The Simbra society moved over to the new selection indexes earlier this year where there is significant emphasis on fertility (Days to Calving and Scrotal Size) in all three indexes. An index value is published when the EBV accuracy for the fertility trait block is above a threshold accuracy value. In other words, at least one of the two fertility traits must have an EBV accuracy above the threshold accuracy value in order for the index value to be published.
Since moving to the new indexes and until the May BREEDPLAN run, the threshold accuracy for the fertility trait block was 10%. However, as of the June BREEDPLAN run the BIC has requested an increase in the publication accuracy requirements for fertility traits to 20%. This means that an index will only be published if either days to calving or scrotal circumference EBVs have an accuracy of higher than 20%. This decision was made to improve the efficacy of selection for fertility traits using the indexes.
It is expected that some animals will be affected by this in which they may not have an index value published when they previously did. Younger animals without fertility performance data are expected to make up a large part of these affected animals. Submitting Days to Calving and scrotal circumference data will contribute towards increased EBV accuracy and thereby increased publication of index values. We encourage all breeders to record days to calving and scrotal circumference information.