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Ministry of Education and Training
National Institute of Animal Science

Use of several agro-industrial by-products
in cattle finishing rations in Eakar district,
Daklak province
By Truong La
The first supervisor: Vu Van Noi, PhD.
The second supervisor: Trinh Xuan Cu, PhD.
A summarized thesis submitted in fulfillment for the Degree of Doctor of Philosophy in Agriculture
of the National Institute of Animal Sciences
Hanoi, August, 2010
Introduction
1. Rational
Agro-industrial by-product resources of Vietnam are abundant (47 million metric tons per
annum); however, utilization of agro-industrial by-products for animal feeding is limited.
According to Animal Production Department (2008) only around 18% of agro-industrial by-
products has been used as animal feeds. Because of feeds for cattle is in a shortage supply,
especially in dry reason, the performance of cattle is still far from their genetic potential.
Daklak province has a plentiful and diversified agro-industrial by-product resource, in this
province; Eakar district has a big source of agro-industrial by-products such as corn cob, corn stover
and cocoa pods. The utilization of these by-product as cattle feeds is necessary to overcome a feed
deficiency. If these by-products are included in finishing cattle with other locally available, cheap
feed ingredients, the economic efficiency of cattle production will be higher. For a sustainable cattle
production system, better utilization of agro-industrial by-products for feeding cattle is an
appropriate strategy. For the above reasons, this study: “Use of several agro-industrial by-products
in cattle finishing rations in Eakar district, Daklak province” was undertaken.
2. Objectives
The main objective of this study is to evaluate the potential of agro-industrial by-product
resources, which can be used for cattle feeding in Eakar district, Daklak province. The evaluation
will be based on the yield, chemical composition and nutritive values of agro-industry by products,

and will be also used for the cattle development strategy in general and for a better utilization of
some agro-industrial by-products in cattle fattening rations in the district in particular
3. Scientific and practical values
The study was successful to evaluate the potential (the yield, chemical composition and
nutritive values) of agro-industrial by-product resources, which can be used for profitable cattle
feeding and can contribute to a sustainable cattle production system
The study was also successful to determine suitable agricultural by-product levels in fattening
rations by using the in vitro-gas production technique and cattle feeding trials
The study recommended some cattle fattening rations that can be applicable in the region.
4. Innovations of the thesis
The study was successful to evaluate the potential (the yield, chemical composition and
nutritive values) of agro-industrial by-product resources, which can be used as a basis for cattle
development strategy in the district.
The study was successful to formulate some cattle finishing rations containing different levels
of agro-industrial by-products such as corn cob, corn stover, cocoa pod and evaluate the efficiency
of these rations on performance of cattle.
The author was the first person in Vietnam formulating some cattle finishing rations containing
cocoa pod- a new source of industrial by-products and evaluating the efficiency of these rations on
performance of cattle.
5. Thesis structure
Thesis contained 4 chapters, 43 tables, 3 diagrams and 14 figures, references, 3 published papers
and an appendix.
Chapter 1: Literature review
Agro-industrial by-products are products with a high biomass from crops and processing industry.
Normally, these by-products have a low quality, low protein content, high fiber content (20-35% DM),
low digestibility (Nguyen Huu Tao and Le Van Lien (2005)
Several ways of treatment such as physical, chemical, biological treatments have been studied to
enhance the quality of rich fiber agro-industrial by-products as cattle feed. (Leng, 2003; Preston, 1995).
In addition, supplementation of protein and starch to based diets of cattle containing rich fiber agro-
industrial by-products has been studied.

In Vietnam, in an attempt to increase meat production and quality and optimize genetic
potentials of cattle breeds, many studies on better utilization of locally available feed resources such
as rice straw, corn stover, molasses, cotton seed…as feeds for finishing cattle have been done so far
(Le Viet Ly, 1995). The results from the mentioned works have shown that with rations containing
locally available feed resources, cattle can have the ADG of 0.5 to 1.1kg/cattle/day). By using
locally available feed resources we can increase the performance of cattle, the economic efficiency
of cattle production and contribute to a friendly environment.
However, most of studies mentioned early focused on treated agro-industrial by-products. It
appeared that use of treated agro-industrial by-products as cattle feeds is only applicable for large scale
farms. For house hold farms, it is necessary to find another solution. For this reason, in our study,
supplementation of protein and energy feeds to the based rations of finishing cattle containing different
levels of agro-industrial by-products was chosen. In addition, a new source of industrial by-product:
cocoa pod was included in the based rations of finishing cattle.
Chapter 2: Materials and methods
2.1. Materials
Agro-industrial byproducts used in the experiments included three kinds: corn cobs, corn stover
and cocoa pods.
Two mature Lai Sind fistulated males were used for the in vitro gas production experiments
Sixty three Lai Sind males at 18-20 months of age were used for fattening experiments
2.2. Experiments of the study
The study included one survey and three experiments. They were:
2.2.1. Survey on the potential of agro-industrial by-product resource, which can be used for cattle
feeding in Eakar district, Daklak province.
2.2.2. Experiment N
o
1: Utilization of corn cob in finishing rations
2.2.3. Experiment N
o
2: Utilization of corn stover in finishing rations
2.2.4. Experiment N

