KHOA HOC KY THUAT THU Y TAP XXI SO 3 - 2014
TiNH HiNH BENH OAU C H A N TREN BO SffA A CAC HO C H A N NUOI, HUYEN Ci) CHI, THANH PHO HO CHI MINH
Nguyin Kiin Cu&ng, Mguyin Vdn Tiin Khoa chdn nudt thu y. Dgt hgc Ndng Ldm TP Hd Chi .Minh
TOM
T A TKhao sat linh hinh benh dau chan a bo sua da dugc thuc hien hi thang 3 dgn thang 5 nam 2013.
lai xa Tan Thanh Dong, huyen Cti Chi, Thanh ph6 H6 Chi Minh. TOng s6 326 con bo ra gi6ng lai Holstein Friesian ctia 44 ho chan nuoi bo sua da dugc khao sat. Benh dau chan dugc xac dinh bang each danh gia diem dang dung (tir 1 - 5 digm), bo dugc xem la bi dau chan khi co digm dang dimg > 3.
Ket qua quan sat cho thay ty le bo bi dau chan trong dan bo khao sat la rk cao (41,4%). Nguyen nhan chu yeu la do bo thuang xuyen bi nh6l, cot trong chuOng va khong ggt mong dinh ky. 86 co m6ng chan dai c6 ty le dau chan (67,7%) cao hom bo co mong chan binh thuang (30,9%) (P < 0,01).
Ty le bo hi dau chan tang dan theo liia de, ty le nay a nhom bo de lua 1, liia 2 va lira 3 ISn lugt la 27,1%; 41,6% va 58,3%. Bo dugc tam UJ 3 - 4 lan/ngay thuong de bi dau chan ban bo dugc tim 2 lan/ngay (43,9% so vai 27,1%; OR = 2,1; P < 0,05).
Chiing dau chan co anh huong rat ldn den the trang ciia bo. Ty le gay 6 nhirng bo bi dau chan cao hon bo khong bi dau chan (34,8% so vai 14,7%; OR = 3,1; P< 0,001).
Tif khoa: Bo sua, Dau chan, Nguy co, The Irang
Assessment of lame prevalence In dairy cow at the small farmers in Cu Chi district, Ho Chi Minh city
Nguyen Kien Cuong, Nguyen Van Tien
SUMMARY
The survey on the lame dairy cow prevalence was earned out from March to May 2013 at Tan Thanh Dong c o m m u n e , Cu Chi district, Ho Chi Minh City. A total of 326 dauy cows ol Holstein Friesian crossbreed from 44 small farmers were observed. These cows were evaluated for lameness by determination of the score ot the arched back, standing appearance (from 1 to 5), the cow was lamed wfien the score was equal or lower than 3.
Tfie prevalence of the lame cow number in this survey was very tiigh (41.4%). This resulted from the cows were usually kept indoor and from the cows with their hooves were not trimmed periodically. The lame prevalence in the cows with long hooves was higher (67 7%) than in the cows with normal hooves (30.9%) (P < 0.01). The lame rate increased by the breeding farrow.
The lame rate in tfie first, second, third breeding farrow was 2 7 . 1 % , 41.6%, 58.3% respectively.
The cows were washed witfi 3 or 4 times per day facing more risk with lameness than the cows were washed with 2 times per day (43.9% vs 2 7 . 1 % , OR - 2 . 1 . P < 0.05).
