Aspects of selection for economic merit in dairy cattle : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Breeding at Massey Uni

Copyright is owned by the Author of the thesis. Permission is given for

a copy to be downloaded by an individual for the purpose of research and

private study only. The thesis may not be reproduced elsewhere without

the permission of the Author.

irl. Da..i:ry Ca..ttle

A thes i s

presented in parti a l ful f i lment o f the requi rements for the degree of

Doctor of Phi losophy in Anima l Breeding at

Massey Univers ity

�ii9�

/I) (f .

ACKNOWLEDGEMENTS

I grateful ly acknowledge the guidance and support of my Chi e f Supervisor Professor Robert Anderson in my endeavours in mathematical and animal breeding statistics .

I would l ike to thank Professor Hugh B l a i r for the guidance of my work , h i s valuable comments on the manuscript and h i s friendly messages .

In particul ar , I would l ike to express my gratitude to Dr Brian Wickham of Livestock Improvement . His encouragement and support in many different ways made this study possibl e .

I would l ike to thank my supervisors Professor Al Rae and Dr Dori an Garrick for the ir help and advi se .

I am grateful to my former col leagues at Livestock Improvement , Dr Pat Shannon , Rob Jackson and Dr John Rende l for sharing thei r ideas and knowledge with me .

I would. l ike to thank Professor B i l l Hohenboken , Professor Leo Dernpfle and the late Dr Reuven Bar-Anan for the ir support and inspirations in matters animal breeding . I am indebted to Dr Bernhard Breier for h i s encouragement and practical advice and our stimulating academic discussions .

I am most grateful to Livestock Improvement to have provided me with this opportunity to further my education and contribute to dairy cattle breeding in New Zeal and .

I am indebted to my parents who encouraged me to search for answers and taught me not to give up .

Fina l l y , I would l ike to thank my husband Karl Matthys for h i s valuable comments on the manuscript of thi s thes i s anc h i s patience , encouragement and understanding during thE f inal phase of my studies .

i ABSTRACT

Economic merit of d a i ry cattle is an important consideration in d a i ry cattl e breeding . I n this thes i s , genetic and economic aspects were combined to quantitatively derive an aggregate genotype with the aim to improve the economic merit of New Zealand da i ry cattle .

Re l ative economic va lues for production traits , l i vewei ght and survival rate were estimated . A profit function was defined for a pasture based milk production system . The effects of changes in several genetic , biologica l and economic parameters on various components of farm profit were s imul ated with a bioeconomic computer model .

The economic value for protein yield was $ 4 . 6 4/kg and

$ 4 . 5 8/kg for Holstein-Fries i an and Jersey cows , fol lowed by

$ 1 . 8 4/kg and $ 1 . 7 5/kg , respectively , for mi lkfat yield . Livewei ght had a negative economic va lue of $ O . 4 9/kg and

$ O . 5 3/kg for Holstein-Friesian and Jersey cows . An increase in survival rate by 1 % had a pos itive economic va lue of

$ 9 . 2 5 and $ 9 . 2 9 for Holstein-Friesian and Jersey cows . A sens i tivity ana lysis showed that decl ining returns for milk reduced economic values for all milk components and s imultaneously increased economic values for l ivewe ight .

The effects of several traits on survival rate were quant i f i ed . An increase in surviva l rate increases a cow ' s prof i tabi l i ty as cows contribute to net farm income only during their l actation years and constitute a cost during the rearing period . After production traits , the f armer ' s overal l opinion of the cow and the traits udder support and udder overal l had the greatest impact on survival rate . These traits were used as selection criteria for survival rate in the s e l ection indexes .

i i variance and covariance components were estimated with

mul ti trai t REML procedures for a l l production , management and conformation traits used in the current selection index . Heri tabi l i ties were

0 . 2 5

for prote in yield and

0 . 2 1

for mi lkfat yield for Holstein-Fries ians and 0 . 1 7 for both trai ts in Jerseys . Genera l l y , parameter estimates did not d i f f e r substantial ly from other popu l ations .

An aggregate genotype as \'I1e l l as sel ection indexes for Hol stein-Fries ians and Jerseys were constructed and we ighting factors calcul ated based on the economic va lues and genetic parameters estimates .

The aggregate genotype included the traits protein yi e l d , milkfat yield , volume , l iveweight and survival rate .

The selection index for Hol stein-Friesians included thE trai ts prote in yield , m i l kfat yield , volume , I i veweight I

udder overal l , overa l l opinion , temperament , milking speec and udder support .