o
3: Utilization of cocoa pods in finishing rations
2.3. Location of the study
Survey on the potential of agro-industrial by-product resource, which can be used for cattle
feeding in Eakar district, was undertaken in the district of Eakar, Daklak province. The chemical
analysis of feeds, in vitro - gas production tests were performed at the Department of Feed Analysis
and Livestock Products, and Department of Animal Feeds, Nutrition and Pasture, National Institute
of Animal Sciences. Finishing trials were conducted in the district of Eakar, Daklak province.
2.4. Methods
2.4.1. General methods
2.4.1.1. Experimental arrangement
Experiments were designed as one factor experiment to examine the effects of three different
levels of agro-industrial by-products in finishing rations on the amount of gas produced, the gas
characteristics and performance of cattle. All experiments were arranged in a completely
randomized block design (CRBD).
2.4.1.2. Feeding standard for ration formulation
The nutritive requirements for cattle in tropics of Kearl (1982), Utah University (USA) were
used for ration formulation.
2.4.1.3. Chemical analysis of animal feeds
All animal feeds and by-products are sampled and analyzed according to the Vietnamese
standards (TCVN). NDF, ADF were determined by the method of Goering and Van Soest (1970).
2.4.2. Methods for specific experiments
2.4.2.1. Survey on the potential of agro-industrial by-product resource, which can be used for
cattle feeding in Eakar district, Daklak province
a. Survey on cattle development situation and agro-industrial by- product output
The survey on cattle population, yield and seasonal utilization of agro-industrial by-products
such as rice straw, molasses, cottonseeds, corn stover, corn cobs, cocoa pods was conducted by
using questionnaires. During the survey, samples of agro-industrial by-products were taken for the
chemical analysis.
b. Chemical composition, nutritional value and characteristics of in vitro gas production of some

agro-industrial by- products and other feeds
The chemical composition of agro-industrial by-products and other feeds as dry matter (DM),
crude protein (CP), crude fiber (CF), lipid, total ash (Ash), NDF and ADF were analyzed using the
above mentioned methods. ME (Metabolisable Energy) of agro-industrial by- products and other
feeds was estimated using DE (Digestible Energy) and TDN (Total Digestible Nutrients). The
equations for estimations as recommended by National Institute of Animal Sciences ( 2003) were :
ME (Kcal/kg CK) = 0,82 * DE
DE (Kcal/kg CK) = 0,04409 * TDN
The characteristics of by-product (corn cobs, corn stover and cocoa pods) digestion were
estimated using in vitro gas production technique recommended by Steingass of Menke (1988) The
amount of gas produced was recorded at different time of incubation: 3, 6, 12, 24, 48, 72 and 96
hours. A specialized software-NEWAY developed by Chen (1997) with the exponential equation of
Orskov and Mc. Donald (1979): P = a + b (1 - e
-ct
) was used to characterize the gas production from
agro-industrial by-products.
Where:
a = the gas produced from the readily fermented organic matter (OM) fraction (ml);
b = the gas produced from the slowly fermented OM fraction (ml),
c = the rate of fermentation of OM fraction (b);
t = incubation time (h)
P = gas produced at time't'
c. Estimation of the potential of agro-industrial by-product resource, which can be used for cattle
feeding in Eakar district, Daklak province
The output of protein and ME from agro-industrial by-products was estimated using the yield,
chemical composition and energy value of these by-products.
The estimation of how many percentage of DM and ME requirements for cattle in this district
can be covered by utilization of main agro-industrial by-products in the district was calculated on
the number of the tropical livestock unit in district per year (one unit for cattle = 250kg or 63kg
0.75

)
(FAO, 2000) and DM and ME requirements for the number of the tropical livestock unit in district
per year (Karl, 1982).
2.4.2.2 Experiment N
o
1: Utilization of corn cob in finishing rations.
This experiment included 2 experiments.
Experiment 1a: Effects of different levels of corn cob in the rations on gas volume and
characteristics of in vitro gas-production of rations
Three rations with three levels of corn cob: 10%, 20%, 30% were used to examine the effects of
different levels of corn cob in the rations on gas volume and characteristics of in vitro gas-
production (Table 2.1). The gas volume and characteristics of in vitro gas-production of each
rations were estimated using in vitro gas production technique recommended by Steingass of
Menke (1988) (see: 2.4.2.1. b).
Experiment 1b : Effects of different levels of corn cob in the rations on performance of finishing
cattle and quality of beef.
Experimental animals
Twenty four Lai Sind young bulls aging of 18-20 months were used in this experiment.
Deworming all cattle was undertaken at the beginning of adaptation period of 14 days. During a 14-
day adaptation period, feeds were offered individually to the animals in exactly the same routine as
was planned for use during the experimental period of 84 day. At the end of the adaptation period,
24 Lai Sind young bulls were randomly allocated in three treatments (three diets) (Table 2.1), each
of 8 animals.
Table 2.1. Chemical composition, nutritive value of feed ingredient and diets used in the experiment
Ration 1-
treatment 1
(10% corncob)
Ration 2-
treatment 2
(20% corncob)

Ration 3-
treatment 3
(30% corncob)
- Molasses 40 40 40
- Cassava meal 24 14 4
- Corn cob 10 20 30
- Cotton seed 11 11 11
- Peanut cake 13 13 13
- Urea 1 1 1
- Mineral premix 1 1 1
Total 100 100 100
- Metabolisable Energy (MJ ME/kg DM) 9.8 9.5 9.2
- Crude protein (g/kg DM) 138.8 137.6 136.4
- Non-structural carbohydrate- NSC (%) 61.3 53.3 45.3
* NSC = 100 - (%NDF + %Pr + %Li + %Ash) (Stiffen et al., 1992; Stokes, 1991).
Rations and feeding
Three rations used in the experiment 1.1 were used in this experiment (Table 2.1). Feeds in
the form of TMR (Total mixed ration) were given individually to each animal at 8 am. and 4 pm.
every day. All animal had a free access to water.
Measurements
The average daily gain (ADG), feed conversion ratio (FCR), beef quality and economic
efficiency were estimated using measurements such as body weight change, feed intake, feed
cost, and slaughter data, which were recorded individually.
2.4.2.3. Experiment N
o
2: Utilization of corn stover in finishing rations
Experiment 2a: Effects of different levels of corn stover in rations on gas volume and
characteristics of in vitro gas production of diets
Three rations with three levels of corn stover: 5%; 15%; 25% were used to examine the effects
of different levels of corn cob in the rations on gas volume and characteristics of in vitro gas-

