Go to Top Go to Bottom
Asian-Australas J Anim Sci > Volume 27(2); 2014 > Article
Li, Xu, Liu, Fang, and Wang: Assessment of the Nutritive Value of Whole Corn Stover and Its Morphological Fractions

Abstract

This study investigated the chemical composition and ruminal degradability of corn stover in three maize-planting regions in Qiqihaer, Heilongjiang Province, China. The whole stover was separated into seven morphological fractions, i.e., leaf blade, leaf sheath, stem rind, stem pith, stem node, ear husk, and corn tassel. The assessment of nutritive value of corn stover and its fractions was performed based on laboratory assays of the morphological proportions, chemical composition, and in situ degradability of dry matter (DM), neutral detergent fiber (NDF), and acid detergent fiber (ADF). The chemical composition of corn stover was significantly different from plant top to bottom (p<0.05). Among the whole corn stover and seven morphological fractions, leaf blade had the highest crude protein (CP) content and the lowest NDF and ADF contents (p<0.05), whereas stem rind had the lowest CP content and the highest ADF and acid detergent lignin (ADL) contents (p<0.05). Ear husk had significantly higher NDF content and relatively lower ADL content than other corn stover fractions. Overall, the effective degradability of DM, NDF, and ADF in rumen was the highest in leaf blade and stem pith, followed by ear husk. The results indicate that leaf blade, ear husk, and stem pith potentially have higher nutritive values than the other fractions of corn stover. This study provides reference data for high-efficiency use of corn stover in feeding ruminants.

INTRODUCTION

Corn stover is one of the main crop straws characterized by multi-source, wide distribution, high abundance, low cost, less competing usage, and great potential for development and utilization. Presently, global annual production of straw is ~2.9 billion ton, with corn stover contributing 35% to the total. In China, the production of corn stover is ~0.3 billion ton, accounting for 56.6% of the national annual production of straw (including the straw of rice, wheat, corn, beans, tubers, oil-bearing crops, cotton, hemp, sugar crops, and other crops) (Zeng et al., 2007).
With an increasing number of poultry and livestock, their competition for food with humans has led to wide concern. Reasonable development and utilization of straw as feed source can provide a material basis for herbivorous livestock such as cows and sheep. To date, a large number of countries, especially developing countries have used straw as feed for their herbivorous livestock. However, the application of straw as feed is largely limited due to the compositional characteristics such as abundant fiber content, low protein level, and low energy.
Previously, a machine for separation of sweet sorghum pith and rind was designed to achieve high-efficiency use of the stalk (Crandell and Worley, 1988). In recent years, the mechanical properties of corn stover stalks have been investigated (Lee et al., 2006; Grundas and Skubisz, 2008), and a device for separation of corn stover rind and pith has been developed in China (Liu and Wang, 2011). It is thought that by separating different parts of the stalk, corn stover can be used more efficiently for different purposes. For example, the rind of corn stover has been used as high-quality fiber to produce glazed paper, high strength corrugated paper, and packaging board, as well as plywood for construction (Zhou et al., 2011), whereas the separated leaf and pith tissues with less fiber content can be used as feed for ruminants. In this way, it is possible to improve the effectiveness of stalk utilization, increase associated income, and benefit the environment, thereby creating tremendous social and economic values.
For better utilization of straw as feed by ruminants, in-depth research needs to be conducted on the physicochemical composition of straw and the anatomy of tissues related to rumen fermentation, as well as other inherent factors. A large body of work shows that the chemical composition and nutritive value of plant tissues vary in different straw fractions of rice and wheat (Sannasgala and Jayasuriya, 1987; Shand et al., 1988; Tan et al., 1995; Vadiveloo, 2000; Wang et al., 2006). However, few reports are available on the major chemical composition of corn stover (Ahmed and Zhu, 2006; Hess et al., 2002), and no study has assessed the nutritive value of different fractions of corn stover for feeding ruminants.
In the present study, we investigated the chemical composition, ruminal degradability, and effective degradability of the whole plant and different fractions of corn stover, and further explored the dynamic variation trend in their nutritive value. The results will provide supporting data for making full use of corn stover as a feed source of ruminants.

