Izvorni znanstveni članak
https://doi.org/10.15567/mljekarstvo.2014.0301
Linear vs. piecewise Weibull model for genetic evaluation of sires for longevity in Simmental cattle
Nikola Raguž
; Josip Juraj Strossmayer University of Osijek, Faculty of Agriculture, Department for Special Zootechnics, Kralja Petra Svačića 1d, 31000 Osijek, Croatia
Sonja Jovanovac
; Josip Juraj Strossmayer University of Osijek, Faculty of Agriculture, Department for Special Zootechnics, Kralja Petra Svačića 1d, 31000 Osijek, Croatia
Gábor Mészáros
; The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
Johann Sölkner
; University of Natural Resources and Life Sciences, Department of Sustanaible Agricultural Systems, Gregor Mendel Strasse 33, A-1180 Vienna, Austria
Sažetak
This study was focused on genetic evaluation of longevity in Croatian Simmental cattle using linear and survival models. The main objective was to create a genetic model that is most appropriate to describe the longevity data. Survival analysis, using piecewise Weibull proportional hazards model, used all information on the length of productive life including censored as well as uncensored observations. Linear models considered culled animals only. The relative milk production within herd had a highest impact on cows’ longevity. In comparison of estimated genetic parameters among methods, survival analysis yielded higher heritability value (0.075) than linear sire (0.037) and linear animal model (0.056). When linear models were used, genetic trend of Simmental bulls for longevity was slightly increasing over the years, unlike a decreasing trend in case of survival analysis methodology. Average reliability of bulls’ breeding values was higher in case of survival analysis. The rank correlations between survival analysis and linear models bulls’ breeding values for longevity were ranged between 0.44 and 0.46 implying huge differences in ranking of sires.
Ključne riječi
longevity; genetic evaluation; linear models; piecewise Weibull model; Simmental cattle
Hrčak ID:
126245
URI
Datum izdavanja:
1.9.2014.
Posjeta: 2.706 *