The considerable effeci of lameness on body condition of the cows was observed. The rate of lean in the lameness group was hlgtier than in non-lameness group (34.8% vs 14,7%; OR = 3.1; P < 0,001)
Key words: Dairy cows, Lameness, Risk, Body condition
KHOA HOC KY THUAT THtJ Y TAP XXI SO 3 - 2014
I. DAT VAN DE
Chan nuoi bo sila a Viet Nam noi chung va TP Ho Chi Minh noi rieng phat trien rat manh trong thap nien vira qua, nhal la tir khi co Quyet dinh ciia Thu tucmg Chinh phii ve mot so bien phap va chinh sach phat trien bo siira Viet Nam thai ky 2001-2010. So lugng bo va san lugng siia ciia ca nuac tang deu tir nam 2001 den 2012 va \kn lugt la 14,6% va 18,4%. Nam 2012, t6ng dan bo siia va long san lugng sira cua ca nuoc la 170 nghin con va 381 nghin tan. TP. HCM van luon dan dau nganh siia ctia ca nuac voi long so bo sira khoang 88 nghin con (chiem 52%) va san lucmg sua khoang 226 nghin tan (chiem 59,2%) (T6ng Xuan Chinh, 2013). Chan nuoi hg gia dinh dong vai tro rat quan trgng trong long dan bo sua a TP. HCM, luy nhien mo hinh chan nuoi nay con rat nhieu han che ve ky thuat vi the nganh chan nuoi nay hien nay cung gap khong il kh6 khan ve ky thuat nhu viem vii, nang suat sinh san kem, dau chan, benh iruyen nhiem ...
NhCmg kho khan nay gay thiet hai rat Ion cho nganh chan nuoi bo sira, nhat la benh dau chan.
Benh dau chan da dugc nghien ciiu rat nhieu tren the gioi va no gay ra thiet hai kinh te rat ldn cho nguoi chan nuoi bo sua. Bo bi dau chan giam dang ke san lugng sua a moi chu ky (Green e M / . 2002; Enting etai, 1997) va chdl lugng sua cung bi anh huang (Enting ei al., 1997). Nang suat sinh san ciia bo bi dau chan cung bi giam rat nhieu nhu khoang each hai lira de keo dai (Enting el al, 1997), kha nang dau thai o lan gieo tinh dau tien thap va nguy ca bi u nang huong tning tang cao ban bo binh thuang (Melendez et al., 2003). Mat khae, bo bi dau chan CO nguy eo bi loai cao gap 8,4 lan so vai bo khong dau chan (Sprecher el al., 1997) va ton kha nhieu chi phi digu hri (Enting et al, 1997).
Cho den nay a Viet Nam chua co hoac co rdt il cac nghign cim day dii vg benh dau ehan tren
bo sira a hg gia dinh, hoac neu eo ciing chi dani gia dua vao trieu chiimg lam sang nhu sung, nong, do, dau va cae ton thuang ben ngoai, vi the CO the chua danh gia toan dien va chinh xac ty Ie dau chan. Nghien euu nay nham muc dich xac dinh ty le betih dau ehan tren bo siia a nong hg dua tren diem dang diimg; phan tich cac yeu to nguy ca co lien quan va danh gia anh huang cua benh dau chan len the trang eua bo.
II. NOI DUNG, VAT UEU
VA PHU'OnVG P H A P 2.1. Noi dung de tai- Xac djnh ty le bo hi dau chan thong qua viec danh gia diem dang dung ciia bo.
- Phan tich va xac dinh cac ygu to nguy co gay dau chan.
- Danh gia anh huang ctia benh dau chan len thg trang ciia bo.
2.2. Vat lieu
Bo sira sinh san giong lai Holstein Friesian (HF) tir lira mgl trd len ctia 44 hg chan nuoi lai cac ho nuoi bo sila eua xa Tan Thanh Dong, huyen Cu Chi, TPHCM.
Thdi gian tien hanh tir ngay 10/3/2013 den 25/5/2013.
2.3. Phu'OTig phap
2.3.1 Phdng van trirc tiip ngudi chan nuoi vdl bang cau hdi ve phuang phap chan nuoi va cham sdc dan bd.
2.3.2 Ddnh gid diim ddng dimg cua bo sinh sdn: dugc tien hanh theo phucmg phap ciia Sprecher va etv (1997) xem Bang 1. Thang diem duoc danh gia tir 1 den 5 diem. Neu bd cd diem dang dimg tit 3 trd len thi xem nhu bj dau chan.
