Genomics and Feed Efficiency: Local research with global implications

By Emilie Belage, University of Guelph in collaboration with Dr. Filippo Miglior, Canadian Dairy Network and co-PI on the project entitled, Increasing feed efficiency and reducing methane emissions through genomics: A new promising goal for the Canadian dairy industry.

The field of genomics has the potential to not only improve the dairy industry at the herd level, but it has implications at national and global levels. A cutting-edge Canadian initiative, led by Dr. Filippo Miglior, of the University of Guelph, in collaboration with Dr. Paul Stothard, of the University of Alberta, seeks to understand how genomics impact feed efficiency and reduce methane production in dairy cattle in a 10-year project launched in 2015. Thanks to the relationship between producers and researchers involved in this project, the researchers and industry expect producers will be able to select for more efficient, less costly animals, while preserving the environment for future generations.

original_424459801What is genomics? 

Genomics is the study of the entirety of genes in a living organism. It helps us understand how genes interact to produce growth and development in an animal or plant. In dairy cows, it helps producers identify which cows have desirable traits, like high production, good reproduction or longevity, which can be passed onto offspring.

 

Importance of genomics and feed efficiency for producers and the planet

Feed is one of the main costs on a dairy farm. Having cows that can convert feed into milk more efficiently is beneficial for the bottom-line and the environment: farmers can select and breed for cows that produce more milk with less feed. What this also means, is that fewer crops need to be grown to feed the same number of animals, potentially freeing cropland for other purposes. Cows that eat less also produce less manure and less methane, an important greenhouse gas (GHG). This is not only important for manure management, as there is less manure that needs to be stored, but it also has implications on the environmental footprint dairy farms have today.  Food production that is environmentally sustainable is becoming more and more important for consumers. There is increased concern and awareness of how the agricultural sector contributes to GHG emissions like methane, and its role in global warming. Dairy farmers’ investment in this research is innovative – by selecting for cattle that produce less methane, dairy farmers can do their part in addressing climate change now and in the future.

Data collection for accuracy of predictions

To be able to select for the feed efficiency trait, investigators needed to collect a lot of different phenotypes (i.e. the observable characteristics) and genotypes (i.e. genetic constitution) from cattle to be able to distinguish which animals are more efficient at converting feed into milk. Using prediction equations, they can look at the genotype from a young animal and predict early on whether that animal will be feed efficient or not. Feed efficiency and methane emissions are expensive traits to measure. It requires highly specialized equipment to accurately measure these phenotypes. With the arrival of genomics, researchers can measure those traits on a small number of animals, and then extrapolate the results on all genotyped populations, which reduces the costs.

Researchers also need a large amount of data to make accurate predictions in genomics, which is why they are collaborating with other countries for this project. The funding provided by Genome Canada, in collaboration with dairy farm organizations and other funders, gives the Canadian dairy sector the ability to measure these phenotypes, but also has the input of expertise from other countries that are also collecting data on these traits, allowing Canada to test its prediction equations for accuracy. Thus, without genomics and without the data consolidation from other countries, it would be impossible to consider feed efficiency and methane emissions in genetic selection strategies.

Real-time farm involvement in the research

 SunAlta Dairy in Ponoka, Alberta is a participating dairy in this project. The Brouwer family was in the middle of building a new free-stall barn for 450 cows and agreed to install the necessary research equipment that measures feed intake for each of the cows. By collaborating with researchers, the Brouwers are able to get a first-hand impression of the value of the research and the value of genomics. “It brings research to the farm so producers can see that the work researchers do has real-life applications and benefits. Producers get to observe these benefits first-hand”, says Dr. Filippo Miglior. Getting data from a commercial herd also allows “real-life” data to be included in the analyses. This allows investigators to get more data (since a commercial herd is often bigger than a research herd at a university research station), and gives them data from a different environment than a research herd, an environment where cows are managed in “real-time” on a dairy farm. Results from this type of research are therefore directly applicable to other commercial herds.

