Original scientific paper

The effect of time elapsed from milking to scoring on udder linear scores and estimation of genetic parameters.

Ante Kasap orcid.org/0000-0002-9763-5357 ; Department of Animal Science and Technology, Faculty of Agriculture, University of Zagreb, Zagreb, Croatia
Dubravko Škorput ; Department of Animal Science and Technology, Faculty of Agriculture, University of Zagreb, Zagreb, Croatia
Dragomir Kompan ; Animal Science Department, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia
Gregor Gorjanc ; Animal Science Department, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia
Boro Mioč ; Department of Animal Science and Technology, Faculty of Agriculture, University of Zagreb, Zagreb, Croatia
Klemen Potočnik ; Animal Science Department, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia

Abstract

The study was conducted on 51,154 Holstein primiparous cows. The purpose of the study was to estimate the impact of time elapsed from last milking until scoring on the properties of udder conformation traits (fore udder attachment, rear udder height, rear udder width, udder depth, and central ligament). The purpose was also to consider the benefits of including this effect in statistical models for estimation of genetic parameters in dairy cattle. A significant (P<0.001) positive linear relationship between scores of udder traits and the time of the scoring was determined. Rear udder height (b = 0.088) and rear udder width (b = 0.091) were affected the most, with the prolongation of time of scoring regarding previous milking. The investigated effect only affected the residual component of variance. Other components of variance did not change considerably when the time from milking to scoring was fitted into a basic statistical model. Estimated heritabilities ranged from 0.15 to 0.27. Slightly higher estimates of heritabilities for all traits, except for the central ligamentum, were determined when this effect was fitted into the model. Udder depth was found to be in strong negative genetic correlation with fore udder attachment (r = -0.436). An almost negligible negative genetic correlation between udder depth and rear udder width was determined (r = -0.086). Genetic correlations between all other traits were positive and low to moderate (r = 0.15 - 0.54). The investigated effect did not noticeably affect estimates of genetic correlations between udder conformation traits.

Keywords

udder conformation traits; time interval; model; genetic evaluation

Hrčak ID:

116182

URI

https://hrcak.srce.hr/116182

Publication date:

13.2.2014.

Article data in other languages: croatian

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