CDCB and USDA AGIL announce updates for the December 6, 2022, triannual evaluation.

International evaluations for clinical mastitis in Brown Swiss
By Rodrigo Mota and Kristen Gaddis
In September 2022, the Brown Swiss clinical mastitis traits (CMA; MAST) successfully completed validation at the Interbull level. Therefore, effective with the December 2022 evaluation, Brown Swiss foreign evaluations will be included in the U.S. Clinical Mastitis evaluations. The impact of this inclusion is expected to be limited, as only two other foreign countries (France and Switzerland) contribute to the CDCB Mastitis evaluation.

Including U.S.-only daughters and herds in Feed Saved
By Ezequiel L. Nicolazzi and Gary Fok
In the August 2022 evaluation, a procedure was implemented to (internally) improve the management of foreign evaluation. The new procedure had an unintended consequence of excluding information on Feed Saved herds and daughters in the format 38 (38alloff) for U.S.-only bulls. This small flaw is now resolved.

Correction to pedigree usage in non-Holstein type traditional evaluation
By Ezequiel L. Nicolazzi and Paul VanRaden
An incorrect sort order in the pedigree file used in the non-Holstein type traditional evaluation was detected and fixed in the December 2022 evaluation. No other trait groups or breeds are affected. The flaw determined a sub-optimal use of the pedigree, not allowing the model to use all the connections for non-Holstein animals. The largest impact, in terms of increase in reliability and changes in PTA, will be observed in pre-2000 bulls. For some individual post-2000 animals (both bulls and cows), variation will be observed. The impact on recent A.I. bulls was limited. Correlations in all traditional type evaluations for Jersey bulls were higher than 99.8% when compared to the official August 2022

Lactanet’s Open Industry Session (OIS), traditionally held before each Genetic Evaluation Board meeting, is your opportunity to gather the latest information on genetic and genomic evaluations straight from the Genetics team and have your feedback heard. The most recent Open Industry Session covered topics related to hoof health, sustainability, breed percentage, and the future publication of cow evaluations. See below for a summary of each OIS topic.

Increased Data and Accuracy of Hoof Health Evaluations
Single-step hoof health evaluations for Holsteins were first introduced in December 2018 using data provided by hoof trimmers. However, the current number of hoof trimmers providing data is still limited. To increase the volume of data in these genetic evaluations, comparable hoof health information from DairyComp can be utilized.

The combined data results in a 61% increase in the number of records and 104% increase in the number of genotyped cows which is useful for single-step evaluations. The increased volume of data from DairyComp also results in a substantial increase in Hoof Health reliability for official sires and genotyped cows. Check back in April 2023 for the implementation!

Sustainability
Sustainability will be the focus of Lactanet’s efforts for the coming years. From a genetic perspective, this includes the current Feed Efficiency evaluations as well as Methane Efficiency planned for April 2023.

Inclusion of Feed Efficiency in LPI and Pro$
Lactanet’s Feed Efficiency evaluations were first introduced in April 2021 for the Holstein breed. As announced earlier this year, this evaluation will include the addition of second lactation data and be added to LPI and Pro$ values starting December 2022. The combined first and second lactation Feed Efficiency will result in a 30% increase in cows with feed intake data and genotypes, providing a better prediction of lifetime efficiency. For proven sires in the genetic base, Feed Efficiency changes will vary with the addition of second lactation data, mostly moving up or down maximally 5 RBV points. Adding Feed Efficiency to the national selection indexes, LPI and Pro$, will also lead to some re-ranking of top animals. Keep an eye out in November for additional details.

Genetic Selection to Reduce Methane Emissions
With climate change becoming a growing global concern, each sector must do its part to reduce its carbon footprint. Dairy Farmers of Canada (DFC) has committed to reaching net-zero greenhouse gas emissions from farm-level production by 2050 and Lactanet’s contribution to these efforts will include genomic evaluation for Methane Efficiency. Selection for reduced methane emissions, without negatively affecting milk production levels, will provide a permanent and cumulative solution to reduce greenhouse gas emissions. Lactanet is using milk mid-infrared.

(MIR) spectroscopy data to predict methane emissions. The single-step genomic evaluation of predicted methane and energy corrected milk will result in Relative Breeding Value (RBV) for Methane Efficiency, allowing producers to select for reduced methane emissions without sacrificing production traits.

Development and Application of “Breed Percentage” Values
Under Canada’s Animal Pedigree Act breed associations designate a Purity Code for each registered animal in accordance with the respective by-laws. Given the evolving by-laws and increased amount of matings across dairy breeds, Lactanet has received requests from industry partners to apply a minimum level of purity for animals

1. to be eligible for top lists based on genetic evaluations and
2. have a publishable lactation and to be included in herd averages for production.

