Using body measurements to estimate live weight of dairy cattle in low-input systems in Senegal

Full Te ms & Condi ions o access and use can be ound a h p://www. and online.com/ac ion/jou nalIn o ma ion?jou nalCode= aa 20 Download by: [Na u al Resou ces Ins i u e Finland (Luke)] Da e: 27 Janua y 2017, A : 04:13 Jou nal o Applied Animal Resea ch ISSN: 0971-2119 (P in ) 0974-1844 (Online) Jou nal homepage: h p://www. and online.com/loi/ aa 20 Using body measu emen s o es ima e li e weigh o dai y ca le in low-inpu sys ems in Senegal S anly Fon Tebug, Ayao Missohou, Souahibou Sou okou Sabi, Ja mo Juga, Elizabe h Jane Poole, Miika Tapio & Ka en Ma shall To ci e his a icle: S anly Fon Tebug, Ayao Missohou, Souahibou Sou okou Sabi, Ja mo Juga, Elizabe h Jane Poole, Miika Tapio & Ka en Ma shall (2016): Using body measu emen s o es ima e li e weigh o dai y ca le in low-inpu sys ems in Senegal, Jou nal o Applied Animal Resea ch, DOI: 10.1080/09712119.2016.1262265 To link o his a icle: h p://dx.doi.o g/10.1080/09712119.2016.1262265 © 2016 The Au ho (s). Published by In o ma UK Limi ed, ading as Taylo & F ancis G oup Published online: 08 Dec 2016. Submi you a icle o his jou nal A icle iews: 136 View ela ed a icles View C ossma k da a Using body measu emen s o es ima e li e weigh o dai y ca le in low-inpu sys ems in Senegal S anly Fon Tebug a , Ayao Missohou b , Souahibou Sou okou Sabi b , Ja mo Juga c , Elizabe h Jane Poole a , Miika Tapio d and Ka en Ma shall a a The In e na ional Li es ock Resea ch Ins i u e, Nai obi, Kenya; b Se ice de Zoo echnie-Alimen a ion, Ecole In e -E a s Des Sciences E Médecines Vé é inai es (EISMV) de Daka , Daka , Sénégal; c Depa men o Ag icul u al Sciences, Uni e si y o Helsinki, Helsinki, Finland; d Na u al Resou ces Ins i u e Finland (Luke), G een echnology, Jokioinen, Finland ABSTRACT We in es iga ed he p edic ion o li e weigh (LW) o dai y ca le in low- o medium-inpu sys ems in Senegal, based on measu emen s o hea gi h (HG) and heigh a he wi he s (HW). A o al o 459 emale dai y ca le, mainly comp ising indigenous Zebu and hei c osses wi h Guze a o Bos Tau us, we e weighed (kg), and hei HG (cm) and HW (cm) de e mined. Fa me s we e asked o p o ide hei own weigh es ima es o each animal. The single explana o y a iable ha explained he mos a ia ion in LW was HG. The bes model o p edic LW om HG o he o e all da a was LW =4.81 HG −437.52 wi h an adjus ed R 2 o 0.85 and a oo mean squa e e o o 34.25 kg co esponding o 11.10% o he mean LW. This model p edic ed he LW o 91–100% o cows and 64– 100% o hei e s wi hin 20% o hei ue-li e weigh , in he weigh ange o abou 100–500 kg. In compa ison, a me s could only es ima e he LW o abou a qua e o hei animals wi hin 20% o hei ue LW. This weigh p edic ion equa ion, when ansla ed in o a weigh band, could p o ide a simple and eliable me hod o ca le keepe s o es ima e he weigh o s udied ca le b eed ypes. ARTICLE HISTORY Recei ed 7 June 2016 Accep ed 11 No embe 2016 KEYWORDS Dai y ca le b eed; weigh es ima ion; hea h gi h; heigh a wi he s 1. In oduc ion The accu a e es ima ion o body weigh o li es ock is impo - an in deciding he slaugh e weigh , eeding le el and wha ea men dose o use (Ulu as e al. 2002; Machila e al. 2008). Among he many me hods used o i s de e mina ion, a weigh- ing scale is conside ed he gold s anda d i he scales used a e well calib a ed (Machila e al. 2008). In mos u al a eas o A ica, ca le a e a ely weighed as weighing ins umen s a e cos ly o ob ain, need echnical main enance and a e di icul o ans- po o li es ock a ms, especially in pas o al and ag o-pas o al sys ems (Machila e al. 2008). Fa me s and ca le ade s o en ely on isual judgemen o de e mine he li e weigh (LW) o animals, which is a subjec i e me hod whose accu acy depends on use