Investigations into the copper status of sheep grazing at different stocking levels : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University

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INVESTIGATIONS INTO THE COPPER STATUS OF SHEEP GRAZING AT DIFFERENT STOCKING LEVELS

A thesis presented in partial fulfilmen t of the requirements for the degree

of Master of Agricultural Science in Animal

Science at Massey University

JOHN RICH ARD STEVENSON

1 974

ABSTRACT

A series of experiments vrere conducted to investigate the p·ossible role of copper in limiting animal production at hieh s tacking rates.

Copper and selenium uere adm inistered to

494

four-tooth Romney ev1es grazing at tvTO different stocking rates, A

s ignificant

(

p <

0, 01 )

increase of

0 . 74

kg in lamb weaning weight was attributable to the supplementation of both elements. A

ii

depression in clean fleece yield

(P< 0 . 05)

and a small improvement in fleece crimp c larity

(P

_<

0. 05 )

were associated with copper and selenium supplementation respectivel y. Althoueh both these effects reach s ign ificance at the

P 0 . 05

level, they are considered to be due to chance.

A

winter fall

(P< 0, 01) in mean p lasma copper level i·Jas recorded in the high-stocked ewes,

Further investigations were undertaken in another flock of

5 50

Romney e1ves. Factors influencing p lasma, liver and vJool copper were determined and relationshi.ps between plasma copper level and various fleece and body variables assessed.

Period and stocking rate were both shown to significantly

(

P<

0,05 )

affect mean plasma coppe r. No effect of lambing rank or age of ewe could be shovm.

A

smal l stocking rate by age

interaction 1vas recorded

(

P<

0. 05

but this is considered to have arisen by chance.

O f eighty one corre lation coefficients determined between plasma copper level and various fleece and body variables, only six were statistically significant

(P< 0. 05).

No biologica l basis could be found to account for those shown to be significant.

They are considered to have arisen by chance.

No effect of stocking rate on either ewe or 'dead' lamb liver copper level could be established.

Monthly vrool copper detennina tions indicated that the mid­

vrinter, pre-lambing sampling vras sign ificantly depressed. No effect of stocking rate, age of evie, or breedinG rank could be established. Significan t

(P< 0 . 05 )

between-sheep differences were apparent.

iii

Concur rent determinations of w oo l zinc indicated a marked depression due to both an increased stocking r ate, and the onset of 1vinter and

/

or pregnancy

(P< 0. o·1 ) • Older ewes had higher mean l'lOOl zinc values (P<0 . 05 ) .

Additional observations on the plasma samples collected

in previous experiments were undertaken. Mean plasma zinc levels were found to be significantly

(P<0.01 )

^depressed by both a higher stocking rate and the onset of winter and

/

or pregnancy.

iv

AC�iOWLEDGEMENTS

The author wishes to thank Dr

G.A.

Wickham for his supervision and encouragement throughout the course of this study. My thanks are also ex tended to Miss L.E. Thomsen anu Miss C. A. Addis for the analysis of the \vool samples, as Hell as to the other members of the Massey University Sheep Husbandry Department 1 s teclmical and far m staff vrho w ere involved in the collection of blood samples and management of the experimental flocks,

Special thanks are also extended to

Dr N . D. Grace, for the collection of the liver biopsy samples and for many helpful discussions.

JVIr R.D. Jmderson, vrho made available his computer programme for variance component estimations.

Professor R.E. Munford, for assistance with statistical analyses.

Dr R.R. B rooks, for permission to use the Atomic Absorption Spectrophotometer.

I-iy appreciation is also extended to Mrs A. F. Barton who has accepted the task of typing this manuscript.

The work was carried out while the author received financial assistance from the Corrigil Trust.

V

TABLE OF CONTENTS

Chapt er Pag e

ABSTRACT i

i

ACKNOWLEDGEMENTS i

v

TABLE OF CON TENTS V

LIST OF T ABLES X

LIST OF FI GURES xii

L IST OF PL ATES xii

LIST OF APPENDICES xiii

INTRODUCTION

2 REVIEW OF LITERATURE

3

2. 1 Distri bution of copp er in body tissues

and fluids 3

2. 1

^•

1 Liv er 3

(a) Influenc e of di et 4

( b) Influ enc e of ag e 4

(c) I nflu enc e of pr egnancy 5

(d) I nflu enc e of br e ed 6

2 . 1

^•

2 Blood 6

(a) Forms and distribution 6

(b) Normal blood copp er l ev els 7

(c) I nflu enc e of di et 7

(d) Influ enc e of pr egnancy 9

( e) I nflu enc e of ag e 1 0

(f) Influ enc e of br e ed and sire 1 1 (g) I nfluenc e of oth er factors 1 1

2.1 . 3 Wool 1 2

Chapter

3

v

i

2.1.4

Mi lk

� 12

2.2

Copper me t abolism

2.2.1

Copper abs orpti on

2.2.2

Copper t rans p or t

2.2.3

Hepati c copper metabolism

2.2.4

Antagoni s t s of copper me tab o li sm

(

a

)

