Powered by OpenAIRE graph
Found an issue? Give us feedback
addClaim

Investigation of Residual Feed Intake in Dairy Cows

Authors: Manafiazar,Ghader;

Investigation of Residual Feed Intake in Dairy Cows

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.

Country
Canada
Related Organizations
Keywords

Dairy, Feed, RFI, Efficiency, Conformation

  • BIP!
    Impact byBIP!
    selected citations
    These citations are derived from selected sources.
    This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
    0
    popularity
    This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
    Average
    influence
    This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
    Average
    impulse
    This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
    Average
Powered by OpenAIRE graph
Found an issue? Give us feedback
selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
0
Average
Average
Average
Related to Research communities
Upload OA version
Are you the author of this publication? Upload your Open Access version to Zenodo!
It’s fast and easy, just two clicks!