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Prediction of feed intake, digestibility and growth rate of sheep
fed basal diets of maize stover supplemented with Desmodium
intortum hay from dry matter degradability of the diets
a,b ,
*
c ,1Adugna Tolera
, Frik Sundstøl
a
Department of Animal Production and Rangeland Management, Awassa College of Agriculture, P.O. Box 5, Awassa, Ethiopia
b
Department of Animal Science, Agricultural University of Norway, P.O. Box 5025, N-1432, Aas, Norway
c
Agricultural University of Norway, Noragric, P.O. Box 5001, N-1432 Aas, Norway
Received 10 August 1999; received in revised form 16 May 2000; accepted 8 June 2000
Abstract
The in sacco dry matter (DM) degradability of diets based on maize stover harvested at three stages of maturity and supplemented with graded levels of desmodium (Desmodium intortum cv. Greenleaf) hay were estimated from degradability of the individual feeds and their corresponding DM intake. The estimated DM degradability of the diets was used for prediction of DM intake (DMI), digestible DM intake (DDMI), DM digestibility (DMD) and growth rate of sheep feeding on the diets. The desmodium hay had significantly higher (P,0.05) DM disappearance than the maize stovers after 4, 8, 16, 24 and 48 h of incubation, as well as higher washing loss (A), degradation rate (c value) and effective DM degradability (ED) than the maize stovers. The washing loss was lowest in maize stover harvested at stage III and, as a consequence, the washing loss of the diets showed a significant decrease (P,0.05) with increasing stage of maturity of the stovers. The DM disappearance after 48 h incubation, washing loss and degradation rate showed a significant increase whereas the insoluble, but potentially degradable, fraction (B ) showed a significant decrease (P,0.05) with increasing level of supplementation. The DM disappearance after 24 and 48 h of incubation, washing loss, ED and degradation rate showed strong positive correlation whereas the insoluble, but potentially degradable, fraction showed a negative correlation with DMI, DMD, DDMI and growth rate. On the other hand, the DM disappearance after 96 h of incubation, potential degradability and the lag phase showed very low correlation with these parameters. In general, the washing loss, ED and the DM disappearance after 24 and 48 h of incubation were found to be simple and reliable predictors of DMI, DDMI, DMD and growth rate. However, the use of the A, B and c values simultaneously in a multiple regression gave a more precise prediction of feed intake, digestibility and growth rate. 2001 Elsevier Science B.V. All rights reserved.
Keywords: Maize stover; Desmodium intortum; In sacco degradability; Feed intake; Digestibility
*Corresponding author. Tel.: 1251-6-200-221; fax: 1251-6- 1. Introduction 200-072.
E-mail address: [email protected] (A. Tolera).
1 Prediction of intake of fibrous roughage is one
Current Address: SACCAR, Private Bag 00108, Gaborone,
Botswana. important aspect of ruminant nutrition. However, the
chemical and physical structures of roughages, which of sheep were determined using intact male lambs define their potential microbial degradation and, (1861.5 kg live weight) of the local sheep from hence, voluntary intake by the host animal, are not southern Ethiopia in a growth experiment followed easy to measure (Hovell et al., 1986), especially in by a digestibility experiment (Tolera and Sundstøl, many developing countries where the necessary 2000). The feeds used in the experiment were maize facilities are not available. Moreover, Ørskov and stover, harvested at three stages of maturity, and Reid (1989) showed that gross chemical analyses are desmodium hay. The maize stovers were harvested at inaccurate predictors of animal performance, where- grain moisture contents of 30, 22 and 12%, which as in sacco dry matter (DM) degradation in nylon were designated as stages I, II and III, respectively. bags appears to be a more promising biological The early harvested stovers were sun-dried in the method of feed evaluation. field, to decrease the stem moisture content for safe Determination of in sacco degradation in nylon storage. The maize stovers harvested at the three bags is a fairly quick and easy method of assessing stages of maturity were used as basal diets sup-the nutritive value of feeds. The method was re- plemented with graded levels (0, 150, 300 and 450 ported to be a promising tool in predicting DM and g / head / day) of desmodium hay in a factorial ar-digestible DM intakes of cereal straws by cattle rangement of treatments (three maturity stages of (Ørskov et al., 1988b), of browse species by goats maize stover 3four levels of desmodium hay sup-(Kibon and Ørskov, 1993) and of crop residues and plementation). The chemical composition of the forages by cattle (Shem et al., 1995) from their maize stovers and desmodium hay used in the rumen degradation characteristics. In general, the experiment is shown in Table 1. The DMI, DMD, degradation characteristics of feeds, determined by DDMI and body-weight change of sheep from these the in sacco method, were used in the predictions of experiments are shown in Table 2. Details of the feed intake, digestibility and animal performance in growth and digestibility experiments were reported terms of growth rate (Ørskov and Ryle, 1990; Kibon by Tolera and Sundstøl (2000).
