The relationship of live animal muscular and skeletal scores, ultrasound measurements and ...

214 Pages·2012·0.98 MB·English

The relationship of live animal muscular
and skeletal scores, ultrasound
measurements and
carcass classification scores
to carcass composition and value
in cattle

by

Stephen Conroy, (B.Agr.Sc)

A thesis submitted to the National University of Ireland, Dublin for the degree of
Doctor of Philosophy.

December 2011

1
School of Agriculture, Food Science and Veterinary Medicine,
University College Dublin, Ireland

2
Teagasc, Grange Beef Research Centre, Dunsany, Co. Meath

Head of School of Agriculture and
1
Food Science Prof. Alex Evans

2
Research Supervisors Dr Michael Drennan
1
Dr David Kenny
Table of contents

Table of contents ii

Declaration viii

Acknowledgements ix

Index of Tables x

Thesis abstract xvi

Chapter 1………………………………………………………………………….. 1
Introduction
1.1 Beef production in Ireland……………………………………………….... 2
1.2 Introduction to experiments……………………………………………….. 4
1.3 References…………………………………………………………………. 8

Chapter 2………………………………………………………………………….. 12
Literature Review
2.1 Live animal muscular and skeletal scores……………………………………… 13
2.1.1 The muscular and skeletal scoring system……………………………….. 13
2.1.2 Errors involved in obtaining live animal scores…………………………. 14
2.1.3 Correlations between muscular and skeletal scores with carcass traits….. 15
2.1.4 Variation explained using live animal muscular and skeletal scores
with carcass traits……………………………………………………….. 17
2.2 Live animal Ultrasound muscle and fat depth measurements…………………. 18
2.2.1 Principles of Ultrasound………………………………………………….. 18
2.2.2 General scanning procedure………………………………………………. 19
2.2.2.1 Animal restraint………………………………………………………. 20
2.2.2.2 Scanning site/position………………………………………………… 20
2.2.2.3 Clipping and Coupling agent…………………………………………. 21
2.2.2.4 Scanning procedure…………………………………………………… 22
2.2.3 Factors affecting the accuracy of ultrasound measurements……………... 22
ii
2.2.3.1 Differences between operator and interpretation…………………….. 22
2.2.3.2 Repeatability of operator……………………………………………... 23
2.2.3.3 Differences between machines……………………………………….. 24
2.2.3.4 Time of scanning……………………………………………………... 25
2.2.3.5 Effect of breed on accuracy…………………………………………... 26
2.2.3.6 Animal Gender……………………………………………………….. 27
2.2.3.7 Ribbing and fat removal……………………………………………….27
2.2.3.8 Extremes in muscle and fat…………………………………………… 28
2.2.4 Heritability of eye muscle area and fat…………………………………… 28
2.2.5 Correlations between ultrasonic measurements of muscle and fat with
carcass traits................................................................................................. 29
2.2.5.1 Carcass meat proportion…………………………………………… 29
2.2.5.2 Carcass fat proportion……………………………………………… 30
2.2.5.3 Carcass bone proportion…………………………………………… 30
2.2.5.4 Proportion of high value cuts in the carcass……………………….. 30
2.2.5.5 Perinepric and Retroperitional fat…………………………………. 30
2.2.5.6 Carcass conformation score………………………………………... 30
2.2.5.7 Carcass fat score…………………………………………………… 31
2.2.6 Variation explained using live animal ultrasound measurements
with carcass traits………………………………………………………… 34
2.3 Carcass conformation and fat scores……………………………………………35
2.3.1 Carcass grading system…………………………………………………… 35
2.3.2 Errors in obtaining carcass classification scores………………………….. 38
2.3.3 Relationship between carcass classes with carcass composition and value 38
2.3.3.1 Carcass conformation score………………………………………... 38
2.3.3.2 Carcass fat score…………………………………………………… 40
2.3.4 Beef yield grades (U.S.D.A grading system)……………………………... 40
2.4 References……………………………………………………………………… 44

