Energy and protein requirements of ruminants. 1491832111

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Energy and Protein Requirements of Ruminants An advisory manual prepared by the AFRC Technical Committee on Responses to Nutrients

\.'~~., '.. J.:, .,

:3 JtilliiJ.ltv

1"-0W

CAB INTERNATIONAL

( 'ontcnts

CAB INTERNATIONAL Wallingford Oxon OXI0 8DE UK

Tel: +44 (0)1491832111

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© CAB INTERNATIONAL 1993. All rights reserved. No part of this publication may be reproduced in any form or by any means, electronically, mechanically, by photocopying, recording or otherwise, withoutthe prior permission of the copyright owners. A catalogue record for this book is available from the British Library. ISBN 0 85198 8512

First printed 1993

Reprinted with corrections 1995

Harvard-style references to this publication should be made as AFRC (1993) with the full reference as: AFRC (1993) Energy and Protein Requirements ofRuminants. An advisory manual prepared by the AFRC Technical Committee on Responses to Nutrients. CAB INTERNATIONAL, Wallingford, UK.

Printed and bound in the UK at the University Press, Cambridge

Preface

xi

Foreword

Acknowledgements

Terminology and Symbols Used

xiii

xv

xvii

Chapter One

Principles and Concepts

1

Mctabolisable Energy

1

Definition of Metabolisable Energy

Definition of Net Energy

Definition of Digestible Energy

Fermentable Metabolisable Energy

Efficiencies of utilisation of ME

Correction for feeding level

Calculation of ME requirements

Principles of diet formulation

The Variable Net Energy system

Metabolisable Protein

Degradation of feed proteins in the rumen

Rumen retention time and outflow rate

Influence of rumen outflow rate on degradability Quickly Degradable Protein, [QDPj Slowly Degradable Protein, [SDPj Effective Rumen Degradable Protein, [ERDPj and ERDP Digestible Undegradable Protein, [DUPj and DUP Effect of Level offeeding (L) upon [ERDPj and [DUPJ offeeds M icrobial protein synthesis in the rumen VIIIIII'S

0/ Microbial Crude Protein synthesis (y)

lst iIIII/f ion 01 M icrobia I Crude Prot ei /I supp!v

1

2

2

3

3

4

6

6

7

9

9

11 12

13

13

13

14

15

15

J(,

I I

V/

( '''1111'111,1

( '''111''11/1

Estimation of Digestible True Protein supply

IX

Efficiencies of utilisation of Metabolisable Protein

19

Efficiency of utilisation of an "ideal" amino acid mixture (k"",) Relative Value (RV) of absorbed amino acid mixtures Working values for efficiency of MP utilisation (k,J

19

19

19

Chapter Two

Requirements for Metabolisable Energy Methods of calculating ME requirements Safety margins

The Net Energy content of animal products Maintenance requirements

II'I~ IlI'I ;1I1l1 II H J 1'1 values of ruminant feeds I '('IIIIClllahlc Mcraholisablc Energy

Methods or diet formulation ILIIHI lormulatcd or computer assisted procedures I )11'1 checking procedure ( 'ornputcr Linear Programming methods

Ilslllg Dry Matter intake functions 21

21

22

23

Pn'd iel ion or performance (;lllWilig animals I ,al'taling animals Respollses to changes in ME intake of lactating animals

Fasting metabolism Activity allowances

23

23

24

('haptcr Five

Uniry Cattle

Requirements for milk Requirements for growth

26

MFa ud MP requirements for lactation

27

I hy matter appetite prediction

29

29

29

I )iel formulation for lactating dairy cattle

Growth of the fleece in sheep Fibre growth in goats

Requirements for pregnancy Allowances for liveweight change in lactating ruminants

Chapter Three

Requirements for Metabolisable Protein Method of calculating MP requirements Safety raargins

Maintenance requirements Basal Endogenous Nitrogen Dermal losses as scurf and hair

Requirements for milk Requirements for growth Growth of fleece in lambs Growth of fleece in ewes Fibre growth in goats

Requirements for pregnancy Allowances for liveweight change in lactating ruminants

Chapter Four

Feed Evaluation and Diet Formulation Nutrient values for ruminant feeds Metabolisable Energy values of ruminant feeds Prediction of ME values from in vivo or in vitro [DOMDI values Prediction of ME of grass silage by NIR spectroscopy

31

l'rcd ict ion of expected milk yield

33

34

34

34

35

35

36

38

38

38

38

39

41

41

41

43

41

45

4X

50

50

50

53

53

53

53

54

55

57

57

59

61

MI': a nd MP requirements for pregnancy

62

66

67

67

Dry matter appetites of pregnant cows

68

Responses of lactating dairy cattle to protein supply I ~llcet of fishmeal on silage intake and digestibility

MI': a nd MP requirements of growing dairy heifers 33

I'll

Dry matter intakes of growing heifers

Chapter Six

Beef Cattle Growing and finishing cattle ME and MP requirements of growing and fattening beef cattle Dry matter appetite prediction Diet formulation for beef cattle Effect of fishmeal on silage intake and digestibility

Sud lcr cows ME and MP requirements of lactating suckler cows I )ry matter appetite prediction Diet formulation for lactating suckler cows Diets for dry/pregnant suckler cows

( 'ha pter Seven Shl'l' 11 Ilill and lowland ewes MI' .md MI' requirements of pregnant ewes 1)1 \ 111.1111'1 ;IPI)("III\' III plq',II;1I11 rwvx

70

70

73

73

73

78

80

83

86

87

87

88

90

91

91

92

\)\

viii

( '/JIII/'lIls

('/JIII/'I1I.\

Diet formulation for pregnant ewes ME and MP requirements for lactating ewes Estimation of ewe milk yields Dry matter appetite of lactating ewes Diet formulation for lactating ewes

94 95 96 97 98 100 100 100 104 105

Growing and fattening lambs Breed and sex corrections ME and MP requirements of growing and fattening lambs Dry matter appetite of lambs Diet formulation for growing and fattening lambs

Chapter Eight &-"'1111"'1,1'1'11

T..-rminology and Symbols Used

i'l '!i: 1

p!

!:'.·I :1 I"~

,!,

ill II'! I

, ThiN )(Iossary of terms, symbols and units is comprehensive, in order that there l. II logical and systematic use of abbreviations in the text of this Manual. The

'1lIIl'lpies used in the construction of the glossary were:

\)ltl'I':RCASE LETTERS are used for energy and nutrient supply (per animal)

,.. tiny, either g/d or MJ/d as appropriate.

Tht' same symbols, enclosed in square brackets, eg [DUP], are used for

tlOlIl'l'lItrations, g/kg or MJ/kg, except where existing usage dictates otherwise.