production (Table 2.1). The gas volume and characteristics of in vitro gas-production of each
rations were estimated using in vitro gas production technique recommended by Steingass of
Menke (1988) (see: 2.4.2.1. b).
Experiment 2b : Effects of different levels of corn stover in the rations on performance of finishing
cattle and quality of beef.
Experimental animals
Twenty four Lai Sind young bulls aging of 18-20 months were used in this experiment.
Deworming all cattle was undertaken at the beginning of adaptation period of 14 days. During a 14-
day adaptation period, feeds were offered individually to the animals in exactly the same routine as
was planned for use during the experimental period of 84 day. At the end of the adaptation period,
24 Lai Sind young bulls were randomly allocated in three treatments (three diets) (Table 2.2), each
of 8 animals.
Table 2.2. Chemical composition, nutritive value of feed ingredient and diets used in the experiment
Ration 1 –
treatment 1
(10% corn
stover)
Ration 2-
treatment 2
(20% corn
stover)
Ration 3-
treatment 3
(30% corn
stover)
- Molasses 46 36 30
- Cassava meal 0 10 16
- Corn cob 25 15 5
- Cotton seed 5 15 25
- Peanut cake 11 11 11

- Urea 11 11 11
- Mineral premix 1 1 1
Total 100 100 100
- Metabolizable energy (MJ ME/kg DM) 9.8 9.7 9.5
- Crude protein (g/kg DM) 132.2 136.3 138.7
- Non-structural carbohydrate- NSC (%) 67.4 58.6 50.5
Rations and feeding
Three rations used in the experiment 2.1 were used in this experiment (Table 2.1). Feed in the
form of TMR (Total mixed ration) was given individually to each animal at 8 am. and 4 pm. every
day. All animal had a free access to water.
Measurements
The average daily gain (ADG), feed conversion ratio (FCR), and economic efficiency were
estimated using measurements such as body weight change, feed intake, and feed cost , which
were recorded individually.
2.4.2.4. Experiment N
o
3: Utilization of cocoa pods in finishing rations
Experiment 3a: Effects of different levels of cocoa pods in rations on gas volume and
characteristics of in vitro gas production of diets.
Three rations with three levels of cocoa pods: 25%; 30%; 35% were used to examine the effects
of different levels of cocoa pods in the rations on gas volume and characteristics of in vitro gas-
production of the ration(Table 2.1). The gas volume and characteristics of in vitro gas-production of
each rations were estimated using in vitro gas production technique recommended by Steingass of
Menke (1988) (see: 2.4.2.1. b).
Experiment 3b : Effects of different levels of cocoa pods in the rations on performance of finishing
cattle and quality of beef.
Experimental animals
Fifteen Lai Sind young bulls aging of 18-20 months were used in this experiment. Deworming
all cattle was undertaken at the beginning of adaptation period of 14 days. During a 14-day
adaptation period, feeds were offered individually to the animals in exactly the same routine as was

planned for use during the experimental period of 84 day. At the end of the adaptation period, 15
Lai Sind young bulls were randomly allocated in three treatments (three diets) (Table 2.3), each of 5
animals.
Table 2.3. Chemical composition, nutritive value of feed ingredient and diets used in the experiment
Ration 1-
Treatment 1
(25% cocoa
pods)
Ration 2-
Treatment 2
(30% cocoa
pods)
Ration 3-
Treatment 3
(35% cocoa
pods)
- Molasses 34 34 34
- Maize meal 26 21 16
-Cacao pods 25 30 35
- Peanut cake 13 13 13
- Urea 1 1 1
- Mineral premix 1 1 1
Total 100 100 100
- Metabolisable energy (MJ ME/kg DM) 9.7 9.5 9.2
- Crude protein (g/kg DM) 138.5 137.9 137.2
- Non-structural carbohydrate- NSC (%) 55.3 53.0 50.5
Rations and feeding
Three rations used in experiment 3.1 were used in this experiment (Table 2.1). Feeds in the
form of TMR (Total mixed ration) were given individually to each animal at 8 am. and 4 pm. every
day. All animal had a free access to water.

Measurements
The average daily gain (ADG), feed conversion ratio (FCR), and economic efficiency were
estimated using measurements such as body weight change, feed intake, and feed cost , which
were recorded individually.
2.4.3. Statistical analysis
The following mathematical model of ANOVA was used to analyze the effects of different
levels of agro-industrial by-products in the rations on gas volume, characteristics of in vitro gas
production of diets, performance of finishing cattle and quality of beef:
Xijk = µ + αi + eik.
Where: Xik is the observed value of replicate k in treatment i
µ is the grand mean
αi is the fixed effect of treatment i
eik is the random error.
If ANOVA indicated a significant effect, then multiple t-tests were applied for comparison
of paired means. All statistical analysis were made using Excel and Minitab software, release
12.1 (1997).
Chapter 3: Result and discussion
3.1. The potential of agro-industrial by-product resource, which can be used for cattle
feeding in Eakar district, Daklak province
3.1.1. Cattle development situation and agro-industrial by- product output
3.1.1.1. Cattle development
Changes of cattle population in Eakar district from 2004 to 2006 are presented in Table 3.1
Table 3.1. The number of cattle through the year in Eakar district
Years Population (head) Growth rate (%)
As % of the province
population (%)
2004 22,111 - 15.8
2005 28,630 129.5 17.7
2006 28,036 98.0 12.7
Average 26,259 112.6 15.4

