Journal article

Milk production of cows grazing pasture supplemented by a partial mixed ration with or without canola meal

MJ Auldist, MM Wright, LC Marett, MC Hannah, E Kennedy, JL Jacobs, WJ Wales

Animal Production Science | CSIRO Publishing | Published : 2018

Abstract

Data from 127539 Hereford and Braford cattle were used to compare estimates of genetic parameters for navel, conformation, precocity, muscling and size visual scores at yearling, using linear and threshold animal models. In a second step, these models were cross-validated using a multinomial logistic regression in order to quantify the association between phenotype and genetic merit for each trait. For navel score, higher heritability was obtained with the threshold model (0.42 ± 0.02) in relation to the linear model (0.22 ± 0.02). However, similar heritability was estimated in both models for conformation, precocity, muscling and size, with values of 0.18 ± 0.01, 0.19 ± 0.01, 0.19 ± 0.01 an..

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Grants

Funding Acknowledgements

The authors are grateful to G. Morris, D. Mapleson, A. McDonald, L. Dorling, D. Wilson, T. Hookey, S. Zeiro, C. MacLeod, T. Phillips and DEDJTR Ellinbank farm staff for assistance with cow feeding and husbandry. This research was funded by the Department of Economic Development, Jobs, Transport and Resources - Victoria, and Dairy Australia (Melbourne, Australia).