Wt'I' elise letters are used for rates, efficiencies and proportions, which are

lither expressed as decimals (not percentages), or with relevant units, eg g/MJ.

e units and abbreviations used for weight, time etc are as in the SI system. rude protein (CP) or (P) is taken as 6.25 x Nitrogen (N). hscripts are used to differentiate between metabolic functions as follows: b c d f

g I m II II

p I W

L

.....

Basal metabolism Concepta/gravid foetus/pregnancy Dermal losses, scurf and hair Liveweight gain Gain/loss in liveweight in lactating animals Lactation Maintenance Nitrogen utilisation, combined with the above set Ovine Production Time in days Wool/fibre growth

rW

Terminology

.\\'11/

l,ll. jI: I

IIW!

Symbols

/I'/II/IIIO/O}{\' III/(/ S\,III/IO/S

Usn!

A

Activity allowance, J/kg/m or kJ/kg/d

II

,." 1

a

Proportion of water soluble N in the total N of a feed

II

1I IIIII I

[ADIN]

Acid Detergent Insoluble Nitrogen in a feed, g/kgDM

B

Derived parameter in equation (14) to predict energy retention

Digestible Undcgraded Protein (N x 6.25), the amount or proport ion of undegraded feed protein that is truly absorbed, gill in a diet or g/kgDM in a feed

"'1/'

True absorbability of amino acids derived from Undegradable Dietary Protein, ie [DUP]/[UDP] (= dsi of INRA 1988)

t

Net Energy, MJ/d or g/kg

1' , 1

1

Ii

l

I"

1

11,1

III

,

11'1

Proportion of potentially degradable N other than water soluble N in the total N of a feed

11.

Net Energy retained in concepta, MJ/d

BEN

Basal Endogenous Nitrogen, g/kg W0 75/d

tt,

Net Energy retained in growing animal, MJ/d

[BF], B%

Butterfat content of milk, g/kg or % per litre

ti,

Net Energy retained or lost in daily weight change in lactating ruminants, MJ/d

C

Concentrate DM fed, kg/d

c

Fractional rumen degradation rate per hour of the b fraction of feed N with time, t

b

1

I

\1\

I II II', 11)\ 11'1

II li;11

Used

Net Energy secreted as milk, MJ/d

(' I

('(I

Net Energy for maintenance, MJ/d Net Energy for maintenance and production, MJ/d

Correction factors used in the calculation of the ME and MP requirements of ruminants

Net Energy content of concepta at time t, MJ (',

Plane of nutnnon correction factor in calculating ME requirements of lactating ruminants

Net Energy retained as wool or goat fibre, MJ/d

w

\CDM)

Corrected Dry Matter, g/kg in grass silage only

CP, [CP]

Crude Protein, g/d in a diet or g/kgDM in a feed

DE, [DE]

Digestible Energy, MJ/d of a diet or MJ/kgDM in a feed

dg

Extent of degradation of feed nitrogen (or CP) at time, t

DMI, [DM]

Dry Matter, intake, kg/d, or content, g/kg in a feed

Energy Value of tissue lost or gained, MJ/kg

DMTP

Digestible Microbial True Protein, g/d, ie truly absorbed in the intestines (= Metabolisable Protein from microbes)

Energy Value of milk, MJ/kg

Empty-body weight, kg Ether Extract (oil), in feed, g/kgDM

I) p. II ~R 0 P] Effective Rumen Degradable dietary Protein (N x 6.25), which has the potential to be captured by rumen microbes at a rumen digesta outflow rate of r/hour

Exponential function using base e

[DMTP]/[MTP] True absorbability of amino acids from Microbial True Protein

I'

Fasting metabolism, MJ/(kg fasted weight)':"

H

Faeces energy, MJ/d

I·I'

l'roport ion of forage in the diet Dry Matter

DOM, [DOMD] Digestible Organic Matter, kg/din a diet or g/kgDM in a feed dsi

True absorbability of amino acids derived from Undegradable Dietary Protein (UDP) as used in INRA (1988), see dup

II

I

l rr nnnoloy v .uu! SI'I/Ibtll.\ I lSI'"

Terminology and Symbols Used

, I

II,

\"

FME, [FME]

Fermentable ME of a diet, MJ/d or MJ/kgDM in a feed

k'l\l

l-Hicicucy lor wool and fibre growth

GE, [GE]

Gross Energy of a diet, MJ/d or MJ/kgDM in a feed

III

Natural logarithm to base e

HDMI

Hay Dry Matter Intake, kg/head/d

il

I

Intake of dietary ME, MJ/d scaled by fasting metabolism, F

II Ill. I" ';;,

III

[IVD]

in vitro digestibility [DOMD], g/kgDM of a feed

I we;

k

Derived parameter in equation (15) to predict energy retention

M,

ME requirement for growth of concepta, MJ/d

k aai

Efficiency with which a mixture of absorbed amino acids in ideal proportions is used for the net synthesis of protein as tissue, fibre or milk

M,

ME requirement for liveweight gain, MJ/d

M,

ME requirement for liveweight change when lactating, MJ/d

k,

Efficiency of utilisation of ME for growth of the concepta

M;

ME requirement for milk production, MJ/d

k,

Efficiency of utilisation of ME for weight gain

Mill

ME requirement for maintenance, MJ/d

kg

Efficiency of utilisation of ME for weight change when lactating

M

ME requirement for maintenance and production, MJ/d

,II II,'

I

Level of feeding as a multiple of MJ of ME for maintenance

01 1\

Lactose content of milk, g/kg or % per litre

W

Liveweight gain or change,

± g or kg/d

.I

IIIII

II 1

',1

1.

1

11

III

~I

II'

11

II' 1

III

I

II II II I 1 I

k,

km

k, k,

My;

ME requirement for wool or fibre growth, MJ/d

M~

Methane energy, MJ/d

(MAD!'I

Modified Acid Detergent Fibre in feed, g/kgDM

Mc·P.

Microbial Crude Protein supply, g/d or g/kg

Efficiency of utilisation of ME for milk production

Efficiency of utilisation of ME for maintenance

. Efficiency of utilisation of mobilised tissue for lactation Net efficiency of utilisation of absorbed amino acids, = 1 for maintenance and = k..; x RV for other purposes

[Mep]

MID

Metabolisable Energy, MJ/kgDM of a diet, see also [ME] for a feed or diet

ME. IMEI

Metabolisable Energy, MJ/d or MJ/kgDM of a feed or diet, see also MID for a diet

k nb

Efficiency for basal metabolism (BEN)

k nc

Efficiency for growth of concepta (pregnancy)

knd

Efficiency for synthesis of scurf and hair

IMEllO,1

Metabolisable Energy from fat (oil), MJ/kgDM in a feed

k.,

Efficiency for growth

IMErr",,1

Metabolisable Energy from fermentation acids, MJ/kgDM in a fermented or ensiled feed

k ng

Efficiency for gain when lactating MI'\{

Metabolisable Energy requirement, MJ/d

k n,

Efficiency for lactation MI',IMI'I

Metabolisahlc Protein, g/d from a diet or g/kgDM of a Iced

1\11 "

M I'

k nlll

JI, ,

IIl11

Efficiency for maintenance ICl!IIIrt'IlICIiI

for j',rowllt or concept", g/d

__ .a......------------------­

\ \ /I

li'TIIIIIIO!ogV IIlId SVIII"O!S Ils('(!

