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Replacement of raw soybean with roasted soybean increased milk production in Holstein cows.
Ciência Rural, v.47, n.5, 2017.
1
Replacement of raw soybean with roasted soybean increased
milk production in Holstein cows
Substituição de soja crua por soja tostada aumentou a
produção de leite em vacas da raça Holandesa
Gilson Sebastião Dias Júnior1 Vítor Augusto Silveira1 Ivan Júnior Ascari1
Renata Apocalypse Nogueira Pereira2 Marina de Arruda Camargo Danés1 Marcos Neves Pereira1*
ISSNe 1678-4596
Ciência Rural, Santa Maria, v.47: 05, e20160002, 2017
Received 01.03.16 Approved 12.21.16 Returned by the author 02.09.17
CR-2016-0024.R2
http://dx.doi.org/10.1590/0103-8478cr20160002
INTRODUCTION
Soy is the main source of true protein
for dairy cows in Brazil and is mainly in the form
of soybean meal, which features high ruminal
degradability (around 65% crude protein (CP)). This
fact, coupled with the prohibition ofusing protein
sources of animal origin, limits the formulation of
diets rich in rumen undegradable protein (RUP). The
replacement of proteinaceous food by high ruminal
degradability foods rich in RUPmight increase
the metabolizable amino acid ow to the animal
(NRC, 2001). Heat treatment of whole soybean is
an alternative for reducing protein degradability
(ABDI et al., 2013).
However, results presented in the literature
regarding the responses in farm animals fed withheat-
treated soy diets are conicting. Studies have shown
that the substitution of raw soybean (RAW) by
roasted soybean (ROS) is responsible for increasing
milk production (FALDET & SATTER, 1991;
FATHI NASRI et al., 2007), which emphasizedthe
importance of raising the dietary content of RUP.
Roasted whole soybean can supply dietary amino
1Departamento de Zootecnia, Universidade Federal de Lavras (UFLA), 37200-000, Lavras, MG, Brasil. E-mail: mpereira@dzo.ua.br.
*Corresponding author.
2Empresa de Pesquisa Agropecuária de Minas Gerais (EPAMIG), Lavras, MG, Brasil.
ABSTRACT: The aim of this study was to evaluate the effect of total replacement of raw whole soybean (RAW) for roastedwhole soybean
(ROS) on the production performance of Holstein cows. Two experiments were carried out usinga simple reversal design where RAW has been
completely replaced by ROS. In experiment 1, 22 cows (175±60 days in milk)were used, and the dietary inclusion level of RAW or ROS was 3.7%
of dry matter (DM). In experiment 2, 16 cows (130±50 days in milk)were used, and thedietary inclusion level of RAW or ROS was 11% of DM.
In both experiments, ROS increased milk production by 1.1kgday-1 without changing fat and protein production. Dry matter intake or milk urea
nitrogenwere not affected by dietary soy source. In experiment 2, plasma glucose concentration was decreased, and allantoin/creatinine ratio in
urine tended to decreasein ROS. Experiment 2 also evaluated the nutrient digestibility and ruminal degradation kinetics of crude protein in two
soybean sources. Roasting had no effect on the digestibility of DM, organic matter, and neutral detergent ber. Roasted whole soybean hadgreater
fraction B and lower protein degradation rate than did RAW; this showed that heat treatment was effective in increasing therumen undegradable
amino acid owto the animal, which suggesteda potential mechanism of action for improved performance observed in ROS.
Key words: non-degradable protein, roasting, milk production.