Future application of results for the Canadian dairy industry

Results from this research can also be applied to herd management. The plan is for selection indexes to be produced, so that farmers can select for animals that are more feed efficient and lower methane emitters. Genomic evaluation for the novel traits will be developed at the Canadian Dairy Network. This research group believes that the addition of those traits will increase the rate of genotyping of young females at the herd level for replacement decisions. The amount of time needed to collect data is significant, which explains the length of the project (10 years). However, the investment is so unique, producers will see results over the long term and for generations to come. The benefits of this research also align with the proAction environmental targets: reduce GHG emissions related to milk production, and the impact on land needed to produce milk. The usefulness of this research will become more relevant over time by breeding for dairy cows that are much more efficient than the ones we have today.

 

Controlling bovine infectious diseases: Canadian research teams aim to produce beneficial results for farmers

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Dr. Herman Barkema, Industrial Research Chair in Infectious Diseases of Dairy Cattle (IRC-IDDC) at the University of Calgary Faculty of Veterinary Medicine has been the Senior Industrial Research Chairholder since April of 2014. The research program of the IRC-IDDC focuses on Johne’s disease and mastitis.

Industrial Research Chair – An industry partnership

Dr. Barkema ensures that every facet of this prestigious research partnership funded by the dairy industry (Alberta Milk, Dairy Farmers of Canada, Westgen Endowment Fund, CanWest DHI, Dairy Farmers of Manitoba, the BC Dairy Association, and the Canadian Dairy Network) and the Natural Sciences and Engineering Research Council (NSERC) of Canada will maximally benefit Canadian dairy producers.

Johne’s prevention and control

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MSc. student Dominique Carson is investigating Johne’s disease in young stock.
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PhD. student Carolyn Corbett is investigating calf-to-calf transmission of Johne’s.

A key element in the strategy to achieving eradication of Johne’s disease from the Canadian dairy herd is the adoption of prevention and control practices by dairy farmers. The results of a recent study by Dr. Barkema and his team reveal that “one-size-fits-all” recommendations for these practices will rarely be sufficient for farmers, and that more personal approaches are needed to tailor recommendations to a farmer’s specific situation.

Moreover, Dr. Barkema’s studies indicate that calf-to-calf transmission of the disease-causing pathogen Mycobacterium avium subspecies paratuberculosis (MAP) can occur, especially in calves housed in groups.

Better understanding the bacteria causing mastitis

In his work as lead of the environment research theme in the Canadian Bovine Mastitis and Milk Quality Research Network (CBMQRN), Dr. Barkema realised that although coagulase-negative staphylococci (CNS) comprise the most common group of bacteria found in udders of lactating cows in Canada, little is actually known about them. Preliminary results from Dr. Barkema’s research indicate that the total prevalence of this group of bacteria is 10%. Some CNS isolates actually inhibit growth of major Gram-positive mastitis pathogens such as Staphylococcus aureus, which might be able to be exploited commercially to reduce mastitis in dairy cows.

Research Chairs – A training ground for the next generation of scientists

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Left to right: Students Diego Nobrega, PhD.,  Larissa Condas, MSc., and Dominique   Carson, MSc.

The training of the next generation of researchers and extension personnel represents an additional benefit to the dairy industry from the IRC-IDDC. The graduate and summer students and postdoctoral fellows working with Dr. Barkema’s team are the boots on the ground and the gloves in the lab carrying out the numerous experiments needed to produce beneficial results for producers.

For the remainder of the 5-year IRC-IDDC, Dr. Barkema and his team will complete the projects currently underway in Johne’s disease and mastitis and will share their research findings in Canada and across the globe with dairy farmers, extension practitioners and government representatives.

Dr. Shannon L. Tracey is from Cross the “T” Consulting. Dr. Herman Barkema is professor of epidemiology of infectious diseases at the University of Calgary’s faculty of veterinary medicine, and holds a joint appointment in the Cumming School of Medicine. He is also a guest professor at Ghent University in Belgium. Barkema leads the environment research theme in the Canadian Bovine Mastitis and Milk Quality Research Network, the Alberta Johne’s Disease Initiative, the Alberta Inflammatory Bowel Disease Consortium, the Clinical Research Unit of the Cumming School of Medicine, the University of Calgary Biostatistics Centre, and the technical committee of the Canadian Voluntary Johne’s Disease Program.