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Chapter 3: ………………………………………………………………………… 59
The relationship of live animal muscular and skeletal scores, ultrasound
measurements and carcass classification scores with carcass composition and value
in steers.
3.1 Abstract………………………………………………………………………… 60
3.2 Introduction……………………………………………………………………. 62
3.3 Materials and methods…………………………………………………………. 63
3.3.1 Animal and management…………………………………………….. 63
3.3.2 Muscular and skeletal scores/measurements………………………… 64
3.3.3 Ultrasound measurements……………………………………………. 65
3.3.4 Carcass measurement………………………………………………… 65
3.3.5 Statistical analysis……………………………………………………. 66
3.4 Results………………………………………………………………………….. 67
3.4.1 Assessors……………………………………………………………... 67
3.4.2 Correlations using live animal muscular scores………………………67
3.4.3 Correlations using skeletal scores……………………………………. 68
3.4.4 Correlations using ultrasonically scanned measurements……………. 69
3.4.5 Correlations using carcass conformation and fat scores……………... 69
3.4.6 Regressions using live animal scores and measurements……………. 70
3.4.7 Regressions using carcass conformation and fat scores……………... 71
3.5 Discussion……………………………………………………………………… 71
3.5.1 Assessors……………………………………………………………... 71
3.5.2 Correlations using live animal scores………………………………... 72
3.5.3 Correlations using skeletal scores……………………………………. 73
3.5.4 Correlations using scanned muscle and fat depth……………………. 74
3.5.5 Correlations using carcass conformation and fat scores……………... 75
3.5.6 Regression of live animal scores and measurements to predict
carcass composition and value……………………………………... 76
3.5.7 Regression of carcass composition and vale on carcass conformation
and fat scores………………………………………………………..78
3.6 Conclusions…………………………………………………………………….. 79
3.7 Implications……………………………………………………………………..79
3.8 Acknowledgments………………………………………………………………79
3.9 References……………………………………………………………………… 80
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Chapter 4: ………………………………………………………………………… 94
The relationship of various muscular and skeletal scores and ultrasound
measurements in the live animal, and carcass classification scores with carcass
composition and value of bulls.
4.1 Abstract………………………………………………………………………… 95
4.2 Introduction…………………………………………………………………….. 97
4.3 Materials and methods…………………………………………………………. 98
4.3.1 Animal and management…………………………………………….. 98
4.3.2 Muscular and skeletal scores / measurements……………………….. 99
4.3.3 Ultrasound measurements……………………………………………. 100
4.3.4 Carcass measurements……………………………………………….. 101
4.3.5 Statistical analysis……………………………………………………. 101
4.4 Results…………………………………………………………………………. 102
4.4.1 Assessors…………………………………………………………….. 102
4.4.2 Correlations between live animal scoring methodologies and
carcass characteristics……………………………………………… 103
4.4.3 Correlations between skeletal scores and carcass characteristics……. 103
4.4.4 Correlations between ultrasound measurements and carcass
characteristics……………………………………………………… 104
4.4.5 Correlations between carcass conformation and fat scores and carcass
characteristics………………………………………………………..105
4.4.6 Regressions using live animal scores/measurements………………….105
4.4.7 Regressions using carcass conformation and fat scores……………... 106
4.5 Discussion……………………………………………………………………… 107
4.5.1 Assessors…………………………………………………………….. 107
4.5.2 Muscular scores……………………………………………………… 107
4.5.3 Skeletal scores……………………………………………………….. 109
4.5.4 Ultrasound muscle and fat depth……………………………………. 110
4.5.5 Carcass conformation and fat scores………………………………… 112
4.6 Conclusions……………………………………………………………………. 114
4.7 Acknowledgments…………………………………………………………….. 114
4.8 References…………………………………………………………………….. 115

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Chapter 5: ………………………………………………………………… ……... 129
Predicting carcass meat, fat and bone proportions from carcass conformation and fat
scores or hindquarter dissection of beef cattle
5.1 Abstract………………………………………………………………………… 130
5.2 Implications……………………………………………………………………..131
5.3 Introduction……………………………………………………………………. 132
5.4 Materials and methods…………………………………………………………. 134
5.4.1 Animals and management……………………………………………. 134
5.4.2 Carcass evaluations and measurements……………………………… 135
5.4.3 Statistical analysis……………………………………………………. 135
5.5 Results…………………………………………………………………………. 137
5.5.1 Prediction equations using carcass conformation and fat scores…….. 137
5.5.2 Prediction equations using hindquarter composition………………… 139
5.6 Discussion……………………………………………………………………… 140
5.6.1 Carcass conformation and fat score prediction equations……………. 140
5.6.2 Hindquarter prediction equations…………………………………….. 143
5.6.3 Genotype effects on prediction bias…………………………………. 144
5.7 Conclusions…………………………………………………………………….. 145
5.8 Acknowledgments………………………………………………………………145
5.9 References……………………………………………………………………… 146