s’expe ience. Body weigh is closely ela ed o body measu emen s, wi h HG gene ally accep ed as he mos sa is ac o y single p edic o o LW in ca le (Fall e al. 1982; Dodo e al. 2001; Yan e al. 2009; Isik e al. 2009; Lesosky e al. 2012; Lukuyu e al. 2016). The me hod is cheap, accu a e and consis en ; hus, many p edic- i e eg ession equa ions a e based on his pa ame e alone o in combina ion wi h o he s. Whils such s udies ha e been ca ied ou in Senegal – he ocal coun y o his s udy –in he pas (Chollou e al. 1978; Fall e al. 1982; Buldgen e al. 1984), hey a e mo e han 30 yea s old and may no be alid o he new c oss and pu e ca le b eed ypes ha a e eme ging in Senegal, p ima ily h ough he use o exo ic b eed ypes ia a i icial insemina ion. The objec i es o his pape we e (1) o de elop a p edic ion equa ion o body weigh es ima ion om body measu emen s ac oss di e en ca le b eeds and c oss-b eeds cu en ly p esen in selec ed low-inpu ca le sys ems in Senegal, which could la e be ansla ed in o a weigh band o use by a me s and (2) o assess he accu acy wi h which a me s in hese sys ems es ima e he weigh o hei ca le. 2. Ma e ials and me hods 2.1. P ojec This s udy was pa o he Senegal Dai y Gene ics p ojec , whose aim is o imp o e dai y p oduc ion and p oduc i i y in Senegal h ough he use o he mos app op ia e b eed ypes. I is pa o he la ge Food A ica p og amme aimed a imp o ing ood secu i y in Wes and Eas A ica (see h ps://po al.m . i/ po al/page/po al/m _en/p ojec s/ ooda ica). 2.2. S udy si es Thiès and Diou bel egions o Senegal had been chosen o he la ge p ojec because o he di e si y o ca le b eed ypes in hese egions. The clima e in bo h egions is o he Sahelian ype cha ac e ized by a sho we season ha spans om July o Oc obe . Annual ain all a ies, wi h an a e age o 662.9 mm (Fall e al. 2006). The li es ock p oduc ion sys em is mainly ag o-pas o al. Ca le a e mainly g azed on na u al © 2016 The Au ho (s). Published by In o ma UK Limi ed, ading as Taylo & F ancis G oup This is an Open Access a icle dis ibu ed unde he e ms o he C ea i e Commons A ibu ion License (h p://c ea i ecommons.o g/licenses/by/4.0/), which pe mi s un es ic ed use, dis i- bu ion, and ep oduc ion in any medium, p o ided he o iginal wo k is p ope ly ci ed. CONTACT S anly Fon Tebug [email p o ec ed]; s anly [email protected] The In e na ional Li es ock Resea ch Ins i u e, PO 30709, Nai obi 00100, Kenya JOURNAL OF APPLIED ANIMAL RESEARCH, 2016 h p://dx.doi.o g/10.1080/09712119.2016.1262265 pas u es and occasionally ecei e c op esidues a he end o he ha es ing pe iod as well as eed concen a es du ing he d y season. 2.3. Da a This s udy was implemen ed be ween No embe 2013 and June 2015 on 484 emale ca le om 84 ca le-keeping a ms in Thiès and Diou bel egions o Senegal. He d we e selec ed based on hei he d composi ion, o ensu e ca le om all exis - ing b eed ypes we e ep esen ed. Da a we e ob ained om each animal: a me -es ima ed li e-weigh in kg; measu ed LW in kg; hea h gi h (HG) measu emen in cm and heigh a he wi he s (HW) in cm. LW was de e mined using an elec onic ca le scale (Iconix FX1 digi al indica o , Senso onic L d, Hamil- on, New Zealand). HG was measu ed by le ing he animal o s and wi h i s head in he no mal posi ion and placing an o din- a y measu ing ape a ound he animal a he poin o he smal- les ci cum e ence jus behind he o elegs and behind he hump o Zebu ca le. The ape was pulled sligh ly abou he animal, igh enough o pull down he hai s bu no o inden in o he lesh (B an on & Salisbu y 1946). HW was measu ed using a measu ing s ick (in cm), as he dis ance om he g ound o he highes poin o he wi he s. Age o each animal was es ima ed in yea s om isual assessmen o e up- ion and wea o ee h and a me ecall, and a b eed g oup was assigned o each animal. Measu