MATERIALS AND METHODS

Sample collection

In mid-September 2011, 30 corn stover samples (waxy maize) were collected from 3 maize-planting regions (n = 10 per region) in Qiqihaer, Heilongjiang Province, northeastern China. The corn stover was dried in good preservation without peeling. Leaf blade, leaf sheath, stem rind, stem pith, stem node, ear husk, and tassel were manually striped from the whole corn stover. Stem rind and stem pith were obtained by stripping from the internode of cornstalk, and stem node was obtained by snipping the line of the joint of culm within 0.8 cm. The corn stover samples were dried at 60°C to constant weight and then ground to powder before use.

Chemical compositional analyses

The chemical composition of whole corn stover and its morphological fractions were assayed as follows: Total dry matter (DM) and organic matter (OM) contents determined by oven drying at 105°C overnight and loss-on-ignition in a muffle furnace at 525°C for 8 h, respectively; the nitrogen (N), calcium (Ca) and phosphorus (P) contents measured following standard methods (AOAC, 1990); the crude protein (CP) content calculated as N×6.25; the ether extract (EE) determined by Soxtec extraction with petroleum ether; the neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) determined following the procedures outlined by Goering and Van Soest (1970) with modifications described by Van Soest et al. (1991).

In situ rumen degradation

In situ rumen degradation of whole corn stover and its morphological fractions were evaluated in 3 ruminally cannulated Chinese - Holstein dry cows (~550 kg BW). The cows were housed in individual tie stalls bedded with rubber on a plank bed and fed diets containing leymus chinensis (28%), corn silage (42%), and concentrate mixture (30%) at maintenance levels. The dried and ground corn stover samples were weighed into dacron bags (12×9 cm; 40 to 45 micron pore size) and incubated in the rumen of cows for different periods, i.e., 0 h, 4 h, 8 h, 12 h, 24 h, 48 h, and 72 h. After incubation, the bags were removed from the rumen, washed in cold water till the rinse solution became clear, and then dried at 60°C for 48 h as described by Karsli and Russell (2002). The rumen degradation kinetics of DM, NDF, and ADF were calculated using a nonlinear model proposed by Ørskov and McDonald (1979) as follows:
y=a+b(1-e-ct)
where,
y = Ruminal degradability of the response variables at time t
t = Incubation time (h)
a = Highly soluble and readily degradable fraction of corn stover (%)
b = Insoluble and slowly degradable fraction of corn stover (%)
c = Rate constant of degradation (% h−1)
e = 2.7182 (The base for natural logarithm)
After the abovementioned parameters were determined, the effective degradability of DM, NDF, and ADF in whole plant, leaf blade, leaf sheath, stem rind, stem pith, stem node, ear husk, and tassel of corn stover were calculated using the equation described by Ørskov and McDonald (1979) as follows:
ED=a+(b×c)/(c+k)
where,
ED = Effective degradability of the response variables
a = Highly soluble and readily degradable fraction of corn stover (%)
b = Insoluble and slowly degradable fraction of corn stover (%)
c = Rate constant of degradation (% h−1)
k = Rate constant of passage (% h−1)
In the calculation of effective degradability, the rate constant of passage was assumed to be 0.025 per hour according to Feed Criteria of Dairy Cows in China (Han, 2007).

Statistical analyses

All data are subjected to one-way ANOVA by using the GLM procedure in SAS (Ver9.0 for Windows). If significant differences (p<0.05) were detected in treatment means by ANOVA, Duncan’s multiple rang test was further applied to mean pairs.

RESULTS

Nutrient composition

The nutrient composition of corn stover substantially varied among different morphological fractions from the whole plant (Table 1). For example, leaf blade had the highest CP content (9.95%) and the lowest NDF and ADF contents (62.28% and 31.12%, respectively) (p<0.05), whereas stem rind had the lowest CP content (1.94%) and the highest ADF and ADL contents (47.59% and 8.32%, respectively) (p<0.05). Ear husk had significantly higher NDF content (82.69%) and relatively lower ADL content (3.60%) compared to other corn stover fractions.
Leaf blade had the highest Ca and P contents (1.01% and 0. 11%, respectively), whereas ear husks had the lowest Ca content (0.21%) and stem pith (and rind) had the lowest P content (0.03%). The OM content of leaf blade was 92.46%, significantly lower than that of other fractions, i.e., 93.05% to 93.78% in tassel and leaf sheath; 95.16% to 95.58% in whole plant, stem pith, and stem node; and 96.92% to 97.27% in ear husk and stem rind. There were no significant differences in the DM content the whole plant and 7 morphological fractions of corn stover (p>0.05) (Table 1).