Chapter 6: ………………………………………………………………………… 157
Live animal muscular scores as predictors of carcass traits in suckler-bred and
artificially reared dairy-bred male cattle
6.1 Abstract………………………………………………………………………… 158
6.2 Introduction……………………………………………………………………. 160
6.3 Materials and methods…………………………………………………………. 161
6.3.1 Animals and management……………………………………………. 161
6.3.2 Muscular and skeletal scores/measurements………………………… 162
6.3.3 Carcass measurements……………………………………………….. 163
6.3.4 Statistical analysis……………………………………………………. 163
6.4 Results…………………………………………………………………………. 165
6.4.1 Prediction equations using live animal scores in bulls………………. 165
6.4.2 Prediction equations using live animal scores in steers……………… 166
vi
6.4.3 Prediction equations using suckler-bred and dairy-bred steer………. 166
6.5 Discussion……………………………………………………………………… 167
6.5.1 Prediction of carcass traits using live animal muscular scores………. 168
6.5.2 Live animal muscular scores as predictors of carcass traits in
suckler-bred and dairy-bred steers…………………………………. 170
6.6 Conclusions……………………………………………………………………. 170
6.7 Implications…………………………………………………………………… 171
6.8 Acknowledgments…………………………………………………………….. 171
6.9 References……………………………………………………………………… 172

Chapter 7 …………………………………………………………………………. 180
Overall summary conclusions and implications
7.1 Thesis summary………………………………………………………………... 181
7.2 Overall conclusions and implications………………………………………….. 189
7.3 Areas of further research……………………………………………………….. 192
7.4 References……………………………………………………………………… 193

Chapter 8 …………………………………………………………………………. 194
Publication List
8.1 Published papers……………………………………………………………….. 195
8.2 Conference proceedings………………………………………………………... 195

vii
Declaration

I declare that this thesis, has not previously been submitted as an exercise for a degree at
the National University of Ireland or any other university and I further declare that the
work embodied in this thesis is my own.

______________________
th
Stephen Conroy, B.Agr.Sc. 30 December 2011

viii
Acknowledgements

Firstly, I would like to acknowledge the opportunity presented to me by Teagasc to
carry out the work embodied in this thesis. I would like to thank my supervisors at
Grange, Dr. Michael Drennan and at University College Dublin, Dr. David Kenny for
their contributions and guidance. To Michael for his knowledge, patience and wisdom
from whom I learned so much that I take with me into each new challenge that is put in
front of me.

Thanks are also due to Dr. Donagh Berry for his help with statistical analysis and for
his encouragement in ensuring that I reached the finishing line. I would also like to
acknowledge and thank Dr. Mark McGee for his contribution, encouragement and
excellent editorial comments throughout this thesis.

Thanks also to the technical and farm staff in the yard for their assistance in the
experimental work. Particular thanks to John Marron, Mattie Cottrell, Martin Ryan and
Joe Farrell. I wish to express my sincere thanks to Dr. Edward O’ Riordon, Dr. Richard
Fallon and Dr. Gerry Keane for their advice and assistance when needed. Thanks to all
my fellow students in Grange in particular, Cariosa, Karl, Bridget, and Cat.
To my college friends Donal, Sinead and William for their support and encouragement.
I also wish to thank Ann Gilsenan and Sinead Caffrey for their secretarial assistance.
To Anne-Marie, thanks for your continued encouragement, patience, and understanding
in the completion of this thesis.

Finally to my parents, Tom and Catherine who have shown continual love and interest
in my work, I dedicate this thesis to you.
ix
List of Tables
Table Title Page
2.1 Correlation coefficients between live animal muscular scores with 16
carcass traits.
2.2 Correlations between live animal skeletal scores with carcass traits. 16
2.3 Correlation coefficients of ultrasonic scanned muscle depth (or area) 32
measurements with carcass traits.
2.4 Correlation coefficients of ultrasonic scanned fat depth measurements 33
with carcass traits.
2.5 Correlation between carcass grades (U.S.D.A standard) with carcass 43
traits.
3.1 Mean, standard deviation and range for live and carcass 86
measurements and yield components of steers.
3.2 Correlations of live animal muscular scores at 8 to 12 months of age 87
with carcass weight, carcass meat, fat and bone proportions,
proportion of high-value cuts in the carcass and meat, perinephric
and retroperitoneal fat, carcass conformation and fat scores and
carcass value.
3.3 Correlations of live animal muscular scores pre-slaughter with 88
carcass weight, carcass meat, fat and bone proportions, proportion of
high-value cuts in the carcass and meat, perinephric and
retroperitoneal fat, carcass conformation and fat scores and carcass
value.
3.4 Correlations of live animal skeletal scores with carcass weight, 89
x