KHOA HQC
C 6 N G N G H |AIMH HUOIMG CUA !\IHIET DO, AlVI DO TROIXIG CHUOIMG KiiM THOIVIG GIO LEM IXIAIXIG S U A T ,
SliXIH TRUOIXIG CUA GA R O S S 3 0 8
Luu Htru MdnhS Nguyin Thi TTianh Giang^, Nguyin Thanh Phi Long^, Nguyin Nhtrt Xudn DungS Pham Ngpc D\i\ Dd V6 Anh Khoa^
T6MTAT
Miic ti€u ctia d l tdi nham khao sat va phdn tich sir anh hudng ctia nhifet dp va am dp I6n nang suat sinh trudng va ti€u tdn thtrc an ctia ga thit gidng Ross 308. Thi nghidm dupc bd tri hodn toan nglu nhifen frfen 3 day chudng nuoi gd cdng nghidp dupc thilt k l theo kilu chudng kin thong gid, mdi day chuong co 3 dpt nudi gd thit frong 42 ngay tirong ting vdi 3 ldn lap lai. Kit qua thi nhi^m cho thdy nhi^t dd cd tuong quan rat chat che vdi tang frpng ctia gd (RM,93) va tifeu tdn thue an (R'= 0,81), frong khi dm d$ co moi tuong quan kha cao vdi hai chi ti6u nay (R''=0,71 vd R^=0,77) qua cdc tudn nuoi. Nhin chung, st; kit hpp eda ca hai ylu td nhiet dd vd dm dp cd quan h$ cao vdi tieu tdn thtic Sn (RM,88). Nhi$t dO vd dm dd chudng nu6i cao CO anh hudng din tang trudng va tieu tdn thtic an cua gd thit. Vi thi. hai ylu td nay can dupc kilm soat chat che. dam bao tinh dn dinh theo tieu chuan trong sudt giai doan nudi duong nham nang cao hon nua hi^u qua san xuat ciia ga thjt gidng Ross 308.
Tirkh6a: NhiStdd, im dd, tang trong, tidu ton thiic an, chudng kin thong gio.
LDATVANDE
Hinh thtic chdn nudi gia cdm ciia Vilt Nam trong nhiing ndm gdn day la: 15% gia cdm dtrpc chdn nudi theo phuong thtic cdng nghilp, 20% gia cdm dupe chdn nudi theo phuong thtic bdn cdng nghilp, trong dd 80% gd cdng nghilp thudc sir qudn ly ciia nude ngodi (Hodng Kim Giao vd Nguyin Thanh Son, 2005). Nhd vdo tiln bd di truyin vd chi dd dinh dudng hpp ly, hiln nay d l dat dupc khdi lupng 2,5 kg chi cdn 6-7 tudn nudi (Fairchild vd Czarick, 2005).
Tuy nhiln, ndng sudt khdng thi dat dupe muc tdi da niu gd thit khdng dupc nudi trong diiu kiln tiiu khi hdu chudng nudi dupc tdi uu hod. Do dd, h i thdng chudng kin thdng gid dd ra ddi vd dua vdo thue t l sdn xudt. Uu diim ciia kilu chudng nay Id kilm sodt dupc nhilt dd gdn tdi hao vdi nhu cau sinh trudng ciia gd trong nhirng thdng miia ndng nhd vdo h i thdng thdng gid phun nude ldm mdt tu ddng, gidm ti ll chit do nhilt, ban chit lay lan binh tir bin ngodi vdo trai, gd dn nhilu, tdng trudng nhanh,... Vi till, mtic tiiu ciia nghiln ciiu la khao sat vd phdn tich sir dnh hudng ciia nhi|t dd vd dm dd lln ndng sudt sinh trudng ciia gd thit gidng Ross 308.
LV^iTU^VA PHUONG PHAP
' Khoa Nong nghifp vd Sinh hpc Cng dyng, trudng D^ii hpc Can Tho
^ Chi eye Thii y An Giang ' Cdng ty Chan nudi Long Binh
NONG NGHlfP VA PHAT TRIEN
N C N G THCNKY 1 - THANG 9/2011
1. Dia diim vd chudng tr^i
Khdo sdt dupc thtrc hiln tai mdt trai chdn nudi gd thjt thuong phdm Ross 308 trong giai doan nudi thjt tir 1-42 ngdy tudi. Thi nghi|m dtroc tiln hdnh trin 3 day chudng, dupc ddt trong mdt khu trai chdn nudi gd thit tai xd Phudc Tdn, huy|n XuyIn Mpe, tinh Bd Ria - Vung tdu. Cdc ddy chudng dupc thilt k l theo ciing kich thudc vd h | thdng thdng gid ldm mdt Nin dupc trdng xi mdng, xung quanh xdy tudng bdng gach cao 0,5 m, cd h | thdng bat nhua cd thi klo lln xudng bdng h i thdng rdng rpc vd ldp ddn chudng dupe rai trdu mpt ldp ddy khoang 20 cm. Mdi chudng: mdi don Ipp tdn. Mat dp nudi: 10-12 con/m^.
Mdi ddy chudng cd kich thudc chudng: rdng 12 m, ddi 120 m, cao 2,15 m. Diln tich Id 1440 m l Mdi day chudng dupc chia ldm 4 d cd kich thirdc bdng nhau, mdi d cd diln tich 480 m^.
Chudng cd ldp ddt quat htit gid, gdm 10 quat dupe bd tri d cudi day chudng va h i thdng tdm ldm mdt gdm 40 tdm dupc ldp d$t 2 bin vdch ddu ddy chudng. Khi qu^t hiit gid hoat dpng, keo theo hoi nude tir tdm lam mat dam bdo duy tri nhi|t dp tir 25 - 27°C, dm dd trung binh tir 65 - 85%, tdc dd gid tiling binh tir 2 - 2,5 m/s.