I," IIIIII"!",!;\' 1111'/ SI'III"O/'l 11,1'-'/

\ \"T

MP r

MP requirement for liveweight gain, g/d

IllMlll

Orgallic Matter Digestibility, g/kg of a diet or feed

MP g

MP requirement for liveweight gain when lactating, g/d

11'1.

Crude Protein content of milk, g/kg or % per litre

MP1

MP requirement for milk production, g/d

I'

Effective degradability of feed N at outflow rate, r/h

MP m

MP requirement for maintenance, g/d

II".

Metabolisability of [GE] at maintenance, [ME]/[GE]

MP w

MP requirement for wool or fibre growth, g/d

1)1 ll'. 11)1>1'1

Quickly Degradable Protein (Nx6.25), g/d of a diet or g/kgDM in a feed

i,l.1

MPR

Metabolisable Protein Requirement, g/d C)IH'/M( 'J>

Limiting efficiency of conversion of QDP to MCP

,ill,]1

MPS

Metabolisable Protein Supply, g/d

I«

Energy retention (E), MJ/d, scaled by fasting metabolism (F)

.llli

MTP, [MTP]

Microbial True Protein, g/d or g/kg

[MTP]/[MCP]

Proportion of Microbial Crude Protein present as True Protein

n

Lactation week number

INal

Ammonia content of silage, g/kg total N

INCDI

Neutral detergent cellulase [DOMD] in a feed, g/kgDM

INCGDj

Neutral detergent cellulase g/kgDM

::11: 1'1

:~ I .

I"~;,

I' 1,1'111

I'll

II

~ I 111

1 •

III 1,,1

,I:

III ,.

1,1

Rumen digesta fractional outflow rate per hour IWP.IIWPI

Rumen Degradable Protein (Nx6.25), g/d in a diet or g/kgDM in a feed, for a given rumen outflow rate, r/h

MV

Relative Value of the amino acid mixture supplied, compared with the ideal amino acid mixture

. II>MI

I1I

I III

+ Gammanase

NP b

'Net Protein equivalent of Basal Endogenous N, g/d

NP c

Net Protein for growth of concepta (pregnancy), g/d

NP d

Net Protein for scurf and hair growth, g/d

NP r

Net Protein accreted in gain, g/d

I 1

'111

1

.1

1

NP g NP I

'II I I

Silage Dry Matter Intake, kg/head/d

[DOMD] in a feed,

IlW, ISDP]

Slowly Degradable Protein (N x 6.25), g/d of a diet or g/kgDM in a feed, for a given outflow rate, r/h

IOP/Mep

Limiting efficiency of conversion of SDP to MCP

tTJ>M I

Toluene Dry Matter content of silage, g/kg

TDMI

Total Dry Matter Intake of a diet, kg/head/d

TI', ITPI

Tissue Protein (ARC 1980) = Net Protein, g/d or g/kg

"

Fraction of total feed N which is completely undegradable

Net Protein accreted or mobilised when lactating, g/d Net Protein secreted in milk, g/d

I/I>P,IUDPI

Undegradable Dietary Protein (N x 6.25), g/d of a diet or g/kgDM in a feed, for a given outflow rate, r/h Urine Energy, MJ/d

NP m

Net Protein for maintenance, g/d

NP w

Net Protein for wool or fibre growth, g/d

III ~

NPN, rNPN]

Non-Protein Nitrogen, g/d of a diet or g/kg in a feed

w"

IODMI

Oven Dry Matter content of the fresh diet or diet, g/kg

w

II

I

~iliJ.

Weight of feed (n) included in a diet, kgDM/d Livcwcight of the animal, kg

\ III'

!i".T/IIT/o!ogy 1/T/11 SYII/hol.\ 11,1'1'11

± g or kg/d

6.W or LWG

Liveweight gain or change,

We

Calf birthweight, kg

Wm

Mature bodyweight of the dam, kg

»,

Liveweight of the animal in week n of lactation, kg

Wo

Total weight of lambs at birth, kg

Y

Yield of milk, kg/d

y

Microbial protein yield in the rumen, gMCP/MJ of FME

Chapter One

I) r inci pies and Concepts

Metabolisable Energy ~" "111' AIH' (1980) ME system is based on a basic relationship between the ;;. Mrillholisahle Energy (ME), intake from a feed or diet and the Net Energy (E) \l11I1~rd or retained in the animal product, both expressed as MJ per day:

E

= ME x k

(1)

WIt,,.,. k is the efficiency of utilisation of ME for the relevant metabolic process. Definition of Metabolisable Energy .Inhol isable Energy (ME) intake is defined by ARC (1980) as the Gross 'I'JI,Y (GE), of the feed less that of the faeces (FE), urine (UE), and mhustible gases (mostly methane, Md, expressed as the SI unit Megajoules of ~ per day (MJ Id) for a diet, or Megajoules per kilogram of feed or diet dry ucr (MJ/kgDM). It represents that portion of the feed energy that can be IIINcd by the animal. ME is defined as: ME = GE - FE - UE - ME

(2)

The

SI unit of energy used, the Megajoule, equal to 1,000 kilojoules (kJ), or I,OOO,OOD joules (J), can be converted to calories, the unit for heat used in PnllK'C, The Netherlands and the USA, by using the exact conversion: 4.184 joules

=

1 calorie

(3)

proport ion of ME in the GE supplied by a diet declines as the level of increases, due to variation in the amounts of energy lost in faeces, .unl IIIcl hanc, ME measurements are defined as being measured at the

AN llll'

rt'rdill/'. (I,), 1111Ill'

11"11 11II" 11:1lilT

.....

level of reeding (L

= I). 1

.'

