Genetic Association Between Herd Survival and Linear Type Traits in Holstein Cows Under Tropical Conditions

Kern, Elisandra Lurdes; Cobuci, Jaime Araújo; Costa, C. N.; McManus, Concepta; Campos, Gabriel Soares; Almeida, Tatiana Prestes de; Campos, Rafael Viegas

doi:10.4081/ijas.2014.3419

Cited by 16 publications

(12 citation statements)

References 31 publications

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“…Boettcher, Jairath, and Dekkers () and Kern et al. () used threshold models for Canadian and Brazilian Holsteins, respectively, whilst numerous other studies have used linear models (e.g. Wiebelitz, Reinhardt, Liu, Erbe, & Simianer, ; Zavadilová & Štípková, ; Zavadilová, Štípková, Němcova, Bouška, & Matějičkova, ).…”

Section: Introductionmentioning

confidence: 99%

Estimation of genetic parameters for functional longevity in the South African Holstein cattle using a piecewise Weibull proportional hazards model

Imbayarwo-Chikosi

Ducrocq

Banga

et al. 2017

J Animal Breeding Genetics

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Non-genetic factors influencing functional longevity and the heritability of the trait were estimated in South African Holsteins using a piecewise Weibull proportional hazards model. Data consisted of records of 161,222 of daughters of 2,051 sires calving between 1995 and 2013. The reference model included fixed time-independent age at first calving and time-dependent interactions involving lactation number, region, season and age of calving, within-herd class of milk production, fat and protein content, class of annual variation in herd size and the random herd-year effect. Random sire and maternal grandsire effects were added to the model to estimate genetic parameters. The within-lactation Weibull baseline hazards were assumed to change at 0, 270, 380 days and at drying date. Within-herd milk production class had the largest contribution to the relative risk of culling. Relative culling risk increased with lower protein and fat per cent production classes and late age at first calving. Cows in large shrinking herds also had high relative risk of culling. The estimate of the sire genetic variance was 0.0472 ± 0.0017 giving a theoretical heritability estimate of 0.11 in the complete absence of censoring. Genetic trends indicated an overall decrease in functional longevity of 0.014 standard deviation from 1995 to 2007. There are opportunities for including the trait in the breeding objective for South African Holstein cattle.

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Section: Introductionmentioning

confidence: 99%

Estimation of genetic parameters for functional longevity in the South African Holstein cattle using a piecewise Weibull proportional hazards model

Imbayarwo-Chikosi

Ducrocq

Banga

et al. 2017

J Animal Breeding Genetics

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“…Heritability estimates in dairy cattle breeds were generally low, ranging from 0.04 (Holtsmark et al, 2009) to 0.15 (Kern et al, 2014). Estimates in beef cattle breeds, however, were higher, ranging from 0.08 (Van Westhuizen et al, 2001) to 0.30 (Maiwashe et al, 2009) probably owing to differences in trait definition between dairy and beef cattle.…”

Section: Threshold Modelsmentioning

confidence: 89%

“…Heritability for longevity has been estimated with TMs in Canadian Holsteins (Boettcher et al, 1999), Spanish Holsteins (Gonzalez-Recio & Alenda, 2007), South African beef cattle (Van Westhuizen et al, 2001), South African Angus (Maiwashe et al, 2009), Norwegian Red (Holtsmark et al, 2009) and Brazilian Holsteins (Kern et al, 2014). Heritability estimates in dairy cattle breeds were generally low, ranging from 0.04 (Holtsmark et al, 2009) to 0.15 (Kern et al, 2014).…”

Section: Threshold Modelsmentioning

confidence: 99%

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Genetic Prediction Models and Heritability Estimates for Functional Longevity in Dairy Cattle

Imbayarwo-Chikosi¹,

Dzama²,

Halimani³

et al. 2015

SA J. An. Sci.

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Longevity is a major component of the breeding objective for dairy cattle in many countries because of its high economic value. The trait has been recommended for inclusion in the breeding objective for dairy cattle in South Africa. Linear models, random regression (RR) models, threshold models (TMs) and proportional hazard models (PH) have been used to evaluate longevity. This paper discusses these methodologies and their advantages and disadvantages. Heritability estimates obtained from these models are also reviewed. Linear methodologies can model binary and actual longevity, while RR and TM methodologies model binary survival. PH procedures model the hazard function of a cow at time t derived from survival from first calving to culling, death or censoring. It is difficult to compare methodologies for sire evaluation and ranking across countries because of the variation in the definition of longevity and the choice of model. Sire estimated breeding values (EBVs) are derived differently for the models. Sire EBVs from PH models are expressed as deviations of the culling risk from the mean of the base sires, expected percentage of daughters still alive after a given number of lactations, expected length of productive life in absolute terms or as standard deviation units. In linear, TM and RR modelling, sire EBVs for longevity have been expressed as deviations of survival from the mean estimated with Best Linear Unbiased Prediction (BLUP). Appropriate models should thus be developed to evaluate functional longevity for possible inclusion in the overall breeding objective for South African dairy cattle. ______________________________________________________________________________________

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Proportional hazard models associated with the survival of dairy goats reared in a tropical environment

Ferreira

Martins

Gouveia

et al. 2020

Small Ruminant Research

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Genetic Association Between Herd Survival and Linear Type Traits in Holstein Cows Under Tropical Conditions

Cited by 16 publications

References 31 publications

Estimation of genetic parameters for functional longevity in the South African Holstein cattle using a piecewise Weibull proportional hazards model

Estimation of genetic parameters for functional longevity in the South African Holstein cattle using a piecewise Weibull proportional hazards model

Genetic Prediction Models and Heritability Estimates for Functional Longevity in Dairy Cattle

Proportional hazard models associated with the survival of dairy goats reared in a tropical environment

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