New calving ease indexes available in January
TO help dairy farmers make more informed breeding choices, official calving ease indexes for Holstein and Friesian sires will be published in the January DairyCo breeding+ proof run.
The indexes will be expressed on a scale from about -4 to +4 around a breed average of 0, with positive figures predicting easier-than-average calvings and negative figures predicting more difficult ones.
This is the first time independent calving ease indexes have been produced in the UK. It follows an industry-wide collaboration and the analysis of around 400,000 calving records, gathered by British farmers as part of regular milk recording or participation in progeny testing.
The two genetic indexes - Direct Calving Ease (dCE) and Maternal Calving Ease (mCE) - together give a complete picture of a bull’s ‘calving performance’.
Marco Winters, director of DairyCo breeding+, says: “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.
“dCE is likely to be of most interest in the first instance, and it is naturally going to be important when breeding maiden heifers. But it shouldn’t be ignored in older cow matings, where it would always be wise to avoid bulls likely to produce very difficult calvings.
He says attention should be paid to mCE as long-term selection for dCE without any regard to mCE could lead to future problems.
This relationship will be familiar to cattle breeders, who are likely to associate easy calvings with smaller calves, but whose smaller calves sometimes go on to have difficult calvings themselves.
“As part of a broader breeding strategy, I’d recommend selecting primarily for Profitable Lifetime Index (PLI) and using the Calving Ease indexes, as well as other fitness traits, as secondary criteria,” says Mr Winters.
For the time being, dCE and mCE will remain as standalone indexes although they may be included within PLI at a future date.