Browsing by Subject "Autocorrelation"

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Mapping genes for resilient dairy cows by means of across-breed genome-wide association analysis
(2025) Keßler, Franziska; Zölch, Maximilian; Wellman, Robin; Bennewitz, Jörn; Keßler, Franziska; Institute of Animal Science, University of Hohenheim, Garbenstr. 17, 70599, Stuttgart, Germany; Zölch, Maximilian; Institute of Animal Science, University of Hohenheim, Garbenstr. 17, 70599, Stuttgart, Germany; Wellman, Robin; Institute of Animal Science, University of Hohenheim, Garbenstr. 17, 70599, Stuttgart, Germany; Bennewitz, Jörn; Institute of Animal Science, University of Hohenheim, Garbenstr. 17, 70599, Stuttgart, Germany
Background: Indicator traits based on variance and autocorrelation of longitudinal data are increasingly used to measure resilience in animal breeding. While these traits show promising heritability and can be routinely collected, their genetic architecture remains poorly understood. We conducted GWAS for three resilience indicators across German Holstein ( n = 2,300), Fleckvieh ( n = 2,330), and Brown Swiss ( n = 1,073) dairy cattle ( Bos Taurus ) populations. The indicators included variance ( ) and autocorrelation ( ) of deviations of observed from predicted daily milk yield and variance of relative daily milk yield ( ). Additionally, we analysed a selection index combining these traits. Prior to GWAS, we examined population structure through multi-dimensional scaling (MDS) and LD patterns, revealing distinct genetic clusters for each breed and similar LD decay patterns. Results: The GWAS results confirmed the polygenic nature of resilience, with multiple genomic regions showing significant associations. Notable signals were detected on BTA5 ( ), BTA14 ( ), BTA2 and BTA8 ( ) for single indicator traits. For selection index resilience, strong suggestive SNPs are located on BTA4 , BTA16 , BTA21 , and BTA27 . Detected regions overlapped with previously reported QTLs for performance, reproduction, longevity and health, providing new insights into the biological pathways underlying dairy cattle resilience. Conclusions: Our findings demonstrate that resilience indicators have a complex genetic architecture with both breed-specific and shared components, supporting their potential use in selective breeding programs while highlighting the importance of careful trait definition.
Toward a resilience selection index with indicator traits in German Holstein dairy cattle
(2025) Keßler, Franziska; Wellmann, Robin; Chagunda, Mizeck G. G.; Benenwitz, Jörn
Resilience expresses the ability of an individual to cope with short-term disturbances and to recover quickly by returning to the original level of performance. It can be measured by variance-based parameters and by the autocorrelation of daily milk yields in dairy cows. The design of resilience indicator traits and their heritabilities and genetic correlations have been studied in detail in recent years. There is a need to combine different resilience indicators in an index. The relevance of resilience indicator traits for incorporation into selection indices arises from their correlations with health traits and longevity. The correlations of diverse resilience indicator traits with health traits and longevity were analyzed. The resilience indicator traits were identified that would lead to the highest correlated selection response in the German selection index for health, and appropriate weights of the resilience indicator traits in a selection index for resilience were derived. Certain variance-based indicators were significantly positively correlated with most of the established health and functional traits, whereas the autocorrelation had a negligible correlation with these traits. A resilience selection index composed of 2 different variance-based resilience indicator traits was most likely to be recommended. Its correlation with overall performance was positive but moderately small. Incorporating more than 2 resilience indicator traits into the index improved the correlated response in health traits only slightly.