The s e l ection index for Jerseys included the traits proteir y i e l d , mi lkfat yield , volume , I i vewe ight , udder overa l l overal l opinion , temperament , mi lking speed and fore udder,

These s e l ection indexes improve the economical ly importan' trai t survival rate included in the aggregate genotyp' through indirect selection us ing tra i ts which can be measure, in the first l actation . This a l l ows the current generatio interval to be mainta ined when selection for survival rate i incorporated in the aggregate genotype .

Abstract

Table of Contents

L i st of Figures

L i st of Tables

1 . INTRODUCTION

TABLE OF CONTENTS

2 . SELECTION FOR MULTIPLE TRAITS ^- A REVIEW

2 . 1 . Methods o f selection for multiple traits 2 . 1 . 1 . Tandem sel ection

2 . 1 . 2 . Independent cul l ing leve l s 2 . 1 . 3 . Sel ection o f extremes

2 . 1 . 4 . Sel ection index methods 2 . 1 . 4 . 1 .

2 . 1 . 4 . 2 . 2 . 1 . 4 . 3 . 2 . 1 . 4 . 4 . 2 . 1 . 4 . 5 . 2 . 1 . 4 . 6 . 2 . 1 . 4 . 7 . 2 . 1 . 4 . 8 .

Optimum selecti on index

Best Linear Unbi ased Prediction Def inition o f aggregate genotype Multiple-stage selection

E f f iciency o f s e l ection index Estimated selection index Substitution i ndex

Indices based on phenotypes

i i i

Page i

i i i

vi i i

x

1 4

5 5 6 8 8 1 1 1 4 1 6 1 7 1 9 2 0 2 1 22 2 . 1 . 4 . 9 . Selection indices with constraints 24 2 . 1 . 4 . 1 0 . Alternatives to index selection 2E

2 . 2 . Estimation of relative economic values 2,

2 . 2 . 1 . Discount rates 2�

2 . 2 . 2 . Profit function - obj ective functi on 3:

2 . 2 . 3 . Methods o f estimating reI . economic values 3' 2 . 2 . 4 . Use of economic indices 4:

2 . 2 . 5 . Non- l inear economic values 4:

2 . 3 .

Effects of errors in parameters on expected genetic gain

2 . 3 . 1 .

Errors in genetic parameters

2 . 3 . 2 .

Errors in economic values

2 . 4 .

The current breeding obj ective for New Zealand

iv

4 4 4 4 4 8

dairy cattl e

4 8

2 . 4 . 1 .

Selection obj ective

4 8

2 . 4 . 2 .

Current selection criteria 51

3 . A BIOECONOMIC MODEL

3 . 1 .

I ntroduction

6 1

3 . 2 .

A bioeconomic mode l for a pasture based mi lk

producti on system

6 2

3 . 3 . Base l ine parameters and variables 6 3

3 . 3 . 1 .

Dairy farm production system parameters

6 4 3 . 3 . 2 .

Metabo l i sable energy avai l abl e

6 5 3 . 3 . 3 .

Uti l i zation/requirements o f metabo l i sable

energy

65

a ) Ma intenance

6 7

b ) Lactation

6 9

c ) Prenatal growth

7 4

d ) Postnatal growth and weight gain

75 3 . 3 . 4 .

Biological animal variables

a ) Mi l k production b ) Liveweight

7 6 7 6 7 7

c ) Replacement rate

7 8

d ) Age distripution of herd

7 8

da ) Estimation o f age distribution

7 9

db ) Estimation of age-production factor

8 2

dc ) Effect on energy requirement for mi l k

8 3

dd ) Effect o n revenue from cul l cows

8 4

e ) Surv ival rate o f cows

8 5

f ) Survival rate of calves ( 0

- 4

days )

8 6

g ) Survival rate of repl aceme�ts

( 4

days

- 2

years )

8 6

h ) Dress ing percentage

8 6

i ) Ratio of cal f weight at birth to cow

l ivewe ight 8 8

v

3 . 3 . 5 .

Economic variables

8 9

a ) Price for m i l k fat , protein and volume

8 9

b ) Price for carcass of mature cow

90

c ) Price for carcass of c a l f

91

d ) Price of cal f sold for rearing

92

e ) Var iabl e costs

f ) Fixed costs g ) Discount rate 3 . 3 . 6 . Obj ective variabl es

3 . 4. Va l idation of bioeconomic model

3 . 4. 1 . Va l idation of conceptua l model 3 . 4 . 2 . Ver i f ication of computeri zed mode l 3 . 4. 3 . Operationa l va l i di ty

4 . RELATIVE ECONO MIC VALUES ESTI MATED WITH THE BIOECONO MIC MODEL

4. 1 .

Introduction

4 . 2 .

