cor'-"eet oospi te the formula error.

llilpootod

Roduction

i."l ?erccnto.u--o

&.lz'rennees per Goooro.tion fi'om

Cul.l.ine those f.i?Jes FniJ.ine to kd.

50

2.75

/1)

2.11

30

1.Z..7

20

o.B3

10

0.29

5

o.O')

T10ao i"lrr...ll'os da:lonatr-ltc

sane

of tho conclusions roac!l.Ou

tv Dcq>ster

und I.crnor

( 1950)

�t "Mass aelootion f'or e. ��tcr of

hieh

inoi<loooo

(or

aca.inet one of 1«7

incidence)

loa& to

sliaht (;ain5 only.

'l'h:l.s ie &lo to wry lOt1 ei'.footiw

rurlt;.:�billv ,

cOI!lbinod mth the fu.ct tbnt

aal.ootion intonaitq is

also

perf'<woe

log. For intcrz:lediote incidence

tbe gains

_obteined 81"0

rolotively hiGh,

but

further e..'Uft

of iDcickmce does not prodme

Clleh greater

ca1na, because the

c1ec1'ea8e in efiecti ve

heri t.£1!)111 v

offsets

ancl even

tuall.y overcomes

tbe increase in aelect1on 1Dte.!lGi

v

cm

this Ghitt. n

eel

� aoleotloa to 11810•

ddlc

in

tea\ to loner the

eot1GD ... �.

pa.rticul.ar]¥

On Uw lnsis

of similar

as:Jllq)tions ond

reasoning

the curpeotA par o:;oorution

in

tbe lcwl

o£ tm.nrrl..nc

� be

calcula.tod•

fnr the c...-:.re t'2hen

onJa

tbose Blli.mDla

p1"'ducinc

tm.ns o.t a

Given lacbin{:

are rota.inod. f'roo

CIOOJUSt

thooo ewes ttJdoh

l: I::lbed.

�so ore

:.;tvon

in ':nble

2.5

a..tld ora prcaonted in p�e�nco

to tboso of

Ch'anc

(195.5)

aa the lc.ttor cppocr to be

in ers:"'re

fuq:lootou

Ga..i.n in

Pereo.'"ltnGO of ':d.nnin._;

EfJOB par Gcnen:.tion froo &:!.vi� thooo 2-"'lt;on

?roducin�

'.:.bina.

5

10

2.00

20

Doe to the �

in

dtlch the data haw boon cl.e.astn.ed and the �

the

e:apectod sa1na ooJ.c-,_.lated•

tbc at!!Ul teneoua

omsidorat:l.on of the 1Dcidence

of

bd.n b.1rtbs and the inaidsnce of

barl"ameae

ctm bo used to �o the o'lerall

bean choaen to 11.1.a8trate

the t;da 1a

la."rlb!Jte

at birth •

aelAaot:lon of tld.ll �

<Dl8 1'l'I:D

&lDOJI68t all

present at

a

the ild:tlal

podttaft

_{ft1pl'OaleatAMl �}

0.

' lnel et barren

to a

lamb� poreon�c

at

birth o£ 96r···•

'1be

expected gains

per c

givoo

in Tnbles 22 and

23

l!YJieo.tc that in t.lte

oft'spt'i.n6 t:,'O!lerO.tion

iooidence of' barl:'enness \1i.ll be

o.8.3.

lass , mile :-!t tbe

sa.oe t1oo

2.5:t·

tlClrE) of the cmes

lm::bi.l\:;

uil1 p�e

t-::tns.

�s

corresponds

to a

lanbin(;

percentc�.::c

o£

just

unlcr

99,

.::;nd represents a

t,cin of

a bout

.3 L:lrbs lx•::n

p.-

100

ovos present

ut k!"Jbint;.