2.Ddngv$t
Khao sat dupe tiln hdnh trin gd thit Ross 308, liic 1 ngay tudi, cd khdi lupng binh qudn Id 37 g, gd con dupc 1 ^ true tiip tir Id dp ciia trai tir dan bd me 57
KHOA HOC CdNG
N G H £do chii trai nhdp con gidng tir Ha Lan va san xuat
tning gidng. Sd gd khao sat d 3 day chudng 1, 2 vd 3 tuong ling Id 13.260 con, 13.6(X) con vd 14.560 con.
3. Td chiie khao sdt
Khao sdt dupc thtrc hiln trin 3 ddy chudng vdi 3 ldn nudi gd liln tiic Qdp lai 3 ldn).
O ca 3 trai diu dp dung chung qui trinh chdm sdc nudi dudng vd ngudn tinic dn.
4. Cdc chi tiiu theo ddi
Nhilt dp (°C) vd dm dd (%): dupc do bdng mdy do cdc thdng sd tiiu khi hau hiiu Kestrel 3000 (do My san xudt vdi dp phdn giai nhilt dp vd am dp la 0,1) tai 3 tiidi diim khdc nhau ti-ong ngdy 6:00,12:00 va 18:00 gid. Vi tri do Id dau chudng, giira chudng vd cudi chudng, mdi vi tri do 3 ldn, lay sd trung binh timg thdi diim, trung binh hang ngdy vd tnmg binh hdngtiidn.
Tdc dp sinh trudng: gd dupc cdn liic 1 ngdy tudi (mdi nhdp) vd cdn ldp lai vdo cudi mdi tudn cho din khi kit thiic thi nghilm (6 tuan). Thdi diim mpt ngay tudi gd dupe cdn theo timg d lim, mdi d can 80 con (tdng cdng 800 con). Vdo cudi tuan 1, gd dupc bdt ngau nhiln tai 9 vi tri khac nhau trong trai, tai mdi V} tri cdn 20 con (180 con/tuan). Nhirng tudn
cdnlai bdt ngau nhiln tai 9 vi tri vd can 10 con tai m6i vi tri khac nhau (90 con/tuan). Cdc chi tiiu vl ndng sudt sinh trudng theo ddi gdm:
- Khdi lirpng binh quan trong tudn (g/con): Tdng khdi lupng chia tdng sd ga dupc can tai mdi thdi diim.
Tdng trpng trong tuan (g): La sir chinh l|ch giira khdi lupng binh qudn tudn sau vd khdi lupng binh qudn tudn trudc.
Tiiu tdn thiic dn trong tudn (g/con): Tdng khdi lupng thiic dn trong tudn chia tdng sd gd cd mdt tai thdi diim tinh
HI sd chuyin hda thiic dn trong tudn: Tiiu tdn trong tudn chia cho tdng trpng trong tudn.
5. Phdn tich thdng kl
Cdc sd Ulu thu thdp dupc xii ly so bd bdng phan mim Excel; d6 so sanh sir khdc biit giira cac nghilm thiic tiln hdnh phdn tich phuong sai vd danh gid quan h i giiia nhilt dp, am dp vdi tdng trpng va tiiu thdn thtic dn; sii dting md hinh hdi qui bdng phdn mim Minitab 13.
BL KET QOAVA THAO LOAN
1. Su thay ddi ciia n h i | t d^ vd dm dd frong
chudng nudi qua cdc tudn tudi ciia gd
Tudn Tuanl Tudn 2 Tuan 3 Tudn 4 Tudn 5 Tudn 6
B d n g l . S v l Trail
p±SD 33,35 ±0,93 30,14 ± 1,24 28,60 ±1,12 27.04 ±0.71 26.29 ±0.61 26,74 ± 0.89
Bang2.Stj
hay ddi nhi|t dd (°C) d cdc tr?i theo tudn Trai 2
p±SD 32.14 ±0.67 30.01 ± 0.53 27,75 ±1,22 26,81 ± 0,73 26,29 ± 0,61 26,20 ±0.77 r tiiay ddi dm dd(%
Trai 3 p±SD 32,42 ±1,35 29,21 ± 1,04 27,44 ±0,42 26.86 ±0,64 25.59 ±0.59 25.84± 0.28 ) 6 cdc trai theo tu<
SEM 1,05 0,96 0,97 0,48 0,36 0,49 n
P 0,10 0,18 0,10 0,81 0,48 0,08
Tudn Tudnl Tudn 2 Tudn 3 Tudn 4 Tudn 5 Tuan 6
Trail p±SD 75,75 ±3,13 77,40 ±2,93 76.50 ±2.87' 81.39 ±2,71 82,34 ±3.75 81.53 ± 1.93"
Trai 2 p±SD 77,01 ± 3.67 73,54 ±3,72 77,31 ± 2.88"
83.87 ±3,32 82,39 ±3,50 82,93 ±1,44"''
Trai 3 p±SD 74,10 ±4,29 76,58 ± 2,68 82,36 ±3,43"
81,40 ± 3,80 83,02 ± 3.17 84.40 ± 2.23''
SEM 13.90 9.85 9.43 10,90 12,10 3,58
P 0,36 0,08 0,00 0,29 0,31 0,04
Ghi chu: Nhiing so trung binh cung hing mang chu si mu khic nhau sai khic cd y nghia tiling kd (P<0,05) tiieo phep tiiuTukey.
Nhilt dp cd khuynh hudng giam dan theo sir d tudn thii hai vd giam tiip din hit tuan thir ba. Sau
phdt triln ciia gd. Giai doan lim ga dupc giir nhilt dd khi hit giai doan tim, nhi|t dp trung bmh ciia ca 3
cao nhat d tuan thii nhat (32-33°C), sau dd giam dan trai biin dpng tii 25-27°C. Nhin chung, khdng cd sir
58 NONG NGHIEP VA PHAT TRIEN NONG THON KY 1 - THANG 9/2011
KHOA HOC
C O N G N G H | khdc biit y nghia (P>0,05) v l nhilt dp trung binhgiira cdc frai qua mdi tudn tudi (Bang 1). Qua quan sdt thtrc tl, d nhilt dp ndy, gd cd bilu hiln ndng so vdi nhilt dp tiiu chudn dia ga Ross 308. Nhilt dp ndy cd thi dtrpc xem la qua cao vd cd thi gdy bdt Ipi cho str sinh ti-udng vd phat triln ctia gd. Nhdn djnh ndy cung phii hpp vdi Aengwanich vd Sunaraks (2004) rdng nhilt dp tdi tm cho su phdt triln ciia gd gid trin 4 tudn hidi Id 18-21°C.