KHOA HOC Kt THUAT THU Y TAP XXI S6 3 - 2014
Bang 1. Thang diem danh gia dang dirng Diem
1
2
3
4
5
Mieuta Hinh Binh thud'ng: bo di/ng tren mong, bdn chan vijng vang va i f l l B A l k
can d6i, va song lung thang khi dung va di Dang di binh ^ W j l ^ ^ ^
thudng, khong kh|p khieng. • • ^ • S ^ M Hai dau chan: bo dirng tren mong. bon chart vung vang va n # j ^ M ^
can doi. va song lu'ng thing khi dirng, ntiung hai cong khi fl^Rfc^^
di chuyen Dang di v i n binh thudng va kliong khap ktiieng w ^ ^ n M B Dau c h i n vira: Bo dirng khong thoai mai, lung cong ca khi ^ » ^ B 4 | l k dirng l i n khi di Dang di hai khap khieng va budc di ngan. T^^W.T' Dau chan nhieu: Bo dung khong thoai mai. lung cong ro if J ^ t ^ u ^ ret. Dang di khap khiing. 86 thudng khap khieng 1 hoac a V ^ ^ ^
nhiiu chan. l / j i m C ^ w Dau chan tram trong: Bo di dirng rit kho khan, lung rit C j f i j f c l '
cong ca khi dirng va di 86 khong co kha nang hoac miln i ffll^^r' cudng chiu luc d 1 hoac nhieu chan. • i ' j w J w M M '
2.3.3 Ddnh gid dg ddi cua mdng: thong qua digm gdc bet ciia ban chan sau so vdi dudng Ihang song lung theo huong din ctia Guyot va
civ (2012) (Bang 2). Mdng cang dai thi goc bet cang ldn. Diem gdc bet dugc cho tir 1 den 3 digm.
Ngu bo cd diem bang 3 xem nhu mong dai.
Bang 2. Thang diem danh gia goc bet ban chan sau so vd'i song lu-ng Dac diem
Diem 1: goc dugc tao bdt ban chan sau so vdi song lu'ng nho hon 17°
Diem 2: goc dugc lao bdi ban chan sau so v6i song lung tu' 17*' - 24°
Hinh minh hoa
M E
mm mm
mm
Diem 3: goc dugc tao / > •; \ C v O C / > ^ bdi ban Chan sau so VOI ^\°j t ^ \ \ 3 ' - ^ -'^J 1 song lung Idn han 24° 1 '
2.3.4 Diim thi trgng cua bo dugc danh gia theo phuang phap ciia Ferguson va ci\ (1997), tir di^m I (rat gSy) dgn 5 (map) vdi khoang each dan vj la 0.25 dicm. va dugc xac djnh. Ngu bd cd di^m thg trang thSp hem 2.5 dugc xem la gay.
2.4. \ u ly so lieu
Cac so heu trong khao sal nay dugc xir ly thdng ke trong phan mem Minitab 15 0. Trac nghiem X' dugc sii dung dg kiem dinh cac yen td cd thg lign quan ldi ly le benh dau chan ! \
KHOA HOC KY THUAT THU Y TAP XXI SO 3 - 2014
sd chenh (Odds Rario - OR) dugc diing de danh gia miic do nguy co ctia cac ygu to. Tuong quan giiia benh dau chan va thg trang ciing dugc xac dinh bang phuang trinh hoi quy tuyen tt'nh.
III. K E T Q U A V A T H A O L U A N 3.1. Tinh hinh chan nuoi dan bd sua 3.1.1. Sd hd vd cffcau ddn bo
Tdng sd 44 hg chan nuoi bd sCa da dugc khao sat, vdi tdng so bd la 667 con. Tinh trung binh moi hg cd 15,2 con bd, hg nuoi nhieu nhit la 30 con va it nhat la 4 con. Ve ca cau dan, bo sinh san (dang khai thac sUa va can sUa) chiem nhigu nhSl (48,8%), k6 dgn la bd hau bi (26,1%), ty le bg (eai va due) va due to lan lugt la 16,5 va 8,6% (Bang 3).