Cadmium , zinc and si lver

(

_b

)

Molybdenum and sulphat e

2.3

Copp er d ef i ciency and f unc tion

13 13 1 5 15 16 16 17

19

2.3.1

Copper and anaemia

19

2.3.2

Copper and enz ootic neonatal ataxia

20 2.3.3

Copper and w oo l keratinization

22 2.3.4

Coppe r and achromatri c bia

25

2.3.5

Copper and ferti lity

26

2. 3. 6

Copper and evre li veweigh t

26

2.3.7

Copper and other disorde rs

26

2.4

Copper requi rements of sheep

SUPPLEMENTAL ADMINIS TRATION OF COPP ER A ND S ELENIU M TO ROMNEY S HEEP

3.1

Int r oducti on

3.2

Materi a ls and me thods

3.2.1

Des c ription of the 'S tress' Fl ock

and

i t s management

3.2.2

Measurement of productive t raits

(a)

She aring

(b) Pre-scouring flee ce grading (c) Staple tensile strength (d) Scouring

(e) Lamb numbers and weights (f ) Lamb weaning weight

--

27

29 29

29

29

32

32

32

32

33

33

33

Chapter

4

3 . 3

3 . 4

vii

3 . 2 . 3

De terminati on o f evle and lamb

copper s t atus

33

(

a

)

Preparat ion of glassware and

equi p m en t

33

(

b

)

Chemic als and ins trumentati on

33 (c) Blood c o ll e ction and analysi s 34 (d) Lamb li ver collec tion and analys is 34 3 . 2 . 4 Pas ture copper analys is

E xperiment a l des ign and s ta tis ti ca l meth o ds

3 . 3 . 1

Blood c oppe r and produc tive t rai t s

(

a

)

Analysis of var iance

(

b

)

Analysis of co variance

(

one covariate

) (

_c

)

_{Analys is of} covariance

(

tvTO c o vari ates

) 3 . 3 . 2 Pas ture and 'Dead' lamb l iver copper

Resul ts

3 . 4 01

Ev;e parame ters

3 . 4 . 2

Woo l parame ters

3 4 . 3

Lamb parame ters

3 . 4 . 4

Pas ture copper le vels

35 35 35 35 36 36 36 37 37 40 40 45

3 . 5

Discussion

45

3 . 5 . 1

S t ocking rat e

46

3 . 5 . 2

Coppe r and selenium supplementati on

47

OBSERVATIONS ON BLOOD AND LIVER COPPER I N ROMNE Y S HEEP

4. 1

I ntroductio n

4. 2

Materia ls and me thods

4 . 2 . 1

Des cription of the 'CPT' flock and i ts manageme nt

4 . 2 . 2

Measurement o f p roduc tive trait s

4 . 2 . 3

De termination of ewe and lamb coppe r s tatus

4. 2 . 4

Pasture copper analys is

50 50 50

50

51

52

52

Chapter

5

4 . 3

S tatistical analysi s

4 . 3 . 1

Blo od copper

4 . 3 . 2

Blood coppe r and produc tive trait associ at ions

4 . 3 .3

Lamb and e1ve li ver copper status

4 . 3 . 4

Esti mation o f the heri tabi li tie s o f b l ood c opper

4 . 4

Resul t s

P lasma copp e r

Liver copper leve ls

Int errelationships between plasma coppe r lev e l and pre lambing livewe ight I nt erre lati onships be tl•reen p lasma copp er level and a number of physical wool att ri but es