I I

Chapter

/'/111"1'''''

0111'

Definition of Net Energy

IMI o lthc feed and one based on the '1lIll'hl'oIdl'llill III IIHlI'1 lI'I(IIIII'd 10 11I:IIl'h lill' /IUMI. known as "Protein 11'11'11111' 1111111' 1~1I1111'n", II'IIVI TIll' AHH' (1'1lI.') proposals arc based on the 1,,'II"lllInl 11 l~ l'II~It'1 III ~dl'll "'I'lh 101 hillalll"lIl).'. a dil'l if their IFME], IERDP] 1111,1 111l11'I'Olllt'lIl~ 11111 III' "C'I'II III Iill' II'cd lailks, and that the calculation of M( 'I' '"l'plv I~ uulv vulul 101 U dl!'l, lallil" thnn a slllgic feed. FI(II11I///011 0/ /)/gl',I'II/I',' };'IIt'

AFRC (1992) describes the limiting efficiency of use of an "ideally" balance amino acid mixture (ka.) as an animal characteristic. In practical ruminant diets lower values are achieved, and the term Relative Value (RV), was introduced b AFRC (1992) (equivalent to Biological Value (BV) in non-ruminant animals) t correct for these effects. These depend on particular feeding circumstances, an, on the amino acid balance in the Digestible Undegraded Protein (DUP), relativ to that in the absorbed amino acids of rumen microbial origin, (DMTP). Users of the system can therefore exercise judgement about the values for RV to b applied in different circumstances, depending on data for RV available. From data on limiting efficiencies of "ideal" amino acid utilisation across a wide range of circumstances, AFRC (1992) estimate that k.ai is at least 0.85. They also decided that kaai for the replenishment of basal endogenous losses of N (BEN. maintenance), will in effect be 1.0 under normal feeding circumstances, as this will be an obligatory demand on the available amino acids.

Thus kOOi is 1.0 for maintenance, and 0.85 for all protein synthetic [unctions. Relative Value of absorbed amino acid mixtures (RV) RV will vary according to the mixture of amino acids supplied to the tissues and AFRC (1992) adopted the following values:

Protein supply

1I11\1lnv, l'slllllllll'd Microlunl Crud« Protein supply, corrections are now required tOt'sl iuuuc the amounts of II'/Il' protein (amino acids) that will be absorbed in the lower digestive tract of the animal. This requires estimates of two fractions:

Growth Pregnancy Lactation Wool

RV RV RV RV

0.7 1.0 0.8 0.3

1',1'1II'

lili

lll

I

'jl

1. True protein content of Mep (MTP), is estimated to be 0.75 of MCP by AFRC (1992), compared to 0.80 suggested by ARC (1980;1984). Other authors have suggested values of 0.70 (Madsen 1985),0.75 (CVB 1991), whilst an EAAP Ring Test suggested values nearer 0.7 (Oldham pers.comm).

Working values for efficiency of MP utilisation (k,J By combining values for kaai (1.0 or 0.85 as appropriate) and RV, the following working values for k, are suggested:

111""

'1

I

I11

1 1

11111, 1' 111

1

2. Digestibility of MTP (DMTP), is estimated to be a constant 0.85, as recommended by ARC (1980;1984), also Madsen (1985) and CVB (1991).

I1II

I 111

1I

111111

1I1 I

I"i 1

The amount of DMTP in the estimated MCP supply is therefore:

lill

"'111\11 1

1;1'11,:1

1

1

1

11

1 1

1

III1

I

'I,

DMTP (g/d) = 0.75 x 0.85 x MCP (g/d) = 0.6375MCP

(22)

Maintenance Growth Pregnancy Lactation Wool

k nm k ng knc k n1 k nw

= = = = =

1.00 0.59 0.85 0.68 0.26

'! I II

20

("IIJr"'" ()1I1'

Chapter Two

I

I'I

1

Requirements for Metabolisable Energy

1

111111

',I!IIII!

a

l-a-{bc/lc + rl)

bc/lc+rl

I nop

SOP

uoP

(QUickly Degraded PI

(Slowly Degraded PI

(UnDegraded PI

Oil

1 0

T O.9{UDP· 6.25AOIN} .

I

I

IMI.I",n~ ... MI/,I

J

-~--

"

IO.lUDP/6.25 + ADIN)

111111' . MCI'

III I I 11M I "'M II

I

IMIIIIIIII'llf I')

I

II

It]

O.25MCP/6.25

I MIl' Mil trrlunl "ll" 11rlll1ll1l

I

. I III

I

Nnl Prnt"lfi

~k,,-

or DMTP + DUP

O.15MTP/6.25

~

MP

The methods of calculating the ME requirements of cattle and sheep detailed in this Chapter are essentially those recommended in the ARC (1980) Technical Review, but incorporating changes in energy requirements recommended by the advisory services Working Party on energy requirements (AFRC 1990), who tested the ARC (1980) proposals on suitable experimental databases, Apart from a number of changes in activity allowances, they recommended a bias correction factor (C4) when calculating the ME requirements of growing and fattening cattle. The ME requirements of goats are taken (with permission) from the manuscript of the TCORN Working Party on "Nutrition of Goats". The general equation for the calculation of ME requirements was given in Chapter One: ME (MJ/d) = Elk (16)

For dairy cattle, lactating sheep and goats, this can be extended to:

I-­

IMetabolisable Protein)

I'

II

II

Methods of calculating ME requirements

M mp (MJ/d) = CL{Em/k m + E/kl

I

+

E/kg

+

EJkJ

(17)

(1 - k,1I6.25

where CL is as defined in equation (12) in Chapter One, and the Net Energy values (E) required are defined in the rest of this Chapter.

BEN

(Basal Endogenous N)

I'! 'III 1111!li

Il

Urine N

\I

r:::7l

M mp (MJ/d) = (Em/k) x In{B/(B - R - I)}

IIIIII!I ,III!II ,1 11

1:

,II II:

For growing cattle and sheep, where energy retention (R), is predicted in accordance with the principles outlined in Chapter One, AFRC (1990) give the calculation of ME requirements as:

Fig. 1.6: Flow chart of the Metabolisable Protein system,

(18)

where Em is the slim of the animal's fasting metabolism (F), and the appropriate activity allow.mr« (t\), and B is as defined by equation (14), (values are in Table I. I), whilst k I', dl'lllll'd !Iv ('qll;111I11\ ( I 'i), both givl'n in Chapter One:

,

)

( IIII/IIN I'II'(}

B = km/(km - k.) k =

~

x

In(~/kf)

AtF H"'IIIII "/1/"/11,\

( 11)

The Net Energy content of animal products

(15 )

('lIl1'lIlalloll of the ME requirements of a ruminant animal as specified above, 11I11"II('s Ihat the Net Energy content (E) of the product, milk, meat, foetus or WIIIII [';111 he estimated, in addition to the Net Energy needed for maintenance plIIl'0ses. The proposals of ARC (1980) for Net Energy requirements of cattle 11111 shn~p are used here, and those of AFRC (1993) for the Net Energy "1I"irel11ents of goats, but they are regrouped by metabolic function and then ",..ell's and class of ruminant. No safety margin has been added to the Net "."xv requirement equations listed below, since any safety margin is applied to , calculated ME requirements, as above.

and scaled energy retention (R) is calculated from: E, (MJ/d) = C4(EV g x i:>. W)

(37)

where C4 = 1.15 for bulls and castrated males = 1.10 for heifers = 1.00 for growing lambs, since no correction factor was suggested by AFRC (1990), and then:

R

= Er/Em

(38)

Safety margins

Maintenance requirements e maintenance ME requirements of cattle, sheep and goats, Mm , are given by: M, (MJ/d) = (F

