Supplementary feeding of dairy cows : a study of the value of greenfeed maize as a summer supplement : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University

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.

SUPPLEMENTARY FEEDING OF DAIRY COWS

A Study of the Value of Greenfe e d Maize as a

Summer Supplement

A Thesis

Presented in Partial Fulfilment of the Requirements For the Degree

of

MASTER OF AGRICULTURAL SCIENCE

THOMAS

J.

KIRLEY

1 977

in

ANIMAL SCIENCE

at

MASSEY UNIVERSITY

ii

ABSTRACT

An experiment is described in which the n ut ritive value of greenfeed maize as a supplement to lactating dairy cows during the Summer dry period was investigated.

F orty Spring calving Friesian cows were allocated to one of hio treatments in a randomised block design experimen t. On e group of 20 cows was fed on grazed pasture alone

(

control

)

on a separate 7.96 ha farmlet while the other group of

2 0

cows was fed a supplement of greenfeed maize in addition to the pasture from a 7.75 ha farmlet.

The farmlets of both groups were divided in to 7 paddocks and the cow8 were rotationally grazed. A

1

week standardisation period was followed by a

5

week experimental period.

The herbage present on both farmlets was estimated at the beginning of the experiment and1during the experiment, estimates of of the pasture remain ing after grazing were made which gave an indication of the grazing intensity.

Tvro crops of greenfeed maize vrere fed, Crop A and Crop B.

Crop A had a low· yield of D M , poor plant den sity and a high weed po:pulation. Crop B had a high plant population with thin stalks and fevr weeds.

Mean daily milk, milk fat, milk protein yields and liveweights were �ot significan tly differen t between groups. There were

sit�nificant differen ces between the slopes of the regression

l:i.nJs relating pretrial to expe rimenta l milk yields

(P

_<

0 . 0 1 )

and m ilk protein yield

(P< 0.05 )

of the two groups. There were s its:1ificant differences

(P

_<

0 . 1 0 )

between the slopes of the regression lines of milk yield against time of the two groups and behreen the lovr yielders. of each group but no significant difference behmcn the high yielders of e ach group.

The con trol group maintained their liveweight during the first half of the trial and lost weight in the second half of the trial.

The naize group lost weight initially then increased steadily in live\veight . However, the differences in mean liveweight between

groups were not statistically significant.

The hich yie lde rs lost more we ight in the se cond half of the trial than the low yie lde rs in the con trol group.

iii

It

\'l"Ould appear that, while the ove rall diffe rence s in the

me:1n daily milk yields between groups were too small to be statistically significan t, the milk yie ld of the con trol group

decline d at a faste r rate than the maize group with the low yie lde rs in the control group de clin ing at the faste st rate. The we ight los·: by the high yielde rs in the control group was slightly greater tha:1 that of the l Oi'l yi e lJ.e rs in the same group. The high

yielde rs in the control group maintained the ir rate of de cline in milk yield similar to that of the supple men te d group an d this vras prob9.bly achieve d by a greater re duction in liveweight re lative to t�e low yie lde rs.

The yie ld of Crop B vlas

1 1 , 008

kg D M

/

ha and the digestibility va.ried from

7 1 . 2 - 7 5 .4 %

of the 0 M . Maize intake was

3 . 0

and ).�

ke

/

n

Mi

^cow

/

day and utilisation

7 6.5

and

82 . 1 %

of the D ^{M for} Crops A and B re spective ly.

The control group comple te d two rotations on the ir farmlet

witit rotation lengths of

1 9

and12 days, At the end of the e xpe riment they we re very short of p9.sture. The maize group had c omplete d one rot:-;.tion in 26 days and had grazed

1 . 1

ha for a second time. They had ade quate supplie s of he rbage at the end of the expe riment.

Supplementation with greenfe ed m9.ize pe rmitte d the adoption of a longe r rotation length, a better distribution of the available pasture ove r the Summe r pe riod and slowe d t he rate of decline in milx yield in the suppleme nte d group.

\

iv

ACKNOWLEDGEMENT S

The author wishes t o expre s s his deep gratitude t o his

supervisor Dr. A . W. F. Davey for invaluable guidanc e and ass i s t ance in all aspects of the s tudy .

Sincere thanks are als o extended t o the f ol l owing :

Professor D . S . Fl ux and D r . G . F . Wi l son

(

Dai ry Hus bandry Department

)

for the i r assistanc e and a dvi c e .