Trong tudn 1 (giai doan tim), chi cd nhilt dd frai 1 (33,35''C) ndm trong khoang biin ddng thich hpp, trong khi d trai 2 vd trai 3 nhilt dp cd phdn thdp hon, ga con cd bilu hiln ndm chum lai vdi nhau. Sang tudn 2 nhilt dp frai 3 (29,21°C) cung tiiap hon ylu cdu, gd tiip tuc bi lanh. Tudn 3 Id khodng thdi gian md miic nhi|t dp tdt nhdt cho tdt ca cdc frai vd tdt nhdt so vdi cdc tudn cdn lai. Ta thdy d tudn 4 frd di, nhilt dp vd str lim thdng khdng khi frong chudng nudi dupc diiu chinh bdng each tdng tdn sd boat ddng ciia h i thdng quat gid cudi chudng. Tuy nhiln, do tdc dd tdng tnrdng ciia gd frong giai doan ndy khd nhanh, kem theo sir tdng hd hdp vd san sinh nhilt lupng nin nhilt dp frong chudng nudi vdn cao hon so vdi yeu cdu. Nhilt dp cao nhat Id frai 1 (26,74- 27,04"'C) vd tiidp nhdt Id d frai 3 (25,84-26,86 "C). Diiu kiln khi hdu d khu vtrc miln Ddng Nam bd vdo miia he rat ndng, nhilt dp vao budi trua bin ngodi chudng nudi gd rat cao (>33°C). O nhilt dp ndy h | thdng lam mdt gdm quat gid vd nudc khdng till lam mdt dii theo nhi|t dp tiiu chudn. Hon nira nhi|t dp frong chudng gidm nhilu se dan din tdng chi phi di|n, nudc. do dd frai chi khdng chi nhi|t dd frong giai doan tdng trudng vd vd bio khdng qud 27°C.
Kit qua xdc dinh dm dd trung binh d cdc frai dupc frinh bdy d bang 2; dm dd cd dnh hudng quan frpng ddi vdi gd con vd nd cd thi giiip cho su diiu hda thdn nhilt ciia gd. Niu dm dp >70% dp dm cd thi dpng lai, tao thdnh gipt nudc vd ldm chudng frai frd nin dm udt, nhtmg niu dm dp <50% gd se bdt ddu mdt nudc vd ldm giam ndng sudt. Am dp tdi uu cho sir phdt triln ciia gd ndm frong khoang 60-70%
(Dowsland,2008).
Am dd dupe do cimg liic vdi nhilt dd, dm dd trung binh hdng tudn ciia ba frai dupc thi hiln frong bang 2. Sii khdc bi|t cd y nghia thdng k l vl dm dp giira ba frai dupc thdy d tudn 3 vd tudn 6 (P<0.05), cdc tudn cdn lai nhin chung khdng cd sir khdc b i i t O hidn 3 am dd frai 3 cao nhat (82,36%), k l din Id ti-ai 2 (77,31%) vd tiidp nhdt d frai 1 (76,5%). Din tiidn 6 dm
dp frai 3 (84,4%) van cao hon fr-ai 2 (82,93%) vd tiai 1 (81,53%). Nhin chung, dm dp d 3 frai dao ddng frong khoang 73,54-84,40%, cao hon nhilu so vdi d l nghi ciia Dowsland (2008) (60-70%). Am dp cao ciing la mdt frong nhung ylu td bdt Ipi cho str phdt triln ciia gd (Adil, 2009). Am dd cao Id nguyin nhdn ciia (0 str vung vdi nudc frong qud trinh udng ciia gd; (u) str bdi thai phdn; (in) su tich tti hoi nirdc dpc theo chudng nudi do h i thdng quat htit ylu hodc bi ngung dot ngpt do Clip di|n. Am dd frai 3 cao hon hai frai cdn lai k l tir tudn tiiir 3 frd di cd thi do dan lanh ddu chudng ddi hon.
Tdm lai, nhilt dd vd dm dd trung binh frong chudng nudi ciia 3 frai diu cao hon so vdi nhilt dp thich hpp cho sir phdt triln ciia gd frong sudt giai doan nudi thit
2. Su thay ddi nhi|t dd vd dm dd frong chudng nudi qua cdc thdi diim frong ngdy
Muc dich ciia vile ting dting chudng kin frong chdn nudi gd cdng nghilp nhdm ban chi chinh lich ldn vl nhilt dp tai cdc thdi diim frong ngdy. Tuy nhiln, sir dao dpng vl nhilt dp giiia cdc budi (sang, trua, chiiu) frong ngdy d cdc frai dupc ghi nhdn Id khd ldn. Hdu h i t sir khdc biet nhilt dp giiia cdc budi d cdc tudn diu cd y nghia thdng k l (P<0,05), ngoai trir nhilt dp d tudn 3 (frai 1) vd tudn 1 (frai 3) Id kha dn dinh (khdng khac biit vl mdt thdng kl). Mdc dii cdc fr^ cd h | thdng diiu hda nhi|t dd, nhung nhi|t dd frong chudng nudi vdo budi trua cd khuynh hudng cao hon budi sdng vd chiiu (Bang 3). Ghi nhdn ndy ciing khd phii hpp vdi Duong Xudn TuyIn vd cdng str. (2008) rdng nhilt dd budi sdng sdm frong chudng vjt de Id thdp nhat cao nhdt Id vdo budi tnra.
it cd sir biin ddng vl dm dd giira cdc budi (sang, tnra, chiiu) frong tudn (Bang 4). Sir khdc bi|t cd y nghia thdng k l dupc tim thdy giira cdc budi d tudn 1 (frai 2), tudn 2 (frai 1 vd 3). Ghi nhdn nay ciing phii hpp vdi Duong Xudn TuyIn vd cdng sir. (2008) rdng dm dp budi sang Id cao nhdt vd thdp nhdt Id budi tnra frong chudng nudi vjt de.