RESUMO: O objetivo deste estudo foi avaliar o efeito da substituição total de soja integral crua (SC) por soja integral tostada (ST) sobre
o desempenho produtivo de vacas Holandês. Foram realizados dois experimentos com delineamento experimental de reversão simples nos
quais a SC foi totalmente substituída por ST. No experimento 1, foram utilizadas 22 vacas (175±60DEL) e o nível de inclusão dietética de
SC ou ST foi de 3,7% na matéria seca (MS). No experimento 2, foram utilizadas 16 vacas (130±50 DEL) e o nível de inclusão dietético de
SC ou ST foi de 11% na MS. Em ambos os experimentos, ST aumentou a produção de leite em 1,1kgd-1, sem alterar as produções de gordura
e proteína. O consumo de MS e nitrogênio uréico no leite não foram afetados pela fonte de soja dietética. No experimento 2, a concentração
de glicose plasmática foi reduzida e a relação alantoína/creatinina na urina tendeu a ser reduzida por ST. O experimento 2 também avaliou
digestibilidade de nutrientes e cinética de degradação ruminal da proteína bruta das duas fontes de soja. Não houve efeito da tostagem nas
digestibilidades da MS, matéria orgânica e FDN. A ST apresentou maior fração B e menor taxa de degradação da proteína do que a SC,
mostrando que o tratamento térmico foi efetivo em aumentar o uxo de aminoácidosnão degradáveis no rúmen para o animal, sugerindo um
potencial mecanismo de ação para a melhora no desempenho observada com ST.
Palavras-chave: proteína não degradável no rúmen, tostagem, podução de leite.
ANIMAL PRODUCTION
2
Ciência Rural, v.47, n.5, 2017.
Dias Júnior et al.
acids in non-degradable form in the rumen, which
can stimulate milk production (FALDET & SATTER,
1991). However, others studies on the replacement
of RAW for ROS did not affect milk production
(AMANLOU et al., 2012; ABDI et al., 2013).
Differences in responses in production
reported in the literature can be attributed to several
factors such as lactation stage and milk production
rate (FATHI NASRI et al., 2007). Furthermore,
the efciency of the roasting process as a means of
reducing protein degradability in soybean depends
on the time and processing temperature. Excessive
heat treatment can reduce protein digestibility and
the availability of certain amino acids in the small
intestine (SCOTT et al., 1991; FATHI NASRI et al.,
2008). Thus, it is important to determine the ruminal
degradability of protein in foods subjected to heat
treatment. However, it is possible to observe a low
numberof studies with regard tothe efciency ofthe
roasting process in ruminal degradability. In addition,
there are no reports in the literature evaluating the use
of ROS in low dietary inclusion levels.
The objective of the present study was to
evaluate the replacement of RAW for ROS on two
dietary inclusion levels on the production performance
of dairy cows. In addition, it aimed to investigate the
ruminal degradation kinetics of protein from two
soybean sources to evaluate the effectiveness of heat
treatment in increasing RUP ow. The hypothesis is
that the replacement of RAW for ROS improves the
production performance of dairy cows due to an increase
in rumen undegradable amino acid ow to the animal.
MATERIALS AND METHODS
The experiments were performed at the
Better Nature Research Center (Ijaci, Minas Gerais,
Brazil) where the animals were housed in a “tie-stall”
barn with ad libitum access to water. In experiment 1,
22 Holstein cows (175±60 days in milk) were paired
based on calving order and milk yield and randomly
assigned to a treatment sequencedelineating simple
reversal design with two periods of 13 days and 10
days to adapt to treatment.
The complete diet (Table 1) was offered
twice daily at approximately 06:00 and 14:00h in
amounts to provide 10.0% orts (as-fed basis). Dry
matter (DM) content (oven-drying at 105°C) of corn
silage was monitored weekly to adjust the proportion
of fresh ingredients and to ensure the constant
composition of ingredients (% DM) of the diet.
The two treatments consisted of the
inclusion of 3.7% of DM offered daily from RAW or
ROS. Both soy sources (Alfa Nutrisoja, Cooperalfa,
Chapecó, Brazil) originated from the same lot
differing only in heat treatment. In the roasting
process, steam injection was used (125°C for 10 to
15min and 2kgf cm-2). Raw soybeans were processed
in a fodder disintegrator without sieves.
