Symposium review: Development, implementation, and perspectives of health evaluations in the United States

摘要

The rate at which new traits are being developed isincreasing, leading to an expanding number of evaluationsprovided to dairy producers, especially for functionaltraits. This review will discuss the developmentand implementation of genetic evaluations for directhealth traits in the United States, as well as potentialfuture developments. Beginning in April 2018, routineofficial genomic evaluations for 6 direct health traitsin Holsteins were made available to US producersfrom the Council on Dairy Cattle Breeding (Bowie,MD). Traits include resistance to milk fever, displacedabomasum, ketosis, clinical mastitis, metritis, andretained placenta. These health traits were includedin net merit indices beginning in August 2018, witha total weight of approximately 2%. Previously, improvementof cow health was primarily made throughchanges to management practices or genetic selectionon indicator traits, such as somatic cell score, productivelife, or livability. Widespread genomic testing nowallows for accelerated improvement of traits with lowheritabilities such as health; however, phenotypes remainessential to the success of genomic evaluations.Establishment and maintenance of data pipelines is acritical component of health trait evaluations, as wellas appropriate data quality control standards. Datastandardization is a necessary process when multipledata sources are involved. Model refinement continues,including implementation of variance adjustments beginningwith the April 2019 evaluation. Mastitis evaluationsare submitted to Interbull along with somaticcell score for international validation and evaluationof udder health. Additional areas of research includeevaluation of other breeds for direct health traits, useof multiple-trait models, and evaluations for additionalfunctional traits such as calf health and feed efficiency.Future developments will require new and continuedcooperation among numerous industry stakeholders.There is more information available than ever beforewith which to make better selection decisions; however,this also makes it increasingly important to provide accurateand unbiased information.