Open Jou nal o Animal Sciences, 2015, 5, 86-98
Published Online Ap il 2015 in SciRes. h p://www.sci p.o g/jou nal/ojas
h p://dx.doi.o g/10.4236/ojas.2015.52011
How o ci e his pape : C iscioni, P., del Ca men López, M., Zena, V. and Fe nández, C. (2015) Hea P oduc ion Pa i ion in
Sheep Fed abo e Main enance om Indi ec Calo ime y Da a. Open Jou nal o Animal Sciences, 5, 86-98.
h p://dx.doi.o g/10.4236/ojas.2015.52011
Hea P oduc ion Pa i ion in Sheep Fed
abo e Main enance om Indi ec
Calo ime y Da a
Pa icia C iscioni1, Ma ía del Ca men López1, Vic o Zena2, Ca los Fe nández1*
1Resea ch Cen e ACUMA, Animal Science Depa men , Poly echnic Uni e si y o Valencia, Valencia, Spain
2In e uni e si y Ins i u e o Bioenginee ing Resea ch and Technology O ien ed o he Human Being,
Uni e sidad Poli écnica de Valencia, Valencia, Spain
Email: *cj e [email protected] .es
Recei ed 11 Feb ua y 2015; accep ed 23 Ma ch 2015; published 27 Ma ch 2015
Copy igh © 2015 by au ho s and Scien i ic Resea ch Publishing Inc.
This wo k is licensed unde he C ea i e Commons A ibu ion In e na ional License (CC BY).
h p://c ea i ecommons.o g/licenses/by/4.0/
Abs ac
The objec i e o his s udy is o compa e he pa i ion o hea ene gy (HE) in wo sheep b eeds by
indi ec calo ime y and in eg al calculus. An expe imen was conduc ed wi h wo Spanish na i e
sheep b eeds (d y and non-p egnan ) which we e ed wi h pelle ed mixed die s abo e main en-
ance. Six Gui as and six Manchegas b eed sheep we e selec ed (58.8 ± 3.1 and 60.2 ± 3.2 kg body
weigh , espec i ely). All sheep we e ed wi h he same concen a e mixed a ion (0.300 kg ce eal
s aw as o age and 0.700 kg concen a e) in wo meals. Hal he daily a ion was o e ed a 800 h
and ano he hal a 1600 h. The sheep had ee access o wa e . Sheep we e alloca ed in me abolic
cages; ene gy balance and gas exchange we e assessed in each sheep. The s a is ical analyses in-
cluded he ixed e ec o b eed and andom e ec o sheep. The me abolic ene gy (ME) o main-
enance ep esen ed 69% o he o al ME in ake and he a e age was 354 kJ pe kg o me abolic
body weigh (kg0.75 BW) on a e age. The basal me abolism (HeE) was g ea e (P < 0.05) in Gui a
han Manchega b eed (270 ± 18 s. 247 ± 15 kJ/kg0.75 BW and day). As sheep we e ed wi h abo e
main enance, he e ained ene gy in he body accoun ed o 22% o he ME in ake and 77% o he
ME in ake was los as hea . 51% o he MEI was con e ed o HeE; 5% was los as physical ac i i y
o s anding and lying down (HjE), and 13% was associa ed wi h he p ocess o eeding and wo k o
diges ion and me abolism (HdE). Wi hin HdE, 47% ep esen ed he cos o in ake and eeding and
54% he cos o diges ion and me abolism. No di e ences in HE pa i ion be ween b eeds we e
ound, al hough Gui a b eed showed less e iciency o ene gy e en ion han Manchega b eed.
The e o e, his s udy demons a ed a en a i e app oach o pa i ioning HE, combining indi ec
calo ime y and in eg al calculus.
*Co esponding au ho .
P. C iscioni e al.
87
Keywo ds
Sheep, Hea P oduc ion Pa i ion
1. In oduc ion
In he las ew decades a g ea numbe o e o s ha e been de o ed o measu ing ene gy expendi u e in animals.
Animals p oduce hea om a a ie y o me abolic p ocesses such as main enance, he mo egula ion, physical
ac i i y and p oduc ion (e.g. deposi ion o body issue, and milk p oduc ion). Indi ec calo ime y has played an
impo an ole in measu ing his ene gy eleased as hea o hea p oduc ion (HE). In open ci cui espi a ion cham-
be s, hea p oduc ion can be calcula ed based on he measu emen s o O2 consump ion and CO2 p oduc ion. The
di ec measu emen o HE by indi ec calo ime y o e s he oppo uni y o e alua e a ia ions among animals in
line wi h hei geno ype, pheno ype o en i onmen al condi ions. Hea ene gy can be u he pa i ioned in o ha
associa ed wi h basal me abolism, olun a y ac i i y, p oduc o ma ion, diges ion and abso p ion, he mal egu-
la ion, hea o e men a ion, and was e o ma ion and exc e ion. Pa i ion o HE in o meaning ul physiological o
me abolic componen s is he mos di icul and con o e sial aspec o all eeding sys ems [1]. The calcula ion o
hea inc emen in p oducing animals needs he pa i ioning o o al HE be ween a componen due o main en-
ance and a componen due o p oduc ion. The as ing hea p oduc ion (FHP) pos eeding depends on he p e-
ious eeding le el, and leng h o as ing, and o en includes a con ibu ion o physical ac i i y. The e o e, ac-
i i y ela ed o al HE is he mos a iable componen o o al ene gy expendi u e [2].