Ruminal disappearance rate

The ruminal disappearance rate of major nutrient contents of corn stover fractions positively increased with the incubation time (Figures 1 to 3). Overall, the DM, NDF and ADF of corn stover fractions disappeared at low rates within the first 12 h in rumen, as indicated by the small slope of the variation curve. After 12-h incubation, the ruminal disappearance rates of DM, NDF, and ADF of corn stover fractions obviously increased.
During rumen incubation, there were significant differences in the ruminal disappearance rate of major nutrient contents among the whole corn stover and different fractions (Tables 2 to 4) (p<0.001). For example, the ruminal disappearance rates of DM, NDF, and ADF of leaf blade, ear husk, and stem pith were significantly higher than those of other corn stover fractions at 48 h and 72 h (leaf blade>ear husk>stem pith). The ruminal disappearance rates of NDF of the abovementioned 3 fractions at 48 h followed the same order: leaf blade>ear husk>stem pith, while that of ADF decreased in the following order: leaf blade>stem pith >ear husk. The corresponding ruminal disappearance rates of NDF and ADF at 72 h both decreased in the following order: stem pith>leaf blade>ear husk. Stem rind had the lowest ruminal disappearance rates of DM, NDF, and ADF at both 48 h and 72 h compared to other morphological fractions.

Effective degradability rate

The effective degradability of major nutrient contents showed different variation trends among the whole corn stover and different fractions (Table 5). Among different corn stover fractions, the effective degradability of DM in rumen was the highest in leaf blade and stem pith, followed by ear husk and whole plant. For the remaining fractions, the effective degradability of DM in rumen followed the order of leaf sheath>corn tassel>stem node>stem rind (p<0.001).
The NDF of corn stover fractions was similar to that of DM, the effective degradability of NDF in rumen was the highest in stem pith and leaf blade, followed by ear husk and whole plant. For other fractions, the effective degradability of NDF in rumen followed the order of stem node>leaf sheath>corn tassel>stem rind (p<0.001).
The ADF of corn stover fractions was similar to that of DM and NDF, the effective degradability of ADF was the highest in stem pith and leaf blade, followed by whole plant and ear husk. For the remaining fractions, the effective degradability of ADF varied in the following order: corn tassel>stem rind>stem node>leaf sheath (p<0.001).

DISCUSSION

Nutrient distribution of different morphological fractions of corn stover

In this study, the results of chemical analysis showed that the nutrient composition of corn stover fractions and whole plant had large differences (Table 1). This is understandable as different plant fractions feature various cell morphologies and thus play various functions with different nutritive values. The CP content occurred at the highest level in leaf blade and tended to decrease from plant top to bottom (Table 1). Such variation in the CP content of corn stover could be attributed to the transition from older to younger tissues (Kalmbacher, 1983), consistent with previous findings by several studies (Tolera and Sundstol, 1999; Madibela et al., 2002).
The NDF and ADF contents occurred at the lowest levels in leaf blade (Table 1), similar to results reported by Schulthess et al. (1995), Tan et al. (1995), and Tang et al. (2006). However, the highest NDF and ADF contents were found in ear husk and stem rind, respectively (Table 1), inconsistent with previous findings by the abovementioned studies. These different results are possibly resulted from different selection of corn plant fractions for chemical compositional analysis.
Results of the present study showed that stem rind had the highest ADF and ADL contents while leaf blade had the lowest NDF and ADF contents (Table 1). Previously, Hay et al. (1953) indicated that corn leaf and stalk contribute a substantial N source to corn kernel (60% and 26%, respectively), and Crawford et al. (1982) reported that corn stalk and leaf are the main N sources of corn kernel. The fiber content was unevenly distributed in corn stover partly because that corn stems contain abundant structural and conducting tissues while the leaves are largely occupied by thin-walled mesophyll cells.
Our results indicate that the Ca and P contents of corn stover are mainly distributed in surface organs, similar to the distribution of mineral elements in other straw crops (Kalmbacher, 1983). This phenomenon can be attributed to plant transpiration which causes substantial evaporation of water content and leads to the deposition of minerals primarily in leaf blade and leaf sheath. Additionally, the results show that the OM content followed the order of stem rind>ear husk>stem node>stem pith>whole plant>leaf sheath>tassel>leaf blade. This observation is associated with the relatively high contents of ADF and lignin in stem rind and NDF in ear husk, with less NDF and ADF in Ca- and P-rich leaf tissues.

