Fall - Auburn University Repository

J. R. HOWES, Dept. of Poultry Science
WALTER GRUB and C. A. ROLLO,
Dept of Ag~ricultural Etigifeering
Call wXith statndt Sevecit st tiine 1cl i)cl itiot is
bectteri that) mrost othiei aliials. TIie
tcamelt's hbeat to~lerance has1 lbec'tt kioxx i
ftti a long tunle, buit olnix i ccelntlv has
tI is ciharacteistAic of the chicken 1becn
learnied.
Sitin iner strie(ss is a tet ii ctined to dIi
scibei thle sti ess to wxh ichlilan atll' inv
expttsed duinPg suimmet. It r epreseit,
total (dis1ruptiotn inl lil aitnals norioal
we lilceing caused'( i~x heait. huidiitx
light radliatitnt and othter factoirs.
Pt tit Il tl are I)CCom-ing' ineasittglx
axi at of itt Ie en xi ott met t inl their ciftorts
to ccot il inicalix, pitodiuce eggs at t (
neat. This is cevidettced Ixv the itncreasing
number 1ic of iiit tttihle(i enirionmet
hoitses ht'iig constiructedi.
One reasoin the Soittheastern Ultiftcd
States is not at leatit ig eggu-pt iditctittn
area is bccattse of diffhcuitx etncoutitered
inl e tntt in icalv ixfroditciir nf0C t(h~diialitx
eggs duiriing the ltong, liot and humid
sit inn er ti 't' v patrts of the i atioti cxper
ience hecat stress inl short periods
xxhein temitperatture (roes xxell oxe c 1000)
F'. WheItn this happens, it is itot wicommutt1
fotr hundreds of ibirdis to (lie as a
resl t of the sudden fiiiflux of ii ttei t x
65
60
55
So2l 4 5
e
90*F
The graphs show effect of high temperature
on laying White Leghorn pullets in Auburn
experiments. There were 80 birds to each
treatment, all on 14 hours light daily and
6000 relative humidity and ventilated at 1
cu. ft. per minute per bird.
VH MER STRES
aL1"NG POULTR
cxpierieinced inl the Southeast. btut thi's
airea i s liietd xwithi suniiflei sttress
th at uisiaaliy h ists foI r sexveral m1oit tIs.
The first lpritlit is ttt i(Iet tifx, the
niin stress factors. TIhis is lieesxarx
to ectulitttticatllx comibat the situiation ilt(]
ibitdics -iiicrutsedt'l icit lotsses antirc
diilced hecat proi t ctit U in th l li d vlx. To
step-n i heat lisses, respira ~t iuon is ittcreased
I panttitg ), lood stiilY ini tile
skini is incireased. xxitigs are( flexed, and
thle birds dlrink ire xxalter. Ruedutced
h1eat pitodluct ion r esutlts frit it retiu ced
prtoduce env'ironmnle ts iargex' free of thle
factors that redtuce egg pirtduictiiin.
Frtont wotrk at AXnhurit anid elsewhere,
i .t appears that hiimiditx reduces egg
prducrtiont and grtx l u~x at tile highlest
tempileratur es. lThis, humidity protlabl
s is otie otf thle lesser evils.
Ptreviotuis reseatrch has sihowxni tat
chaniges itt day ienigthi stimuliate egg produtetioit
antd gruixxth. Sinice chaniges inl
dax' length duiritig Ma "v tot Au gust are
reiatixe 'lx small, patrt of tie aitx erse still)
iner effects mnight he blamied onl lack of
chanige inl dav ienigtht. Ilt xxexer, the extetidcd
1 icrimtd of high termperaturte (at
leatst 4 niionths ) xx iulci appeair to he the
main cause of suimmer stiress iii tfhe Soithelist.
Phx sitl ogists itt D~uke Uiixersitx haxve
actixvity', afppetite, grit lt egg proitti
ttiiit. egg size, aid t~ertilitx.
Effect of high temper atiures tnt egg
xwei ght andii egg fprtodu ictPit is iiliust rated
bx thle graiph. Thetse datai sltixx that
WXh ite Leghoin plicts 1 produ1ce tx a Ii,
(plate goiod eggs at 80) F. It xx:is alsot
ftttitid that these hit os pi tdlice its xxel
at 80) F. ats it .50-60t) F. '[hiis is cotj
trat x tt earlier, limited oiitrk elsexxhere
that sihoxwed 5t0 (0tt F. its the btest tein
petl re for layinitg p~lltl i It.
USD)A xwork hast inidicated that birdis
xwill itot suiti vxe att 100 Ft . atd 6I0%t' relatixve
hittuidits . lliixxei r, ill Aithititi stitdiis
fenliaies nott oitti ixedl under thiese
condtcitiions hut proiduicetd eggs. Slttxx ii
it) the photogiap )l iret liay'is pating ill
cxrevele h imx catmels atre alct to slit x x
ill ilitel ise deseirt lIctat. O il ottf the ilhaiti
mlechailttills pe~rmittinig suitvxal is thle
Based ott the Aitinit ri eseartch resulits,
Ilarge ratnge iii bod 'iv t ciii utratu ite lietxxctt
iiidax atid mitight ( 18-9;3
F.) . Thie camtel is alte to "load" heat
durinig thle (lax anid "uniloa.d" it difntg
the cooiler ntight.
Atubuiirn research in dicates that thle
thicketi potssesses the satiie ltlilitx a is thic
cal.d bu t to at nite lIiIesser diegree.
Thits. chickenis call suiit ic andi prtidtce
iti11IIh hetter if hot datxs ate reliexved b\x
cooul itiglits thlt tlidter conitiinuouis high
temperatures.
Whlt exposed to heat, thicre aic( txx I
actiions that hell) chicketix intitttaiit thetir
col leter] titig heat "tress. inl pultryx itit
heed lex isitig. Especiatllx, ftrint the stitndtpioint
ot ft(e Soiutheatst. results ilioicteo
tha~t lain lg Wh'lite LeglLorti putllets xxill
adtl t~el) \prdutce P xx liii thett telitp)raitorIe
is als high ats 80'- F. Sitce It nalt
nott (eetinlg himtself ill lcix xwxirik lit.
gills to) perspirte at abilitt F., the
piultrx tnait catn seixve its his oxx] it territtiltem.
Whl the itpinattit ht'gii s tio
feel iitit'tiifoit,itc lit' call ainciif his
htells art likesc n fifected. This xxoiuldi
Ibe his signalt to tatke pra ~ctical steps.
illix iatt high tettiptt ,titt s.