Individual cow intake was calculated
between 11 and 13 days, by recording the amount
of feed offered and orts (as-fed basis). Samples of
ingredients and orts were collected daily, stored at
-20°C, and a compound period was formed from
equal amounts of each daily sample. Composite
samples were dried in forced-air oven at 55°C for
72h and ground through a 1-mm screen in a Wiley
mill (A.H. Thomas, Philadelphia, PA). The DM
content was determined by drying at 100°C for 24h
and CP was determined by micro-Kjeldahl analysis
(AOAC, 1990). Ether extract was analyzed according
to AOAC (1990). Ash was analyzed by incineration
at 550°C for 8h. The NDF was analyzed using a TE-
149 ber analyzer (Tecnal Equipamentos, Piracicaba,
Brazil) with amylase and sodium sulde.
Individual daily milk yield was recorded
between 11 and 13 days, and a daily sample
was obtained from the three milking collected
in proportion to the production of each milking.
These samples were placed in vials with bronopol
to determine the fat, protein, lactose, and total
solidcontent (APCBRH, Curitiba, Brazil), through
optical and infrared systems(Bentley 2000, Bentley
Instruments Inc., Chaska, MN).The analysis of milk
urea nitrogen (MUN) concentration was performed
(Chemspec 150 - Bentley Instruments®) using the
Berthelot method (BERGMEYER, 1985). Milk
energy secretion (MilkE, Mcalday-1) was calculated
as [(0.0929 × %fat) + (0.0547 × % protein) + (0.0395
× % lactose)] × kg of milk (NRC, 2001). Energy
corrected milk (ECM, kgday-1) was calculated as
ECM = MilkE/0.70 (assumes 0.70Mcalkg-1 for milk
with 3.7% fat, 3.2% protein, and 4.6% lactose).
In experiment 2, 16 Holstein cows
(130±50 days in milk) were paired based on calving
order and milk yield, and randomly assigned to a
treatment sequence delineating simple reversal
design with two periods of 21 days and 14 days to
adapt to treatment. Treatments were the same as in
experiment 1 with the exception of dietary inclusion
level of RAW or ROS, which was 11% of DM
(Table 1). Diets were offered at 07:00 and 15:00h in
amounts to provide 10.0% orts (as-fed basis).
Individual cow intake was calculated between
16 and 20 days of each period, by recording the amount
of feed offered and orts (as-fed basis). Collections of
Replacement of raw soybean with roasted soybean increased milk production in Holstein cows.
Ciência Rural, v.47, n.5, 2017.
3
samples and their analysis were performed in the same
way as already described in experiment 1.
Cows were milked three times a day under
the same conditions and time of the experiment 1.
Milk yield was measured on the same days of the
assessment of consumption. Milk samples of six
consecutive milking collected between 17 and 19
days were used to determine the total solids content
and MUN (APCBRH) as procedures in experiment 1.
Total-tract apparent digestibility of DM,
organic matter, NDF, and non-NDF organic matter
was determined by total collection of feces performed
in three periods of eight uninterrupted hours between
18 and 20 days of each experimental period (SALVATI
et al., 2015). To obtain a representative sample of
24h without disturbing feed intake and milk yield,
sampling started 8 h later in relation to the collection
done on the previous day. Uniform fecal samples
from each cow were continuously frozen along each
collection day to yield a composite sample at the end
of each period. Fecal composite samples were oven
dried at 55ºC for 72h and NDF and ash contents were
determined according to the methodology described
in experiment 1. Daily intake of digestible organic
matter was calculated by multiplying the consumption
of organic matter measured between 16 and 20 days
by the coefcient of digestibility of organic matter
measured between 18 and 20 days.
Six urine samples from each cow were
obtained concomitantly with collection of feces to
Table 1 - Composition of diets offered in ingredients, and consumed diets in nutrients (% dry matter) in raw soybean (RAW) and roasted
soybean (ROS) treatments (Experiments 1 and 2).