Ruminal degradation of major nutrient components of corn stover and its morphological fractions

The ruminal disappearance rate of corn stover is generally low due to the low protein level, low energy, and rich fiber content. In the present study, the ruminal disappearance rates of various corn stover fractions were found obviously higher at 24 h, 48 h, and 72 h than at 4 to 12 h, similar to the results reported in soybean straw by Maheri-Sis et al. (2011). Regarding the effective degradability of major nutrient contents (e.g., DM, NDF, and ADF), leaf blade, ear husk, and stem pith had significantly higher values while stem rind had the lowest values compared to other corn stover fractions. The difference between ruminal degradation rate and effective degradability of corn stover can be related to the different physical structures and chemical composition of various corn stover fractions. Previously, Hunt et al. (1992) studied the digestibility of different fractions of straw and proposed that the lower the ADL content the higher its digestibility, whereas other studies indicated that lignin content is the primary limiting factor of forage digestion (Jung and Allen, 1995).
Additionally, different physiological functions of various straw fractions are the main factor that influences their digestion and utilization. For example, plant stem mainly plays a supporting role and participates in defense against diseases and pests as well as protection from cold. Thus, stem rind contains relatively high lignin content that is difficult to be digested. On the other hand, leaves mainly conduct photosynthesis and reserve nutrient contents that are easily to be digested. These explain our observation that leaf blade, ear husk and stem pith of corn stover had relatively lower ADF and ADL contents with higher ruminal disappearance rate and effective degradability than other fractions, consistent with previous findings by Hunt et al. (1992) and Tovar-Gomez et al. (1997).

CONCLUSIONS

The chemical composition of corn stover significantly varies in different morphological fractions. Evaluation of the ruminal degradation rate and effective degradability of major nutrient contents of corn stover fractions indicates that leaf blade, ear husk, and stem pith have higher nutrient levels than other fractions of corn stover, thus may have greater nutritive value. This work is of guiding significance to livestock feeding with cost-effective nutritive corn stover fractions.

ACKNOWLEDGEMENTS

This study was supported by the National Science and Technology Support Program of China (No. 2012BAD12B05-1).

Figure 1
Dry matter degradability of whole corn stover and different morphological fractions during rumen incubation for different periods in dry cows.
ajas-27-2-194-6f1.gif
Figure 2
Neutral detergent fiber degradability of whole corn stover and different morphological fractions during rumen incubation for different periods in dry cows.
ajas-27-2-194-6f2.gif
Figure 3
Acid detergent fiber degradability of whole corn stover and different morphological fractions during rumen incubation for different periods in dry cows.
ajas-27-2-194-6f3.gif
Table 1
Chemical composition of whole corn stover and different morphological fractions (%, air-dry basis)
Nutrient Tassel Leaf blade Leaf sheath Stem rind Stem pith Stem node Ear husk Whole plant SEM p-value
DM 92.96 92.88 92.45 93.30 93.26 92.20 93.38 93.38 0.08 0.43
CP 6.60b 9.95a 4.25c 1.94e 3.33d 4.20c 2.26e 4.05c 0.23 <0.01
EE 1.40a 1.49a 1.02bcd 0.60e 1.22abc 0.92cde 0.87de 1.31ab 0.13 0.02
OM 93.05b 92.46a 93.78c 97.27g 95.20d 95.58e 96.92f 95.16d 0.64 <0.01
NDF 71.39c 62.28e 74.81b 71.06c 70.49d 72.33c 82.69a 71.93c 0.62 <0.01
ADF 37.80d 31.12e 39.01c 47.59a 39.05c 39.24c 43.34b 41.36c 0.39 <0.01
ADL 5.78cd 4.43ef 5.72de 8.32a 4.33f 6.80b 3.60f 6.26b 0.34 <0.01
Ca 0.61b 1.01a 0.53c 0.45de 0.41e 0.47df 0.21g 0.40f 0.02 <0.01
P 0.07b 0.11a 0.06bc 0.03c 0.03c 0.05bc 0.07bc 0.05bc 0.01 0.006

a–g Means in the same row with different superscript letters are different at p<0.05.

DM = Dry matter, CP = Crude protein, EE = Ether extract; OM = Organic matter; NDF = Neutral detergent fiber, ADF = Acid detergent fiber, ADL = Acid detergent lignin, P = Phosphorus, Ca = Calcium.

SEM = Standard error of mean.