Calo ime ic echniques can p o ide di ec access o o al HE, and expe imen al in e en ions and compu a-
ional echniques a e equi ed o disen angle i s componen s [3].
The objec i e o his s udy is o p esen he me hodology de eloped in ou labo a o y o moni o o al HE and
he hea inc emen associa ed wi h eeding in wo sheep b eeds by employing indi ec calo ime y and ma he-
ma ical calculus.
2. Ma e ial and Me hods
2.1. Animals and Feeding.
The expe imen al p ocedu e was app o ed by he Animal Use and Ca e Commi ee o he Poly echnic Uni e si y
o Valencia (Spain) and ollowed he codes o p ac ice o animals used in expe imen al wo ks p oposed by he
Eu opean Union [4].
Twel e mul ipa ous, d y and non-p egnan sheep o wo Spanish na i e b eeds we e used in his expe imen .
Gui a b eed belong o Valencia P o ince and Manchega b eed o Cas illa-La Mancha P o ince (Spain), bo h
a e au och honous b eeds and almos no in o ma ion abou ene gy pa i ioning is a ailable om hese b eeds.
Ene gy me abolism in o ma ion would be use ul o ene gy equi emen s pu poses. Six Gui as and six Manchegas
b eed sheep we e selec ed, which had simila body weigh (58.8 ± 3.1 and 60.2 ± 3.2 kg o BW, espec i ely). I
is a ma u e weigh o Gui a [5] and almos o Manchega [6]; ma u e weigh in emales Gui a and Manchega
anged be ween 50 - 60 and 65 - 75 kg, espec i ely. The expe imen was conduc ed as a andom design wi h he
wo b eeds as ixed e ec . All sheep we e ed he same concen a e mixed a ion (0.300 kg ce eal s aw as o age
and 0.700 kg concen a e) in wo meals. Hal he daily a ion was o e ed a 800 h and hal a 1600 h, espec i ely.
Sheep had ee access o wa e . The concen a e was mixed and pelle ed along wi h he p emix. I s chemical
composi ion alues on d y ma e (DM) basis was 92.62% o ganic ma e (OM), 17.19% c ude p o ein (CP),
47.33% neu al de e gen ibe (NDF), 25.37% acid de e gen ibe (ADF), 8.45% s a ch and 18.94 MJ o g oss
ene gy (GE) pe kg DM, ollowing he ecommenda ion o [7] o sheep. Chemical composi ion o ce eal s aw
was: 91.30% OM, 4.21% CP, 77.54% NDF, 50.33% ADF and 0.91% o s a ch.
2.2. Expe imen al Schedule and Measu emen s
Sheep we e ed wi h expe imen al die s in pens o 10 days. Once adap ed o he die , he sheep we e alloca ed
in me abolic c a es o 10 mo e days, in he moneu al condi ions (20˚C o 23˚C as de e mined by a Hobo p obe,
ONSET da a logge s, Cape Cod, MA, USA). Feed in ake, e usals, u ine and aeces we e collec ed, weighed and
P. C iscioni e al.
88
eco ded daily o each sheep o e a collec ion pe iod o 5 days. Faeces we e collec ed in wi e-sc een baske s
placed unde he loo o he me abolic c a es and u ine was collec ed h ough a unnel in o plas ic bucke s con-
aining 100 mlsulphu ic acid o main ain a pH below 3 o la e analysis. Samples o o age and concen a e, e-
usals, aeces and u ine we e s o ed a −20˚C, and hen pooled o chemical analysis. Ruminal luid samples
we e collec ed by s omach ube be o e he mo ning eeding on he las day o he sample collec ion pe iod. Ru-
minal luid pH was immedia ely de e mined using a Model 265A po able pH me e (O ion Resea ch Inc., Be -
e ly, MA, USA). A uminal luid sample was acidi ied wi h H2SO4 and ozen un il la e de e mina ion o am-
monia ni ogen (ammonia-N). Samples o analysis o ola ile a y acids (VFA) we e mixed wi h H3PO4 and
kep ozen un il analysis.
