National sire fertility index explained
By Dairy Herd staff
| Thursday, November 13, 2008
The Sire Conception Rate (SCR) index was introduced to the industry in August and is based on confirmed pregnancies and measures phenotypic service-sire fertility. It replaces estimated relative conception rate (ERCR).
The SCR gives the probability that a specific bull’s straw of semen will result in a pregnancy when compared with other bulls that could have been used, says Duane Norman, research leader with the USDA Animal Improvement Programs Laboratory in Beltsville, Md.
It is expressed as a relative conception rate and reported as a percentage. An average bull has an SCR of 0.0 percent. A bull with an SCR of 3 percent is expected to have a 3 percent higher conception rate than an average bull.
Evaluations are available for active AI and progeny-test bulls with a minimum number of inseminations (300 for
The standard deviation of SCR evaluations was 2.37 percent for August.
