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Permanent link (DOI): https://doi.org/10.7939/R3JX04

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Investigation of Residual Feed Intake in Dairy Cows Open Access

Descriptions

Other title
Subject/Keyword
Conformation
RFI
Dairy
Efficiency
Feed
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Manafiazar,Ghader
Supervisor and department
Wang, Zhiquan
Examining committee member and department
Goonewardene, Laki (Agricultural, Food and Nutritional Science)
Wang, Zhiquan (Agricultural, Food and Nutritional Science)
Thomas, McFadden (Agricultural, Food and Nutritional Science)
Tempelman, Rob (Department of Animal Science)
Okine, Erasmus (Agricultural, Food and Nutritional Science)
Masihito, Oba (Agricultural, Food and Nutritional Science)
Department
Department of Agricultural, Food, and Nutritional Science
Specialization
Animal Science
Date accepted
2013-09-29T20:59:28Z
Graduation date
2013-11
Degree
Doctor of Philosophy
Degree level
Doctoral
Abstract
This thesis research was aimed to develop a residual feed intake (RFI) prediction equation in dairy cattle while accounting for the animals’ multifunctional lactation non-linear energy requirements profiles. The possibility of shortening RFI test period and finding indicator traits for RFI selection were also investigated. A total of 281 first-lactation dairy cows at the Dairy Research and Technology Center of the University of Alberta from June 2007 through October 2012 were used. Individual daily feed intakes, repeated measurements of monthly body weight, and body condition scores of these animals were recorded from 5 to 305 days-in-milk. Milk production and milk composition data were extracted from the Dairy Herd Improvement Program, and their first type classification data was retrieved from the Canadian Dairy Network. To reduce the test period in a lactation, the acquired data from whole lactation (5 to 305 DIM) was subdivided equally into three shortened periods, early, mid, and late stage of lactation. RFI prediction equations were developed for the whole and each of the shortened periods. Each animal, based on its predicted RFI value, was assigned to high (RFI> 0.5 SD) medium (RFI= ± 0.5 SD) or low (RFI< 0.5 SD) RFI classes within each of the test period. Compared with whole lactation, numbers of the animals’ remaining in the same RFI class within any of the shortened test periods were determined to study the consistency of RFI prediction. Moreover, genetic and phenotypic correlations between conformation traits and RFI were estimated to investigate the possibility to use these conformation traits as indicator traits for RFI selection. The results showed that RFI could be predicted in whole, early, mid and late lactation with R-square of 0.68, 0.47, 0.49, and 0.79, respectively. Compared with the whole lactation, most of the animals (65.5%) remained in the same RFI classes in mid stage, so mid RFI prediction could be considered as the best representative of whole RFI in compare with early and late periods. Moreover, combinations of eight conformation traits could be used as indicator traits for RFI selection, since they had high genetic correlation with whole lactation RFI.
Language
English
DOI
doi:10.7939/R3JX04
Rights
Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
Citation for previous publication
Manafiazar, G., T. McFadden, L. Goonewardene, E. Okine, and Z. Wang. 2012.Factors That Affect Energy Efficiency and Indirect Response of Selection for Efficiency on Related Traits: Milk Production - An Up-to-Date Overview of Animal Nutrition, Management and Health. Chapter 6Manafiazar, G., T. McFadden, L. Goonewardene, E. Okine, J. Basarab, P. Li and Z. Wang. 2013. Prediction of Residual Feed Intake for First Lactation Dairy Cows Using Orthogonal Polynomial Random Regression. JDS-13-6560.R3.

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