Why do €uro-Stars change at all?

“Why can’t ICBF just leave the stars alone? If he’s 5 a star bull – just leave him that way”. Of course, it is frustrating when a bull’s figures drop and especially if you are a pedigree breeder who has a young son of that bull whose lower figures now make him very difficult to sell.

This is probably one of the most common questions about the €uro-Star system. ICBF has a large computer, called a database, which receives information about animals daily. Data such as calving surveys, weights, carcass records and death dates are sent to ICBF from farmers, weight recorders, Linear Scorers, Marts & Factories etc.

ICBF takes all this information out of their database 6 times a year and runs it through its genetic evaluation system. The new information is then reflected in a change to the €uro-Stars of animals connected to that data. It could be that the AI Bull that was thought to be easy calving based on his pedigree has turned out to be very hard calving. If you have a son of his then his ‘calving difficulty %’ will also be affected. So, it is crucial to remember that the €uro-Stars of your young bull are affected by his half brothers and sisters in other herds. He may have been born without difficulty in your herd but bear in mind that other farmers had a lot of calving difficulty with that same AI bull in their herds.

The following graphic shows a typical example of how a Young Pedigree Beef Bull’s €uro-Stars can change over time in Ireland:

Integrated database

€uro-Stars changing are a consequence of having a highly integrated database which is receiving data on animals & their relatives from a wide range of sources. It is only right that the most up-to-date view of how a bull is breeding is reflected to farmers so as they can make the most accurate decision.

If a bull’s figures were only based on a small group of progeny that were weighed and assessed once and his figures were ‘fixed’ forever – this might not be a very fair sample of his genes and may inaccurately set his figures too high or too low.

Reliability %

Constantly adding to a bull’s progeny count allows a bull to fully express his genetic potential. Ultimately, we are left with the most accurate picture of how a bull is breeding thus allowing farmers to make the most accurate breeding decision. The ‘reliability %’ of a bull’s index figures will steadily increase as more data is built up on him, his progeny and his relatives. E.g. when a bull is over 90% reliable and is 20% for calving difficulty – he is a hard-calving bull. Regardless of how some farmers had no bother with his calves and no matter if his own shoulders aren’t that wide, too many difficult calvings have been reported by Irish farmers to not have him at such a high calving difficulty figure. Genomics will add to this accuracy and result in bull’s figures fluctuating less frequently.