Nhin chung, frong mdi trai cd sir biin ddng nhi|t dd rat ldn giira cdc thdi diim sang, tnra vd chiiu, rilng dm dd tuong ddi dn djnh. Khdc bi|t chii ylu giira budi sdng so vdi tnra hodc chiiu. Diiu ndy cd thi do anh hudng ciia gid miia ddng bdc tai thdi diim thi nghi|m vd vimg tiiu khi h$u ddc tnmg ciia ddi mii.
3. St; thay ddi nhi|t dd vd dm dd d cdc tr^i frong Cling thdi diim
NONG NGHlfP VA PHAT TRIEN NONG THON - KY 1 - THANG 9/2011
59KHOA HQC
C 6 N G N G H |Nhilt dp giua cac trai frong ciing thdi diim it cd su biin dpng. Khac biit giira cac trai tai cdc thdi diim dupc tim thay cd y nghla thdng kl vao buoi sang (tuan 3, tuan 6) va budi trua (tudn 2). Ddi vdi am dd, su khdc biit ciia cac trai cd y nghia thdng ke vdo budi sdng (tuan 2, tudn 3), budi tnra (tuan 2, tuan 3) vd budi chiiu (tuan 4, tuan 6). Nhu vay am dp d
cac trai cd biin dpng nhilu nhdt or tuan 2 va tudn 3 vao buoi sang vk budi trua. Diiu nay co thi giai tfaicfa la ga dupc cung c ^ ttiuc dn va nudc udng Uln tuc, vi till vao buoi tdi va sang nhilt do trong chudng giam nin cd am dp cao, din trua va chiiu nhilt dp tdng nin am dp giam xudng vao cac thdi diim nay trong ngay.
Bang 3. Six thay ddi nhi|t d6 C^) qua cdc thdi diim trong ngdy
^
"S.
"3.
Thdi diem Sang Tnra Chieu P Sang Tnra Chieu P Sang Tnra Chieu P
Tuan 1
|i±SD 32,71±1,02"
34,17±0,97'' 33,17±0,92'*
0,04 30,93±1,17' 33,29±I,25'' 33,23±1,22"'
0,01 33,23±1,22 33,23±1,22 32,06±1,12
0,19
Tuan 2 p±SD 28,71±1,80"
30,93±1,02'' 30,80±1,24''
0,01 29,20±0,8r 31,03*0,98"
29,86*0,58"
0,00 29,86±0,58"
29,86±0,58'*
30,00±U'' 0,03
Tuan 3 p±SD 28,19±1,18 29,33±1,71 28,27±1,45
0,29 26,19±1,95*
28,64±I,50'' 28,43*0,96"
0,01 28,43±0,96*
28,43±0,96"
27,94±U7"
<0,01
Tudn 4 ji±SD 25,36±1,46*
28,19±0,47"
27,60±0,90"
0,00 25,34±0,87' 27,99±0,83"
27,06±0,71"
0,00 27,06±0,71*
27,06±0,71"
27,51±U7"
<0,01
Tuan 5 p±SD 25,31±0,60*
27,16±0,74"
26,40±0,62"
0,00 25,31±0,60' 27,I6±0,74'' 26.4±0,62"
0,00 26,4±0,62*
26,4±0,62"
26,39±0,76"
<0,01
Tuan 6 H±SD 25,79±0,63*
27,46±1,02"
26,94*1,18*
0,01 25,01*0,60*
27,02*0,98' 26,39*1,19"
0,00 26,39tl,19*
26,39*1,19' 26,54*037*
<0,01
Ghi chu: Nhdng so trung binh cdng cot mang chit so mu khac nhau sai khac co y ngfiia thong ki (P<0,05) tiieo phep tiiuTukey.
Bang 4. Sii thay ddi dm dd (%) qua cdc thdi diim trong ngdy
^
Thdi diim Sang Trua Chieu P Sang Tnra Chieu P Sang Tnra Chieu P
Tuan 1 M*SD 77,34*3,95 73,44*5,32 76,47*1,12
0,17 79,57*3,84*
73,8*5,11"
75,59*3,26'' 0,04 76,87*3,91
71,8*9,27 73,64*536
0,37
Tuan 2 p±SD 82,16*3,64*
75,44*6,10"
74,64*3,20"
0,01 76,29*5,08 70,04*4,49 74,26*4,74
0,07 82,44*2,00*
77,67*4,08"
69,63*5,03*
<0,01
Tuan 3 p*SD 76,46*2,82 74,83*5,15 78,2*4,72
0,37 80,53*3,79 76,04*2,54 75,39*5,29
0,06 83,61*2,17 81,50*3.52 82,00*7.07
Tuan 4 p*SD 83,61*284 79,30*468 81,26*1,58
0,74 84,44*4,18 80,99*5,18 86,24*1,85
0,07 84,79*2,46 78,89*4,17 80,56*6,80
0,69 0,08 Tuan 5
p*SD 80,64*4,58 78,56*3,69 81,79*5,07
0,41 83,36*4,75 80,03*3,27 83,79*3,14
0,16 85,17*1,49 81,79*5,45 82,63*4,04
0,28
Tuan 6 p*SD 82,2*13 80,20*4,49 82,16*2,62
0,40 83,50*4,71 81,29*1.61 84,01*1,26
0,21 85,10*1,47 8239i:335 85,74*2,62
0,06
Ghi chu: Nhiing so trung binh cdng hang mang chit so mu khac nhau sai khac co y nghia thong ki (P<0.05) tiieo phep tiiu Tukey.