Bang 3. Cc cau dan bo khao sat
Nhom bo Dang khai thac sQa Can SLfa Haubi Be {< 6 thang) DLfctfy
Tdng cong
So bo 253
73 174 110 57 667
Ty le (%) 37,9 10,9 26,1 16,5 8,6 100
3.1.2. Phuo'ng thirc chdn nudi vd chdm sdc Vg phuang thiic, tat ca cac hp deu nudi nhdt hoan toan va bd bj cam cot sudt trong chudng cho den khi Ioai. Tat ca cac hg deu khdng bao gid ggt mdng cho bd
Doi vdl lam rira, eac hd deu tam cho bd va rira chudng hi 2 - 4 lan/ngay. Cd 6 hd (13,6%) tam eho bd 2 lan/ngay, 37 hg (84,1%) tam cho bo 3 lan/ ngay va 1 hg (2.3%) tam cho bo 4 lan/
ngay. Tat ea eac hg deu khdng trang bj he thdng quat de lam mat cho bo.
Viec sal trimg chuong trai d cac hd chan nuoi bd sira khdng thudng xuyen va edn nhieu han ehe. Tat ea cac hd dgu sat triing bang vdi bgt.
Cd 5 hd (11,4%o) sat triing mdi luan mgl lan, 2 ho (4,5%) sat trimg hai tuan mgt lan va 37 hp (84,1%.) sal triing lir ba tuan trd len mgt lan.
3.2. Ty le bd bi dau chan
Ket qua phan bd ciia dan bd theo Ihang diem dang diing dugc trinh bay qua Bang 4. Dua vao tigu chuan xgp loai dau chan (diem dang dimg
> 3) thi ly le bd bj dau chan va khong dau chan d khao sal nay lan lugt la 41,4%) va 58,6%.
Bang 4. Ket qua phan bo dan bd khao sat theo thang diem dang di>ng
Diem 1 2 3 4 5 Tong
So bo 150 41 83 38 14 326
Ty le (%) 46,0 12,6 25,5 11,6 4,3
100 j
KHOA HOC KY THUAT THU Y TAP XXI SO 3 - 2014
Ty le bd bj dau chan trong khao sat ciia chiing [oi cao hem rat nhieu so vdi khao sat (10,6%o) :ua Phan Viet Thanh (2010) d TPHCM va Binh Duong. Su khac biet nay cd thg do phuang phap danh gia chting dau chan khac nhau, lac gia trgn chii yeu danh gia dua vao cac trieu chirng lam sang (viem mdng, simg, dau ...). So vdi mgt sd nghien ciiu dAnh (36,8%) (Barkert et ai, 2010) va d Bac Ai Len (32,6%) (Baird et al, 2010), ket qua cua ehung toi vin eao hem, digu nay cd the do dieu kien chan nudi va dia Iy khac nhau.
Tuy nhien, ket qua nay ciia chiing toi thap hon ket qua cua mgt sd nghien ciiu d Anh (45,1%) (Palmer et ai, 2012) va d My (65,2%,) (Sprecher et al., 1997). Cac nghien ciiu trgn cung sit dung phuang phap tuong tu vdi chung tdi dg xac dinh dau chan. Nhu vay yeu td tao nen su khac biet nay cd the do nang suat sua ciia bo d cac nudc tren rat cao so vdi d nudc la. Bd cho nang suat sila cang cao thi nguy co bj dau
chan cang ldn (Green et ai, 2002). Thuc ra, bd cho sura cao thudng cd nhigu nguy co bi ke - tdn huygt va dieu nay lam tang nguy ca dau chan.