ARC (1980) made no recommendations on the question of safety margins, but MAFF (1976), which recommended the adoption of a simplified ME system, since widely used in practice, included a 5 % safety margin in its tables of ME requirements, without giving any statistical argument in support. AFRC (1990) considered the question on a statistical basis, but gave no firm recommendations on the dimensions of a suitable safety margin. Their views can be summarised:

reduces the proportion of cattle underfed by 10%. This is in addition to the inclusion of a bias correction of 1.15 on calculated energy retentions, as on p786. (The example on p787 has the factor of 1.15 in the wrong position - an error confirmed by the authors of TCORN No.5.) 2. Dairy cattle: On p758 it is stated that ARC 1980 ME requirements are 10% too low on average. Table 6.11 on p758 shows that a 10% margin reduces the proportion underfed by 30 %, whilst a 10 % reduction is achieved with a 3 % safety margin. 3. Pregnant ewes: Table 8.9, p779, shows that a 6% safety margin is needed to reduce underfeeding proportion by 10%. 4. Growing sheep: Table 10.9, p785, states that a 15% addition to ME requirements will be needed to achieve the 10% reduction in underfeeding. No recommendations were made for pregnant cows and lactating sheep, as no suitable databases could be found for testing the ME requirements of ARC (19RO). In the light of the above information, and the current practice of using a 5 % safety margin on ME requirements in MAFF (1976), the Sponsors agreed that a 5% safety margin should be added to the ME requirements calculated in accordance witlt ARC (1980) and AFRC (1990). Accordingly, the Tables of ME rcqu! rcmcnts in the later Chapters include this agreed safetv margin of 5 %.

iIJ

+

Aj/k;

(39)

where F = fasting metabolism and A = activity allowance as defined below,

Fasting metabolism Cattle

1. Beef cattle: Table 5.23, p751, shows that a 5% addition to ME requirement

I

.' I

II

fasting metabolism (F) requirements of cattle are given by ARC (1980) as: F (MJ/d) = C1{0.53(W/1.08)o67}

(40)

where Cl = 1.15 for bulls and 1.0 for other cattle.

e factor of 1.08 converts liveweight (W) to fasted body weight as ARC 19HO), Appendix 3.11. Sheep e fasting metabolism (F) requirements of sheep are given by:

()Vl'I'

I year old

F (MJ/d) = Cl {0.25(W/l.08)o.75}

(41)

F (MJ/d) = C1{0.23(W/1.08)o.75}

(42)

where CI -- 1.15for entire ram lambs and 1.0 for females and castrates.

N

('I",/,It'/ 1'\\'(1

HI

Goats

~lIVl' flO (ahle 101 11,,11,,('(1 rwt-s. As many pregnant and lactating ewes are no housed, AHU' (I')')!)) assumed that a housed ewe would walk only 50 metres

AFRC (1993) give the fasting metabolism (F) of goats as: F (MJld) = 0.315W0 75

stand for 14 hours, ami make 14 positional changes per day: (43) A (kJ/d) = (0.13

No correction from fasted weight to liveweight was made by AFRC (1993) in their recommendation, as other estimates of the maintenance ME requirements of goats agreed with the selected value of 0.315/kgW'·7'.

,I "I ,I

:'[1

Horizontal movement Vertical movement Standing for 24 hours Body position change

AFRC (1990) reduced the activity allowance still further,

A (kJ/d) = (0.13 + 3.75 + 1.56)W = 5.44W

2.6J/kgW/metre 28J1kgW/metre 10kJ/kgW/d 26OJ/kgW

(47)

Activity allowance (MIld) for housed, pregnant ewes is 0.0054W

Dairy cattle AFRC (1990) recommended an increase in the activity allowance (A), for lactating dairy cattle, set at 4.3kJ/kgW by ARC (1980). AFRC (1990) assumed 500 metres walked, 14 hours standing and 9 position changes, giving:

A (kJ/d) = (1.30 + 5.83 + 2.34)W = 9.47W

(46

assuming only 9 hours standing and only 6 positional changes per day:

ARC (1980) gives the additional energy costs of activity as follows:

I

+ 5.83 + 3.64)W = 9.6W

Activity allowance (MIld) for housed, lactating ewes is 0.0096W Pregnant ewes

Activity allowances

I'

2.

U""III/,'/I/,·II!.1

Ewes outdoors ARC (1980) did not specify whether an activity allowance was Included in the ME requirements for outdoor ewes in their Table 3.36, and AFRC (1990) assumed it was 1O.6kJ/kgW, as for lambs kept outdoors in Table 3.31, in their testing of the ARC (1980) model, but made no recommendation on the activity of ewes outdoors. The ARC (1980) value of 10.6 kJ/kgW might comprise walking 1000 metres horizontally, standing for 12 hours and making 12 positional changes daily. Its activity allowance would then be:

A (kJ/d) = (2.6 + 5.0 + 3.1)W = 1O.7W

(48)

(44)

Activity allowance (MIld) for a lowland ewe out-of-doors is 0.0107W Activil) allowance (MIld) for lactating dairy cows is 0.0095W For pregnant, non-lactating dairy cattle, AFRC (1990) recommend an activity allowance of 0.0071 W MIld as for housed beef cattle. Beef cattle AFRC (1990) recommended an increase in activity allowance above that of ARC (1980). AFRC (1990) assumed horizontal movement of 200 metres, 12 hours standing and 6 position changes:

A (kJ/d) = (0.52 + 5.00 + 1.56)W = 7.08W

(45)

Activity allowance (MIld) for beef cattle is 0.0071W

Hill ewes Both the distance walked and the vertical movement would be considerably increased for this class of stock, and the AFRC (1993) figures for goats on good quality range are adopted here, ie 5000 metres walking and 100 metres vertical movement per day, in addition to standing for 12 hours and making 12 positional changes, giving:

A (kJ/d) = (13.0 + 2.8 + 5.0 + 3.I)W = 23.9W

(49)

Activity allowance (MIld) for ewes on hill grazing is O.024W Housed fattening lambs AFRC (1990) recommended a lower activity allowance for housed fattening lambs than the ARC (1980) figure of 1O.6kJ/kgW for lambs out-of-doors, The lamb was assumed to walk only 50 metres, stand for 12 hours lind make 6 positional changes per day:

Sheep A (k.l/d)

Housed ewes ARC (1980) did not specify the amount of activity allowance used in calculating the ME requirements of ewes when they were out-of-doors, and

.. (0 1.1 I 5.0

+

1.56)W

= 6.7W

Activuv 1111""111/1" (.111 d) 1," h.. ,111'11 11I11/'lIillg lamb» is ().l)()(J7W

(50)

20

(·!tllll11'1 /'\1'(1

MF /(1'1/1II{1'1II1'1I1,1'

Goats

Il~Vd (M.I/kg)