Heri t ability of plasma copper leve l Pasture copp e r leve ls

4 . 5

Discussion

4 . 5 . 1

P lasma c opper leve l s

4 .5 . 2

Liver copper le ve ls

4 . 5 . 3

Li vev1e ight o f ewe

4 .5 . 4

I nterre lati onshi ps o f coppe r and physi cal wo o l at t ributes

4 . 5 . 5

Heri t ab i l i t y of p lasma copper

4 . 5 . 6

P asture c opper

THE CONCENTRATION B Y MONTH OF COPPER AND ZINC IN THE vlOOL FROM ROMNEY SHEEP

5. 1

Int roducti o n

5. 2

Mat e rials and methods

5. 2. 1

Coll e ction, handling and sto rage o f samples

' 5. 2. 2

Preparati on of wo o l sample s for eleme ntal d etermi na t i o n

5. 2. 3

S tati stical analysi s

viii

52 52

54 54

54 55 55 59 59

60 60 60 64 64 65 66

66 67 6 7

68

68

68

6 9

70

7 0

ChaEter

6

7

5 . 3

Results

5. 3 . 1

Wool copper

5 . 3 . 2

Wool zinc

5 . 4

Discussion

5 . 4 . 1

Wool copper

5 . 4 . 2

Hool zinc

P LASMA ZINC C ONCENTRATIONS IN GRAZING AT TW O STOCKING RATES

6 . 1

Introduction

6 . 2

Materials and methods

6 . 3

Results

6 . 3 . 1

Stress flock

6 .3 . 2

CPT flock

6 . 4

Discussion

ROM NEY SHEEP

GENERAL CONCLUSIONS AND SUM MARY AP PENDICES

BIBLIOGRAPHY

ix

Page

71 71 7 1 74 75 75

77

77

77

78

78

7 9

80

81

84

. 91

T able

3.4 3. 5

LIST OF TABLES

Cal endar of operati ons - S tres s flock ,

1 972

El'i'e paramet ers - mean squares from analys es vari an ce and covari anc e

EvTe parame ters - means

/

adjus ted means and s tan dard errors

Wo o l parame ters - mean squares Wool paramet ers - means

Lam b data - me an s quares from analys es of vari anc e and covari ance

3. 7

Lamb d a t a - means

/

ad jus ted me ans and s t andard

3. 8 4. 1 4.2 4. 3 4.4 4.5 4.6

4.8 4.9 4.10

erro rs

Pas ture c opper

(

ppm

)

Mean s quares from le as t squares analysis o f s to cking rat e and period effe c ts

Mean s quares from leas t s quares analys is of lambing rank and peri od effe c ts

Mean s quares from leas t s quares analys is o f age and pe ri od e ffe cts

Mean squa res from leas t s quares analys is of s t o cking rate and age e ffe c ts

Mean s quares from le ast s quares analys is of age and lambing rank e ffe c ts

Mean s q uares from leas t squares analys is o f s to cking rat e and lambi ng r ank effe c ts o n plasma coppe r

conce ntration

Mean s quares from leas t squares analys is of s to cking.

rate and age effe cts on plasma copper c oncentrati on Main e ffe ct es t im ated means and s t andard erro rs Age-s t o ck ing rat e s ubclass es tim ated means and s tandard erro rs

Co rrelation coeffi c ients between p lasma coppe r conce nt ration and a numbe r o f fleece and b ody vari ables : coeffi ci ents are given within age ­ s to cking rate c las s i fi cati ons as well as averaged o ver these clas s i ficati ons

X

Page

31 38

39 41 42 43

44

45 56 56 56 57 57

57

58 58 59

61

Table

4. 1 1

Variance components - evm winter plasma copper concentration

4. 1 2

Pasture copper levels

4. 1 3

CPT ewe liveweights

(

k g

) 5. 1 Ewe fleece sampling groups

5. 2

Mean squares from analysis of wool copper and zinc concentration

5. 3

Wool copper and zi nc concentration main effect means and standard errors

6. 1

Stress flock squares

Plasma zinc concentration mean

6. 2

Stress :lock -Plasma zinc concentration means

6. 3 6. 4

and standard error CPT flock

CPT flock

Plasma zinc concentrations mean squares P lasma zinc concentration means and standard error

xi

62 62 63 69 7 2 7 3 78

78

79

80

LIS T OF FI GURES

Figure·

5.1 Wool copper concen tration per 28-day period from a mid-side patch

5. 2 Wool zinc concentration per 28-day pe riod from a mid-side patch

LIS T OF PLATES

Plate

4. 1 Liver aspiration biopsy

xii

73 ( a ) 73 ( b )

5 3

Appendix I II III IV

V

LIST

OF

APP ENDICES

Physical and chemical soil parameters Description of the fleece characteristic grading system

Atomic absorption spectrophotometer operating conditions

Aspiration of ovine plasma diluted N·i th copper-free 1-mter

( 1 : 1 ) and copper-free water

Trace element contamination of Vacutainers and polypropylene centrifuge tubes

xiii

Page

84

85

88

89

90