Han niia bd nang suat cao thudng can nhieu thuc an cho san xuat sila nen thdi gian dimg an lau eiing la yeu to nguy co gay dau chan.
3.3. Cac yeu to anh hirdng benh dau chan 3.3.J Lira de
Trong khao sat nay ehiing tdi khdng ghi nhan dugc tudi cua bd vi chu nudi khdng bigl, vl the chi ghi nhan lira de va thudng thi lira de tang theo ludi. Bang 5 cho thay ty le bd bj dau chan lang theo lua de. Nhdm bd lua 1. 2 \ a > 3 cd ty le dau chan ISn lugt la 27,1%, 41,6% \a 58.3%
va su khac biet nay rat cd y nghia Bd co Ilia de cang cao thi cang gia va thdi gian dimg trong chudng ciing nhieu hon vi the mdng ra diu hon va de bi dau chan ban, dieu nay da dugc the hign rat rd trong Bang 5.
Bang 5. Ty le dau chan theo lija de
Lira d e
1 2 23 T o n g
S o b o
129 89 108 326
B o d a u C h a n 35 37 63 135
B o k h o n g d a u c h a n 94 52 45 191
Ty le b o d a u c h a n (%)
27,1a 41,6b 58,3c 41,4
a vd b khdc biet cdy nghia vat P < 0.05;
a vd c khdc biet co y nghTa vdi P < 0,001;
c vd b khdc biit co y nghTa vai P < 0,05.
3.3.2. Dp ddi cua mdng
Dg dai cua mdng dugc thg hien qua do bet ciia gdc ban ehan sau so vdi song lung. Mdng chan sau cang dai thi gdc nay cang ldn. Ket qua cho thay ly le bd co diem gdc bet bang 1, 2 va 3 l4n lugt la 44,8%), 26,7% va 28.5"o Nhu vay so bd dugc xep vao nhdm cd mdng chan dai trong
khao sal nay chiem 28,5%. Kgl qua nay cao hon rat nhigu so vdi khuyen cao (< 10%) ciia Guyot et al., 2012). Mdng eang dai thi nguy ca bi dau chan cang eao, d khao sat nay nhdm bd mdng dai cd ty lg dau chan (67,7%) eao hon 2 lan so vdi bd cd mdng binh Ihudng (30,9%)) va su khac bigt nay rat rat cd y nghTa (P < 0,001) (Bang 6).
KHOA HOC KY THUAT THU Y TAP XXI S6 3 - 2014
Mong Binh thuang Dai Tong so
Bang 6. A n h hyo'ng mong dai len ty le dau chan
86 dau Chan 72 63 135
Bo khong dau 161 30 191
Tong so 233
93 326
Ty le dau chan {%) 30,9 67,7
Trong khao sal nay ty !e bd cd mdng dai kha cao la do cac hd chan nudi khdng ggt mdng trong sudl thdi gian nudi va tat ca bd deu bi cdt suot mgl ehd va it di lai, vi the mdng chan bd mau ra dai va digu nay lam cho bd de bi dau chan. Mgt nghien ctiu d Anh cho thay ty le dau chan trong dan lang theo thdi gian bd d trong ehu6ng (Barkert etal.,2010).
3.3.3 Giai dogn cho sira
Thang cho sua dugc chia lam 3 giai doan: giai doan dau tii' thang 1 - 3, giai doan giUa tir thang 4 - 6 va giai doan cudi lir thang 7 trd di. Bang 7 cho
thSy ty le dau chan giam dan theo giai doan cho sUa, ty le bd dau chan d cac giai doan nay lan Itrgt la 48,2%o, 44,1%) va 38,6%o, mac du su khac biet nay khdng cd y nghia (P > 0,05). Cd thg do giai doan cho sila thudng ngan (vai thang) nen chira anh hudng nhigu den dau chan. Han nua da so bo Ihudng cham mang thai lai sau khi sinh (c6 khi gan 2 nam) nen Ihang eho sila thudng keo dai, vi the khi phan ehia giai doan nhu thg Ihi so bo phan bd khdng deu ciing cd thg anh hudng den ket qua.