The body weigh o each animal was aken a he beginning o he die adap a ion pe iod and a he end o he
ecollec ion pe iod.
Gaseous exchange was measu ed o each ewe du ing 24 h (6 sheep pe b eed, one animal pe day) using a
mobile open-ci cui espi ome y sys em (head-hood) designed o small uminan s. As hal he daily a ion was
o e ed a 800 h and hal a 1600 h, wice a day he head hood d awe was opened, lea ing he ood and a bucke
o wa e inside. In o de o measu e as ing, h ee sheep pe b eed we e andomly selec ed, and dep i ed o ood
o 3 days and he gaseous exchange measu emen was done on day 4.
The espi ome y sys em has a head hood, a low me e (The mal Mass Flowme e Sensy low VT-S, ABB,
Alzenau, Ge many) and ai suc ion p o ided by a cen i ugal an (CST60 Sole Palau Inc., Pa e s del Vallès,
Ba celona, Spain). The me hane (CH4) and ca bon dioxide (CO2) concen a ion we e measu ed using he in a ed
p inciple and oxygen (O2) was measu ed by he pa amagne ic p inciple (Easy low Gas Analyze , model 3020,
ABB, Alzenau, Ge many). Al hough he uni was an au ocalib a ed model, he analyse s we e calib a ed wi h
e e ence gases be o e each es . Fe nández e al. [8] desc ibed he mobile open-ci cui espi ome y sys em used
and he di e ences now a e ha we use a head hood ins ead o a acemask and, he gas exchange da a acquisi-
ion is con inuous. We desc ibed i b ie ly: The sys em was capable o eco d da a a in e als o 1 second. Gas
analyze uni and low me e was connec ed o he compu e (Fuji su Siemens Li ebook Se ies, Pen ium 4 lap op,
Munich, Ge many) by an uni e sal se ial bus (USB) connec o . A se ial communica ion p o ocol was used wi h
i s p og ammable logic con olle s (MODBUS O ganiza ion, Inc., Hopkin on, MA, USA; www.modbus.o g) o
communica ion be ween he analy ical de ices (analyse uni and low me e ) and he compu e . The elec onics
p o o yping pla o m A duino (www.a duino.cc) was used o send da a om he gas analyse uni o LabVIEW7.1
(Na ional Ins umen s, Aus in, Texas, USA) by RS-232 p o ocol in eal ime. The low me e was moni o ed by
a 10 bi analog o digi al con e e (model DS2438; Maxim In eg a ed P oduc s, Inc. Sunny ale, CA, USA).
The whole sys em was calib a ed injec ing pu e N2 in o he head box [9], de e mined g a ime ically using a
p ecision scale. Calib a ion ac o s we e calcula ed acco ding o [10]. The CH4 and CO2 p oduc ion and O2 con-
sump ion we e calcula ed as desc ibed by [11]. An ini ial a mosphe ic ai sample was collec ed and he gas con-
cen a ions we e used as e e ence o calcula ions.
2.3. Chemical Analysis
Feed, eed e usal and eces samples we e i s d ied in a o ced ai o en a 55˚C o 48 h hen g ound o pass a 1
mm sc een be o e analysis. U ine was d ied by lyophiliza ion. Chemical analyses o he die , e usals and eces
we e conduc ed acco ding o me hods o [12] o DM and ash. DM o die s and eces was de e mined by o en-
d ying a 102˚C ± 2˚C o 24 h. Ash concen a ion was measu ed by incine a ion in an elec ic mu le u nace a
550˚C o 6 h o de e mine OM. The NDF and ADF we e measu ed in an ANKOM Fibe Analyze (A220,
ANKOM Technologies, Fai po , NY, USA) acco ding o [13] and [12], espec i ely. NDF was de e mined using
sodium sul i e and alpha amylase. S a ch con en was de e mined by enzyma ic me hod (α-amylase ob ained
om Sigma-Ald ich, S einheim, Ge many) acco ding o [14]. The ni ogen (N) om eed, eces and u ine we e
analysed by he Dumas p inciple (T uSpec CN; LECO Co po a ion, S . Joseph, MI, USA). Mul iplying N by a
ac o o 6.25 con e ed he esul s o CP. The GE con en o he d ied samples ( eed, eces and u ine) was ana-
lyzed by combus ion in an adiaba ic bomb calo ime e (Gallenkamp Au obomb; Loughbo ough, UK).
NH3-N con en o uminal luid samples was analyzed by he Kjeldahl p ocedu e (2300 Kjel ec Analyze Uni
Foss Teca o , Hille ød, Denma k). De e mina ion o uminal VFA was based on he me hod desc ibed by [15]
using a gas ch oma og aph (Fisons 8000 se ies; Fisons Ins umen s SpA, Milan, I aly) equipped wi h a spli /
spli less injec o and lame ioniza ion de ec o .