------------Experiment 1------------ ------------Experiment 2------------
RAW ROS RAW ROS
----------------------------------------------------------------------Diet ingredient, % ofDM----------------------------------------------------------------------
Corn silage 47.7 47.7 46.9 46.9
Ground raw whole soybeans
3.7 - 11.0 -
Ground roasted whole soybeans
coarsely ground roasted whole soybeans
- 3.7 - 10.9
Finely ground corn 16.0 16.0 10.7 10.7
Soybean meal 16.9 16.9 13.0 13.0
Citrus pulp 12.3 12.3 16.2 16.2
HMBi1 0.12 0.12 - -
Urea 0.4 0.4 - -
Magnesium oxide 0.2 0.2 - -
Sodium bicarbonate 0.8 0.8 1.3 1.3
Salt 0.3 0.3 - -
Limestone 1.3 1.3 - -
Minerals and vitamins2
0.3
0.3
-
-
Minerals and vitamins3 - - 1.0 1.0
------------------------------------------------------------------Nutrientcomposition, % ofDM-----------------------------------------------------------------
CP 17.6 17.7 15.9 16.3
NDF 35.0 34.9 36.4 37.3
Ether extract 4.9 4.8 5.1 5.3
Ash 8.5 8.5 6.0 6.1
Non fiber carbohydrates
4
34.0 34.1 36.5 34.7
12-hydroxy-4-(methylthio) butanoic acid (Metasmart, Adisseo Inc., Antony,France).220.0% Ca; 15.0% P; 3.0% S; 3.0% Mg; 100mgkg-1 of
Co; 3,000mgkg-1 of Cu; 180mgkg-1 of I; 3,000mgkg-1 of Mn; 12,000mgkg-1 of Zn; 100,000UIkg-1 of vitamin A; 250,000UIkg-1 of vitamin
D3; 6,250UIkg-1 of vitamin E. 318.5% ofCa; 15.0% of P; 30.0% of S; 30.0% of Mg; 240mgkg-1 of Co; 3,000mgkg-1 of Cu; 180mgkg-1 of I;
8,000mgkg-1 of Mn; 12,000mgkg-1 of Zn; 90mgkg-1 of Se; 100,000UIkg-1 of vitamin A; 250,000UIkg-1 of vitamin D3; 6,250UIkg-1 of
vitamin E.4NCF=100-(CP + NDF + EE + Ash).
4
Ciência Rural, v.47, n.5, 2017.
Dias Júnior et al.
estimate the relative microbial protein synthesis in
the rumen. Each urine subsample was immediately
acidied with 2% (vol/vol) sulfuric acid at 20%
concentration and stored at 4°C until the end of
the collection period when a sample from each
cow was formed with equal proportions of each
subsample. Composite urine samples were diluted
1:4 (urine/water) with distilled water and frozen at
-20°C. Allantoin was performed as described by
CHEN & GOMES (1995), and a commercial kit
(Labtestdiagnostica S.A., Lagoa Santa, Brazil) was
used for the determination of creatinine. Relationship
between urinary allantoin and creatinine was used to
estimate microbial protein ow to the intestine.
On the 20th day of each experimental
period, blood samples were collected from the
coccygeal vessels 12h after the morning feeding in
order to assess plasma glucose concentration. Blood
was collected in tubes a tubes containing potassium
uoride, centrifuged at 1,000 × g for 15min, and the
obtained plasma was frozen at -20°C until analysis of
glucose using a commercial kit (Labtest Diagnóstica
S.A., Lagoa Santa, Brazil).
The protein degradability of RAW and
ROS was evaluated in situ in three cows with rumen
cannula. Five grams of pre-dried samples was
placed in polyester bags (9 × 11cm) and incubated in
triplicate in the rumen at 0, 3, 6, 9, 12, 24 and 72h.
Considering that R is the protein mass on the residue
after incubation and washing of the samples, and I is
the initial mass of the sample, the protein fractions A,
B, and C were calculated as: A (instantly degraded
fraction) = (I-R of time 0)/I; C (indigestible fraction)
= R at time 72/I; B (slowly degrades fraction) = 100
- (A + C).The fractional degradation rate of fraction
B (Kd) was estimated over time as the slope of the
linear regression of the natural logarithm of the
residues as a percentage of sample initially incubated
after subtracting the fraction C values.