Tuy nhien, Green et al., 2002) da ghi nhan bo hay bi dau ehan nhieu nhal vao thang thd 2 va 3 cua chu ky cho sira.
Bang 7. Ty le dau chan theo giai doan cho sCra Giai doan
D^u GiOa Cu6i Tong
So bo 56 68 202 326
Dau Chan 27 30 78 135
Khong dau chan 29 38 124 191
Ty le dau Chan (%) 48,2 44,1 38,6 41,4
3.3.4. Sd ldn tdm trong ngdy
Kel qua khao sal cho thay phan ldn cae hd (S8,6*'o) tam va nia chudng tir 3 - 4 lan/ngay, ehi cd 5 hg (11,4%) thuc hien 2 lan/ngay. Tdng so bd duoc tam tir 3 - 4 lan/ngay la 278 eon va 2 lan/ngay la 48 eon. Kgt qua phan tich eho thay nhdm bo dugc tam tir 3 - 4 lan cd nguy CO bl dau chan (43,9%) gSp 2.1 mn(0R = 2,l;
P < 0,05) so vdi nhdm bd dugc tam 2 lan/ngay (27,1%)) (Bang 8). Viec tam, riia chuong nhieu lan cd the lam mdng bd mgm va de bi hu hai hay dl bj mam benh xam nhap, han nua do am chudng se tang len va vi sinh vat dg phal trien.
Tuy nhign, nhu:ng thdng tin trgn da khong duoc kiem ehiing trong khao sat nay do khong co digu kien.
KHOA HOC KY THUAT THU Y TAP XXIS6 3 - 2014
Bang 8. Anh hu'ang cua so lan tam ri>a len ty le dau chan
Tan suat tam 2 ian
>3ian Tong Cpng
Bo dau Chan 13 122 135
B6 khong dau chan 35 156 191
Ty le dau chan (%) 27,1 43,9
(P<0.05, OR =2,1)
3.4. Anh hudng cua b$nh dau chdn lin thi trgng Ket qua tii Bang 9 cho thdy b8nh dau chan anh hudng rat ldn den thg trang cua bd. Ty le bo
gay trong nhdm dau chan va khong dau chan lan lugt la 34,8% va 14,7%. Kgt qua phan tich eho thay bo bi dau ehan dg hi gay gap 3,1 lan (OR = 3,1; P < 0,001) so vdi bo khdng dau ehan.
Bang 9. Anh hiFO'ng cua chirng dau chan len the trang
Tinh trang dau chdn Co
Khong Tong CQng
So bo khao sat 135 191 326
Bo gay 47 28 75
Bo binh thu'ang 88 163 251
Ty i | bo gay (%) 34,8 14,7
(P < 0,001 vd OR =3,1)
Ket qua khao sat cua ehiing tdi cd the dugc giai thich dua vao nhimg ket qua nghien ciiu d Anh cua Palmer va ctv (2012). Cac tac gia nay da ghi nhan bd cd diem dau chan cang cao thi thai gian an, sd lugng thirc an, va so bila an trong ngay giam. Vi thg nhiing bd dau chan trong khao sat nay khdng thg dimg an lau do dau
chan nen Iugng ihiic an an vao giam va dan dan bd bl gay.
Kgt qua the hien d Bigu dd 1 ciing cho thay CO su tuong quan rat cao (P < 0,001) giira mirc do dau chan va thg trang ciia bd, Bd bi dau chan cang nang (diem dang dimg cang tang) thi the trang cang gay di (diem the trang cang giam).