4. Khdi lupng gd qua cdc tudn tudi
Tuan TuanO Tuan 0-1 Tuan 0- 2 Tuan 0- 3 Tudn 0-4 Tuan 0-5 Tuan 0-6
Bang 5. Kh£
Trail p*SD 37,50*0,49 139,50*3,69*
339,50±2,48*
748,00±14,67*
1.200,0O± 13,33' 1.673,85± 15,02*
2.109,23*35,23*
i lupng gd qua cdc tudn tudi (g/con) Tr?i2
M±SD 38,04*0,64 122,50*6,77' 295,00*5,77"
649,33*12,65"
1.062,00*14,76"
1.516,36*23,35"
1.980,00*23,09"
Trai 3 M*SD 37,05*0,62 106,20*6,15' 304,00*4,59' 669,33*17,55' 1.084,00*1838*
1.534,55*28,42°
1.99636*17,48°
SEM 7,16 32,40 20,80 228,00 224,00 507,00 734,00
P 0,08
<0,01
<0,01
<0,01
<0,01
<0,01
<0,01
Ghi chii: NhOng so tnmg binh cimg hdng mang chir so mu khdc nhau sai khdc coy nghia thong ke (P<0.05) theo phep thd Tukey.
60 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 THANG 9/2011
KHOA HQC CdNG N G H |
Nhin chung, tai mdt sd tiidi diim, nhilt dd vd dm dd khdc hilt cd y nghia tiidng k l , ddc biit Id d tudn 2 vd 3. Tuy nhiln, biin dd dao ddng ciia nhi|t dd khdng ldn, cdn dm dd cd khuynh hudng dn dinh hon d cdc frai tai cdc tiidi diim khao sdt Trong diiu kiln nudi cdng nghilp vdi h i thdng chudng kin, ylu td nhilt dd cd till d l dang kilm sodt hon dm dp. Ca 2 chi tiiu nhilt dd vd dm dd frong thi nghilm diu cao hon miic tdi uu cho sir phdt triln ciia gd nin ddy cung cd till la nguyin nhan tdc ddng tnic tiip din kha ndng sinh trudng ciia gd. Theo Yimianto et al.
(1997) vd Aengwanich vd Simaraks (2004), nhilt dd qud cao hay qud thdp diu Id nguyin nhdn gdy sfress (tic chi) cho gd vd dnh hudng tiiu cue din stic khde ciing nhu giam hiiu qua frong chdn nudi.
Khdi lupng co thi Id chi tiiu h i t stic quan frpng, nd quyit djnh phdn ldn hiiu qua frong chdn nudi vd Id mtic dich ciia vile dp dtmg nhirng thdnh ttm khoa hpc ky thudt nhdm ndng cao khdi lupng co thi frong mpt don vi thdi gian.
Khdi lupng binh qudn ciia gd frong ngdy ddu tiln tuong ddi ddng diu, khdng cd sir khdc b i i t giiia cdc frai. Tuy nhiln kit qua ghi nhdn khdi lupng gd mdt ngay tiidi cao nhdt Id frai 2 (38,04 g), k l Id frai 1 (37,5 g) vd thap nhdt la frai 3 (37,05 g) thdp hon nhilu so vdi chudn (42 g). Dii vdy, khdi lupng qua cdc tudn tudi ctia gd d frai 1 ludn cao hon cdc frai cdn lai frong nhirng tudn tiip theo (P<0,01) nhung van thdp hon so vdi tiiu chudn gidng. Dang chii y nhat la tir tudn 14,
khdi lupng gd khdc biit rdt ddng k l giiia cdc trai. Sii thu h?p vl khdi lupng gd giua trai 2 vd 3 dupc tim thdy d tudn 5 vd 6.
Su chinh l|ch ldn v l khdi lupng ciia gd thi nghilm so vdi tiiu chudn gidng qua cdc tudn tudi cd till Id do (0 ddn gidng bd me de liia ddu nin khdi lupng thdp; khdi lupng ban ddu cung la mdt chi tiiu quan frpng, cd dnh hudng din stic khde cung nhu ndng sudt ciia gd (Watts, 2008; La Thi Thu Minh, 2000); vd (ii) diiu ki|n chudng nudi chua phii hpp.
Khdi lupng gd gid Ross 308 mang tinh di truyin cao, niu nudi khdng dat ndng sudt cao cd thi do diiu kiln tiiu khi hdu chua tdi uu cho sir phdt triln ciia gd
(Adil, 2009).
5. Tang frpng binh qudn ciia gd theo giai do^n tiidi
Theo Trung tdm Chdn dodn vd Cd vdn Thti y (Cdng ty TNHH Charoen Pokphand Vilt Nam, 2007), tdng frpng ciia gd Ross 308 sau mdt tudn tudi ddu tiln phai gdp 4 ldn so vdi Itic mdt ngdy tudi. Tdng frpng binh qudn hdng tudn ctia gd nhanh nhdt frong 3 tudn nudi ddu tiln. Sau tudn tudi thii 3 thi tdng frpng binh qudn hdng tudn lai gidm vd sang tudn thti 6 thi mtic tdng frpng trd nin thdp di so vdi cdc tudn trudc dd. Diiu ndy cd nghia Id gd ldn rdt nhanh frong 3 tudn tudi ddu tiln, ldn nhanh frong tudn tudi 4-5 va chdm dan k l tir tudn thii 6 frd di (Bang 6).