Me:J:c:rs G . Juke s, N . Mc Lean and R. Mc Cleneghan

(

Dairy Hus bandry Department

)

for their s killed techni cal as sistanc e.

Mr �. Hughe s

(

former Pos t-graduate student

)

for his assistance on many oc cas ions .

Mr R. Halford

(

Farm Lands Supervisor

)

^.

Mr D. Baggott

(

Farm Manager No .

1

Dairy Farm

)

and the s taff of No.

1

D�iry farm who made tho anim�l a , lnnd and fac ilities avsilable and who ass is ted in the day to day running of the erperiment .

Mr R. Sims

(

Agrono�y Department

)

f or permis s ion t o use a greenfeed mai z e crop

(

Crop B in text

)

^.

The Town Milk Producers Federat ion who prov ide d financial support t() Massey Univers i t y

:W

hich enabl ed the study to take p lac e . The Iri sh Departme nt of Agricul ture who supp orted me fi nancially

during the perioi of my Mas terate Stud i es .

Mis:> Judy McKe gg for he r s ki ll e d typing of t he final c opy of this thezis .

Final ly, very spe cial thanks are due t o my wife, Mary, and famil y f or their patience , understanding and support throughout the s t udy.

ABSTRACT

ACKNOiriLEDG E�1ENT S LIST OF TABLES

LIST OF FIGURES LIST OF PLATES LIST OF APPENDICES

TABLE OF CONTENTS

CHAPTER I

The Supplementary Feeding of Lactating Dairy Cows - A Review of Literature

1 .1 Introduction

1 . 2

Supplementary Feeding of Grazing Dairy Cows

1 . 2. 1

Supplementary Feeding w hen the Supply

of Grazing Herbage is Adequate

1 . 2 . 2

Supplementary Feeding when the Supply

of Grazing Herbage is Inadequate

1 . 2. 2 . 1

Concentrates as the Supplementary Feed

1 . 2 . 2 . 2

Roughages as the Supplementary Feed

1 . 2 . 3

Responses of Grazing Cows to Supplementary

Feeding

1 . 2 . 3 . 1

Substitution

1 . 2. 3 . 2

Responses to Supplementary Feeding when Grazing Supply is Adequate

i i iv ix

xi xii xiii

2

7

7

1 1

1 2 1 2

1 2

1.2.3.3 Responses to Supplementary Feeding when

Grazing Supply is Inadequate

1.3 Supplementary Feeding of Cows Fed Hay and Silage

As the Basal Ration

1 ^• 3. 1

1 ^• 3. 2

Types of Supplements Fed to Cows on Basal Rations of Conserved

Pasture Horbaeo

_and

Responses from Feeding

Factors which P5fect the Responses of Cows Fed Conserved Pasture Herbage Ad Lib to Supplementary Feeding

1

.4 Maize as a Supplementary Feed for Lactating Cows

1.4 .1 1 ^• 4. 2

Supplementary Feeding v1i th Maize Silage Supplementary Feeding with Greenfeed Maize

1

. 5

Objectives of the Experiment and Choice of Design

2. 1 2.2 2.3

CHAPTER II

Materials and Methods Experimental Animals

General Outline of the Experiment

Experimental Feeds and Feeding

2. 3.1 2.3.2

Grazing System

Greenfeed Maize

14

14

15

21

23 23 26

27

30 30 30 32 32 32

2.4

Experimental Procedures

Page

37 37 37 38 2. 4. 1

2.4.2 2.4.3

Yield and Stage of Maturity of t he Maiz e Crops Chemical C omposit ion of Maiz e and Pasture Digestibil ity of Maiz e and Pasture

2.4.3.1

In Vitro Dige stibility of Maize and Pasture

38 2.4.3.2

In Vivo Digestibility of Maiz e Crop B .