It seemed that cattle population in this district was changed over 3 years, on average, growth
rate was 112.6% per annum. Because cattle population seemed to increase from one year to another,
better utilization of agro-industrial by-products as feeds for cattle needs to be taken into account and
be given the highest priority to overcome a shortage of feed supply.
3.1.1.2. Utilization of agro-industrial by- products in cattle feeding
Results of a survey at 200 farming households farms on the use of by-products for cattle
feeding are presented Table 3.2.
Agro-industrial by-products were underutilized as feeds for cattle in Eakar. On average, there
was only 25.5% of households surveyed using agro-industrial by-products for cattle feeding. There
was also only 14.8% of households surveyed applying treatment solutions of agricultural by-
products before feeding cattle. Sugar cane molasses was used as cattle in most household family
(73.3%). The percentage of households surveyed using rice straw for cattle feeding was 43.3%.
However, only 23.1% households applied urea treatment of rice straw before feeding cattle. The
percentage of households surveyed using corn stover, corn husk, corn cob and cocoa pods for cattle
feeding was 30, 15, 10 and 5 %, respectively. These by-products were mainly used as cattle feeds in
their original forms, the percentage of households surveyed applying any treatments for corn stover,
corn husk, before feeding cattle was 16.7 and 33.3%, respectively.
The utilization of agro-industrial by-products as cattle feeds was mainly in the harvesting
seasons. Rice straw was mainly used as cattle feeds from March to May and from October to
December. Corn stover and cob was mainly used as cattle feeds in July, August, November and
December. Cocoa pods was mainly used as cattle feeds in two harvesting seasons: March, May and
October, December every year. Only sugar cane molasses was used as cattle feeds whole year
round.
Table 3.2. Utilization of agro-industrial by- products in cattle feeding
Agro-industrial
by-products
Number of
households
surveyed
Number of

households
using by-
products
Percentage
(%)
Number of
households
processing
by-products
Percentage
(%)
Rice straw 30 13 43.3 3 23.1
Corn stover 40 12 30.0 2 16.7
Corn husk 40 6 15.0 2 33.3
Corn cob 40 4 10.0 0 0.0
Cotton seeds 20 4 20.0 0 0.0
Cocoa pods 20 1 5.0 0 0.0
Peanut leaves 20 7 35.0 0 0.0
Sugar cane
leaves
30 4 13.3 1 25.0
Molasses 30 22 73.3 0 0.0
Cassava waste 20 2 10.0 1 50.0
Average (%) 25.5 14.8
3.1.2. Agricultural by-product output in Eakar
3.1.2.1. Area, production of main cash crops in Eakar
Area and production of main cash crops in Eakar from 2004 to 2006 are presented in Table 3.3.
Table 3.3. Area (ha) and production (MT*) of main cash crops in Eakar from 2004 to 2006
Plant 2004 2005 2006 Average
Area Prod** Area Prod Area Prod Area Prod

Rice 6,576 37,905 4,942 22,300 7,408 48,850 6,309 36,352
Maize 21,474 74,244 21,929 61,699 20,030 85,643 21,144 73,862
Sweet potato 767 5,022 828 5,341 1,096 6,818 897 5,727
Cassava 2,290 54,125 2,719 54,554 3,330 66,590 2,780 58,423
Sugar cane 2,759 109,460 2,598 96,330 2,875 120,178 2,744 108,656
Cocoa 80 80 120 144 280 336 160 187
Peanut 127 52 159 098 176 148 154 99
Soybean 343 182 220 137 272 227 278 182
Cotton 230 120 120 111 85 86 145 106
* MT: Metric tons; Prod: Production
Among rice, corn, sugarcane, cassava crops, which were main crops in term of area used for
cultivation, cultivated areas for cassava, sugar cane increased over three years. The cultivated area
for sweet potato crops also increased over three years.
The cultivated and production for cocoa, which was low but increased markedly over three
years. In 2006, cultivated area and production for cocoa were only 160 ha and 187 MT, however,
area for cocoa crops in Daklak is projected to be 5,000 ha and area for cocoa crops in Eakar will
increase (Ministry of Agriculture and Rural Development, 2008). In the future, by-product from
cocoa will also increase.
Although area and production of peanut, soybean, cotton crops were low, these crops provided
a good source of rich protein feed for cattle feeding in the district.
3.1.2.2. By product to main product ratios
By product to main product ratios of rice, maize (corn), cocoa crops are presented in Table 3.4.
Table 3.4. By product to main product ratios of rice, maize, cocoa crops in Eakar
Crops
Number of
samples
By product
weight (kg)
Main product
weight (kg)

By product to
main product
ratios
Rice 20 1.65 ± 0.11 1.81 ± 0.10 0.91 ± 0.08
Corn + Stover 20 4.65 ± 0.41 2.30 ± 0.38 2,02 ± 0,29
+ Cob 20 2.10 ± 0.34 7.70 ± 0.50 0.27 ± 0,05
Cocoa 20 1.94 ± 0.29 1.40 ± 0.24 1.38 ± 0.06
It was found out that: by-product to main product ratios of rice, corn, cocoa crops (rice to rice
straw, corn seed to corn stover, corn seed to corn cob and cocoa main product to cocoa pod) were
0.91; 2.02; 0.27 and 1.38, respectively. This by-product to main product ratio of rice straw in our
study was similar to work of Pham The Hue (2007) in Daklak (0.92). However, our figure was
slightly higher than that of Pham Kim Cuong et al., (2002) in Red river delta (0.89) and that
published by FAO (1994) (0.78).
3.1.2.3. Estimation of the potential of agro-industrial by-product resource, which can be used for
cattle feeding in Eakar district, Daklak province
Based on by product to main product ratios of crops in table 3.4, agro-industrial by-
products/year (MT) were calculated and are presented in table 3.5.
Table 3.5. Estimated agro-industrial by-products/year (MT) in the district
Crops
Main product in
the district
By-product in the
district
Total by-product
in province
As % of total by-
product in
province
Rice straw 36,352 33,080 280,156 11.8
Corn 73,862