emen s we e aken in he mo ning o animals ha we e s able- ed, o be o e animals we e aken o he pas u es o hose g azed on pas u es. All animals expe ienced a easonable p e-weighing as pe iod wi h li le a ia ion due o gu - ill a he ime o measu e. To ensu e a consis en me hodology, all measu emen s we e aken by he same pe son. S udy ca le we e assigned o ou main b eed g oups ei he on he basis o a me ecall in o ma ion o , whe e a ailable, geno ype in o ma ion. The b eed g oups (as speci ied u he inTable 1) a e (1) indigenous Zebu, p edominan ly he Zebu Gob a and Zebu Mau e b eeds; (2) indigenous Zebu c ossed wi h Guze a (which will be e e ed o as indigenous Zebu by Guze a abb e ia ed), whe e Guze a is a ecen ly in o- duced Zebu b eed de eloped in B azil om he Kank ei ca le impo ed om India (Ma ian e e al. 1999); (3) indigenous Zebu c osses wi h ecen ly in oduced Bos Tau us (indigenous Zebu by Bos Tau us), whe e Bos Tau us animals p edominan ly comp ise he high milk-yielding b eeds (mainly Mon belia d and Hols ein F iesians) and (4) indigenous Zebu c osses wi h a highe le el o Bos Tau us o pu e Bos Tau us (high Bos Tau us). We asked he a me s o name he b eed ypes o each o he animal’s g andpa en s, ha is, si e o si e, dam o si e, si e o dam and dam o dam. The animal’s p opo ion o ancien (indigenous) Zebu (AZ), ecen Zebu (RZ), ancien Tau ine (AT) and ecen Tau ine (RT) we e hen de e mined, and based on his he animals we e assigned a b eed g oup acco ding o he c i e ia in Table 1. Geno yping was pe o med on 128 o he measu ed animals using he Bo ine 50 K single nucleo ide polymo phism chip ( hese animals we e selec ed on he basis o being a emale wi h lac a ion eco ds, o he pu pose o de e mining he milk yield o he di e en b eed ypes, which will be epo ed elsewhe e). Admix u e (o his and e e ence da a) was analysed based on p ede ined clus e - ing in Bayesian Analysis o Popula ion S uc u e BAPS 6.0 (Co - ande e al. 2008) acco ding o he so wa e ins uc ions. F om he e he p opo ion o AZ, RZ, AT and RT was de e mined o each animal, and animals we e assigned a b eed g oup as pe he c i e ia in Table 1. Da a om 25 o he 484 measu ed ca le we e excluded om u he analysis as hei body weigh was less han 100 kg ( o which no ela ionship be ween LW and body measu emen s was ound). The inal da ase included obse a ions om 459 animals (345 cows (3 o mo e yea s o age), 114 hei e s (22 less han 12 mon hs o age, 42 be ween 12 mon hs and 23 mon hs o age, and 51 be ween 24 mon hs and 35 mon hs o age)). The g oups included 270 indigenous Zebu, 58 indigenous Zebu by Guze a and 46 indigenous Zebu by Bos Tau us, 36 high Bos Tau us and 49 o he s (Table 2). 2.4. Analysis app oach Summa y s a is ics o he da a a e gi en as means and s anda d de ia ion (Table 2). Compa ison o means was de e mined by a one-way analysis o a iance ollowed by Tukey’s hones ly signi ican di e ence. S a is ical signi icance was assessed a p< .05. LW, HG and HW we e app oxima ely no mally dis ibu- ed (Figu e 1). S epwise eg ession wi h backwa ds elimina ion p ocedu e was used o de e mine he bes model o p edic ing LW, based on Akaike’s In o ma ion C i e ion (which conside s bo h he i o he model and model simplici y). The ull model comp ised he independen a iables HG and HW as co- a ia es, and age and b eed as ca ego ical a iables. Simple linea eg ession was also used o p edic LW om HG. The adjus ed coe icien o (mul iple) de e mina ion (adjus ed R 2 ) was also gi en o he models, as an indica o o he amoun o a iance in LW explained by he model. The oo mean squa e e o (RMSE; he same as he s anda d de ia ion o he esiduals), and also he RMSE exp essed as a pe cen o he eal LW, was used an indica o o accu acy o he eg ession es ima es (Yan e al. 2009; Lukuyu e al. 2016). Nine y- i