New National Dairy Research Strategy Announced

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Dairy Farmers of Canada (DFC) has adopted a new strategy to direct its investments in dairy production and human nutrition and health research. Four major themes have been identified:

  1. Dairy farm efficiency and sustainability
  2. Animal health and welfare
  3. Milk composition, quality and safety
  4. Milk products and components in human nutrition and health.

Each theme has targeted outcomes established to ensure that dairy research projects will address the major issues Canadian dairy farmers want solved by research. To view a copy of the strategy, visit www.dairyresearch.ca.

The strategy will serve as an important guide for future research investments by DFC.
As a next step in the planning process, DFC’s call for research proposals will be launched the week of November 14, 2016.  Canadian dairy scientists will be invited to apply for funding for the next Dairy Research Cluster.

To receive the call for proposals announcement and details, please subscribe to our distribution list by clicking on the following link by November 11, 2016DFC Call for Research Proposals Distribution List.

New governance body for national research investments: The Canadian Dairy Research Council

The Canadian Dairy Research Council (CDRC) is a new committee with representation from all provinces and members of the Board of Directors of DFC. The CDRC reports to the DFC Board. It guides the overall development, implementation and delivery of research activities for dairy production, and human nutrition and health research.

The CDRC completed its first mandate in June 2016 and developed DFC’s National Dairy Research Strategy to better coordinate dairy farmers’ research investments at the national and provincial levels. The National Dairy Research Strategy was approved by DFC’s Board of Directors in June 2016 and presented to its General Council in July 2016.

For information on dairy research governance and on research highlights, download our fact sheets at:

 

Understanding Pro$ and the Lifetime Profit Curve

August 2016 marks one year since the introduction of Pro$ as one of Canada’s national genetic selection indexes. Since its inception, Pro$ has been well received by both producers and industry personnel. As a genetic selection tool, Pro$ maximizes genetic response for lifetime profitability, leading to realized daughter profit on farm. The accumulated profit a cow achieves over her lifetime depends on several contributing factors, all of which are reflected in the Pro$ index. Let’s take a closer look to better understand how Pro$ can help Canadian producers develop a herd of profitable cows.

 Lifetime Profit Curve

From the day a heifer calf is born, she starts to incur costs, the majority of which are related to feeding. With an average age at first calving near 26 months, the cost of heifer rearing is roughly $2,800 for Holsteins. Once calved and lactating, a dairy cow starts to generate her primary source of revenue – milk and its components. At the end of each lactation, no revenue is generated during the dry period but expenses continue. This concept of describing how a cow’s profit accumulates over time is its lifetime profit curve, which is shown in Figure 1 for the typical Canadian Holstein. This lifetime profit curve covers the first six years of life since this was the definition of lifetime profit used by Canadian Dairy Network (CDN) to develop Pro$.

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For the typical Holstein in Canada, the complete repayment of costs incurred from birth is achieved by 40 months of age, at which time she is in her second lactation (Figure 1).

Looking closely, it can be seen that each new dry period and subsequent calving leads to higher levels of accumulated lifetime profit compared to the scenario of a cow having only one calving followed by years of consecutive production. Normally, prior to reaching six years of age, the typical cow will have had four calvings, including three dry periods, and is in progress on her fourth lactation. This underlying cycle of reproduction and production is fundamental to the dairy enterprise since heifer calves are required as future replacement animals for the milking herd. On average, about one-third of all lactating Holsteins in Canada stay in the herd to at least the age of six years. Those that do, typically end up with about 40 months of productive life in lactation along with six months for dry periods.

When producers aim to maximize herd profitability, it is important to think of the factors contributing to each cow’s lifetime profit curve, which include:

  • Age at first calving since prior to this point a heifer only incurs costs. The earlier an animal first calves, the sooner it can start paying back those rearing costs.
  • Production levels of milk, fat and protein since these are the primary sources of revenue but they are also associated with some expense, mainly feed costs.
  • Days in lactation since this is the only period during which revenue is generated.
  • Days dry, which is longer with poorer reproduction.
  • Ability to stay in the herd, which reflects a multitude of possible factors.