and Ørskov, 1993; Shem et al., 1995). Ørskov and Ryle (1990) indicated that it would be of great
advantage to be able to predict consumption from the 2.1. In sacco DM degradability of the feeds characteristics of the feed itself. According to
Ør-skov (1994), the solubility or cell content of the Dry matter degradation of the maize stovers and roughage, the insoluble but potentially degradable desmodium hay used in the experiment were de-fraction, degradation rate, the speed at which long termined by incubating about 2.5 g of the dry particles are reduced to small particles and rumen samples, ground to pass through a 2-mm sieve, in outflow rate are the important factors that affect the nylon bags in three rumen fistulated mature rams of intake of poor quality roughages. the Horro sheep from western Ethiopia. The rams The objective of this study was to evaluate the were fed 500 g of desmodium hay, 400 g of maize possibility of predicting DMI, DMD (DM digestibili- stover, 400 g of green alfalfa forage and 100 g of ty), DDMI (digestible DM intake) and growth rate of concentrate mix (50% wheat bran and 50% linseed sheep feeding on maize stover harvested at different cake), which were offered in equal proportions twice stages of maturity and supplemented with graded a day. All of the bags were incubated 1 h after the levels of Desmodium intortum cv Greenleaf (com- sheep were offered feed. The bags were withdrawn monly known as desmodium or Greenleaf de- after 4, 8, 16, 24, 48, 72 and 96 h of incubation, smodium) hay based on DM degradability of the washed for 20 min in a washing machine and dried diets, which was calculated from degradability of the for 48 h at 608C. Washing losses were determined by individual feeds and their corresponding DM intake. soaking two bags per sample in warm tap water (|398C) for 1 h followed by washing and drying as
before.
2. Materials and methods The DM degradation data were fitted to the
2ct
Table 1
a
Chemical composition of maize stover and Desmodium intortum hay used in the experiment
Components Maize stover Desmodium
intortum hay
Stage I Stage II Stage III
Dry matter (DM, %) 93.4 93.7 93.4 89.2
In dry matter(g /kg DM)
Organic matter 926 931 931 922
Crude protein 36 33 31 138
Neutral detergent fibre 772 790 801 533
Acid detergent fibre 455 483 531 351
Acid detergent lignin 50 68 83 97
Cellulose 405 415 458 254
Hemicellulose 317 307 270 182
a
Adapted from Tolera and Sundstøl (2000).
Neway Excel programme (Chen, 1995), where p is slowly degradable, fraction; c5the rate of degra-DM degradation (%) at time t. Since the washing dation of B and the lag phase (L )51 /c log [b /(ae 1
loss (A) was higher than the estimated rapidly b2A)]. The effective DM degradability (ED) was soluble fraction (a), the lag time was estimated calculated as ED5A1[Bc /(c1k)] where A, B and according to McDonald (1981) by fitting the model c are as described above and k is the rumen outflow
2ct
p5A for t#t , and p0 5a1b(12e ) for t.t .0 rate (Dhanoa, 1988). The rumen outflow rate was The degradation characteristics of the feeds were assumed to be 0.03 / h for the maize stovers and defined as A5washing loss (readily soluble fraction); 0.05 / h for the desmodium hay (Ørskov et al., B5(a1b)2A, representing the insoluble, but 1988a).