Table 2
Ruminal disappearance rate (%) of DM from whole corn stover and different morphological fractions
Fraction Ruminal disappearance rate of dry matter at different time points (h)

0 4 8 12 24 48 72
Leaf sheath 8.23±0.37d 11.87±0.27d 14.82±0.29d 21.83±2.07cd 36.04±1.03cd 46.62±1.01d 56.59±2.12b
Leaf blade 16.79±0.55a 19.13±0.30a 22.88±1.21b 25.65±0.31abcd 42.15±1.04b 63.67±1.37a 67.46±0.70a
Stem pith 16.83±0.70a 20.01±0.43a 25.48±1.01a 28.57±1.49a 47.48±0.42a 58.92±0.84b 67.42±2.49a
Stem node 6.70±0.24e 17.28±0.19e 21.05±0.22b 24.00±0.28bcd 27.27±0.23e 43.09e±1.40e 50.18±1.13c
Stem rind 5.16±0.17f 19.32±0.04a 21.62±0.51b 23.72±1.04bcd 28.96±0.79e 39.86±0.84e 44.78±1.08d
Ear husk 4.75±0.21f 9.98±0.25e 17.97±0.60c 26.24±1.65abc 36.58±1.17c 61.30±0.60ab 65.45±1.44a
Tassel 11.52±0.29c 14.97±0.17c 17.18±0.04c 21.43±0.95cd 33.64±2.15d 48.18±1.38cd 50.44±2.82c
Whole plant 13.51±0.28b 17.33±0.23b 21.36±0.27b 27.74±0.44ab 38.54±1.23c 51.53±1.39c 58.78±0.72b
p-value <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
SEM 0.97 0.63 0.68 0.60 1.46 1.62 1.71

a–f Means in the same column with different superscript letters are significantly different at p<0.05;

SEM = Standard error of mean.

Table 3
Ruminal disappearance rate (%) of NDF from whole corn stover and different morphological fractions
Fraction Ruminal disappearance rate neutral detergent fiber at different time points (h)

0 4 8 12 24 48 72
Leaf sheath 1.94±0.51bcd 9.01±0.39e 13.17±0.99e 15.57±1.22e 33.25±1.42cd 45.58±1.24e 54.73±1.89c
Leaf blade 2.01±0.40bcd 17.05±0.28b 18.94±1.40bc 22.20±1.72cd 39.13±1.36b 64.64±1.96a 66.69±1.01a
Stem pith 3.68±0.37a 18.71±0.55a 23.10±0.71a 25.82±1.35ab 47.97±0.58a 59.74±0.75b 68.23±0.62a
Stem node 1.42±0.27cd 13.82±0.54c 17.58±0.10cd 20.08±0.43d 26.19±1.09e 46.85±1.36de 54.68±1.37c
Stem rind 1.04±0.38d 17.60±0.79ab 21.13±1.74ab 25.32±0.43abc 29.50±0.92de 41.65±0.55f 47.89±1.03d
Ear husk 2.39±0.36abcd 5.98±0.22f 15.84±0.32de 24.29±1.88bc 29.61±0.66de 62.03±0.55ab 65.68±1.22a
Tassel 3.26±0.28ab 10.96±0.45d 14.64±1.26e 16.72±0.93e 31.88±1.92cd 49.78±0.31d 50.46±0.68d
Whole plant 2.64±0.44abc 16.61±0.29b 19.32±0.36bc 28.26±0.90a 35.87±1.75bc 53.24±0.73c 60.16±0.68b
p-value 0.003 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
SEM 2.11 0.92 0.73 1.01 1.36 1.63 1.60

a–e Means in the same column with different superscript letters are significantly different at p<0.05;

SEM = Standard error of mean.

Table 4
Ruminal disappearance rate (%) of ADF from whole corn stover and different morphological fractions
Fraction Ruminal disappearance rate of acid detergent fiber at different time points (h)