38 2.4.4

Pasture Availability and Grazing Intensity

39

2.4.5 2.4.6

Maiz e I ntake and Ut il isation

Milk Yield , C ompo s ition and Livewe ight Changes

39 40

2.5

Stat is t ical Analysis

41

41

3. 1 3.2 3.3

3.4 3.5 3.6

2. 5. 1 2.5.2

Preliminary Analysis of the Data

Statist ical Ana lysis of Milk , Milk fat and

Milk Pro t e in Yields , and Livevreight C hanges

41

CHAPTER ^III Results

Gene ral De scription o f t he Maiz e Crops Chemical Analysis of Maiz e and Pastu re Digestibility of Maiz e and Pasture

3. 3.1

^{In Vit}ro Dige stibil ity of Maiz e a nd Pasture

3.3.2

^In Vⁱvo Dige stib il ity of Maiz e and Pas t ure Pas ture Availability and Grazing Int ensity

Maiz e Int ake and Utilisatio n ^{• • .}

Milk Yield, Compo s it ion and Liveweight Changes

3.6.1

Milk Yield

3.6.2

Milk Composition

3.6.3

Liveweight C hanges

42

42

42

42

42

42

50

50

54

54

62

67

C HAPTER IV

Discussion_

70

4. 1

Yi eld of M aize Crop

70

4.2

Nutrit ive Va lue of Mai ze

72

4.2.1

Chemi cal C ompos i t i on

72

4.2.2

Digestibi lity of Greenfeed Maize

72

4.3

Intake of Greenfeed Maize

76

4.4

Re s ponse t o Supplementary Feeding of Greenfeed M ai ze

78

4.5

Practi cal C ons iderations

82

4.6

C onc lusi ons

83

APPENDICES

84

BIBLIOGRAPHY

99

LIST OF TABLES

T:\JLE

--·-

1

_o1 EFFECT OF LEVEL OF CONCENTRATE FEEDING ON MILK

PAGE

YIELD OF SPRING CALVING COWS AT PASTURE (GORDON

1 974 ) 4 1 o2

^SUMMARY OF EXPERIMENTS IN WHICH COWS, vJITH ADEQUATE

SC'FPLIES OF PASTURE HERBAGE vlERE FED SUPPLEMENTARY CONCENTRATE FEEDS.

1o3

RESPONSE TO CONCENTRATE FEEDING, STOCKING RATE AND CALVING DATE (ADAPTED FROM HUTTON AND PARKER

1 967 )

⁰

1 otl-

SUMMARY OF EXPERIMENTS IN vrHICH CO\vS vTITH INADEQUATE

SUPPLIES OF PASTURE HERBAGE \vERE FED SUPPLEMENTARY CONCSNTRATES.

1

_o5 FEEDING LEVELS, IULK YIELDS AND D M INTAKE OF COWS FED CONCENTRATES AS SUPPLEJVT.:SN'l'S TO PASTURE SILAGE

6

9

1 0

AD LIB (GLEESON

1971 )o 1 6

1

_o6 POST CALVING CONCENTRATE FEEDING, SILAGE D M ^INTAKE, MIIJ <: YIELDS, LIVE'ifEIGHT CH..I1.NGES AND RESPONSES TO S�TPLEMENTATION PER COW OF CO#S FED SILAGE AD LIB

(ADAPTED FROM GLEESON

1973 ) 1 7

1 o7

MILK YIELDS OF AUTUMN CALVING COWS FED THREE LEVELS OF CONCE NTRATE SUPPLEMEN'l'ATION AND SILAGE AD LTB

(GL�ESON

1973 ) o 20

1o8 INTAKES OF D M , D E AND MILK YIELDS OF GROUPS OF CO"i!S FED PASTURE SUPPLEMENTED WITH MAIZE SILAGE AND

?1\S!.'iJRE SILAGE (ADAPTED FROM BRYANT AND DONNELLY

1974 )

o

24 2o1 PLAN OF EXPERIMENT

3 . 1

PHYSICAL CHARACTERISTICS OF MAIZE CROP B. AS FED

3o2

CHEMICAL COMPOSITION OF MAIZE (D M BASIS)

3 .3

CHEf'1ICAL COMPOSITION OF PASTURE (D M BASIS).

3 .4

IN VITRO DIGESTIBILITY OF MAIZE (0 M BASIS).

3 1 43 44 45 46 3o5

IN VITRO DIGESTIBILITY OF PASTURE (0 M BASIS).

48

3o6 IN VIVO DIGESTIBILITY OF MAIZE CROP B (0-M BASIS)

49 3 o7

PASTURE AVAILABILITY AT THE BEGINNING OF THE EXPERIMENT

5 1 3o8

:?ASTURE REMAINING AFTER GRAZING BY THE T\ifO GROUPS

OF ^CO.NSo

5 2

TI\I�LE

3.9 MAIZE INTAKE AND UTILISATION

3 . 1 0 MEAN VALUES FOR DAILY MILK YIELD (1) OF TWO GROUPS OF COWS 3 . 11 ��VALUES FOR DAILY MILK YIELD (1) OF HIGH YIELDERS

Ai'IJD

LOW YIELDERS OF

₂

GROUPS OF CO\ifS.