Table 2
Feed intake, DM digestibility (total diet) and body-weight change of sheep feeding on a basal diet of maize stover harvested at three stages
a
of maturity and supplemented with different levels of Desmodium intortum hay
Stover Level of DM intake DM Digestible Body wt
21 0.75
stage of supplement (g kg W ) digestibility DM intake change
21 0.75 21
maturity (g / head / d) (%) (g kg W ) (g day )
Stage I 0 54.2 34.6 22.3 222.7
150 62.4 53.8 35.7 9.2
300 71.9 60.4 43.3 33.8
450 68.4 69.6 46.5 40.5
Mean 64.2 54.6 36.3 15.2
S.E.M. 3.3 4.5 4.3 5.7
Stage II 0 46.4 24.4 16.6 232.4
150 57.6 49.3 31.2 6.0
300 60.8 58.7 36.4 33.6
450 65.2 71.1 44.7 47.0
Mean 57.5 50.9 30.8 13.5
S.E.M. 3.3 5.9 4.3 6.8
Stage III 0 45.6 25.9 14.4 242.2
150 52.7 52.0 28.5 10.7
300 58.5 53.1 31.7 34.1
450 70.8 67.7 46.9 45.5
Mean 56.9 49.8 29.7 12.0
S.E.M. 3.3 5.0 4.1 7.2
a
2.2. Estimated DM degradability of the diets experiments. The in sacco DM disappearance after 4 and 8 h of incubation was significantly higher (P,
The estimated in sacco DM degradability of the 0.05) in maize stover harvested at stage I than at maize-stover-based diets with graded levels of de- stage III. The desmodium hay had significantly smodium hay supplements were determined assum- higher (P,0.05) DM disappearance than the maize ing additive effects of the maize stovers and de- stovers after 4, 8, 16, 24 and 48 h of incubation. The smodium hay as follows. washing loss (A value) was highest in desmodium hay and lowest in maize stover harvested at stage III. (MSDMI3MSISDMD)1(DiDMI3DiISDMD)
In general, the washing loss showed a significant
]]]]]]]]]]
EISDMD5 3100
TDMI
decrease (P,0.05) with increasing stage of maturity where EISDMD5estimated in sacco DM de- of the stover. The insoluble but potentially degrad-gradability of the diet (%); MSDMI5maize stover able fraction (B value) was significantly lower DM intake; MSISDMD5in sacco DM degradability whereas the degradation rate was significantly higher of maize stover; DiDMI5Desmodium intortum hay (P,0.05) in the desmodium hay than in the maize DM intake; DiISDMD5in sacco DM degradability stovers. The maize stover harvested at stage III of Desmodium intortum hay; TDMI5total DM showed an unexpectedly higher (P,0.05) degra-intake.
The EISDMD of the diets was used for prediction
Table 3 of DMI, DMD, DDMI and growth rate of sheep
In sacco DM degradability (%) and degradability characteristics
feeding on these diets based on the intake,
diges-of maize stover and Desmodium intortum hay used in the growth tibility and body-weight change data obtained from and digestibility experiments
the growth and digestibility experiment reported by
Parameters Maize stover Desmodium
Tolera and Sundstøl (2000). intortum hay
Stage I Stage II Stage III 6S.E.
b bc c a
Analysis of variance was carried out on the in b b b a
DMD24h 37.3 36.1 35.7 54.4 1.4
b b b a
sacco DM degradation of the individual feeds using DMD 51.1 49.3 51.7 65.1 1.4 48h
a a a a
a completely randomized design and on the esti- DMD72h 60.6 62.8 59.9 65.8 1.8
a a a a
DMD 67.5 65.4 63.8 67.2 1.4
mated DM degradability of the diets using factorial 96h
b c d a
A 14.6 12.9 11.9 23.6 0.0
arrangement of treatments. Significant differences a a a b
B 63.8 67.0 59.9 44.4 2.2
between means were tested using Duncan’s New ab a bc c
A1B 78.4 79.9 71.8 68.0 2.2
c c b a
Multiple Range test (SAS, 1985; Montgomery, c 0.018 0.017 0.022 0.05 0.001
ab b ab a
1991). Correlation as well as simple and multiple L 1.1 0.7 1.8 2.2 0.4
b b b a
ED 38.0 37.3 37.7 45.8 0.9
linear regression analyses were performed on the
R.S.D. 2.4 2.5 2.6 2.3
data to examine the relationships of DMI, DMD,
a,b,c
DDMI and growth rate of the sheep with estimated Means with one or more similar superscripts within a row are not significantly different (P.0.05).
in sacco DM degradability of the diets (SAS, 1985).