When examining Pro$ values, higher bulls are expected to produce more profitable daughters compared to lower Pro$ bulls. This means that the average lifetime profit curve for daughters of high Pro$ sires will be somewhat different, and higher, compared to daughters of poorer Pro$ sires. CDN recently conducted an analysis to help demonstrate how the key factors contributing to a cow’s lifetime profit curve vary between sires that are higher or lower for Pro$. To conduct this analysis only older sires could be used since their daughters would have to have been born early enough to have had the opportunity to reach six years of age. Table 1 provides various statistics describing the performance of daughters of the sires that were in either the top 10% for Pro$ of the group included in the analysis, or the bottom 10% for Pro$, relative to the daughters of the middle 10% of sires for Pro$.

screen-shot-2016-09-27-at-4-47-46-amRelative to daughters of the middle group of sires for Pro$, 7.4% more daughters of the top Pro$ sires and 6.0% fewer daughters of the bottom Pro$ sires stayed in the herd to six years of age. Evidently, longevity is a crucial component of lifetime profitability. By looking specifically at the daughters that stayed in the herd until at least six years of age, we can illustrate the profitability differences, beyond longevity, that exist between the two sire groups based on Pro$. For example, daughters of the top group for Pro$ calved younger, had more days of productive life and produced more milk, fat and protein than daughters of average Pro$ sires. On the other hand, daughters of the bottom sire group for Pro$ had an older age at first calving, fewer days in production, spent more days dry and produced significantly less than daughters of average Pro$ sires.

Since all these performance measures impact profitability, there is a clear difference in the average accumulated profit to six years of age, based on all daughters, for each of the two sire groups by Pro$. Daughters of the top sire group for Pro$ generated an extra $1,300 profit to six years than daughters of the middle sire group, while daughters of the bottom sire group generated $1,200 less profit to six years than daughters of the middle group. Bottom line is that selecting sires based on Pro$ produces daughters with higher lifetime profit curves and improved herd profitability.

  • Authors: Brian Van Doormaal, General Manager, CDN and Lynsay Beavers, Industry Liaison Coordinator, CDN

 

 

Canadian dairy scientists awarded for research excellence!

In recent weeks, eight Canadian dairy scientists were recognized domestically and internationally for their contributions to dairy science in the areas of animal nutrition, food safety, animal care and welfare and animal health.

Dairy Farmers of Canada congratulates these dairy researchers for their achievements in dairy science and their contributions to innovating in Canadian dairy. All researchers are currently carrying out research on behalf of the dairy sector in projects co-financed by DFC or member organizations.

Drs. Trevor DeVries, Filippo Miglior, Kees Plaizier and Michael Steele received awards from the Canadian Society of Animal Science (CSAS) ; and, Drs. Hélène Lapierre, Xin Zhao and Micheal Steele received awards from the American Dairy Science Association (ADSA) at the Joint Annual meeting held in Salt Lake City, Utah last week. Drs. Marina von Keyserlingk and Dan Weary received the first Ruminant Well-Being Award from the World Buiatracs Association (sponsored by Boehringer Ingelheim Animal Health) in early July.

What follows is a short description of the awards received and the researchers’ current work in the Canadian dairy industry.

CSAS AWARDS

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Dr. Filippo Miglior, chief of research and strategic development, Canadian Dairy Network – Award in Technical Innovation in Enhancing Production of Safe Affordable Food 

Dr. Filippo Miglior is a world renowned dairy cattle geneticist working in the areas of genetic evaluation and improvement. He is responsible for the management of research projects for dairy cattle genetic improvement financed by the CDN and the lead on strategic planning and research priorities for the organization. He is the lead investigator in two major dairy genetics and genomics projects in the Dairy Research Cluster and a co-investigator in two others. He is also co-leading a $10.3 million dollar project funded by partners, including CDN and Genome Canada, to increase dairy cattle feed efficiency and reduce GHG emissions from dairy cattle.