Lowland goats AFRC (1993) accept the ARC (1980) estimates of the components of activity allowances for ruminants as applying to goats. They assume that a goat on lowland pasture will walk 3000 metres horizontally, move vertically 100 metres, stand for 12 hours, and make 12 positional changes daily, giving: (51) A (kJ/d) = (7.8 + 2.8 + 5.0 + 3.1)W = 18.7W Activity allowance (MIld) for a lowland goat is O.019W Hill and mountain goats For goats kept on "good quality range", AFRC (1993) increase the distance walked to 5000 metres, and the vertical distance to 100 metres, which with 12 hours standing and 12 positional changes, gives:

A (kJ/d) = (13

+ 2.8 + 5 + 3.1)W

= O.0328IBF] + 0.0025d + 2.2033

Thus the activity allowance (MIld) for goats on hill grazing is O.024W

Requirements for milk Cattle

AFRC (1990) recommend that the energy value of milk, [EVI] , can be predicted

with adequate precision by using one of the equations of Tyrell & Reid (1965):

Failing information on the butterfat content, [BF], of ewe's milk, a weighted mean value of 70g/kg butterfat can be used, giving a range of values for [EVI] of 4.5 rising to 4.7MJ/kg milk over the ewe's lactation. Sebek & Everts (1992), working with meat producing breeds of sheep, derived an equation for the [EV,] of such ewes' milk based on the fat, protein lind lactose content determined by NIR machine calibrated on cow's milk: [EV,] (MJ/kg)

= 0.04194[BF] + 0.01585[P] + 0.2141[La]

2

The adjusted r value was 0.99 and the residual standard deviation

Anglo-Nubian

M, (MJ/d)

= (Y x

3.355)/lG

(59)

Saanen/Toggenburg

M, (MJ/d)

= (Y x

2.835)/lG

(60)

[EVa (MJ/kg)

= 0.0376[BF] + 0.0209[P] + 0.948

(54)

Requirements for growth

[EVa (MJ/kg)

= 0.0406[BF] +

(55)

Cattle

(53)

where [EF] is butterfat, [Pi is Crude Protein and [La] is lactose content, glkg.

The standard errors of estimate of the equations were ± 0.035,0.066 and 0.089. The ME required for lactation, MI , is then calculated from: M, (MJ/d)

= (Y x

[EV,D/k,

(56)

where Y is the milk yield in kgld. Sheep

AFRC (1990) recommends the use of the equation of Brett et al. (1972) for the (FVII. of ewes' milk:

prediction of till' energy value,

± 0.09MJ.

The Report of the TCORN Working Party on the "Nutrition of Goats" (AFRC 1993) gives the energy content of milk, [EVa, from two breeds of goats, the Anglo-Nubian and the Saanen/Toggenburg as 3.355 and 2.835MJ/kg milk respectively. The equations of Tyrell & Reid (1965) can be used if the butterfat, protein or lactose contents of the milk are known, as for dairy cattle. The M, requirement for lactation of these breeds is therefore:

= 0.0384[BF] + 0.0223[P] + 0.0199[La]

1.509

(58)

Goats

[EV,] (MJ/kg)

- 0.108

(57)

where d is the number of days of lactation of the ewe.

(52)

= 23.9W

27

ARC (1980), p148, gives a quadratic equation to predict the energy value, [EVg], of weight gains of cattle, for castrates of medium-sized breeds as follows:

C2(4.1

+ 0.0332W - 0.000009W2)

[EVg] (MJ/kg)

(61) (1 - C3 x 0.1475"W)

where C3 = 1 when plane of nutrition. L, > 1 and = 0 when L < 1, C2 corrects for mature body size and sex of the animal. in accordance with the values given in Table 2.1. AJilH' tl')')()),

1,l1d,- " 11, SII)',",esled a breed classification into early,

uu-dium .uu l 1.,1 values in kg are given in Table 2.3.

11Irlllwl~llJlll

11I1IIn 7.:1: C.lIl

.'t~

hllUIV

.' J

"flU' "

l'".,,".V I ••' IIhwllllll

I I

Bmml

'tll',',I'X

I 1111111 """ 1,ICI°oldll

I I

• ,"11111 II"VIIII

AVllhlt.

: ;1111"1""1 ill

D.vpu

II, II,

(;111IIIIIIII~;

H.,.h" II

III

111I1!;1l~1I1

I III Ii "I" 11nll

II

II

Triplet

3.3 3.9 4.5 5.0 5.5 6.0

5.4 6.4 7.3 8.2 9.0 9.8

6.3 7.5 8.7 9.7 10.8 11.8

(kq) as affected by dam's breed.

III1'hw"'lI h'

.11 lI"tI

Twin

(72)

where Wm is the mature bodyweight of the dam.

I

Single

Goats

Birthweight

AFRC (1993) calculated the daily deposition of energy in the gravid foetus of dairy and fibre goats carrying twins or triplets, using equations derived for sheep (Robinson et al. 1977). The mean weights of the kids at birth were taken as 3.95kg each for twins and 3.65kg each for triplets of dairy goats, and 2.75kg each for twins and 2.25kg each for triplets of Cashmere goats. The ARC (1980) equations for ewes, (73) and (74) above, are used in calculating the ME requirements of pregnant goats, as they give similar results to those of Robinson et at. (1977), using total weight of kids instead of total weight of lambs.

37 39 39 43 44 44 45

,

1

')11

Sheep

Allowances for liveweight change in lactating ruminants

AIH' ()lJHO), pH, gives the total energy content at time t (I;, MJ), for the gravid foetus in pregnant sheep for a 4kg lamb as:

Cows

1'1'

1 1111 1I1

10glO(Et) = 3.322 -

4,97ge~,00643t

(73)

, :111 1 111 1

11,111111111

AFRC (1990) then calculate the daily energy retention, Ee, as follows:

I

I I 1

I

Ee, MJ/d = 0.25Wo(E, x O,07372e~,00643t )

(74)

111I1I1111

1"1,1,11

Ill

i

where t is number of days from conception, and Wo is the total weight of lambs at birth in kg. Total lamb birthweights for ewes of different bodyweight are given in Table 2.4, using the equations of Donald & Russell (1970), adopted by AFRC (1990) .

...",~I

ARC (1980), p38, adopted a value of 26MJ/kg empty-body weight gain for lactating cattle, equivalent to 26/1.09 = 23. 85MJ/kg liveweight gain (ARC 1980, p42), but this was the same as that adopted for adult sheep, because of the wide variation at that time in published estimates for dairy cattle energy values. Recent work based on the serial slaughter and carcass analysis of lactating Holstein/Friesian dairy cows has now been published by Gibb et at. (1992), who report mean net energy values [EVg] of 17.3MJ/kg liveweight loss and 20.9MJ/kg liveweight gain, with an overall mean of 19.3MJ/kg liveweight change. A value of 19MJ/kg liveweight change has been adopted here:

/EVJ [or livcwcight change in lactating cows - 19MJ/kg

(75)

.i2

t haptrr Two

For liveweight loss in cows, ARC (1980), p94, specifies that mobilised body reserves can be utilised with an efficiency (k.) of 0.84 for the synthesis of milk. Thus:

ME from liveweight loss in lactating cows = (19 X 0.84)1k( MJlkg

(76)

Chapter Three

Requirements for Metabolisable Protein

For a dietary energy concentration (MID) of 11.5MJ/kgDM (qm = 0.61), k, is 0.634, so equation (76) gives a value of 25 .2MJ of ME per kg liveweight loss.