Data of the experiments1 and 2 were
analyzed using the PROC GLM of SAS (9.1, Cary,
NC, USA). The model used for the analysis: Yijkl =
µ + Bi + Vj(i) + Pk + Tl + eijkl.; where: Yijkl= dependent
variable; µ = overall mean; Bi = block effect (i = 1,
2...11 in exp. 1; i = 1, 2... 8 in exp. 2); Vj(i) = cow effect
within block (j = 1, 2... 22 in exp. 1; j = 1,... 16 in exp.
2); Pk= period effect (k = 1 or 2); Tl = effect of the
treatment (l = RAW and ROS); eijkl = experimental
error, independent, with normal distribution, mean
zero and variance σ². Data of the degradability
testwere analyzed using the PROC GLM. The model
used for the analysis:Yij = µ +Ai + Tj + eij; where: Yij=
dependent variable; µ = overall mean; Ai = animal
effect (i = 1, 2 and 3); Tj = effect of the treatment
(j = RAW and ROS); eijkl = experimental error,
independent, with normal distribution, mean zero
and variance σ². Statistical signicance and trends
were considered at P≤0.05 and P>0.05 to P≤0.10,
respectively.
RESULTS AND DISCUSSION
Consumption of DM (experiments 1 and 2,
table 2) or digestible organic matterwas not affected
by the treatments (experiment 2, table 2). Similarly,
FALDET & SATTER (1991) reported no difference
in dry matter intake (DMI) when comparing raw or
roastedisonitrogen soy diets provided for dairy cows
with alfalfa silage as the only forage.
The substitution of RAW by ROS in
both dietary inclusion levels (3.7 and 10.9% of DM)
promoted a positive response in milk performance
(Table 2) with increments in daily secretions of milk
(1.1kgday-1) and lactose (0.06kgday-1). Furthermore,
the production of solids increased in experiment 1
and tended to increase in experiment 2, and milk yield
corrected for energy tended to increase in experiment
1 with ROS treatment.The response in performance
to roasted soybean is variable. With the inclusion of
13% of DM in diets, FALDET & SATTER (1991)
reported an increase of 4.5kgday-1 in milk yield with
ROS replacing RAW. However, in other studies,
responses were not observed with the addition of
roasted soybean in production (AMANLOU et al.,
2012; ABDI et al., 2013).
The highest milk yield observed with ROS
treatment in two experiments was related to their
increased lactose production (Table 2). Stimulation
of lactose production in response to increased
protein availability in the intestine has been observed
in several studies (LEMOSQUET et al., 2009;
GALINDO et al., 2011), which suggested a possible
mechanism of action related to an increased input
of RUP in roasted soybean treatment. Amino acids
are precursors in hepatic gluconeogenesis, and can
increase glucose availability for lactose synthesis
(LEMOSQUET et al., 2009).
An increased glucose intake from amino
acid could be veried by an increase of plasma
glucose inROS treatment, which was not observed in
experiment 2 (Table 2). In fact, plasma glucose was
decreased in the ROS treatment. The concentration
of a metabolite in blood resultedfrom the production
and absorption of intestinal processes vs. utilization
by tissue cells. Roasted soybean treatment increased
lactose production and tended to increase the
Replacement of raw soybean with roasted soybean increased milk production in Holstein cows.
Ciência Rural, v.47, n.5, 2017.
5
production of solids (experiment 2) through processes
that utilize glucose as a precursor or as an energy
source and NADPH. Therefore, it is plausible to
speculate that glucose extracted from the mammary
gland was increased in the ROS treatment to meet
this increased demand, thus reducing their plasma
concentration (BOUTINAUD et al., 2008).