- Stover 149,200 994,109 15.0
- Cob 19,940 132,876 15.0
Cocoa 187 258 670 38.4
The amount of rice straw in Eakar district was estimated to be 33,080 MT/year in the district,
accounting for 11.8% of rice straw in the province.
Among thee crops, amount of corn stover in Eakar district appeared to be the highest. The
reasons were that cultivated area of corn was the largest, corn seed yield was high and also corn
seed to corn stover ratio was the highest (2.02).
The amount of corn stover and corn cob in Eakar district was estimated to be 149,200 and
19,940 MT/year in the district, accounting for 15% of corn stover and corn cob in the province.
The amount of cocoa pods in Eakar district was low and estimated to be only 258 MT. This
amount occupied by 38.4% of total cocoa pods in the province.
3.1.3. Chemical composition, nutritional value and characteristics of in vitro gas production of
some agro-industrial by- products
3.1.3.1. Chemical composition and nutritional value of some agro-industrial by- products
* Chemical composition
Table 3.6. Chemical composition of some agro-industrial by- products (%)
By- product DM
Crude
protein
Lipid Fiber Ash NDF ADF
Corn stover 90.13 4.10 0.70 34.41 3.35 72.21 38.91
Corn cob 91.81 2.86 1.01 38.44 1.38 85.80 47.79
Cocoa pods 89.45 6.82 1.43 28.62 8.32 56.50 43.63
Among three by-products tested, crude protein (CP) content of corn cocoa pods was the highest
(6.82%), followed by CP content of corn stover (4.10%). The CP content of corn cob was the
lowest (2.86%). Among them, fiber and NDF content of corn cob was the highest, followed by fiber
content corn stover. The fiber, NDF contents of cocoa pods was the lowest. Compared to the rest,
cocoa pods were rich in he ash content.
All of these by-product was characterized by a low CP and high fiber contents. When using

them for feeding beef cattle, it is necessary to supplement rations with other ingredients, which are
rich in CP and non structural carbohydrate (NSC).
Nutritional value of several by-products
Nutritional value of some agro-industrial by- products is presented in table 3.7
Table 3.7. Nutritional value of some agro-industrial by- products
No By product TDN (%) ME (Kcal/kgDM)
1 Corn stover 42.89 1,551
2 Corn cob 46.08 1,666
3 Cocoa pods 44.30 1,602
Results showed that the total digestive nutrients (TDN) of three agricultural by-product were
relatively high from 42.89% to 46.08%. TDN of corn cob was the highest, followed by TDN of
cocoa pods. TDN of corn stover was the lowest. A similar trend was also observed in the
metabolisable energy (ME) content. The ME content of corn cob was the highest, followed by ME
of cocoa pods. The ME content of corn stover was the lowest.
The ME content of corn stover in our study (1,551 Kcal/kgDM), however, was lower than that
published by the National Institute of Animal Husbandry (2003) (1,711-1,962 kcal ME/kgDM).
3.1.3.2. Characteristics of in vitro gas production of some agro-industrial by- products
The cumulative in vitro gas production from some agro-industrial by- products is presented in
table 3.8.
Table 3.8. Cumulative in vitro gas production from some agro-industrial by- products
By-product Cumulative in vitro gas production at different time of incubation (ml/200mg DM)
3 h 6 h 12 h 24 h 48 h 72 h 96 h
Corn stover 2.36
a
4.57
a
9.03
a
22.64
a

35.94
a
42.45
a
45.31
a
Corn cob 0.41
b
0.96
b
2.61
b
10.45
c
25.98
b
35.19
b
39.45
b
Cocoa pods 2.43
a
6.29
a
10.14
a
18.39
b
27.14
b

37.00
b
40.72
b
SEM 0.82 1.11 1.13 1.65 1.83 2.22 1.88
Values bearing different superscripts a, b, c in columns differ significantly (P <0.05).
After 3 to 12 hour incubation, the cumulative in vitro gas production of corn stover and cocoa
pods was similar (P> 0.05) and higher than that of corn cob. After 24 hours of incubation, the
cumulative in vitro gas production from three agro-industrial by-products was different (P> 0.05).
The cumulative in vitro gas production from corn stover was the highest (22.64 ml), followed
by that from cocoa pods (18.39 ml). The cumulative in vitro gas production from corn cob was the
lowest (10.45 ml). After 96 hours of incubation, the cumulative gas volume from cocoa pods and
from corn cob was similar (P >0.05) and lower than that from corn stover (P <0.05).
It appeared that cocoa pods was fermented rapidly in the first phage and then they were
fermented slowly in the second and third phage of incubation.
The characteristics of in vitro gas production of the above agro-industrial by- products are
presented in table 3.9.
Table 3.9. Characteristics of in vitro gas production of three agro-industrial by- products
By product a (ml) b (ml) a + b (ml) c (%/h) Lag phase (h)
Corn stover 2.36
a
43.38
a
45.73
a
0.003 4.03
b
Corn cob 0.41
b
37.52

b
37.93
b
0.001 5.70
a
Cocoa pod 2.43
a
39.33
b
41.76
a
0.002 1.13
c
SEM 0.82 2.27 2.31 0.35
Values bearing different superscripts a, b, c in columns differ significantly (P <0.05);a = the gas produced
from the readily fermented organic matter (OM) fraction (ml); b = the gas produced from the slowly
fermented OM fraction (ml), c = the rate of fermentation of OM fraction (b); (a + b) = the potential gas
production from the total degraded OM of the sample.
As can bee seen from table 3.9, while parameter a of cocoa pod was high and its lag phage was
lower; parameter a of corn cob was the lowest and its lag phage was the highest. It indicated that the
readily fermented organic matter (OM) fraction of cocoa pod was higher than that of corn stover
and much higher than that of corn cob. However, the potential gas production from the total
degraded OM (a + b) of cocoa pod and corn stover was similar (P>0.05) and was higher than that of
corn cob. This finding indicated that the total degraded OM of corn cob was lower than that of
cocoa and corn stover. The higher contents of fiber content (38.44%), NDF and ADF may
contribute to the lower total degraded OM of corn cob and therefore the lower potential gas
production from the total degraded OM (a + b) of corn cob. The higher content of fiber in the feeds
is, the lower the rate of fermentation is because ruminal microorganisms need time to penetrate into
plant cells.
3.1.3.3. Estimation of DM, CP and ME yields from three agro-industrial by- products and number