P. C iscioni e al.
89
2.4. Calcula ions
Theme abolizable ene gy in ake (MEI) was calcula ed as he di e ence be ween g oss ene gy in ake (GEI) and
ene gy losses in eces, u ine and CH4 (wi h an ene gy equi alen alue o 39.5 kJ/L CH4 [16].
The HE was de e mined om measu emen s o O2 consump ion, CO2 and CH4 p oduc ion, and u ine N (Nu ),
using he equa ion [16]:
HE (kJ) = 16.18 × O2 + 5.02 × CO2 − 2.17 × CH4 − 5.99 × Nu
whe e gases we e exp essed in li e s pe hou s and Nu in g ams pe day. The body issue ene gy (REbody) was
calcula ed as MEI - HE.
The ene gy associa ed wi h he oxida ion o p o ein (OXP), ca bohyd a e (OXCHO) and a (OXF) was cal-
cula ed by he me hod o [17] and [18] o uminan s. The p oduc ion o ola ile a y acid om ca bohyd a e
e men a ion is ollowed by CO2 and CH4 p oduc ion. A a io CO2:CH4 o 3:1 and 1.7:1 o high g ain and high
o age die s, espec i ely [19]. The CO2 p oduc ion om oxida ion (CO2x) was calcula ed as CO2 − (CO2:CH4 ×
CH4). The calcula ions we e ca ied as ollowing:
OXP = 6.25 × Nu × 18.42 (kJ/g),
OXCHO = (−2.968 × O2 + 4.174 × CO2x − 2.446 × Nu ) × 17.58 (kJ/g),
OXF = (1.719 × O2 − 1.719 × CO2x − 1.963 × Nu ) × 39.76 (kJ/g).
Then, he HE om oxida ion (HxE) was:
HxE (kJ) = 16.18 × O2 + 5.02 × CO2x − 5.99 × Nu .
Gases we e exp essed in li e s pe hou s and Nu in g ams pe day. The non p o ein espi a o y quo ien om
oxida ion o nu ien s (RQnpx) was de e mined as: RQnpx = (CO2x – (Nu × 6.25 × 0.774))/(O2 – (Nu × 6.25 ×
0.957).
As we men ioned abo e, e ained o eco e ed ene gy was de e mined as he di e ence be ween MEI and he
HE. Hea ene gy associa ed wi h REbody (H E) and ME used o issue gain (ME ) we e based on an assumed e -
iciency o die a y ME use o issue gain o 0.75 [20]. The e o e, ME o main enance (MEm) was es ima ed by
di e ence be ween MEI and ME , and he e iciency o use o ME o main enance (km) as basal me abolic a e
o e MEm. The N balance (N e ained) was de e mined as well, by di e ence among N in ake and eces plus
u ine.
2.5. Hea P oduc ion Pa i ion
The o al HE consis o many componen s: basal me abolism (HeE), hea associa ed wi h olun a y ac i i y (HjE),
hea o p oduc o ma ion (H E), hea o he mal egula ion (HcE), hea o syn hesis and exc e ion o was e
p oduc s (HwE), hea o diges ion (HdE) and hea o e men a ion (H E). This ene gy e ms was de ined acco d-
ing o [1].
HE = HeE + HjE + H E + HcE + HwE + HdE + H E.
Due o he animals being in a he moneu al and non-s ess ul en i onmen , HcE was assumed o be ze o. The
NRC [1] de ines he hea inc emen o eeding (HiE) as:
HiE = H E + HdE + H E + HwE.
In ou ial we conside ed HwE negligible and, H E = HE – HxE.
The e o e, he HE was pa i ioned be ween componen s due o eed in ake, physical ac i i y, and basal me a-
bolic a e. This pa i ioning is desc ibed as ollows.
HE = HeE + HjE + HiE.
The main enance equi emen s consis o basal me abolic a e plus he ac i i y inc emen , and a e usually de-
ined as FHP; he e o e we de ine FHP as a sum o wo componen s; HeE and HjE. The HeE co esponded o
he minimum ene gy expendi u e o es ing, heal hy, non- ep oduc i e, as ing and adul animal ha a e in a he -
moneu al en i onmen du ing he inac i e ci cadian phase [21]. The ac i i y inc emen was assumed in ou s udy
as he di e ence be ween FHP and HeE.
HjE = FHP – HeE.
The e m de ined by NRC [1] as hea o diges ion (HdE) includes he ene gy cos o ea ing, umina ion, wo k
o diges ion and nu ien me abolism. The HdE was de e mined as ollows:
HdE = HE – HeE – H E – HjE.
