Canadian Dairy Network (CDN) held an Open Industry Session on Wednesday, October 24,
2018 at the St. Hyacinthe Congress Centre, which was followed, as usual, by a meeting of the
Genetic Evaluation Board (GEB) the following day. The following is a summary of the
discussions and recommendations resulting from that GEB meeting held the next day, which will
be considered by the CDN Board of Directors for approval at its meeting on December 10,
2018.
- Following a comprehensive presentation related to the publication of Direct Genomic
Values (DGV) and a lengthy discussion period during the Open Industry Session, the GEB
members continued discussions during its meeting the following day. A summary of those
discussions has been circulated by CDN in a separate document and is available upon
request. In the end, given the technical nature of the GEB mandate, as an advisory
committee to the CDN Board of Directors, the GEB felt there was no science-based reason
to change the direction of its original recommendation made last April for CDN to no longer
publish DGV for any animals or make them available in any data files. Consideration of
non-technical points on this topic and an implementation plan fall within the responsibility of
the CDN Board of Directors. - The GEB discussed some final details associated with the transition of Somatic Cell Score
expression to the Relative Breeding Value (RBV) scale used for all other functional traits, to
be effective December 2018. As a consequence the GEB made the following
recommendations:
- That evaluations for the Mastitis Resistance (MR) index be labelled as official when the evaluation for Somatic Cell Score meets the minimum criteria for official status.
- That CDN develop a Cow Genetic Evaluation Details page on its web site for providing genetic evaluations for traits with official status that do not otherwise appear on the animal’s Genetic Evaluation Summary page.
- That CDN examine the use of single step methodology for calculating Clinical Mastitis genomic evaluations for possible implementation in the future. This approach is expected to increase the accuracy compared to current genomic evaluations and/or allow CDN to expand the availability of this trait to other breeds.
- That CDN assess the current range of bull evaluations for Mastitis Resistance in the Ayrshire and Jersey breeds and consider making any required modifications given that these breeds do not have genomic evaluations for Clinical Mastitis, which is the case for Holstein.
- Also effective December 2018 are official genetic and genomic evaluations for additional hoof health traits in Holsteins, over and above Digital Dermatitis that was introduced in December 2017. On this topic, the GEB made the following recommendations:
- That Holstein breed evaluations for eight hoof lesions, namely Digital Dermatitis (DD), Interdigital Dermatitis (ID), Heel Horn Erosion (HHE), Sole Ulcer (SU), Toe Ulcer (TU), White Line Lesion (WL), Sole Hemorrhage (SH) and Interdigital Hyperplasia (IH), be added to the “Health” page linked to each sire’s Genetic Evaluation Details page.
- That the proposed formula for combining evaluations for the eight lesions into a single Hoof Health (HH) index be approved for implementation by CDN.
That CDN continue its effort towards the development of a national strategy to have more hoof health data collected from herds across Canada with the aim of increasing the accuracy of genomic evaluations in Holsteins as well as expanding the availability of these traits to other breeds where possible.
Given the intent of CDN to introduce updated formula for Pro$ and LPI in April 2019, the GEB reviewed the results of analysis conducted to date and made the following recommendations:
- Following discussions with Ayrshire Canada, the Pro$ index will be introduced in the Ayrshire breed in addition to the Holstein and Jersey breeds.
- That that genetic base used for Pro$ be defined such that published values are easily comparable over time and the units of expression reflect the expected difference in daughter profitability in dollar terms.
- That CDN continue the ongoing research effort to account for different maintenance costs according to a cow’s body size when developing the updated Pro$ formula. To achieve this goal in a sustainable manner for the longer term, the industry should develop a national strategy for collecting body weight data on a routine basis.
- That the Hoof Health (HH) index to be introduced in December 2018 be added in April 2019 to the Durability component of the Holstein LPI formula, along with Feet & Legs, in an effort to improve both the resistance to hoof lesions as well as mobility.
- That CDN continue the consultation process with breed associations to assess options of different LPI formula and present recommendations at the next Open Industry Session planned for February 2019.The GEB reviewed the results of work at CDN examining options for improving genetic and genomic evaluations for calving performance traits, namely calving ease and calf survival. Supporting the direction of this ongoing research effort, the GEB recommended the following:
- That CDN verify that calvings resulting from reproductive technologies such as embryo transfer, where the dam giving birth to the calf is not the same as the genetic dam, be excluded from genetic evaluation calculations for calving performance.
- Given that both Canada and United States are reviewing their current calving performance evaluation systems, that CDN and CDCB have technical discussions to improve the correlation of bull proofs for calving traits between the two countries.
- With the increased accuracy from genomics to evaluate Direct Herd Life based on actual
daughter survival data, the GEB discussed the value of continuing to also estimate an
Indirect Herd Life evaluation based on a prediction formula that combines evaluations for
several traits. After considering different options, the GEB recommended that CDN conduct
an analysis to examine the impact of removing Indirect Herd Life as a predictor trait of
daughter survival that is combined with Direct Herd Life to derive the officially published
evaluations for Herd Life. Results of such an analysis will be presented at one or both of
the Open Industry Sessions and GEB meetings to be held in 2019. - The GEB discussed two topics related to the registration status and/or purity level of Jersey
animals displayed on the CDN web site, with the following recommendations:
- That CDN implement an automated check based on pedigree information available for A.I. sires such that only sires whose daughters qualify for herdbook registration by Jersey Canada can be designated as having “Active” status for semen marketed in Canada.
- In response to correspondence received from Jersey Canada, that CDN examine ways to increase the visibility of purity levels and/or Breed Base Representation (BBR) values calculated by CDCB, especially for genomic young sires and heifers.
- The next Open Industry Session will be held on Tuesday, February 12, 2019 at the Holiday Inn in Guelph, Ontario, with the Genetic Evaluation Board meeting the following day.