of cattle can be reared in the districts when using three agro-industrial by- products
Estimation of DM, CP and ME yields from three agro-industrial by- products
Based on total agro-industrial by-products/year, their chemical composition and nutritive
values, Dry matter, CP and ME yields from three agro-industrial by- products yields were estimated
and are presented in table 3.10.
Among three by-products, corn stover yielded the highest DM, CP and total ME, followed by
corn cob. Cocoa yielded the lowest DM, CP and total ME/year.
In total, every year, corn, cocoa crops can provide more than 150 thousand MT DM, 6 thousand
MT CP and around 240 million Mcal ME, if all of these by-products will be used for cattle feeding.
The number of cattle can be reared in the districts when using three agro-industrial by- products
Table 3.10. Dry matter, crude protein and metabolisable energy yields from three agro-industrial
by-products in the district
By-product
By-product
yield (fresh
basis) (MT)
Dry matter
(MT)
Crude Protein
(MT)
Total ME (Mcal
ME)
Corn stover 149,200 134,475 5,514 208,570,845
Corn cob 19,940 18,309 524 30,503,510
Cocoa pod 258 231 16 361,971
Total 169,398 153,015 6,050 239,444,066
Using the tropical livestock unit for cattle and their requirements for DM, CP and ME, the
number of cattle, which can be reared in the districts when using three agro-industrial by-products,
was calculated and is presented in table 3.11.
Table 3.11. The estimation of the number of cattle can be reared in the districts when using three

agro-industrial by- products
1 Number of cattle/year
(based on DM yield)
- DM yield (MT) 153,015
- DM requirement (MT/head/year) 2.7
- Number of cattle can be kept (head) 56,672
2 Number of cattle/year
(based on ME yield)
- ME yield (Mcal) 239,444,066
- ME requirement (Mcal/head/year) 4,190
- Number of cattle can be kept (head) 57,141
From the above estimations, it was revealed that three agro-industrial by- products in the
district can provide enough DM and ME for around 57,000 cattle with the body weight of 250 kg,
average daily gain of 500 g/head/day, if all of these by-products will be used as cattle feeds.
In summary, from the results of the survey, it was concluded that the agro-industrial by-product
resource in Eakar district was abundant and can be used for fattening beef cattle to convert the
locally available and cheap feeds into beef of a high economic efficiency. It was also concluded
that agro-industrial by-products are characterized by the high fiber content, poor nutritive value and
that supplementation to cattle rations containing agro-industrial by-products is necessary to the
development of a sustainable cattle production.
3.2. Utilization of corn cob in finishing rations.
3.2.1. Effects of different levels of corn cob in the rations on gas volume and characteristics of
in vitro gas-production of rations (Experiment 1a)
The cumulative in vitro gas production from rations differing in percentage of corn cob is
presented in table 3.12.
Table 3.12. Cumulative in vitro gas production from rations differing in percentage of corn cob
Ration Cumulative in vitro gas production at different time of incubation (ml/200mg DM)
3 h 6 h 12h 24h 48h 72 h 96 h
10% corn cob 6.50 12.24
b

35.37
a
56.03
a
67.12
a
69.99
a
71.52
a
20% corn cob 6.22 14.57
a
35.16
a
51.48
b
61.19
b
64.89
b
66.63
b
30% corn cob 6.29 14.42
a
28.48
b
42.43
c
51.96
c

55.66
c
57.14
c
SEM 0.68 0.67 1.07 0.78 0.55 1.31 1.31
Values bearing different superscripts a, b, c in columns differ significantly (P <0.05).
After 3 hour incubation, the cumulative in vitro gas production of rations differing in the
percentage of corn cob started to be different. However, the cumulative in vitro gas production of
rations containing 10 and 20% of corn cob was still similar. The similar trend was also observed in
the cumulative in vitro gas production of rations after 12 hour incubation.
After 24 to 96 hours of in vitro incubation, the cumulative in vitro gas production of rations
differing in the percentage of corn cob was significantly (P<0.05). The cumulative in vitro gas
production was the highest of the ration containing 10% corn cob, followed by that of the ration
containing 20% corn cob. The lowest cumulative in vitro gas production was observed in the ration
containing 30% corn cob.
It was concluded that the level of corn cob in the rations had a negative effect on in vitro gas
production of rations.
Characteristics of in vitro gas production of rations differing in corn cob levels are presented in
table 3.13.
Table 3.13. Characteristics of in vitro gas production of rations differing in corn cob levels
Ration a + b c RSD
10% corn cob 71.13
a
0.067 2.648
a
20% corn cob 65.47
b
0.070 1.832
b
30% corn cob 56.40

c
0.061 0.919
c
SEM 1.04 0.00 0.16
Values bearing different superscripts a, b, c in columns differ significantly (P <0.05).
As can bee seen from table 3.13, the potential gas production from the total degraded OM (a+b)
of rations containing different levels of corn cob was significantly different (P<0.05). The level of
corn cob in the rations had a negative effect on the potential gas production from the total degraded
OM (a + b) of rations. The higher the level of corn cob in the ration was, the lower the potential gas
production from the total degraded OM (a + b) of the ration was.
3.2.2. Effects of different levels of corn cob in the rations on performance of finishing cattle and
quality of beef. (Experiment 1b)
3.2.2.1. Live weight change of cattle
The live weight change of cattle fed on three rations differing in corn cob levels is presented in
table 3.14.
Table 3.14. Live weight change of cattle
Parameter
Ration 1
(10% corn cob)
Ration 2
(20% corn cob)
Ration 3
(30% corn cob)
SEM
Initial body weight (kg) 190.9 191.4 191.1 5.2
Final body weight(kg) 253.4 249.3 244.3 5.9
Average daily gain (kg/cattle/day) 0.745
a
0.689
b