In addition to the effects related to glucose
availability to the mammary gland, the largest amino
acid supply can also act in intramammary metabolism
altering metabolic pathways that prioritize lactose
synthesis. LEMOSQUET et al. (2009) observed an
increase in ratio between lactose secreted in milk and
glucose extracted from the blood by the mammary
gland in response to casein infusion in the duodenum
accompanied by a decrease inplasma glucose
concentration as observed in this study.When more
glucose is targeted for lactose synthesis, the energy
demand of the mammary gland must be supplied
by other substrates such asβ-hydroxybutyricacid
(LEMOSQUET et al., 2009). The mechanism by
which amino acids have caused this change of
metabolic pathways is not understood but may be
related to its own amino acids being oxidized and
used as an energy source for the cell, which releases
glucose for anabolic functions such as lactose
synthesis (RAGGIO et al., 2006).
Increased milk yield without the
concomitant increase in DM intake resulted in an
increasing trend in feed efciency with roasted soybean
diet in experiment 1 (Table 2). Roasting had no effect
on MUN concentration (Table 2), which suggests
that the change in soybean protein degradability
did not affect ruminal nitrogen availability and
probably the absorption of metabolizable protein of
microbial origin. However, in experiment 2,there was
a reducing trend in the allantoin/creatinine ratio with
roasted soybean treatment, which can be attributed to
Table 2 - Milk composition, performance (Experiment 1), production performance, milk solids, allantoin/creatinine ratio in urine and
plasma glucose concentration in dairy cows fed with diets containing raw soybean (RAW) or roasted soybean (ROS)
(Experiment 2).
-----------------Experiment 1----------------- -----------------Experiment 2-----------------
RAW ROS SEM P RAW ROS SEM P
DMI (kgday-1) 1 20.5 20.4 0.30 0.76 19.1 19.5 0.39 0.51
DOMI (kgday-1) 2 - - - - 13.3 13.2 0.31 0.80
Milk (kgday-1) 30.8 31.9 0.32 0.03 29.1 30.2 0.40 0.05
ECM (kgday-1) 3 28.0 29.1 0.47 0.09 27.3 28.4 0.52 0.18
Fat (kgday-1) 0.94 0.98 0.02 0.24 0.98 0.99 0.02 0.58
Protein(kgday-1) 0.96 0.98 0.01 0.11 0.89 0.91 0.01 0.22
Lactose (kgday-1) 1.42 1.48 0.02 0.01 1.33 1.39 0.02 0.03
Solids (kgday-1) 3.61 3.76 0.05 0.04 3.19 3.29 0.07 0.08
Fat (% no leite)
3.07 3.13 0.06 0.55 3.38 3.30 0.05 0.30
Protein (% in milk)
3.15 3.12 0.01 0.09 3.06 3.04 0.02 0.33
Lactose (% in milk)
4.62 4.67 0.02 0.06 4.57 4.60 0.02 0.22
Solids (%in milk)
11.79 11.88 0.06 0.30 11.01 10.999 0.04 0.17
MUN (mgdL-1)4 14.9 15.1 0.31 0.65 11.9 11.9 0.28 0.84
MilkE (Mcalday-1)5 19.6 20.4 0.30 0.09 19.2 19.7 0.27 0.18
Efficiency (Mcalkg-1)6 0.96 1.01 0.02 0.09 - - - -
Efficiency (Mcalkg-1)7 - - - - 1.49 1.50 0.03 0.21
Allantoin/creatinine ratio - - - - 2.2 1.6 0.24 0.08
Plama glucose (mgdL-1) - - - - 54.8 51.4 0.90 0.01
1
Dry matter intake.2Digestible Organic matter intake.3ECM = Energy corrected milk. 4Milk urea nitrogen.5MilkE= Milk energy secretion.
6
Efficiency =Milk energy/DMI. 7Efficiency = Milk energy/DOMI.
6
Ciência Rural, v.47, n.5, 2017.
Dias Júnior et al.
a small reduction in the amount of degradable protein
available to the microorganisms in the rumen as a
result of soybean roasting.
The apparent digestibility of DM, organic
matter, and digestibility ofnon-NDF organic matter
digestibility tended to decreasein the roasted
soybean treatment (Table 3), which might suggest
a limitation of microbial growth due to reduced
protein ruminal degradation of this ingredient,
especially when considered in conjunction with
the reduction of allantoin/creatinine (Table 2) from
the same treatment. However, as mentioned above,
the MUN levels do not conrm this hypothesis.