Tuan 0-1 Tuan 1-2 Tuan 2-3 Tuan 3-4 Tuan 4-5 Tuan 5-6 Tuan 0-2 Tuan 0-3 Tuan 0-4 Tuan 0-5 Tudn 0-6
Trail p±SD 101,91*3,70*
200,00*5,77*
408,50*14,40*
452,00*21,27*
472,00*16,87 434,00*43,26 302,00*2,85*
710,50*14,48*
1.162,40*13,60*
1.63435*13,90*
2.068,43*36,70*
Tr?i2 p±SD
84,28*6,80"
172,50*7,91' 35433*1635' 412,68*13,50' 451,00*26,85 467,00*23,12 256,96*6,03' 611,10*12,55' 1.023,80*14,50' 1.474,83*21,10' 1.941,86*22,70'
Tr?i3 M±SD
68,94*5,95' 198,00*8,23*
36533*19,93' 414,67*25,88' 450,00*27,08 461,00*29,98 266,95*4,68' 632,25*1735' 1.046,95*18,40' 1.496,90*23,20' 1.957,91*17,00'
SEM 31,80 54,50 291,00 435,00 580,00 1101,00 22,10 223,00 245,00 393,00 718,00
P
<0,01
<0,01
<0,01
<0,01 0,08 0,08
<0,01
<0,01
<0,01
<0,01
<0,01 Ghi chii: Nhirng sd tnmg binh cung hang mang chic so mii khdc nhau sai khdc cd y nghia thdng ke (P<0,05) theophip thir Tukey.
Tdng frpng ciia gd frong tudn tudi ddu tiln ciia cdc fr^ rdt thdp so vdi miic tdng khdi binh thudng ciia gd (frdng 142 g, mdi 140 g), cao nhdt Id frai 1 (101,91 g, gdp 2,72 ldn so vdi khdi lupng ban ddu), k l
din Id tied 2 (84,28 g, gdp 2,22 ldn so vdi frpng lupng ban ddu) vd tiidp nhat Id frai 3 (68,94 g, gap 1,86 ldn so vdi khdi lupng ban ddu). Sir khdc bi^t nay rdt cd y nghia tiidng kl(P<0,01).
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C Q N GNGHE Trong khdo sat nay, d tudn 2 vd 3 ga cd mtic tdng
frpng gdn gap ddi so vdi tuan trudc dd, cu thi frong tiian 2 mtic tdng frpng (1,96, 2,05 vd 2,87 ldn) vd bidn 3 (2,04, 2,05 vd 1,85 ldn) tirong ting tii frai 1 din frai 3. Tir tudn 4 frd vl sau tdng frpng giam lai, sti tdng frpng ciia gd frong giai doan ndy phii hpp vdi quy ludt phdt triln cua gd, din liic xuat chudng (tudn 6), miic dp tdng frpng giam ddn theo chiiu hudng frai 1 > frai 3 > frai 2. Su khdc biit cd y nghia vl tdng frpng frong sudt qud frinh dupe tim thay giira frai 1 vdi frai 2 vd frai3(P<0,01).
Nhin chung, tdng frpng binh qudn ciia 3 frai qua Bdng 7. Tilu tdn tinic dn ciia gd
giai doan tiiap hon nhilu so vdi tilu chudn gidng (Bang 1 vd 2). Su khdng dat tdng frpng ciia gd cd th^
do nhilt dd va am dp chudng nudi cao frong sudt qua trinh thi nghilm, dm dd cao sinh ra nhilu khi doc, frong dd cd ammoniac. Theo Trung tdm Chdn do^
vd Cd van Thii y (Cdng ty TNHH Charoen Pokphaai Vilt Nam, 2007), khi ammoniac cd till lam gidm 2055 tdng frpng cua gd 7 ngay tudi. Khdi lupng gd 7 ngay tudi khdng dat miic tdi tm se giam lam ndng sudt ga thit frong sudt cdc giai doan sau (Garden, 2008).
6. Tilu tdn thiic dn d cdc frai thi nghi|m (g/con)
Tuan 0-1Tuan 1-2 Tuan 2-3 Tuan 3-4 Tuan 4-5 Tuan 5-6 Tuan 0-2 Tuan 0-3 Tuan 0-4 Tudn 0-5 Tuan 0-6
Tr^il M±SD 152,10*59,41 311,85*44,64 526,50*95,81 775,93*81,93 954,67*48,59*
962,99*65,40*
463,95*101,58 990,45*193,20 1.766,38*274,60 2.721,05*273,90 3.684,04*338,40
Tr^i 2 p±SD 135,49*47,25 284,52*45,17 475,49*96,81 797,88*93,97 1.018,57*32,30' 1.092,29*26,91'
420,01*9132 895,50*187,30 1.693,38*280,70 2.711,95*309,80 3.804,24*336,30
Tr?ii 3 p±SD 122,88*34,20 257,86*60,32 461,51*80,74 736,93*72,54 971,76*54,56*' 1.103,76*26,29'
380,74*94,13 842,25*174,6 1.579,18*246,7 2.550,94*300,30 3.654,70*325,70
P 0,53 0,17 039 0,41 0,05 0,00 0,29 033 0,43 0,49 0,68 Ghi chii: Nhirng sd trung binh ciing hang mang chir sd mii khdc nhau sai khdc cd y nghia thdng ke (P<0,05) theo phep thir Tukey.
Lupng thtic dn tilu thti hang ngay phan dnh tinh frang siic khoe, tdc dp sinh trudng ciia dan gd vd chat lupng ciia thiic dn. Kha ndng tilu thu thirc dn ciia ddn gd phu thudc vdo cac ylu td nhu: nhilt dp, dnh sdng, chat lupng thiic dn, diiu kiln chdm sdc nudi dudng, tdc ddng ngoai canh (Hudng dan ky thudt chdn nudi gd Cobb, 2008).