£
•5
h
B
Fitted Line Plot
Y= 3.31-0,21X. 3=0,718, R-Sq= 12,4%, R-Sq{adj)=12,l%
W + i
1 2 3 4 5 Diem dang dung (X)Bieu do 1. Tirong quan giOa mtpc 66 6au chan va the tr^ng (P < 0,001)
KHOA HQC KY THUAT THC Y TAP XXI S6 3 - 2014
IV. KET LUAN
Ty le dau chan tren dan bd sHa cua cac hg chan nudi huyen Cii Chi, Thanh phd Hd Chi Minh rat eao. Nguyen nhan chu ygu la do ngudi chan nudi khdng dinh ky ggt mdng va bd bi cam cot sudt mgl chd h-ong chudng. Ty le dau chan tang dan theo lira de. Viee tam rira chudng tit 3 - 4 lan/
ngay cung gdp phan lam tang nguy ca dau ehan.
Benh dau chan cd anh hudng rat Idn den the trang cua bd. Bd bi dau ehan cang nang thi cang dg bi gay.
T A I L I E U T H A M K H A O 1. BAIRD L.G., LOGUE D.N., CARSON
A.F., MCCOY M.A., O'CONNELL N.E., 2010. Key housing and management factors affecting lameness levels on Northem Ireland dairy farms. In: Proc. Br. Soc. Anim.
Sci., Belfast, Cambridge University Press, Cambridge, UK, p 169.
2. BARKERZE.,LEACHK.A.,WHAYH.R„
BELLN.J., MAIN D.J.C, 2010. Assessment of lameness prevalence and associated risk factors in dairy herds in England and Wales.
Journal of Dairy Science, 93: 932-941.
3. ENTING H., KOOIJ D., DIJKHUIZEN A.A., HUIRNE R.B.M., NOORDHUIZEN- STASSEN E.N., 1997, Economic losses due lo clinical lameness in dauy cattle. Livestock Production Science, 49: 259-267.
4. FERGUSON J.D., GALLIGAN D.T., THOMSEN N., 1994. Principal descriptors of body condition score in Holstein cows.
Journal of Dairy Science,!!'. 2695-2703.
5 GREEN L.E., HEDGES V.J., SCHUKKEN Y.H., BLOWEY R.W., PACKINGTON
- A.J., 2002. The impact of clinical lamena on the milk yield of dairy cows. Joumal i Dairy Science, 85: 2250-2256. ; 6. GUYOT H., TPffiRON L., SIMON A
HANZEN C , ROLLIN R, LAMAIN G 2012. Caraet clinique en medecine d troupeau. Faculle de Medecine Veterinain Universite de Liege. Belgique, lOlp.
7. MELENDEZ R, BARTOLOME J ARCHBALD L.R, DONOVAN A., 2003 The association between lameness, ovaria cysts and fertility in lactating dairy cows Theriogenology, 59: 927-937.
8. PALMERA.M., LAWR, ANI O'CONNELLE.N., 2012. Relationship between lameness and feeding behaviou in cubicle-housed Holstein-Friesian dair cows. Applied Animal Behaviour Science 140: 121-127.
9. PHAN VIET THANH, 2010. Nghien cin cae ygu td anh hudng va thu nghiem mo sd bien phap phdng tri benh chan mdng ch(
bd sila khu vuc Ddng Nam Bg. Luain van t^
nghiep thac sT, Dai hgc Ndng Lam TPHCM
Viet Nam. 3 10. SPRECHER D.J., HOSTETLER D.Ej
KANEENE J.B., 1997. A lameness scoiinj system that uses posture and gait to predi^
dairy cattle reproductive performance Theriogenology, 4!: 1179-1187.
11. TONG XUAN CHINH, 2013. Khao sat danh gia tinh hinh san xuat va thi tnrdng sq nam 2012, du doan nam 2013. Trang web http://www.vietnamdairy.org.vn/vi/news php?nid=1304 (10/11/13).
Ngay nhan: 9.1.2014 Phanbien;10.3.2014