Material and methods

4. 3.

Milk production

4. 3 . 1 .

Protein

4. 3 . 2 .

Mi lkfat

4. 3 . 3 .

Lactose

4. 3 . 4.

Volume

4 . 4. Liveweight

4. 4 . 1 .

Effects of l iveweight changes

4. 4. 2 .

Economic value of l iveweight

4. 5 .

Replacement rate

4. 6 .

Compari son of economic va lues

5 . SENSITIVITY ANALYSIS 5 . 1 .

Economic variables

5 . 1 . 1 .

Returns for milk components

92 96 99 1 0 1

1 0 1 1 0 2 1 0 2 1 0 3

1 0 7 1 0 7 1 0 8

III III

1 1 8 1 2 6 1 3 2 1 3 3 1 3 3 1 3 5 1 41 1 45

1 4S 1 5 C 1 5 C

a ) Protein b ) Mi lkfat c ) Lactose d ) Volume

5 . 1 . 2 .

Returns for carcass of mature cow

5 . 1 . 3 .

Returns for carcass of ca l f

5 . 1 . 4 .

Costs o f inputs 5 . 2 . Biologica l vari ables

5 . 2 . 1 .

Metabol isable energy ava i l able

5 . 2 . 2 .

Biological animal parameters

5 . 3 .

Compari son of variables for sensitivity impact

6 . EFFECTS OF TRAITS OTHER THAN PRODUCTION ON S URVIVAL RATES

6 . 1 .

I ntroduction

6 . 2 . Material and methods

6 . 3 .

Results

6 . 4 .

Conclus ion

7 . AN AGGREGATE GENOTYPE AND SELECTION INDE XES FOR NEW ZEALAND DAIRY CATTLE·

EST I MATION OF GENETIC PARAMETERS FOR THEIR IMPLEMENTATION

vi

1 5 3 1 5 8

1 6 2

1 6 4 1 6 6 1 6 8 1 7 0 1 7 2 1 7 3

1 7 5

1 8 0

1 8 2 1 8 2

1 8 2 1 8 4 1 94

1 95

7 . 1 .

An aggregate genotype for New Zealand dairy cattl e

1 95 7 . 2 .

Selection indexes for New Zeal and dairy cattle 197

7 . 2 . 1 .

Hol stein-Fries ians

1 97

7 . 2 . 2 .

Jerseys

1 9E

7 . 3 .

Genetic parameters for selecti on obj ectives and selection criteria

7 . 3 . 1 .

Introduction

7 . 3 . 2 .

Material and methods

7 . 3 . 3 .

Results and di scuss ion

1 9�

1 9�

2 0 : 2 0 (

a ) Heritabi l ities

b) Phenotypic corre lations c ) Genetic corre lations 7 . 4 . Conclus ion

8.

SELECTION INDE XES 8 . 1 .

Introduction

8 . 2 . Selection index equations

8 . 3 . Results and di scuss ion 8 . 4 . Conc lusion

9. CONCLUSION

1 0 . APPENDI X

1 0 . 1 .

APL-code of bioeconomic model

1 0 . 2 . APL-code for calculating s e l ection index

v i i

2 0 8 2 1 2 2 1 4 2 1 9

2 2 0 2 2 0 2 2 0

2 2 8 2 2 9

2 3 0

2 3 4 2 3 4

coefficients 2 4 0

1 0 . 3 . Tables o f genetic parameters

for Hol stein-Fr i e s i ans , Jerseys and Ayrshires

2 4 2

10 . 4 . Publ ications 2 5 0

11 . PUBLICATIONS ARISING FROM THESI S 2 8 9

1 2 . BIBLIOGRAPHY 2 91

vi i i LIST OF F IG URES

Figure

Page

3 . 1 . Flowchart of bioecono mic model .

6 3 a

4. 1 . Revenue per ha f ro m mi lk , sum of mi lk and bobby ca lves ,

sum of mi lk , bobby calves and cul l cows and pro f i t per ha def ined as sum of revenue from mi lk , bobby ca lves and cul l cows minus variabl e costs at dif ferent leve l s of protein yield per cow for Holstei n -Friesians and

Jerseys . 1 1 6

4. 2 . Revenue per ha from mi lk , sum o f mi lk and bobby calves , sum of mi lk , bobby calves and cul l cows and profit per ha defined as sum of revenue from mi lk , bobby ca lves and cul l cows minus variabl e costs at di f ferent leve l s o f mi lkfat yi eld per cow for Holstein-Friesians and

Jerseys .