Then, HdE was di ided in HE o ea ing (HdEe) and HdE o diges ion and me abolism (HdEdm). The cos o
P. C iscioni e al.
90
ea ing is de ined in he li e a u e as he ac o p ehending, bi ing, chewing, sali a ing and swallowing h oughou
a ime pe iod (use o be 15 minu es, acco ding o [22] and [2]). In ou s udy he cos o ea ing (HdEe) is guided
by he inc ease in HE om he momen ha eed is o e ed on he eede o 3 hou s la e , and we measu e he
peak a ea unde he cu e. The HdEdm was ob ained by di e ence and we assumed included he wo k o diges-
ion and me abolism. The wo HdE componen s include umina ion and mus include he ene gy cos (oxygen
consump ion) o gas oin es inal and hepa ic o gans, al hough each o hese ac i i ies was no quan i ies.
HdE = HdEe + HdEdm.
Figu e 1 shows some nomencla u e desc ibed abo e and we can ealize ha he pa i ion o HdE in HdEe and
HdEdm is heo ical, based on he cu e pa e n o he me abolic a e (HE).
2.6. Da a Analyses
The quan i ica ion o pa i ioning HE was de eloped by in eg al calculus in R ( e sion 2.12.2, R Founda ion o
S a is ical Compu ing, Viena, Aus ia). Du a ion o gas exchange was ixed a 1 day, and he ime uni was mi-
nu es.
The in eg a ed a eas we e:
HE = The To al Hea P oduc ion in ed and as ed animal was de e mined using in eg al o cu es o med by
da a om indi ec calo ime y.
HiE = Di e ence o in eg als o HE and FHP.
FHP = In eg al o as ing hea p oduc ion, di ided in HeE and HjE.
HjE = Di e ence o in eg als FHP and HeE.
HeE alue was de e mined as he a ea unde he cu e de ined by he alue epea ed mo e equen ly (mode)
o he mean alues o da a ob ained om he espi ome y o 3 as ing animals, once he highes alues we e
d opped, which could be caused by mo emen s.
HdEe = Di e ence o in eg als o o al HE and FHP in an app oxima e 3-hou pe iod a e eeding.
H E = Is he di e ence be ween in eg als o HE and HxE.
De ini e in eg al o a signal can be in e p e ed as he a ea unde he cu e. This nume ic in eg a ion allows us
o e alua e he de ined in eg al o a con inuous unc ion in a closed in e al wi h he desi ed accu acy, and i
consis s in he adjus men o a polynomial o a se o poin s and hen in eg a ing hem.
The in eg al o each cu e was based on he apezium me hod. The sum o hese a eas o apeziums can be
app oxima ed o he in eg al ha ep esen s he a ea unde he cu e, acco ding o he ollowing equa ion:
Figu e 1. Example o hea p oduc ion (HE) pa i ioning and hei componen s: as ing hea p oduc ion (FHP), basal
me abolism (HeE), hea associa ed wi h olun a y ac i i y (HjE), hea o diges ion (HdE), hea o eeding du ing 3
hou s (HdEe), hea a e 3 hou s o eeding o nex in ake (HdEdm). FHP = HeE + HjE; HdE = HdEe + HdEdm.

P. C iscioni e al.
91
1
Δ
n
h
ii
ih
S x
α
αα
=
= ⋅
∑
whe e
S
α
ep esen he a ea o empo al se ies
i
x
α
o in e als
Δi
α
o one minu e o inc ease du ing 24
hou s co esponding o he animal α. In his s udy he
S
α
and
i
x
α
alues can be eplaced by he desc ip ions
in Table 1.
The e ec s o b eed on hea pa i ion we e analyzed using he PROC MIXED o [23]. The expe imen was
conduc ed in a andomized design and he model o he dependen a iables included he ixed e ec o b eed and
andom e ec o sheep. The ollowing s a is ical model was used: Y = μ + α (B) + sheep + ε whe e Y is he de-
penden a iable, μ is he o e all mean, B is he b eed (Manchega and Gui a), sheep is andom e ec and ε is
he andom e o . E ec s we e decla ed signi ican a P < 0.05 and P- alues be ween 0.05 and 0.10 we e con-
side ed as a end. S uden ’s es was used o compa ison be ween b eeds.
3. Resul s
The da a on ene gy in ake and ou pu s o he sheep, eco ding du ing he calo ime ic measu emen , a e p e-
sen ed in Table 2. No signi ican di e ence was obse ed o he ene gy balance be ween b eeds.
HE pa i ioning a e shown in Table 3. The as ing me abolism in sheep was measu ed a day 4 a e h ee
days o s a a ion, when espi a ion quo ien has usually allen o abou 0.70 [24]. No di e ences we e obse ed
o FHP be ween b eeds (258 kJ/kg0.75 BW and day, on a e age). The basal me abolism (HeE) was signi ican ly
(P < 0.05) highe o Gui a han Manchega b eed (270 s. 247 kJ/kg0.75 BW and day, espec i ely) and no di -
e ences o ac i i y we e ound (27 kJ/kg0.75 BW and day).