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Dr. Trevor DeVries, Associate Professor, Department of Animal Biosciences, University of Guelph – Animal Industries Award, Extension and Public Service 

Dr. DeVries has made considerable contributions to the Canadian dairy industry through his research and extension work on the effects of feeding management and housing on behaviour in dairy cattle. He was a technical lead, contributor and advisor in the development of the Dairy Farmers of Canada’s proAction animal care program and has been a member of its technical committee. Recently, Trevor delivered extension information on dairy cattle care and comfort through a webinar series for Canadian dairy farmers developed by DFC and Valacta. The webinar series provides important information on the evaluation of cow comfort, comfortable surfaces and comfortable spaces based on the latest research financed by farmers in the Dairy Research Cluster. To view the recorded webinars delivered by Trevor and transfer expert Julie Baillargeon (Valacta), visit www.dairyknowledge.ca.

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Dr. Michael Steele, Assistant Professor, Department of agriculture, food and nutritional science, University of Alberta –  Young Scientist Award (CSAS) and the Lallemand Animal Nutrition Award for Scientific Excellence in Dairy Nutrition (ADSA) 

Dr. Michael Steele’s area of investigation is to understand how early-life nutrition and management programs can imprint the calf’s biological outcomes later in life ; uncover and evaluate feeding schemes and bioactive nutrients that display the properties necessary to improve gut health in dairy calves ; and, characterize the ruminal and intestinal adaptations during the transition to high energy diets in early lactation using feeding schemes based commonly fed commercial dairy rations.

His lab holds a keen interest in the implementation of novel feeding schemes with innovative feeding systems, such as automated calf feeders and automated milking systems.

Plaizier

 

Dr. Kees Plaizier, Professor
 and Associate Dept Head, 
Director of Ruminant Research Unit at the University of Manitoba – Award for Excellence in Nutrition and Meat Sciences 

Dr. Kees Plaizier has made important contributions to the Manitoban and Canadian dairy sector. His research include: the impact of sub-acute ruminal acidosis (SARA) on health and production of dairy cows ; environment sustainability of Dairy Farms ; dry cow management ; yeast culture products ; diagnosis of subacute ruminal acidosis and, evaluation of ruminant feeds. One of his research projects carried out for Manitoba dairy farmers provided critical information to develop best management practices to optimize the use of phosphorus in the diet of their cows.

ADSA AWARDS

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Dr. Hélène Lapierre, Research Scientist, AAFC, Shrebrooke, Quebec – American Feed Industry Association Award 

The award is given to an individual who made an important contribution to research of dairy cattle nutrition. Dr. Lapierre is leading a major research project under the Dairy Research Cluster, the outcomes of which aim to better balance feed rations for dairy cows, and reduce protein in the ration while maintaining cow health. The recommendations that will result in balancing feed rations can potentially increase an average farms’ revenues by about $0.15 per cow per day, or almost $4,000 per year, through savings on feed costs for the cows. Reducing the proportion of protein in dairy cow rations from an average of 18.1% to a realistic 16.5%, will allow Canada to cut its nitrogen emissions by 17,000 tonnes a year and save $77.5 million annually.

Dairy Farmers of Canada is a proud investor in her research. For a summary of her work, click on the link that follows to read the article entitled, New approach to feeding cows benefits both farmers and the environment.

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Dr. Xin Zhao, Professor of animal physiology, McGill University – West Agro Inc. Award 

The West Agro Inc. award was given to Dr. Zhao in recognition of his outstanding research of milk quality as affected by control of mastitis, management of milking, and practices in production of milk.

Dr. Zhao is the successful recipient of research grants provided by DFC and the Canadian Dairy Network to investigate the genetics of bovine milk cholesterol content and to investigate the interaction between pathogens and hosts in mastitis. He and his team are interested in understanding how the microbial virulence strategies affect the nature and magnitude of the host response and how the resulting immune response influences the course of infection.

Canadian Dairy Science Students Share Knowledge at ADSA meeting

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Congratulations to all the Canadian dairy science students that took part in the American Dairy Science Association meetings last week in Salt Lake City! More than 20 students had posters at the event to present their findings and share knowledge with more than two thousand dairy scientists and dairy stakeholders from around the world.


DID YOU KNOW…DFC investments in dairy production and human nutrition and health research support training for 130 students across Canada!


 

Marina von Keyserlingk and Dan Weary of the University of British Columbia win first Ruminant Well-being Award, World Buiatrics Congress 2016

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Drs. von Keyserlingk and Weary, University of British Columbia, Canada, won the first Ruminant Well-being Award presented in early July at the World Buiatrics Congress in Ireland. The award provides the €15,000 and sponsored by Boehringer Ingelheim Animal Health.