So vdi djnh miic ciia gidng, tilu tdn thiic dn binh qudn ctia gd d cdc frai thap hon (VD: tudn 1: 160 g (chuan), 122,88 g (frai 3), 135,49 g (frai 2) va 152,1 g (frai 1)). Cd nhilu nguyin nhdn dan din su tilu tdn thiic dn khdng dat ylu cdu, frong dd am dp chudng nudi cao keo ddi qua cdc giai doan cung cd thi la nguyin nhdn tac ddng true tiip. Theo Duong Thanh lilm (2003), khi am dp cao keo ddi cd till gay tdn thuong niim mac tiip xiic, giam tinh ngon miing vdi thiic dn, ga se gidm lupng thiic dn dn vao. Trong 3 frai, chi cd tilu tdn tiiiic dn d frai 1 gdn bdng so vdi tilu chudn (frdng 4.876 g, mai 4.411 g). Vdi miic dn nhu vdy, tdc dp tdng trudng ciia ga d frai 2 va 3 cd thi si thdp hon frai 1. Thiic dn cung cap chat dinh dudng
cho str tdng trudng do dd thiic dn dn vdo dting chudn thi tdc dp tdng trudng se cao (Vii Duy Giang, 2009).
Lupng thiic dn tilu thti frong tudn ciia gd tdng ddn diu tir tudn 1-6 va khdng cd sir khdc bi|t y nghia thdng kl. Tuy nhiln, niu chi tinh rilng frong tudn 5 hodc 6 thi chi tilu nay cd str khdc biit y nghia (P<0,05). Nhu v^y, lirpng thtic dn tilu thti phan dnh mtic dp tdng frpng ciia gd qua cdc giai doan. Nhirng ga cd siic tdng trudng tdt d tudn dau tiln thi si tifiu thu thtic dn nhilu hon frong 5 tudn tiip theo, ddy c6 till la ylu td hinh thanh nin tang thi chat, stic frdng kiln vd stic khde, giiip cho sir tilu hda vd hdp tiiu dudng chat ciia thtic dn mdi tdt hon d tudn cudi cimg.
Sir chinh lich vl lirpng thtic dn tilu tdn todn ky khdng cd y nghia (khoang 150 g/con) giira cdc tr?i, nhung niu tinh cho toan frai (khoang 13.000 con), thi chi phi nay la kha ldn.
7. H | sd chuyin hda thue dn
HI sd chuyin hda tiiirc dn (HSCHTA) phan dnh
ndng suat ciing nhu hiiu qua kinh tl frong chdn nudi
gd tiijt Thdng tiiudng, HSCHTA ctia ga frong 3 \uk
62 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 THANG 9/2011
KHOA HQC
C Q N G N G H Itudi ddu tiln Id thap nhat (Watis, 2008). Diiu ndy cd nghia Id frong giai doan ddu, h i i u qua nudi gd se Id kinh t l nhdt do tilu tdn thue dn thdp nhdt md tdng frpng lai nhanh nhat so vdi cdc giai doan sau (Vu Duy Giang, 2009). K i t qua tiii n g h i l m cho tiidy, HSCHTA qua cdc tudn tudi ciing tuan theo chiiu hudng dd (Bang 8). Tuy nhiln, so vdi tilu chudn gidng (con frdng 1,70 vd con mdi 1,81), HCSHTA d 3 frai vdn cao hon (1,78-1,96). HSCHTA tiidp nhdt dupc tim thdy d tudn 3 (1,26 -1,34) vd cao nhdt d tudn cudi (2.21-2.39).
Xet v l diiu kiln tilu khi hdu; n h i l t dp d tudn 3 (27,44-28,60°C) dat tdi uu n h d t gdn vdi khoang cho phep ciia nhilt dp tilu chuan (27-29°C). Cd t h i day la nguyin nhdn chinh lam cho HSCHTA d tudn 3 thdp nhdt K i t qua phdn tich thdng k l chi ra rdng: giira HSCHTA vd n h i l t dp cd mdi tuong quan d ca 3 frai (P<0,5). K i t qua phan tich nay cung cd t h i m nhan dinh cua May et al. (1998) rdng: n h i l t dp cd mdt mdi liln quan rat mdt thilt frong str tdng trudng vd sir chuyin hda thiic dn ctia gd gid sau 3 tudn tudi vd cang anh hudng ldn hon frong str gia tdng khdi co t h i ciia gd.
Bdng 8. H | sd chuyin hda thiic dn ciia gd till
Tudn 0-1 Tudn 1-2 Tudn 2-3 Tuan 3-4 Tuan 4-5 Tudn 5-6 Tuan 0-2 Tudn 0-3 Tuan 04 Tudn 0-5 Tudn 0-6
nghilm (kj Trail
1.49 1.56 1.29 1,72 2,01 2.21 1,54 1.39 1,52 1.66 1.78
sTA/kgfT
Trai 2 1.60 1,65 1.34 1.93 2.24 2.36 1,63 1,46 1.65 1.83 1.96
D
Trai 3 1.44 1.42 1.26 1,78 2,16 2,39 1,43 1,33 1,51 1,70 1,87
8. Tuong quan giiia n h i | t dd vd dm dO vdi tdng frpng vd tilu tdn tinic dn ciia gd thi n g h i | m
K i t qud tiii nghilm cho tiiay diiu kiln tilu khi hau frong frai chdn nudi anh hudng true tiip l l n tdng frpng vd tilu tdn thtic dn ciia gd thi nghilm.
Phdn tich mdi quan h i giira n h i l t dd vd am dp vdi tdng frpng vd tilu tdn thtic dn cua gd tiiit Ross 308 cho tiidy, n h i | t dd anh hudng tiiic tiip lln tdng frpng (R2=0,93) (phuong h i n h 1) hon Id dm dp (R2=0,71) (phuong trinh 2). Khi n h i l t dd tdng cao tiii tdng frpng giam. Ca hai y l u td n h i | t dd vd am dd cd
quan h i rat chdt che vdi tdng frpng ciia gd (RM,95) (phuong frinh 3). Tirong hi, nhilt dd tdng ciing ldm giam lupng thiic dn dn vdo ctia gd (P? = 0,81) (phuong trinh 4), nhilt dd cd quan h i vdi lupng dn vdo cao hon dm dp (R^= 0,77). Nhin chung, ca hai y l u td nhilt dp vd dm dd d i u anh hudng l l n tieu thti thtic dn vd tdng frpng cua gd.