DMD4h5DM disappearance after 4 h of incubation (%); DMD8h5DM disappearance after 8 h of incubation (%); DMD16h5DM disappearance after 16 h of incubation (%);
3. Results DMD24h5DM disappearance after 24 h of incubation (%);
DMD48h5DM disappearance after 48 h of incubation (%); DMD72h5DM disappearance after 72 h of incubation (%); 3.1. DM degradability of the individual feeds
DMD96h5DM disappearance after 96 h of incubation (%); A5
washing loss (%); B5insoluble but slowly degradable (%); A1
Table 3 shows the in sacco DM disappearance and B5potential degradability (%); c5degradation rate (/ h); L5lag degradability characteristics of the maize stovers and time (h); ED5effective degradability (%); R.S.D.5residual
dation rate than the stover harvested at stages I and (P,0.001) with DMI, DMD, DDMI and growth II. The potential degradability (A1B ) was signifi- rate. The degradation rate was positively correlated cantly lower (P,0.05) in the desmodium hay than in whereas the insoluble, but potentially degradable, the maize stovers harvested at stages I and II. The fraction was negatively correlated with DMI (P,
lag time was significantly higher (P,0.05) in de- 0.01) and with DMD, DDMI and growth rate (P,
smodium hay than in maize stover harvested at stage 0.001). DMD and growth rate were negatively II and it also tended to be higher (P.0.05) in maize correlated (P,0.05) with the potential degradability stover harvested at stage III than in the stover and positively correlated (P,0.05) with the lag harvested at stages I and II. The effective de- phase.
gradability (ED) was significantly higher (P,0.05) Table 6 shows equations predicting DMI of sheep in the desmodium hay than in the maize stovers. from DM disappearance and DM degradability characteristics of the diets. Using simple linear 3.2. Estimated DM degradability of the diets regression, the A value was the best predictor of DM intake followed by DMD24h, ED and DMD48h. The Table 4 shows the estimated DM degradability of lag phase and the potential degradability were very a basal diet of maize stover harvested at three stages poor predictors of feed intake. The DM disappear-of maturity and supplemented with graded levels disappear-of ance after 72 h of incubation (DMD72h) and the DM desmodium hay. When maize stover harvested at disappearance after 96 h of incubation (DMD96h) stage II was used as a basal diet, its estimated DM also had very low precision in predicting DMI. The disappearance after 48 h of incubation (DMD48h) use of A and B or A and c in multiple regressions was significantly lower than that of diets based on improved the coefficient of determination by one maize stover harvested at stages I and III. The percentage unit over the use of the A value alone. washing loss of the diets showed a significant When A, B and c were used together in a multiple decrease (P,0.05) with increasing stage of maturity regression, they accounted for 91% of the variation of the stover. The potential degradability was sig- in feed intake. However, addition of the lag phase nificantly lower whereas the degradation rate and the could not improve the precision of prediction any lag time were significantly higher (P,0.05) in the further.
diets based on stage III maize stover than those Equations predicting DDMI of the sheep from DM based on stovers harvested at stages I and II. disappearance and DM degradability characteristics The DMD48h, washing loss, degradation rate and of the diets are shown in Table 7. The soluble effective degradability showed a significant increase fraction (A) was the best single predictor, accounting whereas the insoluble, but slowly degradable, frac- for 95% of the variation in DDMI. The DMD24h, tion showed a significant decrease (P,0.05) with ED, DMD48h, c and B accounted for 93, 90, 88, 79 increasing level of supplementation. The lag time and 72% of the variation in DDMI, respectively. The was lowest at 0 and highest (P,0.05) at 450 g of lag phase, potential degradability and DMD96h were supplementation and generally showed an increasing poor predictors of DDMI (P.0.05). The use of A trend with increasing level of supplementation. and B or A and c in multiple regressions improved the coefficient of determination by one percentage 3.3. Prediction of feed intake, digestibility and unit over the use of the A value alone. However, the body-weight change of sheep use of A, B and c values together in a multiple regression could not improve the prediction ability Table 5 shows the correlation of feed intake, any further. On the other hand, the addition of the digestibility and body-weight change of sheep with lag phase to A, B and c values in a multiple estimated in sacco DM degradability of the diet. The regression decreased the precision of prediction to DM disappearance after 24 h of incubation 91%.
charac-Table 4
Estimated DM degradability of total diet based on maize stover harvested at three stages of maturity and supplemented with graded levels of
Desmodium intortum hay
Parameters Supplement Stage of maturity of stover level (g / head / day)
Stage I Stage II Stage III Mean 6S.E.