Dan and Nina are two of the three co-chairholders of the NSERC Industrial Research Chair on Dairy Cattle Welfare co-sponsored by DFC and dairy sector partners for the past 15 years. For more information on their areas of research and contributions to the Canadian dairy sector, visit www.dairyresearch.ca.

 

 

Top Honours for Canadian Dairy Scientists

Top Honours for Canadian Dairy Scientists

Congratulations to Canadian Dairy scientists, Drs. Anne-Marie de Passillé (University of British Columbia) and Ian Doohoo (Mastitis Network, University of PEI) for their inauguration as Honorary PhDs of Veterinary Medicine from the University of Helsinki on June 5, 2015 in Helsinki, Finland. The ceremony is a three-day event (declared as one of the finest in the Academic world…). The President of the Republic of Finland was also among the ten individuals receiving their Honoray PhD. What follows is the write up on each one provided by the University of Helsinki:

Adjunct Professor Anne Marie de Passillé

Anne Marie de Passillé is an internationally esteemed researcher focusing on the behaviour of production animals. She has retired from the position of senior researcher at Agri-Food Canada but continues her research work as Adjunct Professor at the University of British Columbia.

In 1995, Dr. de Passillé, and her husband working in the same field, started collaborating with the researchers of the then new field of science in Finland, the study of animal welfare and behaviour. It is largely due to her that the faculty’s researchers on the subject are today very well connected internationally and active in the scientific community. The teaching, guidance and research collaboration of the faculty with Anne Marie de Passillé has enabled the development of a once minor field of study into one of international renown.

Professor Ian Dohoo

Ian Dohoo is Professor Emeritus of Epidemiology at the University of Prince Edward Island in Charlottetown, Canada. He is a leading researcher in veterinary epidemiology who publishes actively. He is one of the pioneers in the creation of computer-based follow-up methods used in animal health research.

Prof. Dohoo has meritoriously taught the fundamentals of epidemiology to several generations of veterinarians. His courses, e.g. the yearly NOVA courses of the Nordic countries, have formed the basis for the epidemiological and statistical know-how of many Finnish researchers, and still continue to do so for the greater part of the doctoral students of the faculty. Furthermore, he has authored course books for veterinary epidemiology. Prof. Dohoo is an exceptionally motivating and good teacher who has been able to inspire his students. He has received several prizes for teaching and research as well as honorary doctorates from the University of Guelph and the Swedish University of Agricultural Sciences.

Got an opinion on dairy research?

Don’t forget to Have Your Say in Canadian Dairy Research at: www.dairyresearch.ca

See us at these coming events:

May 27-28, 2015, Montreal, Quebec

Canadian Bovine Mastitis and Milk Quality Research Network

Annual Scientific Meeting

May 28, 2015, Elora, Ontario

Livestock Research and Innovation Centre – Elora Dairy Facility Open House

June 1-2, 2015, Quebec City, Quebec

STELA Symposium 2015

June 23-24, Edmonton, Alberta

DRECA Forum

July 13-15, Vancouver, British Columbia

Dairy Farmers of Canada Annual General Meeting

Impact of Genetic and Genomic Evaluation Improvements

Impact of Genetic and Genomic Evaluation Improvements

A fundamental principle and mandate of CDN is to provide the most accurate genetic evaluations possible for all dairy breeds in Canada. The arrival of genomics over five years ago has increased the challenges associated with this key objective. CDN geneticists have worked hard in recent years to identify improvements to methods used to calculate traditional genetic evaluations as well as genomic evaluations. Through the process of research and presentation of results to industry partners, various genetic and genomic evaluation improvements will be implemented in April 2015 in addition to the usual annual genetic base update. These improvements have shown to provide more accurate evaluations going forward but will result in a significant one-time adjustment that especially impacts elite genomic young bulls and genotyped heifers. Breeders and industry organizations must adjust their criteria and selection decisions according to the narrowed scale of genomic evaluations at the extreme levels.