0 4 8 12 24 48 72
Leaf sheath 1.87±0.31b 5.96±0.38e 14.79±0.59cd 16.67±0.87d 29.05±0.67c 43.25±1.49c 51.96±2.53de
Leaf blade 2.36±0.16ab 16.97±0.71bc 18.58±1.28b 19.80±0.21cd 33.57±1.26b 60.36±2.16a 63.68±0.83ab
Stem pith 2.35±0.47ab 18.14±0.35ab 22.94±0.37a 24.94±1.63 49.52±0.65a 60.35±0.77a 66.04±0.88a
Stem node 1.34±0.41b 14.27±0.48d 16.94±0.45bc 19.74±0.25cd 23.14±0.4.3d 46.74±1.53c 54.03±0.83d
Stem rind 1.41±0.31b 18.74±0.16a 21.21±0.87a 24.76±1.21ab 31.33±1.19bc 43.03±1.11c 49.24±1.30e
Ear husk 3.33±0.26a 4.79±0.14e 14.17±0.53d 22.37±1.00bc 30.41±0.36bc 57.89±1.06a 61.10±1.41bc
Tassel 3.08±0.30a 13.69±0.68d 16.25±0.41cd 19.08±0.51cd 33.75±1.84b 53.21±0.64b 53.23±0.84d
Whole plant 2.18±0.44ab 15.39±0.79cd 18.97±0.42b 26.15±0.77a 32.87±1.60bc 51.69±1.19b 59.09±1.03c
p-value 0.09 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
SEM 0.17 1.07 0.66 0.75 1.44 1..39 1.21

a–e Means in the same column with different letters are statistically different at p<0.05;

SEM = Standard error of mean.

Table 5
The effective degradability (ED, %) of dry matter, neutral detergent fiber, and acid detergent fiber of whole corn stover and different morphological fractions
Fraction Dry matter Neutral detergent fiber Acid detergent fiber
Leaf sheath 36.40±0.70d 34.12±0.66d 32.21±0.64e
Leaf blade 46.44±0.37a 43.70±0.53b 41.25±0.57b
Stem node 32.73±0.40e 34.23±0.19d 33.45±0.34e
Stem pith 45.81±0.54a 45.69±0.18a 45.26±0.15a
Stem rind 31.95±0.44e 32.72±0.47e 33.55±0.79e
Ear husk 42.34±0.10b 40.68±0.17c 38.21±0.07c
Tassel 35.05±0.44d 33.59±2.64e 36.08±0.17e
Whole plant 40.37±0.09c 39.84±0.27c 38.42±0.14c
p (ED) <0.001 <0.001 <0.001
SEM (ED) 1.12 0.99 0.87

a–f Mean values in the same column followed by different letters are statistically different at p<0.05.

ED = Effective degradability (%); SEM = Standard error of mean.

REFERENCES

Ahmed A, Zhu JY. 2006. Cornstalk as a source of fiber and energy. New technologies in non-wood fiber pulping and papermaking. Zhan HY, Chen FG, Fu SY, editorsSouth China University of Technology Press; Guangzhou: p. 1–4.

AOAC. 1990. Official method of analysis. 15th EdnAssociation of Official Analytical Chemists; Washington DC., USA: p. 66–88.

Crandell EB, Worley JW. 1988. Optimization of a device for separating sweet sorghum pith. American Society of Agricultural Engineers (88-6550); p. 12

Crawford TW, Rending VV, Bordabent FE. 1982. Source fluxes and sinks of nitrogen during early reproductive growth of maize. Plant Physiol 70:1654–1660.
crossref pmid pmc
Goering HK, Van Soest PJ. 1970. Forage fibre analysis (apparatus, reagents, procedures and some applications). Agricultural Handbook 379. Agricultural Research Services, USDA; Washington DC:

Grundas S, Skubisz G. 2008. Physical properties of cereal grainand rape stem. Res Agr Eng 54:80–90.
crossref
Han YW. 2007. Assessment on feed criteria of dairy cattle in China. Chin J Feed Rev 9:28–29.

Hay RE, Earley EB, Deutkr EE. 1953. Concentration and translocation of nitrogen compounds in the corn plant (Zea mays) during grain development. Plant Physiol 28:606–621.
crossref pmid pmc
Hess JA, Olson AE, Jacobs RS. 2002. Wisconsin corn stover - Part 1: Chemical composition. In : Proceedings of TAPPI 2002 Fall Technical Conference; TAPPI Press.

Hunt CW, Kezar W, Vinande R. 1992. Yield, chemical composition, and ruminal fermentability of corn whole plant, ear, and stover as affected by hybrid. Prod Agric 5:286–290.
crossref
Lee S, Shupe TF, Hse CY. 2006. Mechanical and physical properties of agro-based fiberboard. Holz als Roh- und Werkstoff 64:74–79.
crossref
Liu L, Wang D. 2011. Experimental study on separating mechanism of corn straw. J Northeast Agricultural University 42:43–47. (in Chinese)

Jung HG, Allen MS. 1995. Characteristics of plant cell walls affecting intake and digestibility of forages by ruminants. J Anim Sci 73:2774–2790.
crossref pmid
Karsli MA, Russell JR. 2002. Prediction of the voluntary intake and digestibility of forage-based diets from chemical composition and ruminal degradation characteristics. Turk Vet Anim Sci 26:249–255.

