Using Random Regression Models to Genetically Evaluate Functional Longevity Traits in North American Angus Cattle

Abstract

This study aimed to propose novel longevity indicators by comparing genetic parameters for traditional (TL; i.e., the cow’s lifespan after the first calving) and functional (FL; i.e., how long the cow stayed in the herd while also calving; assuming no missing (FLa) or missing (FLb) records for unknown calving) longevity, considering different culling reasons (natural death, structural problems, disease, fertility, performance, and miscellaneous). Longevity definitions were evaluated from 2 to 15 years of age, using single- and multiple-trait Bayesian random regression models (RRM). The RRM fitting heterogenous residual variance and fourth order Legendre polynomials were considered as the optimal models for the majority of longevity indicators. The average heritability estimates over ages for FLb (from 0.08 to 0.25) were always higher than those for FLa (from 0.07 to 0.19), and higher or equal to the ones estimated for TL (from 0.07 to 0.23), considering the different culling reasons. The average genetic correlations estimated between ages were low to moderate (~0.40), for all longevity definitions and culling reasons. However, removing the extreme ages (i.e., 2 and >12 years) increased the average correlation between ages (from ~0.40 to >0.70). The genetic correlations estimated between culling reasons were low (0.12 and 0.20 on average, considering all ages and ages between 3 and 12 years old, respectively), indicating that longevity based on different culling reasons should be considered as different traits in the genetic evaluations. Higher average genetic correlations (estimated from 3 to 12 years old) were observed between TL and FLb (0.73) in comparison to TL and FLa (0.64), or FLa and FLb (0.65). Consequently, a higher average proportion of commonly-selected sires, for the top 1% sires, was also observed between TL and FLb (91.74%), compared to TL and FLa (59.68%), or FLa and FLb (61.01%). Higher prediction accuracies for the expected daughter performances (calculated based on the pedigree information) were obtained for FLb in comparison to TL and FLa. Our findings indicate that FLb is preferred for the genetic evaluation of longevity. In addition, it is recommended including multiple longevity traits based on different groups of culling reasons in a selection sub-index, as they are genetically-different traits. Genetic selection based on breeding values at the age of four years is expected to result in greater selection responses for increased longevity in North American Angus cattle.

Haplotype-Based Single-Step GWAS for Yearling Temperament in American Angus Cattle

“…The ataxin 10 gene ( ATXN10 ), annotated in the neuron projection development GO_BP, was previously associated with longevity traits in Chinese Holstein cattle [ 52 ]. Longevity is a productive trait that is affected to some degree by the cattle’s temperament, as aggressiveness is an undesirable trait and is a culling criterion in American Angus [ 53 ]. The ADAM metallopeptidase domain 10 ( ADAM10 ) gene was already identified as a biomarker for Alzheimer’s disease in humans, with functions related to the cleavage amyloid precursors that act during the inflammation process of senile plaques [ 54 ].…”

Genetic analysis for sow stayability at different parities in purebred Landrace and Large White pigs

“…Factors affecting stayability can be divided into voluntary and involuntary. The latter affects “functional” stayability (e.g., Abe et al, 2020 ; Oliveira et al, 2020 ; Valencia‐Posadas et al, 2017 ), which might be a trait to be truly improved. However, it is often difficult to use detailed information about reasons for culling.…”

Genetic Modeling and Genomic Analyses of Yearling Temperament in American Angus Cattle and Its Relationship With Productive Efficiency and Resilience Traits

“…In beef cattle, yearling temperament is associated with the length of productive life of the animal ( Oliveira et al, 2020 ), as it is one of the voluntary culling reasons. QTLs annotated for longevity also overlapped with regions for yearling temperament.…”