Read the full extension article here: https://www.dairyresearch.ca/news.php

Update on Proofs for Identical Twin Sires

Identical twins have identical genotypes. Pedigree-based genetic evaluation systems treat identical animals as full-sibs. This strategy was known to be suboptimal since it assumes that identical twins only have 50% of their genes in common, when in reality they have the exact same DNA and identical genotypes. For purposes of genetic evaluations, identical twins are expected to transmit the exact same genetic potential to their progeny. However, before genomics it was very difficult to prove that animals were genetically identical.

Since the identification of genetically identical animals was no longer an issue in the genomic era, Canadian Dairy Network (CDN) implemented an improved methodology in 2011 for handling proofs of identical males. As long as they were born after April 1, 2006, any pair of sires identified as having identical DNA via genotyping received the same genetic and genomic evaluations. Identical sires that were already progeny proven as of December 2010 continued to be evaluated as if they were regular full brothers.

Identical sires are treated as one individual animal by pooling their daughter information and calculating one domestic genetic evaluation. For example, if one sire in the pair has 300 daughters and its identical brother has 200 daughters, both sires receive the same genetic evaluation based on the combined group of 500 daughters. Pooling daughter information increases the reliability of their combined proof, compared to treating them as full-sibs in the past. The same proof for identical sires is sent to Interbull for the calculation of MACE evaluations on other country scales. Depending on how the other country, say United States for example, handles the MACE evaluation from Interbull in addition to any daughter data that either brother may have in that country, identical twins may receive differing official evaluations in other countries.

Case Study – Jordan and Jerrick

Identical twins Gillette Jordan and Gillette Jerrick were first progeny proven in August 2010 and ranked #1 and #7 LPI, respectively, including genomics. As a result, they were both returned to active service and widely used across the country, although Jordan was also previously used as a high-ranking genomic young bull. Since these bulls were born prior to April 1, 2006, their proofs remained separate. Now, both have thousands of daughters in lactation and type classified. Although over 80% of their daughter production data is still from first lactation, these bulls serve as an excellent example of how proofs of identical sires evolve over time (Figure 1).

When first proven in August 2010, the bulls had an LPI difference of 278 points based solely on their traditional proof without genomics. Over the following months and years, their traditional proofs fluctuated to some degree, both upwards and downwards, with the largest difference between them exceeding 400 LPI points. As of April 2013, the variation in the LPI scale was halved and the average LPI was increased by 1700 points so the differences between Jordan and Jerrick for LPI and its components were reduced as expected. Once both bulls reached over 1,700 production daughters in May 2014, their LPI difference before including genomics has consistently been less than 100 points.

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Table 1 shows the difference in traditional proofs without genomics between the identical brothers as of December 2014. Jordan is currently 80 LPI points higher than Jerrick, mainly because his production proof still exceeds that of Jerrick’s, but by far less than it did during the first 6 months after these bulls were officially progeny proven. In terms of type traits, the brothers now only differ from each other by one point or less. Being that Health and Fertility traits are generally low heritability, more daughter data in first and subsequent lactations is required in order to reach high levels of reliability. For this reason, more difference between these bulls still exists for traits like Herd Life, Daughter Calving Ability, Temperament, Milking Speed and Mastitis Resistance. It is expected that as the reliability of their proofs for functional traits increases due to the accumulation of daughter information, their evaluations will continue to become more similar over time, as has been the case with Production and Conformation traits.

Table 1: Proof Differences as of December 2014: Jordan versus Jerrick

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Summary

The current CDN policy for calculating proofs for genetically identical brothers still raises some controversy and questions from breeders. Based on the observed evolution of traditional proofs for Jordan and Jerrick, excluding genomics, there is no indication that the policy should be altered. Since both bulls have the same genotype, the inclusion of genomic information for official proofs reduces the observed differences in published evaluations even further. Based on their semen usage in Canada, Gillette Stanleycup and Gillette Windhammer, and possibly Gillette Wildthing and Gillette Willrock, are two other pairs of identical brothers that may serve as case studies in the future but it will take a few more years before they have thousands of daughters with sufficient data for first and subsequent lactations.

Authors: Lynsay Beavers, Industry Liaison Coordinator, CDN, Brian Van Doormaal, General Manager, CDN

Date: December 2014