August 2023 Evaluation Changes: What’s New?

A handful of changes are implemented for the U.S. genetic evaluations on August 8, 2023, as announced
by the Council on Dairy Cattle Breeding and USDA Animal Genomics Improvement Laboratory.

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First publication of Constructed IDs in Bull and Cow Files
By Ezequiel Nicolazzi and Jose Carrillo

“Constructed IDs” have been implemented since the April 2023 evaluation. However, official bull and cow files at the time did not include these IDs, as none of the animals released had pedigree enhancements linked to the procedure.

By August 2023, Constructed IDs are expected to be included in both bull and cow files.

Learn more at www.uscdcb.com
• Constructed IDs Frequently Asked Questions
• Constructed IDs: Eliminating Pedigree Dead Ends

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More records used in Gestation Length, Cow and Heifer Livability
By Ezequiel Nicolazzi, Jay Megonigal and Paul VanRaden

More records will be used Gestation Length (GL), Cow Livability (LIV), and Heifer Livability (HLV) in August 2023 compared to previous runs. Investigations into a possible modification of the cutoff date used for these three traits illustrated the necessity to correct the procedure and include four additional months of data.

This change had a negligible impact on all breeds, and only a slightly higher variability in single animals was observed.

A better definition of the way breed codes are managed in GL extraction program was also introduced. This change had only a slight negative effect on pre-1980 bulls.

Since GL is not included in NM$, none of the changes reported for GL will affect Net Merit $ (NM$). The increased number of records in LIV and HLV had nearly no impact on NM$.

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Exclusion of France from PTAs foreign dam exchange
By Ezequiel Nicolazzi and Jay Megonigal

CDCB regularly exchanges pedigrees and traditional PTAs of females with many countries. This exchange program is mutually beneficial to all countries as it allows the inclusion of direct Predicted Transmitting Abilities (PTAs) instead of a less reliable domestic Parent Average (PA) or generalized breed average value (when no information is available). In the August 2022 evaluation, France implemented a single-step model which eliminated the availability of traditional-only evaluations on the animals of interest. During the April 2023 evaluation, we received confirmation that these French values would not be available in the near future. This situation is similar to the exclusion communicated in April 2023 with New Zealand, but for different reasons.

Therefore, in the August 2023 evaluation, females that previously received direct PTA from France will receive PAs, resulting in larger variations in their evaluations and the evaluations of their progeny.

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Revised breed edits in Interbull evaluations
By Rodrigo Mota and Ezequiel Nicolazzi

Stricter rules have been implemented to include Interbull evaluations in U.S. evaluations. During a routine post-April review, a group of bulls not receiving Interbull evaluations was identified. An investigation revealed a flaw in the logic for bulls with Interbull evaluations in multiple breed bases or in a breed base different from the one used in the U.S. The new rules will exclude any evaluation not in line with the domestic breed of evaluation.

The most noticeable impact of this new procedure will be on 45 genotyped animals (29 Brown Swiss and 15 Holstein); they will now receive the more reliable Interbull evaluation as originally intended.