It r..'1ll3t be 6q?hesiooa.. llorJ-ewr, fJLt t..lrls ro='..!.':plo ::md tho

f'ic-Lii'Os

presented

in ?eblos 22. and 23 ore and

apply only

to the c�

t'lhero cl1 coos oi' <.1.

civo..'l

l::::J.b:ll\ ; at-..:..t-..13 .:;roup m� rot .inod

for brco�.

Furtha..�, tJm uothoC.. of culcuJ.L:.til'ltj c�.ootod cnina req·rl..Y"Os Q.Il osti."".ete

of

horit:lrlliiv'

on �om

lWPothcticCJJ

o.;ale.

�stor

�ld !�-·nor

(19:;£>)

!.uvo Ca-Jonstr��tc..td the orror:J involved in

ooti:::.:_�tin:; .;::i.!Ul on the b�.sis of' visible cc.�c hor:it.:cbilitioa fu_ U1o e2.se

of ch:::.rc.£tcrs

f:Jlliflt.

· L'1to tr: .

r::ntu:.:l.zy

a.�L:si ve cL:lsses. Fur both the cc.sce tmen cl..l in the desired clc..ss el�e selootoo. and r;hcn a.

proporti.on of

indiviiliKJ.l.a in the undosiroll ck.sn rust 2l.so be

rot..!.inccl•

tbt!q point

out

t.t-u.;.t only

Otcl.1 dis.orepancles

exi3t betvnm

t1w acttcl :md

the expected cn.i.ns uh�

tho solect1on intcnBi 1:\f is low.

ond

cspccj.� Phere

the incidence of

tbe ohorooter i.s neDr

SO,

o.nd the addi ti:vo hcri Ui.li

1w on

the untler

�

sccle is srnn.

The �t ot the incidence ot

l:Janoenneu, trr!m11ng,

aelection

intenait3,

ancl aeaetic

Geale pccu.llarit:ies . on

the

gldne to be a�pootea frcD aeleotloa

011

subsequent

lii"otizro roprodueti ve porforrKnco •

tht� the

ooleotion of ilan'On l:tros

(

t1, X

100)

.,.

)

(r

x

100)

s 1'lock I ��'-'*tS� ...

25

55

;;() 1 0

1.:0

50

e..�it an a� of nud>or

laobs bom

per ewe of x, y and z

rospoctivoly,

n.t OOI!J8 rubsoquent

laob:inc,

o.nd thet the flock a.� in the same _yeur is

i.

'lben, lattln,a '\ represent

t.bo

aubOf)(flont

lamb

produotlon cU.!':ferance between

x

=

(y - x)

=

'

(a - 7)

=

tt

(s - z)

=

1t,

+ tt

•• •

Y =

(x

+

\)

+ +

100

=

la.Z

+ I8.;, +

�rs

=

:In.:

₊

I8(x

₊

1;,)

₊

:t.r<x

*

te,

₊

tt)

= x + I8.tb +

:r,.c�

_+-

tt>

.•. <�i)

•

-I8� - �(�

+

tt)

• • • • • •

• • • •

(1 )

(y -.i)

and

(: - i )

• • • • • • • • • •

(2)

• • • • • • • • • •

(3)

1..ett:in6 Bn• ss•

ADd

s..r

represent the

proportion

of tho

be.rt"en. sinc.lo­

bouring.

and

tr�

eros retu.ined tor t\!rtbcr

broedin.':; roapcctiwJ.¥

• c.nd

aosumi.ng

that

twJ.n-boa.ri.ns

ewes ore retnined in

proferenee

to

sine;le­

�

ewes.

1!ihleh 1D turn

are more clesirnble then barren ems.

the fb�

�

these

four i'omuloo the

�octod. t;ainD to�

diffo..."'Cnt lovolo of

cullin.u•

u...lild for v-....r-.L..�tiona in

1;,

und tt have been calculD.tod, ror t'locl:a I a..'1d

II.

b ooobino.tion� oonaiclo:rod nro =

�

Gc..oo a.

0.14-

(;coo

b.

o.oo

In document A study of some aspects of selection for the fertility of New Zealand Romney ewes : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science (Page 93-98)