Kalmbacher RS. 1983. Distribution of dry matter and chemical constituents in plant parts of four florida native grasses. J Range Manag 36:298–301.
crossref
Madibela OR, Boitumelo WS, Manthe C, Raditedu I. 2002. Chemical composition and in vitro dry matter digestibility of local landraces of sweet sorghum in Botswana. Livest. Res. Rural Develop. 14:2www.cipav.org.co/lrrd/lrrd14/4/madi144.htm
crossref pmid pmc
Maheri-Sis N, Abdollahi-Ziveh B, Salamatdoustnobar R, Ahmadzadeh A, Aghajanzadeh-Golshani A, Mohebbizadeh M. 2011. Determining nutritive value of soybean straw for ruminants using nylon bags technique. Pakistan J Nutr 10:838–841.

Ørskov ER, McDonald I. 1979. The estimation of protein degradability in the rumen from incubation measurements weighted according to rate of passage. J Agric Sci 92:499–503.
crossref
Sannasgala K, Jayasuriya MCN. 1987. The influence of plant fractions on the digestibility of rice straw. Biol Waste 20:153–156.
crossref
Schulthess U, Tedla A, Mohammed-Saleem MA, Said AN. 1995. Effects of variety, altitude, and undersowing with legumes on the nutritive value of wheat straw. Exp Agric 31:169–176.
crossref
Shand WJ, Ørskov ER, Morrice LAF. 1988. Rumen degradation of straw 5. Botanical fractions and degradability of different varieties of oat and wheat straws. Anim Prod 47:387–392.
crossref
Tan ZL, Chen HP, He LH, Fang RJ, Xing TX. 1995. Variation in the nutritional characteristics of wheat straw. Anim Feed Sci Technol 53:337–344.
crossref
Tang SX, Tang ZL, Zhou CS, Jiang HL, Jiang YM, Sheng LX. 2006. A comparison of in vitro fermentation characteristics of different botanical fractions of mature maize stover. J Anim Feed Sci 15:505–515.
crossref
Tolera A, Sundstol F. 1999. Morphological fractions of maize stover harvested at different stages of grain maturity and nutritive value of different fractions of the stover. Anim Feed Sci Technol 81:1–16.
crossref
Tovar-Gomez MR, Emile JC, Michalet-Doreau B, Barriere Y. 1997. In situ degradation kinetics of maize hybrid stalks. Anim Feed Sci Technol 68:77–88.
crossref
Vadiveloo J. 2000. Nutritional properties of the leaf and stem of rice straw. Anim Feed Sci Technol 83:57–65.
crossref
Van Soest PJ, Robertson JB, Lewis BA. 1991. Methods for dietary neutral detergent fiber and non starch polysaccharides in relation to animal nutrition. J Dairy Sci 74:3583–3597.
crossref pmid
Wang HF, Wu YM, Liu JX, Qian Q. 2006. Morphological fractions, chemical compositions and in vitro gas production of rice straw from wild and brittle culm 1 variety harvested at different growth stages. Anim Feed Sci Technol 129:159–171.
crossref
Zeng X, Ma Y, Ma L. 2007. Utilization of straw in biomass energy in China. Renew Sustain Energy Rev 11:976–987.
crossref
Zhou X, Tan L, Zhang W, Lv CL, Zheng F, Zhang R, Du GB, Tang BJ, Liu XY. 2011. Enzymatic hydrolysis lignin derived from corn stover as an intrinsic binder for bio-composites manufacture: Effect of fiber moisture content and pressing temperature on boards’ properties. BioResour 6:253–264.



Editorial Office
Asian-Australasian Association of Animal Production Societies(AAAP)
Room 708 Sammo Sporex, 23, Sillim-ro 59-gil, Gwanak-gu, Seoul 08776, Korea   
TEL : +82-2-888-6558    FAX : +82-2-888-6559   
E-mail : jongkha@hotmail.com               

Copyright © 2019 by Asian-Australasian Journal of Animal Sciences. All rights reserved.

Close layer
prev next