The following is a summary of the discussions and recommendations resulting from the Genetic Evaluation Board (GEB) meeting held on Wednesday, October 23, 2013, which was preceded by an Open Industry Session at the Holiday Inn in Guelph, Ontario. The Canadian Dairy Network (CDN) Board of Directors will consider the following GEB recommendations for approval at its meeting on December 12, 2013.
• After assessing the current status of the planned December 2013 implementation of official genetic evaluations for Mastitis Resistance, the GEB recommended that it be postponed until August 2014. This extra time prior to official publication allows CDN to (a) finalize how the clinical mastitis evaluations for first lactation versus later lactations get published relative to existing proofs for Somatic Cell Score, (b) estimate genomic evaluations for the clinical mastitis traits, (c) provide preliminary bull proof files to industry partners, and (d) assess how Mastitis Resistance could best be incorporated into the LPI formula for some breeds.
• The GEB recommended that CDN use the “Average Merit of Mates” to identify bulls with non random semen usage in Canada and implement an adjustment for production and major type traits to reduce possible bias in domestic evaluations for progeny proven sires. The development and implementation of this adjustment was deemed as the highest priority of all research efforts at CDN in the coming months with a report expected at the March 2014 Open Industry Session and GEB meeting and official implementation in April 2014.
• On the cow side, the GEB recommended that CDN continue the development of the proposed approach to normalize the differences (known as Mendelian Sampling terms) between traditional genetic evaluations and the Sire x Maternal Grandsire pedigree index. This normalization methodology has the desired general effects of reducing the range of cow evaluations at the high end without treating elite cows as if they were all equally over-evaluated. The target date for official implementation of this adjustment to cow evaluations for production and type traits is August 2014 to allow for presentation at the Open Industry Session and GEB meeting in March 2014 as well as for the preparation of appropriate extension information.
• The GEB discussed the results of the CDN analysis quantifying rates of genetic progress achieved in each dairy breed as well as the relative selection emphasis placed on various traits. For the Holstein breed, the analysis comparing various scenarios for modifying the current LPI formula was also reviewed. In general, the GEB expressed strong support towards increasing the weight of the Health & Fertility component in LPI from 15% to 20%, at least for Holsteins. As it relates to the Production and Durability components, the GEB requested that CDN conduct further analysis of key options including an assessment of predicted rates of genetic gain for major traits in accordance with possible changes to the existing LPI formula. CDN staff is available to present analysis results to each breed association and continue the consultation process prior to making LPI formula recommendations at the next Open Industry Session in March 2014. In addition, CDN plans to conduct an updated analysis associating LPI to profit at the cow level with the goal of facilitating the translation of LPI values into economic benefits.
• Given the positive feedback received from industry partners and breeders attending the preceding Open Industry Session, the GEB recommended that CDN continue to pursue the inclusion of a new adjustment in the LPI formula aimed at crediting outcross males and females relative to the population of heifers and cows in each breed in Canada. The overall goal of this strategy is to balance the rapid rates of genetic progress achievable with genomics with a more controlled rate of increase in inbreeding levels in Canadian dairy breeds.
• Following the presentation of concept and preliminary results by CDN, the GEB recommended that CDN proceed with the development of a simplified procedure for estimating the Reliability of Direct Genomic Values (DGVs) for each trait with implementation in the Holstein breed targeted for August 2014. Key advantages for the proposed simplified approach include (a) the opportunity to include large numbers of genotyped cows in the reference population, (b) reduction in computer processing time at CDN, (c) greater flexibility associated with genomic evaluation services provided to industry partners.
• Given the pending completion of the Holstein Proven Sire Genotyping project funded by Zoetis Canada, the GEB requested that CDN conduct a specific genomic validation analysis tomquantify the gain in accuracy of prediction that was achieved for each trait due to the addition of over 2,000 newly genotyped progeny proven sires to the Holstein reference population.
• Following a research analysis examining the “behaviour” de-regressed MACE evaluations included for the estimation of genomic evaluations in Holsteins, the GEB recommended that research continue in this area. Suggestions for further analysis include genomic validation tests as well as an assessment of the impact on the accuracy of prediction when a minimum Reliability is imposed on MACE evaluations for each trait before the sire is included in the reference population for genomics.
• The GEB recommended that CDN document previous annual genomic validation test results as reference material in order to quantify the improvement in accuracy of genomic evaluations in Canada since implementation in 2009. In addition to assessing the gain in accuracy observed with genomics and the appropriate scaling of evaluations for young bulls compared to progeny proven sires, CDN should also monitor the reduction in the average over-estimation of top LPI young bull achieved over time with the improvement of evaluation methods in Canada.
• The GEB supported the calculation and publication by CDN of Carrier Probabilities for the various “Haplotypes Affecting Fertility” identified in each breed, in addition to the distribution of such values to A.I. organizations for possible use in genetic mating programs offered to Canadian producers as an effective means for controlling the associated frequency in each breed.
• The GEB received a report from CDN outlining a specific concern expressed by industry partners following the implementation of the new Semen Fertility bull evaluation system in August 2013. For some bulls with both conventional and sexed semen available for use in Canada, it is possible that their official Semen Fertility ratings are biased downwards due to the inappropriate inclusion of non-identified inseminations made using sexed semen. This issue also has a potential impact on the accuracy of genetic evaluations for Daughter Fertility and stems from the absence of reporting the use of all sexed semen. In the short term, CDN will apply more stringent edit criteria that will ultimately exclude a significant volume of insemination data provided to CDN via the milk recording channels. Going forward, however, dairy producers, A.I. organizations, DHI partners and breed associations must all be diligent in recording all breedings made with sexed semen otherwise it will be assumed as one using conventional semen. Accurate recording of the use of sexed semen can only be achieved by using the complete 11-character semen code that includes the “A.I. Code”, “Breed Code” and “Bull Number”, instead of short names and/or registration numbers.
• Following a detailed analysis of the accuracy of MACE evaluations for foreign proven sires as predictors of their future official domestic proofs in Canada, the GEB recommended that CDN investigate opportunities to improve MACE evaluations as soon as possible for specific “index” traits including Feet & Legs, Rump, Herd Life, Daughter Fertility and Daughter Calving Ability.
• Based on the impact analysis conducted by CDN as well as a review of the planned service schedule developed by Interbull, the GEB recommended that CDN submit the required data for participation in the December 2013 Implementation Run of the Genomic MACE evaluation services and target the official publication of Genomic MACE evaluations for foreign genotyped A.I. young bulls starting April 2014. CDN will label such evaluations as “IGI”, meaning Interbull Genomic Index, on the animal’s Genetic Evaluation Summary page and when they appear on their parents’ list of progeny but such foreign young sires will not have a specific Genomic Evaluation Details page since their genotype will not be in the CDN database.
• The GEB requested that CDN submit the official “combined” production evaluations for Milk, Fat and Protein yields, instead of the “weighted” proofs, to the Interbull Test Run in January 2014 in order to conduct an impact analysis. Conditional upon an acceptable review of the results, the GEB recommended that CDN continue submitting official “combined” production proofs for Interbull MACE evaluations on a routine basis starting as early as April 2014.
• In an effort to increase the international interest in and exposure to Canadian evaluations and genetics, the GEB recommended that CDN expand its web site to include more languages, especially for the main query tools.
• The next Open Industry Session will be held on Tuesday, March 4th, 2014 in the region of St. Hyacinthe, Québec, which will be followed the next day by a meeting of the Genetic Evaluation Board.
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.