e pe cen p edic ion in e als we e de e mined as he p edic ed alue ± wice he RMSE. The i o he eg ession models we e also e i ied by checking he esidual Table 1. C i e ia o b eed g oup de ini ion, o animals assigned o a b eed g oup by ei he a me ecall in o ma ion o geno ype in o ma ion. C i e ia o b eed g oup assignmen , based on p opo ions o AZ, RZ and RT a B eed g oup name Fa me ecall in o ma ion Geno ype in o ma ion Indigneous Zebu 1.00 AZ 0.88–0.99 AZ Indigenous Zebu by Guze a 0.50–0.75 AZ; 0.25–0.50 RZ 0.39–0.86 AZ; 0.13–0.61 RZ Indigneous Zebu by Bos Tau us 0.50–0.75 AZ; 0.25–0.50 RT 0.38–0.84 AZ; 0.13–0.61 RT High Bos Tau us 0.00–0.25 AZ; 0.75–1.00 RT 0–0.36 AZ; 0.63–0.98 RT O he s O he b eed ypes o unknown b eed in o ma ion a Whe e AZ e e s o ancien (indigenous) Zebu b eeds; RZ, ecen ly in oduced Zebu b eeds; and RT, ecen ly in oduced Bos Tau us b eeds. AZ b eeds a e mainly Zebu Gob a and Zebu Mau e, RZ b eeds a e mainly Guze a , and RT b eeds a e mainly Hols ein F iesians and Mon belia d. 2S. F. TEBUG ET AL. plo s. All analyses we e pe o med in R (R Co e Team, 2012), wi h s ep AIC unc ion om he MASS package used o back- wa d s epwise elimina ion eg ession, and lm unc ion was used o simple linea eg ession. 3. Resul s and discussion 3.1. Obse ed body measu emen s and hei co ela ions Summa y s a is ics o LW, HG and HW o adul and hei e s o he a ious b eed g oups a e gi en in Table 2. LW, o cows, anged om 110 o 618 kg, HG om 110 o 213 cm and HW om 95 o 161 cm. LW, HG and HW we e lowe o cows o he indigenous Zebu and Zebu by Guze a b eed g oups, in compa ison o ha o he indigenous Zebu by Bos Tau us and high Bos Tau us b eed g oups (p< .05). Fo example, indigen- ous Zebu cows had a mean LW (mean ± SD) o 302.7 (60.9) kg, whils ha o he high Bos Tau us was 392.2 (113.9) kg. Simila esul s we e no ound o hei e , howe e , likely due o he di e en age p o iles o young animals o he di e en b eed g oups. The LW ange o cows o he indigenous Zebu b eed g oup ound in his s udy is compa able o a p e iously epo ed weigh ange o adul Zebu Gob a in Senegal o 250–350 kg Table 2. Summa y s a is ics 1 o he inal da a se o measu ed li e weigh (LW), hea -gi h (HG) and heigh a he wi he s (HW), o cows and hei e s o he di e en b eed g oups 2 . Indigenous Zebu Indigenous Zebu by Guze a Indigenous Zebu by Bos Tau us High Bos Tau us O he NMean SD NMean SD NMean SD NMean SD NMean SD LW (kg) Cow 215 302.74 a,b 60.87 40 310.68 a,c 61.90 32 383.19 d 129.35 16 392.25 d 113.94 42 326.36 b,c 78.01 Hei e 55 226.07 a,b,c 71.23 18 200.89 a,d 42.82 14 243.53 b,d,e, 87.96 20 279.25 e,g 125.94 7 281.71 c, ,g 78.93 HG (cm) Cow 215 153.51 a,b 11.73 40 155.65 a,c 13.90 32 167.56 d 22.00 16 171.31 d 19.95 42 157.33 b,c 13.44 Hei e 55 138.98 a,b,c 15.25 18 134.11 a,d 12.02 14 145.64 b,d,e, 17.50 20 150.70 e,g 25.55 7 150.29 c, ,g 15.1 HW (cm) Cow 215 117.75 a,b 6.71 40 119.00 a,c 6.43 32 122.62 d 12.94 16 126.00 d 9.76 42 118.62 b,c 7.05 Hei e 55 110.58 a,b,c,d 7.70 18 108.89 a,e, ,g 8.52 14 114.5 b,e,h,i 9.40 20 113.55 c, ,h,j 12.61 7 116.00 d,g,i,j 6.98 1 N= numbe o eco ds; SD = s anda d de ia ion. 2 Means wi hin a ow bea ing he same supe sc ip a e no s a is ically di e en (p> .05). Figu e 1. F equency his og ams o LW o li e weigh (a), hea h gi h (b) and heigh a he wi he s (c). JOURNAL OF APPLIED ANIMAL RESEARCH 3 (Missohou e al. 1997). The a e age LW, HG and HW measu es o cows o high Bos Tau us ound in his s udy we e gene ally lowe compa ed o 419–781 kg, 176–223 cm and 125–150 cm epo ed o Hols ein F iesians cows in a de eloped coun y con ex (Yan e al. 2009), likely due o he lowe eeding le el o animals in his s udy in compa ison o ha in he de eloped wo ld, and because he high Bos Tau us g oup in his s udy we e no always pu e-b ed (see Table 1). A s