1 2 4

4 . 3 . Revenue per ha from mi lk , sum o f mi lk and bobby calves , sum of mi lk , bobby ca lves and cul l cows and pro f i t per ha def ined as sum of revenue from mi lk , bobby calves and cul l cows minus variable costs at di fferent leve l s of lactose yield per cow for Holstein-Fries ians and

Jerseys . 1 3 1

4. 4. Revenue per ha from mi lk , sum o f mi lk and bobby calves ,

sum of mi lk , bobby calves and cul l cows and pro f i t per

ha defined as the sum of revenue fro m mi lk , bobby ca lves

and cul l cows minus variable costs at different level s

of l iveweight f o r Hol ste in -Fries ians and Jerseys . 1 40

4.5 . Revenue per ha from mi l k , sum of mi lk and bobby calves ,

sum of mi lk , bobby calves and cul l cows and pro f i t per

ha de fined as the sum of revenue fro m mi lk , bobby calves

and cul l cows minus variabl e costs at di f ferent levels

of repl ace ment rate def ined as the reciprocal of

herdl ife for Hol stein-Friesians and Jerseys . 1 44

ix

5 . 1 . Real pri ces for mi lkfat and meat fro m cul l cows and bobby calves during the l ast 2 0 years . 1 5 1 5 . 2 . Changes in econo mic val ues for protein , mi lkfat , lactose and l iveweight for Hol s tein-Friesians and Jerseys with an increasing price for protein . 1 5 5 5 . 3 . Changes i n economic values for protein , mi lkfat , lactose and l iveweight for Ho lstein-Friesians and Jerseys with an increasing price for mi lkfat . 1 6 1 5 . 4. Changes in economic va lues for protein , mi lkfat , lactose and l iveweight for Holstein-Friesians and Jerseys due to

changes in volume penal ty . 1 6 5

x

LIST OF TABLES

Table Page

Chapter 3

3 . 1 . Dairy farm production syste m para meters e mployed in the

bioeconomic model . 6 4

3 . 2 . Esti mates for ME re quirement for mi lk co mponents . 7 4 3 . 2 . Milk production statistics for 1 9 9 0 / 9 1 season for

Holstein-Fries ians and Jerseys .

7 7

3 . 3 . Statistical parameters for production per cow by age for

Hol stein-Fries ians and Jerseys . 8 0

3 . 4. Proportion of cows i n each age group for Holstein-

Fries ian and Jersey. 8 1

3 . 5 . Age-production factors for Holstein-Fries ian and Jersey

. � . ..,

.for d i fferent replace ment rates .

8 4

3 . 6 . Expected dressing percentages for Holstein-Friesian and

Jersey cows . 8 8

3 . 7 . Variable costs per cow.

9 :::

3 . 8 . Total mi l ki ng t i me esti mates for Holstein-Fries ian anc Jersey cows .

3 . 9 . Co mpari son of production para meters derived fro m a l experi ment and the bioeconomic model f or Hol stein·

Friesians and Jerseys . 1 0

Chapter 4

4. 1 . Phenotypi c and geneti c para meters employed for Holste i n

Friesian s and Jerseys . 1 1

xi 4 . 2 . Changes in energy requirements , revenue and cost per cow and per ha for Hol stein-Fries i ans and Jers e ys for

,

different levels of protein yi eld . 1 1 3 4 . 3 . Production para meters , profit per ha and econo mi c values at di f ferent levels of protein yield per cow for Holstein-Friesian and Jersey cows . 1 1 7 4 . 4 . Changes in energy re quirements , revenue and costs per cow and per ha for Hol stein-Friesians and Jers e ys with dif ferent l evels of mi lkfat yield . 1 2 0 4 . 5 . Production para meters , profit per ha and econo mic values at d i fferent leve l s of mi lkfat yi eld per cow for Holstein-Friesians and Jerseys .

1 2 5

4 . 6 . Changes in energy requirements , revenue and

cow and per ha for Hol stein-Friesian with l evels of l actose yield .

costs per d i fferent 1 2 8 4 . 7 . Production parameters , profit per ha and economic values at di f ferent level s of lactose yield per cow for

Holstein-Friesians and Jerseys .

1 3 2

4 . 8 . Changes i n energy re quirements , revenue and costs per cow and per ha for Hol stein-Fries ians and Jerse ys for d i fferent l evels of l iveweight . 1 3 7 4 . 9 . Production parameters , profit per ha and econo mic values at d i fferent l evels of l iveweight for Hol stein-Friesians

4 . 1 0 .

4 . 1 1 .

4 . 1 2 .

and Jerseys . 1 4 1

Production parameters , profit per h a and economi c values at different leve l s of replace ment rate E for Holstein-Friesians and Jerse ys .