Ewes ARC (1980), p24, recommend that the energy content of empty-body weight change for sheep should be taken as 26MJlkg, so correcting by 1.09 to convert to liveweight gain or loss:

= 23.85MJlkg

(77)

Method of calculating MP requirements

ME from liveweight loss in lactating ewes = (23.85 x 0.84)1k[ Ml/kg

(78)

Due to the factorial nature of the AFRC (1992) system for the calculation of the total MP requirement of ruminants, the requirement for each relevant metabolic function is calculated separately and then these are summed. These total MP requirements are independent of dietary energy and protein concentrations and plane of nutrition, which affect MP supply, not requirement. The proposals of ARC (1980) concerning the Tissue Protein, [TPj, ie Net Protein, [NPj, contents of animal tissues and secretions are relied upon, with only minor exceptions. The calculation of the Metabolisable Protein Requirements (MPR) is given by:

[EVJ for liveweight gain in lactating ewes

For a dietary energy concentration (MID) of 11.5MJ/kgDM (qm = 0.61), k, is 0.634, so equation (78) gives a value of 31.6MJ of ME per kg liveweight loss.

Goats AFRC (1994), having reviewed the published data, decided to adopt the ARC (1980) value of 23.9MJ/kg liveweight change for the EVg of lactating ewes for lactating dairy goats. Equations (77) and (78) for lactating ewes are therefore also to be used for Iactating dairy goats. A nominalliveweight loss of 1 kg/week for the first month of lactation, as suggested by INRA (1988), is also adopted.

ME requirement of lactating goats are reduced by 4.6MJ/d in the first 4 weeks.

MPR (g/d) = NPb/k nb

+

if NPg >

+

NPdlk nd

+

NP/knl

+

NP/k nc

+

NP/knf

NPglk ng+ NPw/knw

(79)

0, and where:

NPb

=

NP d

= 6.25

6.25 x BEN (g/d) where BEN X

= 0.35Wo.75

(g/d) (as ARC 1984)

0.018Wo. 75 (g/d) (as ARC 1980)

NP1 = Milk yield (kg/d) x milk true protein content (g/kg) (kg/d) x protein in gain (g/kg) (as ARC 1980)

NPf =

b.W

NPg =

b.W

NP,

protein gain in foetus and gravid uterus (g/d) (as ARC 1980)

NI'"

() K \ """I ,'Iowlh (I'./d) (as ARC 19RO)

(kg/d) x protein in liveweight change (g/kg) of lactating ruminants (as AFRC 1992)

!1 /.J

I

II

Note: When there is liveweight loss, and NPg is negative, then the term NP/k nK becomes NPg , since the efficiency of mobilisation is assumed in the system to be J. 0, so that in this case, NPg = MPg , retaining the negative sign.

III

Safety margin

('OIlWr! ing to

Crude Protein by the factor of 6.25, and allowing for H'ljulrement for basal maintenance (MP b) is: MP b (g/d)

=

k.b =

6.25 x 0.35Wo.75/1.00 = 2.1875Wo.75

jiil· III

An agreed safety margin of 5 % has been used in calculating all the summated Metabolisable Protein requirements tabulated in later Chapters, but the calculations given below are without this additional 5%.

:1 1II1

II II' 1

il .

Cattle and goats

MP d (g/d)

Cattle and goats The maintenance NP requirements of cattle and goats, NP ms are the sum of their Basal Endogenous Nitrogen (BEN or NPb) needs plus dermal losses as scurf and hair (NP d) : (80) NP m (g/d) = NPb + NPd

11.

Illi

= 6.25 x 0.018WO·75/1.00 = 0.1125WO· 75

II

The efficiency of utilisation of absorbed amino acids for milk protein synthesis (k n,) has been specified as 0.68, so that:

As knm = 1.0, equation (80) can be converted to MP m requirements: MP\ (g/kg milk) = (True protein content of milk)/0.68 MP m (g/d) = MP b

+

MP d = 2.30WO.

75

(81)

II',

I,

):

II

I 'II

(87)

where MPb and MPd are defined by equations (85) and (86) below. Cattle Ewes

11'1:1

illill

(86)

Requirements for milk

or 1.471 x (True protein content of milk)

I

(85)

An allowance for dermal losses of protein as scurf and hair (MPd) should be Included, where k.d = 1.00:

Maintenance requirements

II

!!

1.00,

Dermal losses as scurf and hair

1:1

I

35

MI'RI'l(u;r('II/('1IIS

CI/II{I/t'f Tllr/'/'

Wool growth in 'ewes is regarded as part of their maintenance requirement for MP (see equation 89), so that: MP m (g/d) = MP b

+ MP w

= 2.1875WO· 75

+ 2004

The Crude Protein content of milk is reported by MMB laboratories as percent per litre of milk (P%), which contains about 0.95 true protein. The mean density of milk is 1.03kg per litre, so that for a milk crude protein of P% per litre: MP J (g/kg milk)

(82)

=

(1.471 x P% x 10 x 0.95)/1.03 = 13.57P%

(88)

Growing lambs

Sheep

ARC (1980) suggest that wool growth in lambs is proportional to their rate of liveweight gain, and no allowance for scurf and hair losses is made. Therefore the maintenance MP for lambs is:

ARC (1980), p47, recommends a value of 7.66g true protein N/kg of ewe's milk, equivalent to 7.66 x 6.38 = 48.9g true protein/kg milk, which gives: MP j (g/kg milk)

MPm(g/d) = 2.1875WO·75

=

1.471 x 48.9

= 71.9

(89)

(83) Goats

Basal Endogenous Nitrogen ARC (1980) did not deal with the nutrient requirements of goats, but INRA The Basal Endogenous Nitrogen (BEN) requirements of cattle, sheep and goats are the renamed Total Endogenous N (TEN) recommendations of ARC (1984): I

.J

BEN (gN/d) = 0.35W0 75

(1988), p176, quotes the true protein content of goats' milk as 29g/kg. The

Report of the TCORN Working Party on the "Nutrition of Goats" (AFRC 1993) the Crude Protein content of milk from two breeds of goats, the Anglo­ Nubian and the Saanell/Toggenhurg, as 16 and 29g/kg respectively Morant

~ives

(R4)

MI'

Chapter Three

{(,

Sheep

tpers.commi found that the true protein fraction of goats' milk averaged 0.9 of the Crude Protein content, so that the MP, requirement is therefore:

Anglo-Nubian

MP 1 (g/kg milk)

= 1.471

SaanenlToggenburg

MP 1 (g/kg milk)

=

x 36 x 0.9

1.471 x 29 x 0.9

= 47.7 (90)

AIH' (llJHO), p149, gives two equations to predict the protein retention in fleece tree livewcight gain (NP r), namely:

=

Malt'S, castrates

NP r (g/d)

=

b.W(160.4 - 1.22W

+ 0.0105WZ)

(94)

Females

NPr(g/d)

=

b.W(156.1-1.94W

+ 0.0173WZ)

(95)

38.4

(91)

Requirements for growth

where l

/48

Appendix /I

Degradability parameters a

=

c Grass silage [FMEl

= 0.06

List of Equations

+ 0.61 x buffer solubility

(147)

Beef cattle

a+b+u=1

(14R)

SDMI (kg/d)

rea - dgs)/(dgs' a - b)

(149)

W075(24.96 - 539.7C + 0.108[TDM] - 0.0264Na + 0.0458[DOMDDI1000 (163)

[FME] (MJ/kgDM) = 0.90[ME] - [MEfaJ

Brewery byproducts

/49

[FME] (MJ/kgDM)

= 0.95[ME]

- [MEfaJ

(150)

=

coarse diets TDMI (g/kgWo. 75)

(151)

TDMI (g/kgW0 75)

fine diets

=

24.1 + 106.5qm + 0.37C%

(164)

=

116.8 - 46.6qm

(165)

Grass silage [FMEl only Lactation curve for suckler cows Y (kg/d) [FME] (MJ/kgDM)

=

[ME](OA67 + 0.00136[ODM] - 0.00000115[ODM]2) (152)

Cattle: prediction of gain '"W (kg/d) = E/(X + 0.1475Eg)

= C2(4.1 +

Dry matter intake

(153)

O.0332W - O.OOOOO9W2) taken from equation (61)

DMI (kg/d) = MER/(M/D)

Dairy cattle DMI (kg/d) = 0.076 + OA04C + O.013W - 0.129n + 4. 12IoglO(n) + O.14Y

(154)

8.0nO. 121 x e-ll· OO48n

(166)

Dry matter intake: Pregnant ewes, hay HDMI (kg/d)

where X

=

silage

=

C(1.9 - 0.076T - 0.002033[DOMDJ) + 0.0024441 DOMDI - 0.09565LS + 0.01891Ws - 1.44 (167)

I (g/kgW)

=

SDMI (kg/d)

0.202[DOMD] - 0.0905W - 0.0273N a + 11.62

= 0.00IW{0.946xI - 0.204(C x I)

+ 0.569}

(lhR) ( 1(9)

(155) Lactating ewes, hay

SDMI (kg/d)

=

-3.74 - 0.387C + 1.486(F+P) + 0.0066Wn + 0.0136[DOMDI (156)

.

SDMI (kg/d)

=

75) I (g/kgWo.

= 0.103[DM]

SDMI (kg/d)

=

TDMI (kg/d)

-3.74 - 0.387C + 0.1055Y + 0.0066Wn + 0.0136[DOMD] (157) + 0.0516[DOMD]- 0.05Na + 45

=

O.OOIW{I - 0.0691(1 xC) + 2.027C}

(170)

I (g/kgW) = 0.0481[DOMD] - 5.25

(171)

TDMI (kg/d) = 0.028W

(172)

(158)

= 0.00IW{0.946 x I - 0.0204(1 x C)

silage TDMI (kg/d)

(1.068xI - 0.00247(IxC) - 0.00337C 2 _ 1O.9)Wo.75/1000 + 0.00175y2 (159)

I (g/kgW)

=

+ 0.65 + C} (173)

0.0232[DOMD] - 0.1041W - 0.0314Na + 13.36

Lactation curve for dairy cattle

TDMI (kg/d) = 0.026W

(174)

(175)

Lambs, coarse diets Y (kg/d)

= exp{a

- btl(1 + ktl) + ctl 2 + d/t}

(160) TDMI (kg/d)

Y (kg/d)

= exp{3.25

- 0.5tl(1 + 0.39tl) - 0.86/t}

Dry matter intake: Pregnant cattle

TDMI (kg/d) = {I50.3 - 78qm - OA08W}WO·7511000

Lambs, silage only =

{0.000311IfDOMD]-0.00478C-0.lI02}W17;

{I04.7qm + 0.307W - 15.0}Wo.7511000

(176)

(161) fine diets

SDMI(kg/d)

=

(I()ll

SDMI (kg/d)

=

0.046W0 75

(177)

(178)

/50

11/1/1I'1Ic!1.I /I

Subject Index

Lactating goats DMI (g/d) = 423.2Y DMI (kg/d) = 0.42Y

+ 27.8EBWo 75 +

440AW

+ O.024Wo. 75 + O.4AW +

DMI (kg/d) = 0.062W0 75

+

6.75F%

0.7Fp

+ 0.0305Y

(17'») (lXO) (I X1.1

Lactation curve for goats Y (kg/d) = 3.47exp{-0.618(l

+

t1/2)t1 - 0.0707t1 2

-

1.0lt}

(IX2)

Dry matter intake:

Adult goats

DMI (kg/d) = {l30.9qm

Pregnant goats

+

DMI (kg/d) = 0.53

0.384W ­ 18.75}Wo.75/1000

( 181)

+ 0.0135W

(184 )

Acetic acid, gross energy 48 Acid Detergent Insoluble Nitrogen 14,47,48 Activity allowances 24 body position change of 24 cattle beef, housed 24 dairy, housed 24 pregnant 24 goats hill and mountain 26 lowland 26 horizontal movement of 24 sheep lactating, housed 25 outdoors 25 pregnant 25 hill ewes, grazing 25 standing 24 vertical movement 24 Amino acids, utilisation of 19 Ammonia content of silage 60,78,93 Basal Endogenous Nitrogen, cattle, goats and sheep 34 Beef cattle 73-90 castrates activity allowance 24 calf hirthweights 30 dLTII\;d losses \.') !I 1('1 n.lllll.k·, X I. X.'

Dry Matter intake 7X Energy Value or gains

n

breed effects 27 energy rctcntion

bias correction 22 fasting metabolism 23 ME requirements 74-75 MP requirements 74-75 Net Protein in gains 36 breed effects 36

females see Heifers

males, intact see Bulls

Net Protein in gains 36

breed corrections 36 Bias correction factor, cattle 22 Birth weights of calves 30

goat kids 31

lambs 30, 31

Body position change, energy cost 24 Body weight empty 31,32,38,39,40, 109 conversion to liveweight 31 fasted 22 conversion to liveweight 23 mature 30 Breed classification, beef cattle 28 Breed corrections beef cattle 28

goats 27, 29, 35, 38

growing lambs 100

1\,'

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