Bull News January 2010

Unprecedented dominance of Oman and his sons continues with the latest run

This week’s Holstein bull proof run from DairyCo breeding+ (published Tuesday 12 January) may look like more of the same with a continued dominance by Oman and his sons. But beneath the surface, there are some new bulls quietly emerging; two brand new Calving Ease indexes adding important independent management information; and a significant reduction in all figures brought about by the five-yearly base change (see box) which takes place this month.

So, Oman himself (O-Bee Manfred Justice) retains his remarkable stronghold on the number one position when ranked on Profitable Lifetime Index (£PLI), in real terms improving his performance as more UK daughters (now 795) contribute to his proof. His PLI of £257, although in actual terms lower than last August’s figure, reflects continued improvement in his daughters’ exceptional performance for production, health and fitness traits.

Oman’s new direct Calving Ease index (dCE%) further strengthens his status, which at +3.4 is one of the best in the top 10.

“This confirms him an easy calving sire and means that 3.4 percent more than average of the calvings by Oman are easy,” explains geneticist Marco Winters, director of DairyCo breeding+. “The new Calving Ease indexes are expressed as a ‘percent easy calvings’ on a scale of around -4 to +4 around a breed average of zero. Positive figures indicate that calvings are predicted to be easier than average and negative figures predict more difficult calvings.”

Alongside dCE% (predicting the ease with which a calf by that sire will be born), a second, maternal Calving Ease (mCE%) figure will also be published, indicating the ease with which a daughter of that sire is expected to give birth. Oman scores well here too, with a better-than-average mCE% of +0.5.

“Of course, dCE% will be of most interest, particularly when breeding heifers,” says Mr Winters. “But both indexes should be considered, as long-term selection for dCE% without any regard to mCE% could set up problems for the future.”

There’s no change in the bulls ranked immediately beneath Oman, with his son, Man-O-Man, retaining his second position with the best overall production potential (kg fat plus protein) of available bulls and the best mCE% of the top 10.

Morningview Legend holds firm in third place, with good all-round production, health and fitness, while Via Thelo makes his debut in the top 10, thanks to a strong performance in longevity and daughter Fertility Index. However, the announcement of his untimely death late last year, may restrict his impact on the UK population.

The first and only bull which is not an Oman bloodline to contribute to the top 10 comes in the form of well-know second crop sire, Braedale Goldwyn. Now with approaching 2,000 UK daughters contributing to his proof, he has the highest type score of the leading PLI bulls.

Full brothers Otto and Eight rank sixth and eighth (probably a first to have two full brothers in the top 10), with Otto gaining ground thanks to an improvement in his Lifespan to +0.3, despite the observed base change for this trait.

Also ranking equal sixth is Co-op Oman Lloyd, improving his ranking and now the highest milk bull in the top 10.

High component bull, Timmer Tyson remains in ninth place, and adds a +3.5 score for dCE%, making him the easiest calving sire in the top 10.

Best daughter fertility bull in the top 10 is Bogard with a Fertility Index of +5.9.

The highest new UK-proven bulls are Woodmarsh Talisman (a Talent son from the well-know Mtoto Melody family) and Cogent Loaded (a son of Titanic from Tugolo Looking, also the dam of the proven Cogent Loader).

Talisman has a good all round proof with the right emphasis on all of the fitness traits, particularly Fertility Index at 4.2. His PLI is £148; Type Merit is 2.1.

Loaded similarly scores well for fitness traits; has a TM of 1.9 and an overall PLI of £119.

Commenting on the unprecedented domination of the proof run by sons of Oman, Mr Winters says: “I am not unduly worried by this as these bulls tend to have the production, health and fitness qualities required by profit-driven and welfare-conscious dairy farmers.

“The UK has a further advantage as neither Oman’s sire (Manfred) nor maternal grandsire (Elton) were much used in this country, giving us plenty of scope to use these bloodlines without a major risk of inbreeding.

“Of course, dairy farmers will have to keep an eye on the narrowing of bloodlines as time passes, but as sons from other sires – such a Shottle, Goldwyn, Ramos, and Laudan – start to come on stream, there should be plenty of scope in the years ahead to retain genetic variation.”

A table of the top 30 available Holstein bulls ranked on the latest PLI (January 2010) appears below. Type Merit is supplied by Holstein UK.

A base change in the dairy bull proofs takes place every five years to account for the genetic improvement which has been made across the various traits. Without it, figures would continue to go up and up and the breed average of zero would become increasingly irrelevant as it would reflect animals which were average many years ago.

This month, the average has been reset to zero, and this figure reflects the average genetic merit of cows born in 2005. Cattle of this age form the backbone of the national dairy herd so it’s convenient to compare bulls which are being considered for use against this figure.

Because of the base change, Holstein bull proofs this month will change as follows:

This means, for example, that a bull whose PLI has gone down by £35 since the last proof run (in August 2009) is in reality exactly the same as at that time.

There are two new Calving Ease indexes – one for Direct Calving Ease (dCE%) and one for Maternal Calving Ease (mCE%).

dCE% gives a prediction of the ease with which a calf by that sire will be born and mCE% predicts the ease with which a daughter of that sire will give birth.

The indexes are expressed on a ‘percent easy calvings’ scale of about -4 to +4 around a breed average of zero. Positive figures indicate that calvings are predicted to be easier than average and negative figures predict more difficult calvings. For example, a score of +3 means that three percent more than average of the calvings are expected to be easy.

The new index, published by DairyCo breeding+, is the result of research undertaken at SAC and largely funded by Defra with additional support from the Scottish Government, DairyCo, NMR, CIS, Holstein UK, Genus ABS and Cogent.

The AI companies’ own figures which were used in the past were a useful predictor of calving ease but this new independent index expresses all figures on a common UK scale and makes it far easier for farmers to compare bulls from different studs.

Calving Ease indexes are not currently included in PLI but may be used in this index at a future date.