udy on dai y ca le in Kenya (Lukuyu e al. 2016) whe e animals mainly com- p ised he Small Eas A ican Zebu (SEAZ) c ossed a di e en le els o exo ic b eeds gene ally ga e lowe LW, HG and HW han ha epo ed he e, e lec ing he di e en s a u es o he main Zebu ypes in he wo s udies. The high s anda d de ia ions obse ed o LW, HG and HW wi hin a pa icula b eed g oup a e also in line wi h p e ious s udies (Fall e al. 1982; Dodo e al. 2001; Yan e al. 2009), and would la gely e lec he di e si y o ca le managemen p ac- ices wi hin ou s udy si es. Fo all animals, he co ela ion ( ) be ween LW and HG was high a = 0.92, and he co ela ion be ween LW and HW and be ween HW and HG was mode a e a = 0.78 and a = 0.77, espec i ely. The co ela ions epo ed abo e a e simila o o he s udies ha ound a co ela ion be ween LW and HW o 0.88–0.97 , and a co ela ion be ween LW and HW o HG o 0.65–0.92 in Wes A ica (Chollou e al. 1978; Fall e al. 1982; Dodo e al. 2001). 3.2. P edic ion o LW P edic ion equa ions o LW o di e en models, o he en i e da ase as well as selec ed subse s o animals (sex and b eed g oups), a e gi en in Table 3. Fo he en i e da ase , he bes model o p edic LW was LW =4.08 HG + 1.61 HW +1.42 (Age) −520.90 , yielding an adjus ed R 2 o 0.86 and a RMSE o 32.81 co esponding o 11.02% o he mean LW. The bes models o a ious subse s o da a (which a ied acco ding o he da a subse ) had an adjus ed R 2 anging om 0.79 o 0.94 and a RMSE anging om 29.27 o 39.24 kg (9.36%–12.33% o he mean LW). As he aim o his p ojec was o de elop an easy- o-use ool o p edic LW o animals (wi hin a known p edic ion in e al) om body measu emen s –such as a body measu emen o weigh con e sion able o weigh band –we we e in e es ed in a model wi h a single explana o y a iable and ha could be used ac oss he ange o ca le ypes p esen in he s udy si es. The single explana o y a iable ha explained he mos a ia ion was HG, consis en wi h p e ious s udies (Dodo e al. 2001; Yan e al. 2009;Lesoskye al.2012; Lukuyu e al. 2016). P edic ing LW om HG alone, he model o he o e all da a was LW = 4.81 HG–437.52, which had an adjus ed R 2 o 0.85, and a RMSE o 34.25 kg co e- sponding o 11.10% o he mean LW. Thus, basing a ool on his equa ion would enable a me s o p edic he LW o emale animals o 100 kg o a leas 500 kg, o wi hin 34.25 kg o he eal LW in 68% o he cases. Figu e 2 shows a plo o his model in ela ion o ou da a. A compa ison o p edic ed LW o eal LW, o adul s and hei e s o he a ious b eed g oups and ia he model Table 3. Reg ession equa ions p edic ing li e weigh om di e en models, o all animals o selec ed subse s. G oup o animals Reg ession equa ion Adjus ed R 2 RMSE a RMSE as % eal LW P edic ion ia bes model ( o ha speci ic g oup o animals) All LW = 4.08 HG + 1.61 HW + 1.42 Age–520.90 0.8585 32.81 11.02 Cow LW = 1.42 HG + 4.32 HW + 1.19 Age–536.06 0.8165 33.51 10.54 Hei e LW = 3.42 HG + 2.30 HW–504.55 0.8820 29.27 12.33 Indigenous Zebu LW = 3.41 HG + 1.42 HW + 1.63 Age–461.27 0.7860 32.31 11.25 Indigenous Zebu by Guze a LW = 3.34 HG + 1.24 HW + 4.56 Age–384.53 0.8276 30.63 11.07 Indigenous Zebu by Bos Tau us LW = 4.70 HG + 1.70 HW–624.06 0.9370 31.58 9.36 High Bos Tau us LW = 5.00 HG–470.17 0.9064 39.24 11.91 P edic ion ia HG only All LW = 4.81 HG–437.52 0.8465 34.25 11.05 Cow LW = 4.87 HG–444.07 0.8059 34.41 10.82 Hei e LW = 4.39 HG–384.48 0.8611 31.82 13.43 Indigenous Zebu LW = 4.45 HG–384.11 0.7685 33.66 11.72 Indigenous Zebu by Guze a LW = 4.25 HG–357.56 0.8018 33.31 12.04 Indigenous Zebu by Bos Tau us LW = 5.47 HG–543.33 0.9301 33.64 9.96 High Bos Tau us LW = 5.00 HG–470.17 0.9064 39.24 11.91 a Roo mean squa e e o . Figu e 2. Rela ionship be ween li e weigh (LW) and hea -gi h (HG) o he en i e da ase o he equa ion LW = 4.81 HG–437.52, and wi h di e en symbols used o di e en b eed g oups. The model line is ep esen ed by he hick solid line, and 95% p edic ion in e als o he model a e ep esen ed by dashed lines. 