Table 1. De ini ion o he a eas and empo al se ies used in he nume ical in eg a ion.
S
α
i
x
α
hn-h1
HE ( o al hea p oduc ion) Heαi (hea p oduc ion pe hou ) 24 hou s
FHP ( as ing hea p oduc ion) hpαi (hea p oduc ion pe hou ) 24 hou s
HiE (hea inc emen ) hiEαi (hea inc emen pe hou ) 24 hou s
HdEe (Hea inc emen pos inges ion) hdEcgαi (hea inc emen pe hou ) App ox. 3 hou s
H E (hea o e men a ion) h Eαi (hea inc emen pe hou ) 24 hou s
Table 2. D y ma e in ake (g/d) and ene gy balance (kJ/kg0.75 BW) in wo sheep b eeds.
B eeds SEM1 P- alue
Gui as Manchegas
LW2, kg 58.0 60.2 1.16 0.981
DMI3, g/d 883.3 984.8 45.23 0.287
Ene gy balance, kJ/kg0.75 BW
GEI4 803 854 25.3 0.34
E
5
eces 226 260 28.8 0.56
E u ine 41 29 5.5 0.31
E me hane 50 46 3.5 0.66
ME6 487 518 13.4 0.260
RE7body 99 124 14.1 0.42
REp o ein 48 70 7.4 0.11
RE a 52 54 12.6 0.98
ME gain 132 165 18.8 0.42
ME main enance 354 353 8.3 0.95
km8 0.77 0.70 0.021 0.099
1SEM = s anda d e o o he mean; 2BW = body weigh ; 3DMI = d y ma e in ake; 4GEI = g oss ene gy in ake; 5E = ene gy; 6ME = me abolizable
ene gy in ake; 7RE = e ained ene gy; 8km = e iciency o ME.
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92
Table 3. HE pa i ioning (kJ/kg0.75 BW) and HE pa i ioning pe MEI (%) in wo sheep b eeds.
B eeds SEM1 P- alue
Gui as Manchegas
HE pa i ioning, kJ/kg0.75 BW
HE2 387 394 5.5 0.56
H E3 33 41 4.7 0.42
HeE4 270 247 4.0 0.02
HjE
5
23 30 1.2 0.453
FHP6 293 277 2.8 0.19
HdE7 54 71 8.8 0.39
HdEe8 24 31 5.3 0.57
HdEdm9 30 40 5.4 0.16
HiE10 61 77 8.7 0.40
HE pa i ioning pe MEI11, %
RE12body/MEI 20 23 2.4 0.58
REp o ein/MEI 10 14 1.3 0.12
RE a /MEI 11 10 2.4 0.81
HE/MEI 80 77 2.4 0.58
H E/MEI 7 8 0.8 0.57
HeE/MEI 56 48 1.8 0.02
HjE/MEI 5 6 0.2 0.01
FHP/MEI 60 54 1.8 0.06
HdE/MEI 11 14 2.0 0.49
HdEe/MEI 5 6 1.2 0.61
HdEdm/MEI 5 8 1.2 0.21
HiE/MEI 13 15 2.0 0.52
1SEM = s anda d e o o he mean; 2HE = hea p oduc ion; 3H E = hea o p oduc o ma ion; 4HeE = basal me abolism; 5HjE = hea associa ed wi h
olun a y ac i i y; 6FHP = as ing hea p oduc ion; 7HdE = hea o diges ion; 8HdEe = hea o ea ing; 9HdEdm = hea o diges ion and me abolism;
10HiE = hea inc emen o eeding; 11MEI = me abolizable ene gy in ake; 12RE = e ained ene gy.
The a ia ion in HE associa ed wi h eeding (HdE) was no signi ican ly di e en be ween b eeds (62 kJ/
kg0.75 BW and day, on a e age). No signi ican di e ences we e obse ed o he wo componen s ela ed o hen;
ea ing-chewing- umina ion (HdEe) and umina ion-diges ion-me abolism (HdEdm).
The p opo ional con ibu ion o HxE due o oxida ion o nu ien s is shown in Table 4. No di e ences we e
obse ed o HxE and OXF and, di e ences we e ound in OXCHO and OXP; lowe OXCHO (P < 0.05; 75 s.
129 kJ/kg0.75 BW) and highe OXP (P < 0.01; 52 s. 30 kJ/kg0.75 BW) in Gui a han in Manchega b eed o
sheep.