Comparison o f decrease i n stocking rates pe l phenotypic standard deviation i ncrease in variou�

traits for Hol stein-Friesians and Jers e ys . 1 4 1 Economic values per cow for Holstein-Friesians an

Jerseys . 1 4

xi i

Chapter 5

5 . 1 . Prices for mi lkfat , cul l cow carcass and bobby calves . 1 5 2 5 . 2. Changes in pro fit per ha and per cow with increas ing protein prices for Hol stein -Friesians and Jerse ys . 1 5 7 5 . 3 . Changes in prof i t per ha and per cow and econo mic values for mi lk prices predicted for 2 0 0 1 and 2 0 1 1 . 1 5 8 5 . 4. Changes i n prof i t per ha and per cow resulting from increas ing mi l kfat prices for Hol stein-Fries ians and

Jerse ys .

1 6 2

5 . 5 . Changes in prof i t per ha and per cow due to an increased value for lactose for Holstein-Friesian and Jersey. 1 6 4 5 . 6 . Changes i n prof i t per ha and per cow with increased

costs for vol u me for Hol stein-Fries ian and Jersey. 1 6 6 5 . 7 . Changes i n prof i t per ha and per cow resulting from changes in returns for cow meat for Holstein -Fries ians

and Jerseys . 1 6 8

5 . 8 . Changes i n prof i t per ha and per cow resulting from changes in returns for ca l f meat for Holstein-Friesians

and Jerseys .

1 6 9

5 . 9 . Changes i n prof it per cow and per ha with a 1 0 % increase in variabl e costs , a 1 0 % increase in stock prices and a 2 % i ncrease i n interest rate for Holstein-Fries ians and

5 . 1 0 .

5 . 1 1 .

Jers e ys .

1 71

Changes i n econo mic values per ha due to changes in

OM

grown , uti l i sation and energy content o f

OM . 1 7 4

Changes in stocking rate , profit per ha and economic val ues per ha resulting f ro m a

1 0%

i ncrease in biological

variables

for Holste i n -

Fr ies ians and Jers e ys . 1 7 8

x i i i Chapter 6

6 . 1 .

Number of cows with production , management and survival information at d i f ferent lactations . 1 8 3

6 . 2 .

Means and standard deviations o f production and non­

production tra its of primiparous cows imcluded in the

analys i s .

1 8 5

6 . 3 .

Means and standard devi ations for survival rates between

subsequent l actations . 1 8 7

6 . 4.

Part i a l regress ion coefficients for traits affecting survival rate f rom

1 nt

to

2 �

lactation .

1 8 8 6 . 5 .

Standardi sed partial regression coefficients for traits affecting survival rate from

1 rst

to

2 nd

lactation .

1 9 0 6 . 6 .

Part i a l regression coe f f icients for tra its affecting survival rate from

rst

to

3 rd

lactation .

1 9 1 6 . 7 .

Part i a l regress i on coefficients for traits affectin<?

survival rate f rom

1 ut

to

4�

l actation . 1 9 3

Chapter 7

7 . 1 .

Number of records for estimating vari ance and covarianc(

components for producti on and non-producti on traits . 2 0:

7 . 2 .

Heritabil ities of se lection obj ectives in the aggregat genotype and selection criteria in the selectio

indexes . 2 0

7 . 3 . Phenotypic correlations between selection criteri

included i n the selection indexes . 2 1

7 . 4.

Genetic corre lations between traits in aggregat

genotype and criteria in selection index . 2 :

xiv Chapter 8

8 . 1 . Phenotypic var i ances and covari ances used for

determining we ighting factors for selection indexes . 2 2 4

8 . 2 .

Genetic vari ances and covariances used i n determining

weighting factors for se lection indexes .

2 2 6 8 . 3 .

Weighting factors ( $/cow/annum )

i ncluded i n the selection Friesians ) and _1J ( Jerseys ) .

for selection criteria indexes 1M ( Holste in-

2 2 8

Chapter 1 0 ^- Appendix

1 0 . 1 .

1 0 .2 .

1 0 . 3 .

Adj usted means , phenotypic and addi ti ve genetic vari ances and heri tabi l i ty estimates with thei r standard deviations and standard errors for producti on and non-production traits for primiparous Holstein-Fries i an , Jersey and Ayrshire

cows .

2 42

Heritab i l i ty and phenotypic and genetic correlation estimates for primiparous Holste in­

Fries i an , Jersey and Ayrsh i re cows .

2 45

standard errors for heritabi l i ty and phenotypic and genetic correlation estimates for primiparous Holstein-Fri e s i an , Jersey and Ayrshire cows .

2 48