4S. F. TEBUG ET AL. LW =4.81HG −437.52, showed ha , on a e age, cows o he indigenous Zebu and indigenous Zebu by Guze a b eed g oups ha e hei weigh nei he s ongly unde - o o e es i- ma ed, whils cows o indigenous Zebu by Bos Tau us, high Bos Tau us and o he b eed g oups ended o ha e hei weigh unde es ima ed (by 7.36, 4.76 and 7.10 kg, espec i ely). Hei e s o all b eed g oups ended o ha e hei weigh o e es ima ed, by 3.64–11.26 kg depending on he b eed g oup (Table 4). Ac oss he di e en b eed g oups, he pe cen ages o cows whose weigh was p edic ed wi hin 20%, 10% o 5% o hei ue LW was a leas 91%, 59% and 35%, espec i ely. Fo hei e s, hese igu es we e lowe a 77%, 55% and 34% (exclud- ing he indigenous Zebu by Bos Tau us hei e s, which had pa - icula ly low alues o 64%, 50% and 21%), pa ly a ibu able o he lowe weigh s o younge emales (Table 4). These pe cen- ages, and pa icula ly hose o hei e s, we e lowe han he 70% o animals wi hin 10%, and 41% wi hin 5%, epo ed o LW es ima ion om HG measu es in 24 mon hs old N’dama ca le aised on a esea ch a m in Senegal (Fall e al. 1982). This, howe e , is o be expec ed gi en he a ie y o b eeds, ages o animals and managemen p ac ices included in ou s udies compa ed o ha o he Fall e al. (1982) s udy. Es ima ion o ca le weigh o wi hin 20% o hei ue weigh is conside ed as an accu acy ange o e e ina y d ug dosing (Machila e al. 2008; Lesosky e al. 2012). Fo cows, his was achie ed o 92.73% o he o e all cases, whils o hei e s his was achie ed o 83.48% o he o e all cases. Thus, he HG model p esen ed he e can be conside ed as a easonable way o p edic he weigh o cows o pu poses o d ug dosing, bu o o he pu poses whe e mo e accu acy is equi ed (e.g. selec ion o ca le on LW), he use o a p ope weigh scale is p e e ed (ILCA/IER 1978; Goe e al. 2001). 3.3. Compa ison o exis ing models o LW p edic ion o Wes A ican ca le LW p edic ions om HG measu emen s o ca le in Wes A ica, om six p io s udies in addi ion o ou s udy, a e shown in Figu e 3, wi h he eg ession equa ions and coun y and b eed o animal included (whe e known) o hese p io s udies gi en in Table 5. The p edic ed weigh om ou s udy ended be highe in compa ison o ha in o he s udies, excep a lowe HGs. Resul s o ou s udy we e close o ha o a p io s udy on Zebu Gob a in Senegal (Chollou e al. 1978), which makes sense gi en ha he majo i y o animals in ou s udy we e Zebu Gob a o hei c osses. The ela ionship be ween LW and o he body measu emen s including HG has been shown o be in luenced by sex, b eed and age (Buldgen e al. 1984; Sow e al. 1991; Ozkaya & Bozku 2009), p o iding an explana ion o he di e en models esul ing om he di e en s udies. 3.4. Fa me s’abili y o es ima e weigh An addi ional componen o his s udy was o compa e a me s’ es ima e o he weigh o he animal o he measu ed LW. The co ela ion be ween hese wo a iables was low a 0.53 o he en i e da ase . As shown in Figu e 4, a me s ended o unde - es ima e he weigh o hei animals. On a e age, and o cows, he indigenous Zebu, Zebu by Guze a , Zebu by Bos Tau us and high Bos Tau us b eed g oups we e unde es ima ed by 115.60 (92.46), 109.10 (83.56), 94.05 (99.47), 149.65(109.18) and 173.81 (118.32) kg, espec i ely (means, and s anda d de ia ions in Table 4. Li e-weigh p edic ions o cows and hei e s o he di e en b eed g oups, using he o e all eg ession equa ion LW = 4.81 HG–437.52, and o he summa y in o ma ion in ela ion o his. B eed g oup Animal age g oup N Li e weigh p edic ions om hea -gi h (kg) Mean p edic ed weigh less mean eal li e weigh Pe cen age o animals wi h a p edic ed li e-weigh wi hin he indica ed pe cen age o hei ue li e-weigh Mean SD 