d
A (washing loss), 0 14.6 12.9 11.9 13.1 0.8
c
B (insoluble 0 63.8 67.0 59.9 63.6 2.1
b
but potentially 150 58.6 60.5 55.5 58.2 1.4
c
degradable), % 300 55.1 56.1 52.6 54.6 1.0
d
degradability), % 150 75.6 76.5 70.7 74.3 1.9
bc
c (degradation 0 0.018 0.017 0.023 0.019 0.002
c
rate), / h 150 0.026 0.027 0.031 0.028 0.001
b
300 0.032 0.033 0.035 0.034 0.001
a
450 0.04 0.038 0.04 0.039 0.001
b b a
ED (effective 0 38.1 37.3 37.7 37.7 0.2
c
degradability), % 150 40.2 39.7 40.0 40.0 0.1
b
300 41.6 41.4 41.5 41.5 0.04
a
Means with one or more similar superscripts within a row or within a column are not significantly different (P.0.05).
determi-Table 5 multiple regressions further increased the coefficient Pearson correlation coefficients of the relationship between esti- of determination to 95%, and the addition of L in the mated in sacco DM degradability characteristics of the diet and
multiple regression further increased the coefficient feed intake, digestibility and body-weight change in sheep
of determination to 96%. Dry matter Dry matter Digestible Growth
intake digestibility DM intake rate
DMD24 h 0.89*** 0.97*** 0.97*** 0.98*** 4. Discussion DMD48 h 0.85*** 0.95*** 0.94*** 0.95***
DMD72 h 0.64* 0.74** 0.73** 0.78**
NS NS NS The higher washing loss in earlier harvested maize
DMD96 h 0.67* 0.47 0.55 0.41
A 0.94*** 0.97*** 0.98*** 0.96*** stover and in the desmodium hay indicates the
B 20.75** 20.88*** 20.85*** 20.88*** presence of more soluble components in these feeds.
NS NS
A1B 20.41 20.58* 20.53 20.59* The same explanation holds true for the increased
c 0.77** 0.92*** 0.89*** 0.93***
NS NS estimated washing loss at earlier stages of maturity
L 0.45 0.59* 0.55 0.59*
of the stover and with increasing level of desmodium ED 0.87*** 0.97*** 0.95*** 0.97***
hay supplementation of the diets. The increased Significance level: NS5P.0.05; *5P,0.05; **5P,0.01;
washing loss observed with increasing level of ***5P,0.001; For other abbreviations, see Table 2.
supplementation was due to the higher washing loss nation to 96%. However, the use of A, B, c or the in desmodium hay and the additive effect of the addition of L in a multiple regression could not stover and desmodium hay in DM degradability. improve the precision of prediction any further. Desmodium hay supplementation also improved the The DMD24h and ED were the best predictors of estimated DM degradation rate of the diets due to the growth rate followed by the washing loss, DMD48h, significantly higher degradation rate of the de-degradation rate and the insoluble, but potentially smodium hay than the stovers. Moreover, forage degradable, fraction (Table 9). The DMD96h had the legume supplementation enhances the degradation of lowest precision of predicting growth rate followed the basal roughage by providing readily fermentable by the lag phase, potential degradability and substrates and thereby creating a more favourable DMD72h. The use of A and B in multiple regressions environment for rumen micro-organisms. According-improved the coefficient of determination by three ly, Ndlovu and Buchanan-Smith (1985) showed that percentage units over the use of the A value alone, to alfalfa supplementation to poor quality roughages 94%, whereas the use of A and c or A, B and c in increased rates of disappearance of DM and cell wall
Table 6
0.75
Prediction of dry matter intake by sheep ( y) of the total diet (g / kg W / day) from DM degradability of the diet
2
Table 7
0.75
Prediction of digestible dry matter intake by sheep ( y) of the total diet (g / kg W / day) from DM degradability of the diet
2
Factor(s) Equation R RMSE P
DMD24 h y5 284.712.7DMD24h 0.93 3.4 ,0.001
DMD48 h y5 2149.913.3DMD48 h 0.88 4.8 ,0.001
DMD72 h y5 2367.316.4DMD72h 0.49 9.2 ,0.01
DMD96 h y5 2366.916.04DMD96h 0.23 11.4 50.066
A y5 244.814.6A 0.95 2.9 ,0.001
B y5151.122.1B 0.72 7.2 ,0.001
c y5 211.211447.97c 0.79 6.3 ,0.001
L y55.7117.1L 0.30 11.4 50.066
(A1B ) y5182.022.03(A1B ) 0.28 11.5 50.077
ED y5 298.313.1ED 0.90 3.6 ,0.001
A B y5 217.0214.1A20.33B 0.96 2.9 ,0.001
A c y5 242.0514.03A1221.12c 0.96 2.9 ,0.001
A B c y5 22.114.2A20.54B2169.3c 0.96 3.0 ,0.001
A B c L y5 2168.215.2A11.5B1362.7c111.6L 0.91 3.2 ,0.001
RMSE5Root mean square error. For other abbreviations, see Table 2.