No signi ican di e ences we e obse ed in N balance, only Gui a b eed shown g ea e (P < 0.05) alues in
u ine N compa ed wi h Manchega b eed: 0.65 s. 0.35 g/kg0.75 BW, espec i ely (Table 5). Table 6 shows he
uminal pa ame e s like, pH, ammonia-N and VFA. Highe ammonia-N alues (P < 0.05) we e ob ained in-
Gui a b eed compa ed wi h Manchega b eed (22.8 s. 17.81 mg/dL, espec i ely) and nume ical lowe VFA (P
= 0.056) in Gui a compa ed wi h Manchega (33.49 s. 37.46 mmol/L).
4. Discussion
4.1. HE Pa i ion: Ac i i y
The HjE es ima ed in ou expe imen included only he ac o s anding and lying down. The a e age alue o
HjE, in sheep alloca ed in me abolic cages was 27 kJ/kg0.75 BW and day. This alue ep esen s he 8.5% o he
HeE (exp essed on FHP he alues is 10% on a e age). NRC [25] sugges ed ha ene gy equi emen s o ac i -
i y we e 10% o FHP o s all ed sheep.
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93
Table 4. Ene gy (kJ/kg0.75 BW) associa ed wi h he oxida ion o nu ien s and hei pe cen age o e HxE in wo sheep b eeds.
B eeds SEM1 P- alue
Gui as Manchegas
Oxida ion o nu ien s, (kJ/kg0.75 BW)
HxE2 381 389 5.8 0.52
H E3 7 6 0.7 0.65
OXP4 52 30 4.6 0.01
OXCHO5 72 129 19.1 0.04
OXF6 256 229 16.2 0.43
OXP/HxE, % 14 8 1.2 0.02
OXCHO/HxE, % 19 33 5.0 0.05
OXF/HxE, % 68 59 4.5 0.36
RQnpx7 0.81 0.87 0.033 0.521
HxE/MEI8, % 78 76 2.3 0.60
H E/MEI, % 1.3 1.2 0.14 0.521
1SEM = s anda d e o o he mean; 2HxE = hea p oduc ion o oxida ion; 3H E = hea o e men a ion; 4OXP = ene gy associa ed wi h he oxida ion
o p o ein; 5OXCHO = ene gy associa ed wi h he oxida ion o ca bohyd a e; 6OXF = ene gy associa ed wi h he oxida ion o a ; 7RQnpx = non p o-
ein espi a o y quo ien om oxida ion o nu ien s; 8MEI = me abolizable ene gy in ake.
Table 5. Ni ogen balance (g/kg0.75 BW) in wo sheep b eeds.
B eeds SEM1 P- alue
Gui as Manchegas
N2 in ake 1.28 1.19 0.033 0.211
N eces 0.30 0.35 0.031 0.429
N u ine 0.65 0.35 0.060 0.003
N e ained 0.33 0.49 0.050 0.109
RP o ein3, g/d 43 64 6.2 0.09
RFa 4, g/d 27 29 8.1 0.58
Gain, g/d 199 285 23.3 0.12
1SEM = s anda d e o o he mean; 2N = ni ogen; 3RP o ein = e ained p o ein; 4RFa = e ained a .
Table 6. pH, ammonia N and ola ile a y acids (VFA) in wo sheep b eeds.
B eeds SEM1 P- alue
Gui as Manchegas
pH 7.30 7.22 0.172 0.652
Ammonia N2, mg/dL 22.80 17.81 3.256 0.048
To al VFA3, mmol/L 33.49 37.46 3.276 0.056
VFA, mmol/L
Ace ic 23.47 26.43 1.552 0.081
P opionic 6.70 5.80 0.982 0.18
Isobu y ic 0.88 0.68 0.111 0.07
Bu y ic 3.55 3.15 0.573 0.55
Iso ale ic 1.28 0.93 0.142 0.24
N- ale ic 0.51 0.32 0.024 0.48
N-cap oic 0.07 0.09 0.003 0.35
1SEM = s anda d e o o he mean; 2N = ni ogen; 3VFA = ola ile a y acids.
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Calo ime ic s udies ha e es ablished he ollowing ene gy cos o a ious physical ac i i ies by uminan s
animals [26], and s anding compa ed wi h lying esul in a cos o 10 kJ/kg BW and day. In ou s udy we as-
sumed ha Manchega made mo e posi ion changes han Gui a b eed (63 compa ed wi h 48 posi ion changes,
espec i ely). Goa s no mally p e e s anding while eeding and, in ou s udy mo e ac i i y (s anding up) and
mo e DMI was ound in Manchega sheep han Gui a b eed (985 s. 883 g DMI/d, espec i ely). Howe e , al-
hough nume ically di e en , DMI was no signi ican and conside ing DMI as pe cen age o BW, bo h b eeds
showed simila DMI (1.6% BW). I we exp ess HjE pe g am o DMI we ob ain 0.55 and 0.66 kJ HjE/g DMI o
Gui a and Manchega b eed, espec i ely. The e o e, he g ea e alue o physical ac i i y in Manchega b eed
was no due o nume ically highe DMI.
