Holstein sire summary evaluations now give you a better handle on calving-ease bulls.
The new value is called “daughter-calving ease.” It combines two factors — the ability of a bull’s daughter to deliver a calf easily, and the tendency for her calf to experience an easy delivery, says Chuck Sattler, vice president of dairy progeny testing and genetic research at Select Sires in Plain City, Ohio.
The evaluations are expressed on the same scale as “service-sire calving ease” — the traditional calving-ease value that has been available for the past 20 years.
However, the reliability of the “daughter calving ease” value is low for many AI sires, so use it with caution, Sattler advises. To do so, include it in a selection index as a way to improve overall calving performance or to prevent calving difficulty from getting worse, he adds.