3.12

MEP� VALUES FOR DAILY MILK FAT Y IELDS (g) A�� FAT

CO�TENT OF T'�TO GROUPS OF COilS.

3.:3 MEAN VALUES FOR DAILY MILK PROTEIN YIELDS (g) AND

PROTEIN CONTENT OF TWO GROUPS OF COWS.

3.14

MEAN VALUES FOR LIVEitlEIGHTS (:kg)

OF TvlO GROUPS OF COilS.

4.1 �WNTHLY RAINFALL (mm) DURING SUMMER 1 97 5/76 AND

C0l1H)ARISONS WITH 5 YEAR AND 30 YEAR AVERAGES (DATA SUPPLIED BY D.S.I.R. PALMERSTON NORTH).

4 .�: DIGESTIBILITY OF GRESNFEED NAIZE (0 r1 BASIS).

CON?ARISONS BET'tlEEN THIS STUDY AND PUBLISHED VALUES.

4 o 3 COMPARISON OF IN VIVO

_AND

IN VITRO MEASURENENTS OF

MAIZE

SILAGE (

_HARR

IS 1 963 ).

53 55

59

63 65 68

71

73

75

LIST OF FIGURES

1.1 RATE OJ<,PAS·rURE GRO.N'TH (CUMBERLAND 1974)

2.1

MAP OF NO. 1 DAIRY FARM.

3.1

�JIEAN DAILY MILK YIELD DURING PRETRIAL

_AND

EXY���UJVIENTAL PERIODS.

3�2

THE RELATIONSHIP

BET'dEEN

PRETRIAL

_AND

EXPERHJIENTAL MILK YIELDS.

3

.

₎

'l'liE RELA'riONSHIP BET\,TEEN E

_XP

E R

_HlEN

TA L MILK

_YIELD

AND

TIME.

3.4-

MEAN DAILY MILK YIELD DURING PRETRIAL

_AND

EA'TE�UMENTAL PERIODS OF HIGH

_A..TW

LOW YIELDING COWS

HT

EACH G:?:.OrJP.

3.5

RET,A'riONStHP

BET\,TEEN TlfiLK Y

I

E

L

^D AND TIME

FOR

_HIG-H

AND LO\v YIELDERS

_IN TVlO GROUPS.

3oG MEA.l'i[ DAILY FAT

Y

I

_EL

D

_S

(g) .�.ND FAT % DURING PRETRIAL

AND EXPERIMENTAL PERIODS.

3.7

MEAN DAILY MILK PROTEIN YIELD (g) AND PROTEIN%

DURING PRETRIAL AND EXPERIMENTAL PERIODS.

3.8

LIVEWEIGHTS (kg) OF TWO GROUPS OF COWS AND HIGH AND LOW

_YIELDERS

IN EACH

_GROUP.

4.1 D M INTAKE REQUIRED BY M AIZE GROUP OF COWS DURING

PAGE

27

33

5 6 57 5 8

60

61

64 66

69

THE EXPERIMENT (CALCULATIONS BASED ON M.A.F.F. 1 97 5 ) . 77 4.2 SIMPLIFIED MODEL TO DESCRIBE THE RELATIONSHIP OF

FOOD TO MILK AND LIVEWEIGHT IN DAIRY COWS ACCORDING

TO RESPONSES TO LEVEL OF INTAKE (FROM BROSTER 1 976). 80

LIST OF PLATES

PLATE

2.1

GREENFEED MAIZE CROP B .

2.2

GREENFEED MAIZE STRIP, CUT WITH MOWER, PRIOR TO FEEDING.

2.3

FEEDING OF GRESNFEED r-lAIZE.

2.4

REFUSALS OF GREENFEED MAIZE.

35

35

36

36

APPENDIX

I II III IV

LIST OF APPENDICES

DETAILS OF GREENFEED ��IZE CROPS EXPERTI1SNTAL COI'lS

IN

VIVO DIGESTIBILITY OF GREENFEED ��IZE ANALYSIS OF MILK YIELD DATA

PAGE

84

85

86

94