Quan h i giua n h i l t dp vd dm dd vdi tdng frpng gd thi nghilm:
Yi= 1977 - 57,8 Xj; RSD = 39,20; R^ = 0,93 (1).
Yi= - 2471 + 35,2 X2; RSD = 82,15; R^ = 0,71 (2).
Yi= 99947,8 Xi-(-8,74 X2, RSD= 35,08; R^ = 0,95 (3) Quan h i giira nhilt dp vd dm dd vdi tilu tdn thiic dn cua gd thifc
¥2= 4275 - 128Xi, RSD = 160,1; R^ = 0,81 (4).
¥2= - 6372 -I- 87,8X2; RSD = 173,5; R^= 0,77 (5).
¥2= - 765-77,3X1-145,0X2; RSD= 128,5; R^= 0,88 (6).
nr. KET LOAN
Trong diiu kiln chdn nudi gd thjt Ross 308 d qui md cdng nghilp theo h | thdng chudng kin, y l u td n h i | t dp vd dm dp cdn dupe k i l m sodt chdt che vd dn dinh. Si; biin ddng ciia n h i | t dd vd dm dp dpc theo qud trinh nudi cd dnh hudng d i n cdc tinh frang ndng sudt ciia ga thit Ross 308 nhu khdi lupng co t h i , tdng frpng, tilu tdn thtic dn, h | sd chuyin hod thiic dn. Vi t h i hiiu qua chdn nudi se khdng dat dupc tdi uu.
TAIUEO THAM KHAO
1. Duong Thanh Lilm, 2003. Chdn nudi gia cdm.
Trudng Dai hpc Ndng Ldm Thdnh phd Hd Chi Minh.
2. Duong Xudn TuyIn, L l Thanh Hdi vd Hodng Vdn T i | u , 2008. H i | n frang n h i | t dd, dm dd vd cudng dd dnh sdng ciia chudng nudi ciia vit de tai frai v}t gidng Vigova. V i | n Chdn nudi Thuy Phuong, Hd Ndi.
3. Hodng Kim Giao, Nguyin Thanh Son, 2005.
Chiin lupc phdt friln chdn nudi gia cdm giai doan 2005-2020 0 Vilt Nam. Thdng tin Hilp hdi Gia cdm Viet Nam.
4. Hudng dan ky thudt chdn nudi gd Cobb (2008) (www.cobb-vanfress.com).
5. Ld Thj Thu Minh, 2000. Bdi gidng chdn nudi gia cdm. Khoa Ndng nghilp Sinh hpc va Ung dtmg.
Trudfig Dai hpc Cdn Tho.
NONG NGHlfP VA PHAT TRIEN NONG
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C Q N G N G H |6. Trung tdm Chan dodn va Cd vdn Thii y C^ng ty CP Vilt Nam, 2007. Ky tiiudt chdm sdc gd tiiit tiieo phuong phdp cdng nghilp.
7. Vu Duy Giang, 2009. Nudi tdt gd broiler ngay tir khi mdi nd d l tdng kha ndng miln dich. Ddc san khoa hpc ky thudt thiic dn chdn nudi, ndm thii VII.
8. Adil Akyuz, 2009. Effect of some climates parameters of Environmentally unconfrollable broiler houses on broiler performance. J. Anim. Vet Adv. 8 (12): 2608-2612.
9. Aengwanich and Simaraks, 2004. Pathology of heart, lung, liver and kidney in broilers under chronic heat sfress. Songklanakarin J. Sci. Technol.
26:417-424.
10. Dowsland I., 2008. Broiler foot healtii confrolling foot pad dermatitis. Technical services manager. Aviagen.
11. Ensminger, M. E., Olentine, C. G., Jr., 1978.
Feeds and Nutrition, 1st Ed.; Ensminger Publishing Company: Clovis, CA
12. Fafrchild B. D., Czarick M., 2005. Chickens Broiler Housing. Encyclopedia of Animal Science, 205-213.
13. Garden, M., 2008. Broiler managerment for birds grovm to low kill weights. Region technical manager turkey. Middle East and Africa Aviagen.
14. May, J. D., B. D. Lott and J. D. Simmon^
1998. The effect ofenvfronmental temperature and body weight on growth rate and feed: gain of male broilers. Poulby Sci. 77:499-501.
15. Watts, D., 2008. Getting tiie breeder chick started. Regional technical manager. Western Europe.
16. ¥unianto, B. V. D., Hayashi, KL, Kaneda, S., Ohtiiska, A., Tomita, ¥., 1997. Effect of envfronmental temperature on muscle protein turnover and heat production in tube-fed broiler chickens. Br.J.Nufr. 77: 897-909.
EFFECTS OF TEMPERATURE AND HUMXDITY IN VENTILATTVE CLOSED HOUSING SYSTEM ON GROWTH PERFORMANCE OF ROSS 308 BROILERS
Luu Huu Manh, Nguyen Thi Thanh Giang, Nguyen Thanh Phi Long, Nguyen Nhut Xuan Dung, Pham Ngoc Du, Do Vo Anh Khoa
Summary
The objectives of the study were to survey and analysis effects of temperature and humidity on growth performance and feed comsumption of Ross 308 broilers. The study was, therefore, allocated in a completely randomized design with three replications in three different farms. Results demonstrated that high environmental temperature and air's moisture had close relationship with daily gain (R^=0.93 and R^=0.71, respectively) and feed consumption (R^= 0.81 and R^=0.77, respectively), in which temperature factor was more important In combination of both factors, it showed a high correlation coefficient
(R^=0.88) for feed consumption. High housing temperature and humidity may affect productivity and health of experimental herd. Thus, two these factors must be carefully confrolled to ensure their stability during production period in fiirther efforts to improve production efficiency of the Ross 308 chicken.
Keywords: Temperature, humidity, daily gain, feed consumption, ventilative closed housing.
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