20% 10% 5% Indigenous Zebu Cow 215 300.85 56.43 −1.89 91.16 62.33 35.35 Hei e 55 230.98 73.36 4.90 85.45 63.64 34.55 Indigenous Zebuby Guze a Cow 40 311.16 57.80 0.48 92.50 67.50 37.50 Hei e 18 207.56 66.84 6.66 77.78 55.56 44.44 Indigenous Zebuby Bos Tau us Cow 32 375.83 98.84 −7.36 93.75 68.75 56.25 Hei e 14 254.80 87.14 11.26 64.29 50.00 21.43 High Bos Tau us Cow 16 386.51 95.95 −5.76 100.00 67.25 50.00 Hei e 20 287.35 122.88 8.10 95.00 60.00 35.00 O he Cow 42 319.25 64.64 −7.10 95.24 59.52 35.71 Hei e 7 285.35 72.61 3.64 100.00 85.71 57.14 Figu e 3. Li e weigh p edic ions om hea gi h measu emen s o ca le in Wes A ica, om di e en s udies. JOURNAL OF APPLIED ANIMAL RESEARCH 5 b acke s). Only 25.5% o animals had a a me -es ima ed weigh wi hin 20% o hei ue weigh , and only 7.0% o animals had a a me -es ima ed weigh wi hin 5% o hei ue weigh . The unde es ima ion o ca le weigh by a me s ag eed wi h he indings o Machila e al. (2008) in Kenya, whe e 85.7% o ca le had hei body weigh s unde es ima ed by hei Table 5. Model equa ions o p edic ing li e weigh om hea -gi h measu emen s o ca le in Wes A ica, om di e en s udies. Ca le b eed Ca le age ange (yea s) Ca le sex a Coun y Equa ion b R 2 Re e ence Va ious, bu p edominan ly indigenous Zebu 1–18 F Senegal LW = 4.81 HG–437.52 0.85 c P esen s udy Zebu Gob a 0.25 –5 M, F Senegal LW = 0.02 HG 2 + 2.54 HG + 83.32 –Chollou e al. (1978) Djako e (c oss be ween Zebu Gob a and N’dama) ≤4 F Senegal LW = 3.13 HG–215.32 –Buldgen e al. (1984) Ndama 1 –2.5 M, F Senegal LW = 3.43 HG–278.83 –Fall e al. (1982) Zebu Peul and Mau e 0–2 Mali LW = 3.43 HG–278.82 –ILCA/IER (1978) Zebu Azawak –M, F LW = 0.002 HG 2 + 1.31 HG–24.12 0.92 Dodo e al. (2001) Gudali –M, F Nige ia LW = 0.002 HG 2 –4.88 HG–438 –Bu anend an e al. (1980) a M = Male; F = Female. b LW is li e weigh in kg and HG is hea gi h measu emen in cm. c Adjus ed R 2 . Figu e 4. Sca e plo o a me -es ima ed li e weigh e sus eal li e weigh o he whole da ase (a) and a ious b eed g oups: (b) indigenous Zebu; (c) indigenous Zebu by Guze a ; (d) indigenous Zebu by Bos Tau us; (e) high Bos Tau us and ( ) o he s. 6S. F. TEBUG ET AL. owne s. The high unde es ima ion o LW by a me s aises con- ce ns o widesp ead unde -dosing o ca le wi h e e ina y d ugs, a majo ou e o d ug esis ance (Dijk e al. 2015), especially in sub-Saha an A ica whe e animal owne s and animal heal h p o ide s wi h limi ed aining a e o en espon- sible o he adminis a ion o d ugs o li es ock (Cheneau e al. 2004). 4. Conclusion The aim o his s udy was o p o ide a me s wi h a simple and eliable ool o es ima ing he LW in ca le. The model de el- oped p edic ed he LW o 91–100% o cow and 64–100% o hei e ca le wi hin 20% o hei ue LW, dependen on he b eed g oup, in he weigh ange o abou 100–500 kg. This model, in he u u e, can be ansla ed in o an easy- o-use ool such as weigh band o a me s, who only co ec ly es i- ma ed he LW o abou a qua e o hei animals wi hin 20% o hei ue LW. Mos models de eloped in di e en egions in Senegal and Wes A ica unde es ima ed he weigh o animals in his s udy, which sugges s a need o alida e he equa ion on u he ca le b eeds, age and sex g oups in o de o achie e a wide applica ion o he model. Disclosu e s a emen No po en ial con lic o in e es was epo ed by he au ho s. Funding This wo k was ca ied ou as pa o la ge esea ch p ojec ‘Senegal Dai y Gene ics’(h p://senegaldai y.wo dp ess.com/), unded by he Finnish Min- is y o Fo eign A ai s unde he WP2 o he Food A ica P og am. The au ho s also g a e ully acknowledge unding om he Uni e si y o Helsinki, Finland. Ou app ecia ion also goes o pa icipa ing a me s o p esen ing hei animals o his s udy. Re e ences B an on C, Salisbu y GW. 1946. The es ima ion o he weigh o bulls om hea gi h measu emen s. J Dai y Sci. 29:141–143. Buldgen A, Compe e R, Riboux A. 1984. Reche che d’une o mule ba ymé ique adap ée aux bo ins de ype Djako é des éle ages illageois du Sénégal O ien al. T opicul u a. 2:86–90. Bu anend an V, Umoh JE, Abubaka BY. 1980. An e alua ion o body size as ela ed o weigh o h ee Wes A ican b eeds o ca le in Nige ia. J Ag ic Sci. 95:219–224. Cheneau Y, ElId issi AH, Wa d D. 2004. An assessmen o he s eng hs and weaknesses o cu en e e ina y sys ems in he de eloping wo ld. Re Sci Tech In O Epizoo . 