0.633
c
0.033
Values bearing different superscripts a, b, c in rows differ significantly (P<0.05).
The average daily gain (ADG) of cattle fed on rations differing in corn cob levels was
statistically different (P<0.05). The ADG of cattle fed on the ration with 10% of corn cob was the
highest, followed by that of cattle fed on the ration with 20% of corn cob. The lowest ADG was
observed in cattle fed on the ration with 30 % corn cob.
The ADG of finishing cattle decreased when the level of corn cob increased in the ration. The
reasons was that corn cob is agricultural by-products with a high fiber content; therefore the higher
level of corn cob in the ration will increase the fiber content in diets. Consequently, digestibility of
the ration will decrease and ADG will reduce.
On the other hands, when the fiber content increases, the non-structural carbohydrate (NSC) of
the rations decreases. In this experiment, the calculated NSC level decreased from ration 1 to ration
2 and ration 3 (61.3%, 53.3%, 45.3%). NSC plays a very important role in feed digestibility, feed
intake and ADG of beef and dairy cattle. Bowman et al., (2004) showed that reduced NSC in the
ration of beef cattle led to a low dry matter and protein intakes and digestive protein.
It seemed that the ration with a higher potential gas production from the total degraded OM
(a+b) when feeding cattle will give a higher ADG of cattle.
3.2.2.2. Feed intake and feed conversion ratio (FCR)
The feed intake and feed conversion ratio (FCR) of cattle fed on three rations differing in the
corn cob level are presented in table 3.15.
Table 3.15. Feed intake and feed conversion ratio (FCR) of cattle fed on three rations differing in
the corn cob level
Ration 1
(10% corn cob)
Ration 2
(20% corn cob)
Ration 3
(30% corn cob)

SEM
DM intake (kg/head/day) 5.36 5.35 5.37 0.11
DM intake as % liveweight (%) 2.41 2.43 2.47 0.07
FCR (kg DM/kg gain) 7.21
c
7.77
b
8.51
a
0.39
Energy utilization efficiency (g
gain/MJ ME)
14.21
a
13.54
b
12.80
c
0.66
Values bearing different superscripts a, b, c in rows differ significantly (P<0.05).
Although ADG was different, DM intake (kg/head/day) and DM intake as % live weight of cattle
fed on three rations differing in the corn cob level was not significantly different. It indicated that
the palatability of the rations was similar. DM intake (kg/head/day) of cattle in our experiment, which
ranged from 5.35 to 5.37, was in agreement with Kearl (1982) and INRA (1989). According to Kearl (1982),
The DM intake requirement of cattle weighing 150-205 kg, gaining 0.5 kg/head/day was 4.2 - 6.2
kgDM/head/day. According to INRA (1989) DM intake requirement of cattle weighing 150-250 kg,
gaining 0.5 kg/head/day was 3.5 to 5.6 kg DM/head/day. However, DM intake (kgDM/head/day) of
cattle in our experiment was higher than that recommended by AFRC (1993) for the similar type of
cattle (3.7 to 4.9 kg DM/head/day).
Because different ADG and similar feed intake of cattle fed on three rations differing in the

corn cob level, FCR (kg DM/kg gain) and energy utilization efficiency (g gain/MJ ME) of cattle
were significantly different (P<0.05).
3.2.2.3. Dressing and lean meat percentage of cattle
The dressing and lean meat percentages (%) of cattle fed on three rations differing in the corn
cob level are presented in table 3.16.
The dressing and lean meat percentages of cattle fed on three rations differing in the corn cob
level tended to decrease gradually from ration 1 to ration 2 and ration 3 with increased levels of
corn cob in the rations. However, the differences in the dressing and lean meat percentages of cattle
were only observed in ration 2 and 3 (P>0.05).
Thus, the level of corn cobs in the finishing rations had a negative effect on the dressing and
lean meat percentages of cattle. Our result of the dressing percentage of cattle was similar to the
work by Vu Van Noi et al., (1994), they found out that the dressing percentage of Lai Sind cattle
ranged from 44.8 to 47.7%.
Table 3.16. Dressing and lean meat percentages (%) of cattle fed on three rations differing in the
corn cob level
Paramater
Ration 1
(10% corn cob)
Ration 2
(20% corn cob)
Ration 3
(30% corn cob)
SEM
N
o
of cattle slaughtered (head) 3 3 3
Dressing (%) 47.5
a
46.2
ab

