Bulls for spring calving will boost milk components

Producers calving in spring will be some way through the breeding process for next year’s calvings so may feel reassured to see stability in the across-breed Spring Calving Index (£SCI) rankings, published this week by AHDB Dairy.

Intended for use exclusively by producers block calving in spring, operating grazing-based systems and targeting milk production of around 4,500kg/head, the £SCI ranking sees the Danish-bred Jersey, VJ Tester retain his existing lead.

Featuring negative milk volume with exceptionally high percentages of fat and protein, Tester also transmits long lifespans (LS +0.6) and excellent fitness (SCC Index -15 and FI +10.8) as well as low feed costs for maintenance (Maintenance -61). His SCI is £451.

Also retaining his position is the second-ranking VJ Link (SCI £413), another Danish-bred Jersey. The maintenance cost of Link’s daughters is also exceptionally low (Maintenance -62), while high fat and protein percentages again complement good daughter fitness, fertility and lifespans. SCC Index is -9; LS is +0.3 and FI is an impressive +14.0.

Even higher for daughter fertility is the highest ranking British Friesian in the shape of Catlane Caleb, who features the trait for which the breed is renowned. With a SCI of £408 and a FI of +14.5, he is the best fertility improver in the top 10 and also brings low maintenance costs and long lifespans.

The highest ranking Holstein, Gen-I-Beq Lavaman, weighs in with a SCI of £394, and with a breeding pattern – somewhat different from the Jerseys – which features a far higher volume of milk with very good total solids production without improving percentage of fat. He too offers good daughter fertility (FI +8.8).

Kings-Ransom Erdman is the second Holstein in the top five, and with a SCI of £390, he is level-pegging with the Danish Jersey, VJ Lure. Erdman features the highest volume of milk and total milk solids in the top 10, although will not improve milk quality. However, SCC Index is the best in the top 10 at -19, and he will also improve lifespans and fertility.

Meanwhile, Lure will make big improvements to percentage fat and protein and will cut feed costs through lower maintenance requirements (Maintenance -63).

“With a top 20 which features nine Jerseys, nine Holsteins and two British Friesians – and many other breeds in the top 100 rankings – there is plenty of variety across breeds from which grazing-based farmers calving in spring can make their breeding choices,” says Marco Winters, head of genetics for AHDB Dairy.

“However, it’s very important for breeders to remember that the £SCI list is an across-breed ranking, which means the figures they see are very different from the same bulls’ figures on their own breed rankings,” he continues.

“This means the figures are not comparable in any way to the individual breed rankings and they should only be used in the context of the Spring Calving Index.”

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