Table 8
Prediction of dry matter digestibility by sheep ( y) of the total diet (%) from DM degradability of the diet
2
Factor(s) Equation R RMSE P
DMD24 h y5 291.213.4DMD24h 0.94 3.7 ,0.001
DMD48 h y5 2173.514.0DMD48 h 0.91 5.0 ,0.001
DMD72 h y5 2437.017.8DMD72h 0.50 11.1 ,0.01
DMD96 h y5 2365.516.3DMD96h 0.14 14.5 50.123
A y5 240.715.5A 0.93 4.3 ,0.001
B y5201.222.6B 0.77 7.8 ,0.001
c y5 22.8511821.2c 0.84 6.5 ,0.001
L y516.7122.5L 0.35 13.3 50.043
(A1B ) y5252.722.7(A1B ) 0.34 13.4 50.046
ED y5 2138.614.5ED 0.94 3.9 ,0.001
A B y523.714.29A20.8B 0.95 3.7 ,0.001
A c y5 233.113.95A1619.3c 0.96 3.6 ,0.001
A B c y5 216.414.0A20.2B1456.3c 0.96 3.9 ,0.001
A B c L y5 2182.215.0A11.8B1987.1c111.6L 0.96 4.1 ,0.001
RMSE5Root mean square error, For other abbreviations, see Table 2.
from nylon bags. Similarly, Kabatange and Shayo these parameters. The poor correlation of potential (1991) reported that supplementation of Leucaena degradability with DMI is consistent with the find-leucocephala hay to maize stover resulted in in- ings of Carro et al. (1991). The A value, ED, creased DM disappearance from nylon bags at DMD24h, DMD48h and the c value were the best different incubation times and in improved degra- predictors of DMI, DMD, DDMI and growth rate in dation characteristics. a simple linear regression equation. In contrast, the The DMD24h, DMD48h, A, ED and c values lag phase, potential degradability, DMD96h and showed strong positive correlation whereas the B DMD72h were relatively poor predictors of feed value showed a negative correlation with DMI, intake, digestibility and growth rate.
popu-Table 9
Prediction of growth rate ( y) of sheep (g / day) from DM degradability of the diet
2
RMSE5Root mean square error. For other abbreviations, see Table 2.
lation and its enzyme systems, because they are a rate. According to Yalc¸in et al. (1998), the potential degradability of cereal straws was not related to source of nutrients for the rumen’s micro-organisms
growth rate and was poorly related to DM intake. (Carro et al., 1991). Thus, it is logical that the A and
Fonseca et al. (1998) also reported that the potential c values of the feed have a relatively high precision
degradability had the lowest precision of predicting of predicting feed intake, digestibility and growth
DMI, DDMI and live weight change. The potential rate. Ferri et al. (1998) also showed that both the A
degradability represents the fraction that would be and c values had high positive correlation with DMI,
degraded if samples were incubated in the rumen for DDMI and DMD. Carro et al. (1991) found
signifi-a prolonged period signifi-and is not the ssignifi-ame signifi-as the in vivo cant relationships between voluntary feed intake and
situation. Roughages with similar potential de-the soluble fraction of de-the DM, de-the rate of
degra-gradabilities could have different rumen retention dation of DM and the rate of degradation of NDF.
times and, consequently, different in vivo digestibili-However, the best fit was obtained when both the
ty and voluntary intake (Carro et al., 1991). soluble fraction and the rate of degradation of the
The highly significant relationship of ED with feed DM were included in a multiple regression. On the
intake, digestibility and growth rate, found in the other hand, contrary to what would normally be
present study, is in conformity with the findings of expected, Chermiti et al. (1996) could not find any
Stensig et al. (1994a) who showed a significant correlation between DMI and the degradation rate of
2
hays and straws. linear relationship (R 50.77) between ED and in
relation-ship. Thus, Madsen et al. (1994) and Stensig et al. References
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