23:351–359, 401. Chollou M, Denis JP, Gauche D. 1978. Calcul d’une o mule ba ymé ique adap ée au zébu Gob a. Re Déle age Médecine Vé Pays T op. 31:447–450. Co ande J, Ma inen P, Si én J, Tang J. 2008. Enhanced Bayesian modelling in BAPS so wa e o lea ning gene ic s uc u es o popula ions. BMC Bioin o m. 9:539. doi:10.1186/1471-2105-9-53 Dijk, J. an, Eagle, SJ, Gillespie, AV, Smi h, RF, Holman, AN, Williams, HJ. 2015. Visual weigh es ima ion and he isk o unde dosing dai y ca le. Ve Rec. 177, 75–75. Dodo K, Pandey VS, Illiassou MS. 2001. U ilisa ion de la ba ymé ie pou l’es- ima ion du poids chez le zébu Azawak au Nige . Re Déle age Médecine Vé Pays T op. 54:63–68. Fall A, Diop M, Sand o d J, Wissocq YJ, Du kin J, T ail JC. 1982. E alua ion des p oduc i i és des o ins Djallonke e des au ins N’Dama au Cen e de eche ches zoo echniques de Kolda, Sénégal. Addis Ababa: ILCA. Fall S, Niyogi D, Semazzi FHM. 2006. Analysis o mean clima e condi ions in Senegal (1971–98). Ea h In e ac . 10:1–40. Goe MR, Alld edge JR, Ligh D. 2001. Use o hea gi h o p edic body weigh o wo king oxen in he E hiopian highlands. Li es P od Sci. 69:187–195. ILCA/IER. 1978. E alua ion o he p oduc i i ies o Mau e and Peul ca le b eeds a he Sahelian s a ion, Niono, Mali. Addis Ababa: ILCA. Isik HB, Topcu Y, Gule O. 2009. De e mina ion o he ac o s a ec ing li e weigh gain using ac o analysis and s epwise eg ession model. J Appl Anim Res. 35:161–164. Lesosky M, Dumas S, Con adie I, Handel IG, Jennings A, Thumbi S, Toye P, B ons oo BM de C. 2012. A li e weigh -hea gi h ela ionship o accu- a e dosing o eas A ican sho ho n zebu ca le. T op Anim Heal h P od. 45:311–316. Lukuyu MN, Gibson JP, Sa age DB, Duncan AJ, Mujibi FDN, Okeyo AM. 2016. Use o body linea measu emen s o es ima e li eweigh o c ossb ed dai y ca le in smallholde a ms in Kenya. Sp inge Plus. 5:63. doi:10. 1186/s40064-016-1698-3 Machila N, Fè e EM, Maudlin I, Eisle MC. 2008. Fa me es ima ion o li e body weigh o ca le: implica ions o e e ina y d ug dosing in Eas A ica. P e Ve Med. 87:394–403. Ma ian e A da S, Albuque que M do SM, do Egi o AA, McManus C. 1999. Ad ances in he B azilian animal gene ic esou ces conse a ion p o- g amme. Anim Gene Resou Resou Géné iques Anim Recu Gené icos Anim. 25:107–121. Missohou A, Bankole AA, Niang AT, Ragounandea G, Talaki E, Bi a I. 1997.Le Zébu Gob a: Ca ac è es e hniques e pe o mances zoo echniques. Ani Gene Resou In o m. 22:53–60. Ozkaya S, Bozku Y. 2009. The accu acy o p edic ion o body weigh om body measu emen s in bee ca le. A ch Tie z. 4:371–377. R Co e Team. 2012. R: a language and en i onmen o s a is ical compu ing. R Founda ion o S a is ical Compu ing, Vienna, Aus ia. A ailable om: h p://www.R-p ojec .o g/ Sow RS, Denis JP, T ail JCM, Thiongane PI, Mbaye M. 1991.No esu la ba ymé ie comme moyen de sélec ion indi ec e du poids i chez le zébu Gob a au Sénégal. Re Déle age Médecine Vé Pays T op. 44:97–100. Ulu as Z, Saa ci M, ÖZLüTüRK A. 2002. P edic ion o body weigh s om body measu emen s in Eas Ana olian Red cal es. Indian J Anim Sci. 72:878–881. Yan T, Mayne CS, Pa e son DC, Agnew RE. 2009. P edic ion o body weigh and emp y body composi ion using body size measu emen s in lac a ing dai y cows. Li es Sci. 124:233–241. JOURNAL OF APPLIED ANIMAL RESEARCH 7