In addition, the digestibility of NDF is mostly
affected bya limitation in microbial growth or
activity, and this wasnot different among treatments
(Table 3). Fecal nutrient analyses were not corrected
for microbial contribution. Even though such
contribution to DM and NDF is not as pronounced
as it is to CP (which is why CP digestibility was
not assessed), it still exists and might increase
variation around these numbers.
The in situ rumen degradability test had
a higher percentage of instantly degradable fraction
(fraction A) in RAWthan in ROS. In contrast,an
increase in fraction B was foundowing to heat
treatment, but no differences in degradation rate in
fraction B and fraction C between treatments were
found (Table 3). Considering a solid passage rate
of 6%/h for both treatments,protein fractions and
kd shown in table 3 and using the equation of NRC
(2001), RAW presented an RUPof 50% and a ROS
of 59%, which indicatedthat the roasting process was
effective in reducing ruminal degradation protein
without increasing fraction C.
Since the treatments did not alter DMI, the
contribution of endogenous protein to metabolizable
protein ow is assumed to be the same between RAW
and ROS. With that, by calculating the RUP values
in the consumption of soybean in experiment 2 and
assuming the same content of CP for both soybeans
and 85% of intestinal digestibility of protein (NRC,
2001), the difference between the metabolizable
protein from ROS and RAW is only 69gday-1.
This difference is unlikely to explain increases in
glucose availability or use of amino acids as an
energy source in the mammary gland.It is important
to emphasize that the kd values obtained in this
experiment are much lower than the valuesreported
in theNRC (2001) for RAW and ROS (10.9%/hand
9.3%/h, respectively), which indicatedthat 69g
can potentially be overestimated. Therefore, the
mechanism by which ROS increased production of
lactose and milk solids may be related to the input of
a specic amino acid that has a regulatory function
in intramammary metabolism.
Table 3 - Apparent digestibility of nutrients in the total digestive tract of dairy cows fed with diets containing raw soybean (RAW) and
roastedsoybean (ROS) (Experiment 2), and ruminal degradation kinetics of crude protein in RAW and ROS (degradability test).
----------------
------------------------------- Apparent digestibility of nutrients in the total digestive tract -----------------------------------------------
RAW
ROS
SEM
P
----------------------------%-----------------------------
DMD
1
71.2 69.1 0.89 0.10
OMD2
74.0
72.2
0.78
0.10
NDFD3
53.7
53.0
1.73
0.78
Non-NDFOMD4
86.6
84.7
0.65
0.06
-------------------------------------------------------------------Ruminal degradation kinetics-----------------------------------------------------------------
RAW
ROS
SEM
P
---------------------------% of CP-------------------------
--
A5
20.9
15.4
1.3
0.01
B6
74.8
81.0
1.0
0.01
C7
4.3
3.6
1.0
0.63
--------------------------%/h--------------------------
B (Kd)8
3.8
2.7
0.45
0.17
1
Dry matter digestibility .2Organic matter digestibility. 3Neutral detergent fiber digestibility.4Non-NDF organic matter digestibility.5A =
instantly degraded fraction.
6B = slowly degrades fraction.7C = indigestible fraction. 8Fractional degradation rate of fraction B with r2 was
0.89 for RAW and 0.91 for ROS.
Replacement of raw soybean with roasted soybean increased milk production in Holstein cows.
Ciência Rural, v.47, n.5, 2017.
7
CONCLUSION
The replacement of RAW by ROS on
both dietary inclusion levels tested resulted in an
increased milk yield without affecting consumption
and milk composition, which suggestedthat heat
treatment was effective in increasing theow of
rumen undegradable amino acids of soy bean to
the animal. The in situ degradability test showed
that the roasting process was effective in reducing
ruminal degradability of soybean protein.
BIOETHICS AND BIOSSECURITY
COMMITTEE APPROVAL
The protocol was approved by the Universidade
Federal de Lavras Bioethic Committee in Utilization of Animals
(protocol no 040/2010).
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