The following is a summary of the discussions and recommendations resulting from the
Genetic Evaluation Board (GEB) meeting held on Thursday, October 13, 2011, which was
preceded by an Open Industry Session at the Delta Guelph Hotel and Conference Centre in
Guelph, Ontario. The Canadian Dairy Network (CDN) Board of Directors will consider the
following GEB recommendations for approval at its meeting on December 19-20, 2011.
• The GEB recommended that CDN include the Holstein genotypes received from Italy and
the United Kingdom in official Canadian genomic evaluations starting with the December
2011 release. This genotype exchange yields more than 3,500 additional reference sires for
estimating marker effects in Canada with an expected combined total of nearly 16,000 by
December 2011.
• Based on research results showing the gain in imputation accuracy using the new 6K
genotypes compared to the 3K genotypes, the GEB recommended that CDN include
genotypes from the Illumina 6K panel in Canadian genomic evaluations for each breed,
effective immediately. It was agreed to assign Reliability values for genomic evaluations
resulting from 6K genotypes in a manner equal to if they had been 50K genotypes.
• The GEB also recommended that CDN conduct a research analysis to quantify the
magnitude of change in DGV based on 6K versus 50K genotypes, depending on the
amount of pedigree and ancestral genotypes available.
• No changes were recommended at this time regarding the criteria for inclusion on various
top LPI lists for cows and heifers but the GEB will give consideration to this point at its next
meeting.
• For the Ayrshire breed, the GEB recommended that CDN use the 50K portion of available
high density (HD) genotypes to estimate unofficial genomic evaluations starting December
2011. Monthly unofficial genomic evaluations will be provided to authorized AI
organizations for review and consideration for young sire selection programs. When
feasible, CDN shall also release female genomic evaluations for only production traits to
their owners as unofficial information usable for management purposes but not for
publication and/or advertising.
• Given the industry need to receive regular and timely evidence of the accuracy of genomics
in terms of genetic selection, it is recommended that CDN perform genomic validation
testing (both backward and forward validation) at least annually for as many traits as
possible. In addition, further research is required to determine the most appropriate
Reliability estimate to publish with genomic evaluations.
• Given the increased importance of Reliability values associated with genetic evaluations for
genomically tested young sires compared to progeny proven sires, the GEB recommended
that CDN conduct an analysis and industry extension to consider the publication of 90%
confidence range values associated with Reliability values on a trait-by-trait basis.
• In order to be consistent with the principle of pooling daughter groups for males with
identical genotypes, the GEB recommended that CDN aim to apply the simplified approach
of blending genetic evaluations for females with identical genotypes, effective April 2012,
possibly starting with a pre-defined heifer population by birth date.
• The GEB recommended that CDN implement the proposed approach for rescaling LPI
values by halving the standard deviation and range of the progeny proven bulls while
maintaining the level of LPI values for the group of highest bulls. CDN shall communicate
this recommendation to each breed association for their feedback and support prior to
implementation, no earlier than April 2012.
• Following the discovery by USDA of five new “Haplotypes Impacting Fertility”, including
three for Holstein, one for Jersey and one for Brown Swiss, and the subsequent publication
of “Carrier” and “Free” lists by the appropriate breed association in the United States, the
GEB recommended that CDN adopt the proposed strategy, effective December 2011, for
calculating “Carrier Probability” values for each animal in the CDN database and displaying
such values on the “Pedigree” page for each animal on the CDN web site. Given that
evidence exists that some animals may change carrier status based on the current
haplotyping procedure, displayed Carrier Probability values will range from 1% to 99%. It
was also recommended that CDN make the Carrier Probability values for the new
haplotypes as well as for Brachyspina, based on laboratory testing results, available to
industry partners for use in genetic mating programs for managing matings between carrier
animals.
• Given the continued research and development in the area of Body Condition Score (BCS),
the GEB recommended that CDN aim to publish official genetic evaluations for this trait in
2012, including submission of bull proofs to the Interbull test run in January 2012. Method
and scale of expression of BCS evaluations is yet to be finalized.
• Based on research conducted jointly between CDN and the University of Guelph, the GEB
recommended that preliminary genetic evaluation results for Mastitis Resistance be
presented at the next Open Industry Session and GEB meeting in March 2012, with official
implementation by 2013.
• The GEB thoroughly discussed the various research results and planned projects
examining the stability of production evaluations. It is recommended that CDN give high
priority to examining alternatives for combining the individual lactation evaluations for each
of milk, fat and protein yields into the single published proof per trait.
• The next Open Industry Session will be held on Tuesday, March 20th, 2012 at the Hôtel des
Seigneurs in St. Hyacinthe, Québec, which will be followed by a meeting of the Genetic
Evaluation Board the next day.
If there are any questions, concerns or comments regarding the recommendations of the
Genetic Evaluation Board, as outlined in this summary, please feel free to contact committee
members listed at http://www.cdn.ca/committees-geb.php or by contacting Brian Van Doormaal
directly at Canadian Dairy Network.
|