The Genetic Evaluation Board and Industry Standards Committee recommended that Lactanet develop and implement the calculation of a “Breed Percentage” value to address such requests. Lactanet will continue work to finalize results and rules for each breed prior to consulting with breed associations. Official implementation will happen on a breed-by-breed basis over the coming months and into 2023.

Proposed Future Publication of Cow Evaluations
The proposed future publication of cow evaluations was initially presented in June 2022 and has been supported by the Lactanet’s Genetic Evaluation Board. Currently, Lactanet has two sets of cow evaluations for production traits official indexes and management indexes, that each serve different purposes.

Lactanet sees two opportunities to change cow evaluations. Firstly, to revise the current criteria for designating cow production evaluations as official. This would include all cows with publishable lactations also having official production indexes and each cow having one production evaluation that is updated monthly.

The second opportunity is the introduction of genomic evaluation services for non-herdbook females in Canada by offering a Canadian genomic evaluation as an alternative to buying one from the United States. These changes are expected to follow the changes to publishable lactations that will take effect in January 2023.

For additional information including the presentation handouts, please see our Virtual Open Industry Session page and be sure to join us at the next session!

CDN Author: Hannah Sweett, Knowledge Transfer Advisor

The A.I. sector has seen a consistent use of semen from genomic young bulls which has accelerated the rate of genetic progress. To look at the national trends in the use of genomic bulls, Lactanet analyzed the number of young bulls with daughters in Canada between 2000 and 2019.

The total number of young bulls marketed in Canada has not significantly changed since 2002, averaging 422 (Figure 1). However, what has changed is the number of A.I. companies producing genomic bulls from their own breeding programs. Since the adoption of genomics, young bulls bred by A.I. companies have risen from 3% in 2011 to 42% in 2019. This is mainly due to the rise in A.I. company ownership of elite females that have produced the next generation of elite genomic bulls. Between 2014 and 2019, bulls bred by A.I. companies from an A.I. bred and owned dam increased from 34% to 52%. These statistics are based on prefixes that all major A.I. companies have introduced during the genomics era and do not include any prefixes for breeders that may have a close affiliation or agreement with a given A.I. company.

The percentage of bulls in A.I. that resulted from embryo transfer or manipulation is also on the rise, now surpassing 95% (Figure 1), mainly due to the increased adoption of new reproductive technologies such as in vitro fertilization (IVF).

Another trend in genomic young bulls is their increase in genetic merit. Figure 2 and Figure 3 show the average LPI and Pro$ of Holstein bulls marketed in Canada, respectively. Genomic bulls born in 2019 that now have daughters born in Canada currently have an average genetic merit of 3332 LPI and $2419 for Pro$. During the five years prior to the introduction of genomics in 2009, the average annual increase in the genetic merit of young bulls used in Canada was 84 LPI points and $189 for Pro$. For the first years after genomics was introduced, the average annual gain was the most rapid at 131 LPI points and $323 for Pro$. Since genomics has now been fully adopted, the average genetic level of young bulls used in Canada born in the most recent years has increased by an average of 124 LPI points and $280 Pro$ per year. This translates to an annual rate of gain in LPI and Pro$ that is 1.5 times faster than before genomics was introduced. We can therefore expect genomic bulls born this year will increase the average lifetime profit of their daughters by more than $280 compared to daughters of young bulls born in 2021 and by $560 compared to daughters of A.I. bulls born in 2020.

We are also seeing a rise in the number of young bulls with favourable genes such as A2 for beta casein. Since the introduction of genomics, the proportion of genomic bulls with an A2 genotype available has increased from roughly 50% for bulls born in 2010 to 98% for those born in 2019. More importantly, selection in favour of A2A2 bulls has gradually increased the frequency of this desired genotype among A.I. bulls marketed in Canada, which surpassed the 50% mark in recent years. The polled status is also now available for over 80% of these bulls and the frequency of polled sires among those used in Canada reached 13% for those born in 2019.

Summary
It is clear genomic young bulls will continue to be marketed in Canada and see significant usage due to their genetic superiority. As new strategies are taken by A.I. companies, including the ownership of females to source the next generation of elite genomic bulls, young sires of high genetic merit will continue to be offered to Canadian producers. In the most recent years, the year-over-year gain in the average genetic merit of young bulls used in Canada has been 124 LPI points and $280 for Pro$. This means that continued strong rates of genetic progress in the Canadian Holstein population can be expected in the future.

Author: Hannah Sweett, Knowledge Transfer Advisor – Genetics Portfolio Allison Fleming, Geneticist 

Source: CDN.ca