4.2. HE Pa i ioning: Feeding
The HE has been shown o inc ease du ing eeding in sheep [22] like in o he mammals. Con inuous measu e-
men s o espi a o y exchange consis en ly show ha HE in sheep inc eases apidly by 40% - 80% du ing a cou se
o a meal. This inc ease pe sis ed e en h ough meals las ing up o 2 hou s bu declines he ea e apidly o a es
no mo e han 15% - 20% g ea e han hose eco ded be o e a meal (Figu e 1).
Mos o he s udies calcula ed he cos o ea ing o a sho pe iod o ime (15 minu es) and he a e o in ake
was eco ded (g DM pe minu e o bi es pe minu e). This cos is calcula ed om he inc emen in HE abo e he
a e age HE o he p e- eeding pe iod. And i was ela ed o he ype and amoun o eed consumed and also o
he ime spen on ea ing. Ou me hodology was comple ely di e en , wi h wo eeding pe iods and 24 hou s o
con inuous HE measu emen , he measu es we e based on he g ea e peak o HE a e eeding combined wi h
nume ical in eg a ion. The e o e ou esul s a e no compa able due ha we did no eco d he a e o in ake. We
ound ha he cos o in ake du ing 6 hou s ( wo meals) we e 28 kJ HdEe/kg0.75 BW and day on a e age, and he
cos o diges ion and me abolism succeeding 18 hou s was 35 kJ HdEdm/kg0.75 BW and day. The cos o in ake
wi h wo meals ep esen he 47% o he o al HdE, while 54% would be he cos o diges ion and me abolism o
he sheep on he me abolic cages wi h almos minimal physical ac i i y. The HdEe o wo meals accoun o 6%
o he MEI, while 7% o he MEI was expended in HdEdm, and no compa able esul was ound om he li e a-
u e (Table 3). The H E was mo e ela ed o he cos o me hane p oduced han o al cos o e men a ion, and
due o his eason H E was de e mined by di e ence be ween HE and HxE, wi h alues o 7 kJ/kg0.75 BW, on a -
e age (Table 4).
In ou s udy, whe e sheep we e ed abo e main enance wi h mixed die and concen a e pelle ed and, non-
locomo ion and he mal s ess was conside ed, he HiE ep esen ed 14% o he MEI. The o al ene gy cos o
inges ion and diges ion a e consis en ly 40% o 50% o HiE o o ages bu a e less o ba ley pelle s; 24% - 37%
[27].
4.3. ME o Main enance
Feeding le el in ou ial was es ima ed as 1.5 imes main enance, hence he sheep was in posi i e issue ene gy
balance, and some o he MEI is being di ec ed owa ds issue ene gy gain. The MEm was es ima ed by di e -
ence be ween MEI and ME and he alue ob ained was 354 kJ/kg0.75 BW and day on a e age. The e iciency o
use o ME o main enance was 0.74 on a e age (sligh ly highe han NRC [25]), because we ha e a concomi-
an ene gy use o main enance and gain.
The e o e, nex a e age alues we e obse ed (Table 3); he MEm ep esen ed he 69% o he o al MEI in
his s udy. As sheep we e ed abo e main enance, he REbody accoun o 23% o he MEI and, 77% o he MEI
was los as hea (HE). Wi hin HE, 51% o he MEI d o e o basal me abolism (HeE), 5.3% was los as physical
ac i i y o s anding and lying down (HjE), and 13% was associa ed wi h he p ocess o eeding and wo k o di-
ges ion and me abolism.
Re iewing he li e a u e, we ound a iabili y in de e mina ion o es ima ion o MEm. Manchega sheep had a
alue o 383 kJ/kg0.75 BW in he s udy [28] and day and [29] [30] in Gui a sheep ound a alue o 352 kJ/kg0.75
BW and day and 391 kJ/kg0.75 BW, espec i elyand an e iciency o use o ME o main enance o 0.64 (km).
The es ima ed MEm equi emen in Segu eña sheep by linea eg ession was 374 kJ/kg0.75 BW and he e i-
ciency o u ilisa ion o ME o main enance (km) was 0.72 [31]. Nine epo s [32] sugges MEm anging om
305 o 460 kJ/kg0.75 BW, and [33] es ima ed a MEm o Menz sheep o he E hiopian highlands 422 kJ/kg0.75
BW and day. The sys ems [25] and [34] adop ed an a e age alue o 321 and 397 kJ/kg0.75 BW, espec i ely due
o he ac ha FHP s. eeding ial o , calo ime y s udies s. o he me hods, gi e di e en alues. O he s [35]