herd, which started seven years ago and combines high milk volume and solids with a somatic cell count index of -29.
Guarantee, who is a Bryceholme SS Boastful – himself a Supersire son – excels at the new mastitis predicted transmitting ability (PTA), with a score of -5.
Another Canadian newcomer – Progenesis Padawan – sits in fourth position. This son of S-S-I Montross Jedi transmit high milk volumes and weights of fat and protein, has a fertility index of +15.1, a PLI of £761 and type merit of 2.51.
Lying in fifth place is the first UK bull in the rankings, which is the exceptional all-rounder and Penmanship son Prehan Lancaster (PLI+759) from Northern Irish breeder Stuart Smith.
This bull’s maintenance index is -2, indicating his daughters will cost less to maintain than the breed average. His dam – Prehen Shamrock Lady VG85 – gave 9,755kg at 4.1% fat and 3.13% protein as a heifer.
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De-su Holsteins have produced De-Su Rookie 11057 (PLI £669), the number one daughter-proven sire on the UK market. This moves the Bookem son up 44 points over the past four months.
He boasts a top-10 cell count at -25, a very strong lifespan index of 0.7 and the best PTA for mastitis (-4), a new AHDB evaluation launched this month working on scale of -5 to +5.
Second in the rankings is former number one bull Lavaman (PLI £635), who has nearly 800 daughters in the UK and a 99% reliable production index.
At third is a newcomer to the top-10, as S-S-I Shamrock Mystic (£626), which has been boosted by an improved daughter fertility index (+16.5).
Tollenaars AltaMicro remains in the top five, having his positioned strengthened by UK daughter information. He brings a fertility index of +17.7 and a PLI of £625.
At number five is Kings-Ransom Erman (PLI £623), who has been overtaken by steadily improving sires. He was number one in December 2016.
British Friesian sire Catlane Chad remains number one outside the Holstein breed (PLI £496). He rates highly for low cell count transmission (SCC index -16) and daughter mastitis resistance, which scores at -5, one of the the best in the breed.
Herdmate Catlane Caleb lifts his PLI to £400, seeing yield drop 190kg but extreme components (+0.31% fat and +0.14% protein), which sees him in second place.
In third, Kirkby Jupiter (PI £387) is the highest type transmitter in the top five (TM 2.45), followed by Kirkby Major (PLI £326).
New into the top five is Skyhigh Patrol (Rocket 3 x Glen Albyn), transmitting the highest milk volume of the top five and offering a PLI of £290.
Up from second to first is VJ Hilario, who has seen his PLI lift to £558. VJ Summit (£539) moves up to second place, bolstered by his lifespan PTA moving to +0.6.
In third place is Sunset Canyon Dazzler (PLI £516), which has benefited from newly included genomic information included in Holstein indexing for many years.
Next are VJ Link (PLI £474), a former number one sire, and VJ Zlager (PLI £471).
A Swedish Red, which qualifies to rank on the Ayrshire list, has continued to lead the rankings. VR Gobel (PLI £578) has a good lifespan index (+0.6) and mastitis PTA (-3).
Newcomer VR Hattrick (PLI £529), the progeny of Haslev and Gunnarstorp comes into the top two as a high production sire.
In third is VR Hammer (£ 482) and behind is Gunnarstorp (PLI £464), who holds on to fourth position, now with 690 UK daughters, who is followed by Pell Pers (PLI £545).
A low-maintenance bull leads the spring calving index, a specific block-calving ranking of bulls suitable for grass-based, 4,500kg-a-head systems.
Once again Jersey and British Friesians lead the index, with Jersey bull VJ Tester pipping VJ Summit. With low daughter maintenance costs (-69) and +0.8 for lifespan, Tester retains his number one spot.
High daughter fertility bulls VJ Hilario and VJ Linkremain in the top five and are joined by VJ Juris and Sunset Canyon Dazzler.
In seventh is noted Friesian Catlane Caleb, the first of two British Friesians in the top ten, the other being Catlane Chad in 10th.