45.0
b
0.76
Lean meat percentage (%) 39.9
a
38.5
ab
37.7
b
1.07
Values bearing different superscripts a, b, c in rows differ significantly (P <0.05).
The similar dressing and lean meat percentages of 46.3 to 48.6% and of 39.5 - 41.82% was also
found in the work by Nguyen Tuan Hung and Dang Vu Binh (2004) on Lai Sind cattle.
The pH of meat is an important parameter for assessing meat quality. pH of beef form cattle in
this experiment measured at different intervals after slaughtering is presented in Table 3.17.
Table 3.17. pH values of sir loin at different intervals after slaughtering
Time after slaughtering
Ration 1
(10% corn cob)
Ration 2
(20% corn cob)
Ration 3
(30% corn cob)
SEM
01 h 6.70 6.61 6.55 0.06
12 h 5.93 5.84 5.81 0.05
48 h 5.52 5.61 5.60 0.10
8 days 5.51 5.49 5.45 0.05
The pH values of sir loin of beef in this experiment tended to decrease from treatment 1 (ration
1) to treatment 3 (ration 3) as affected by the level of corn cob in the rations. However, the effects

of the level of corn cob in the rations on pH values of sir loin of beef were not significantly
(P>0.05). The pH values of sir loin of beef reduced quickly from 1 to 48 hours after slaughtering
and then were stable. The reason is that during 24 - 48 hours after slaughtering, glycogen in muscles
was continuously oxidized and produced lactic acid. An increased lactic acid level will reduce the
pH value of meat. When all glycogen in muscles was oxidized, the pH level will be stable reaching
the value of 5.5, which is so called the ultimate pH (Page et al., 2001).
As can be seen from table 3.17, the pH value of sir loin of beef from cattle in this experiment
after 48 hour slaughtering, which ranged from 5.45 to 5.49, met the pH standards of meat published
by Page et al., (2001). According to Page et al., (2001) the ultimate pH standards of meat was 5.4 to
5.59. According to USDA (1997), meat pH value <5.85 was considered as the standard pH.
The water holding capacity of meat after slaughtering is very important in evaluating beef
quality. The water loss percentage of beef at different time after slaughtering measured is presented
in table 3.18.
Table 3.18. Water loss percentage of beef at different time after slaughtering (%)
Time after slaughtering
Ration 1
(10% corn cob)
Ration 2
(20% corn cob)
Ration 3
(30% corn cob)
SEM
After 36 h 1.30 1.35 1.32 0.05
After 48 h 1.85 1.79 1.73 0.13
After 8 days 4.14 4.03 4.28 0.21
It seemed that the level of corn cob in the rations had no effect on water loss percentage of beef
at different time after slaughtering (P>0.05). After 36 hour and 8 day slaughtering, water loss
percentage of beef from cattle fed on rations differing in corn cob levels varied from 1.3 to 1.35 and
4.03 to 4.28, respectively.
As can be seen from table 3.19, the level of corn cob in the rations had no effect on chemical

composition of beef meat.
Table 3.19. Chemical composition of beef meat in the experiment (%)
Parameter
Ration 1
(10% corn cob)
Ration 2
(20% corn cob)
Ration 3
(30% corn cob)
SEM
Dry matter 26.06 26.56 26.91 0.58
Crude protein 21.21 20.70 20.45 1.15
Lipid 4.55 4.07 3.99 0.33
Total ash 1.39 1.41 1.32 0.15
3.2.2.4. Economic efficiency of beef fattening
The feed cost (Vietnam dong/kg feed) reduced from ration 1 to ration 3 (3,180VND;
2,990VND; 2,800VND) when the corn cob level in the rations increased from 10 to 30 %. The
reason was that the purchase cost of corn cob was cheaper than that of the other ingredients. This
explained why the level of corn cob increased, ADG decreased but the net profit
(VND/cattle/month) was similar. The net profit (VND/cattle/month) was 194,410VND;
190,893VND and 184,279VND for rations 1, 2 and 3, respectively.
3.3. Use corn stover in beef finishing rations
3.3.1. Effects of different levels of corn stover in the rations on gas volume and characteristics of
in vitro gas-production of rations (Experiment 2a)
The cumulative in vitro gas production from rations differing in percentage of corn stover is
presented in table 3.20.
Table 3.20. Cumulative in vitro gas production from rations differing in corn stover levels
Ration Cumulative in vitro gas production at different time of incubation
(ml/200mg DM)
3 h 6 h 12 h 24 h 48 h 72 h 96 h

5% corn stover 5.38
b
11.66
b
28.34
a
48.41
a
57.91
a
63.11
a
64.18
a
15% corn stover 7.33
a
14.86
a
35.93
a
48.46
a
58.55
a
58.54
a
58.90
ab
25% corn stover 5.79
b

11.95
b
23.35
b
37.29
b
48.33
b
51.59
b
53.40
b
SEM 0.72 1.23 1.82 1.59 1.38 2.36 2.75
Values bearing different superscripts a, b, c in columns differ significantly (P<0.05).
After 3 hour incubation, the cumulative in vitro gas production of rations differing in the
percentage of corn stover started to be different. However, the cumulative in vitro gas production of
rations containing 5 and 25% of corn stover was still similar. The similar trend was observed in the
cumulative in vitro gas production of rations after 6 hour incubation.
After 24 to 96 hours of in vitro incubation, however, only a significant difference in the
cumulative in vitro gas production was found between rations having 5 to 15% corn stover and the
ration having 25 % corn stover (P< 0.05). After 24 to 96 hours of in vitro incubation, the cumulative
in vitro gas production was similar for rations having 5 and 15% corn stover (P>0.05).
The cumulative in vitro gas production was the highest of the ration containing 5% corn stover,
followed by that of the ration containing 15% corn cob. The lowest cumulative in vitro gas
production was observed in the ration containing 25% corn cob.
It was concluded that the level of corn cob in the rations had a negative effect on in vitro gas
production of rations.
The characteristics of in vitro gas production of rations differing in corn stover levels are
presented in table 3.21.
Table 3.21. Characteristics of in vitro gas production of rations differing in corn stover levels

Ration a + b c RSD
5% corn stover 63.90
a
0.059 2.093
a
15% corn stover 59.53
a
0.073 1.328
b
25% corn stover 53.40
b
0.051 0.725
c
SEM 2.40 0.203
Values bearing different superscripts a, b, c in columns differ significantly (P<0.05).
As can bee seen from table 3.21, the potential gas production from the total degraded OM (a +
b) of rations containing 5 and 15 % corn stover was significantly different (P< 0.05) with the
potential gas production from the total degraded OM (a + b) of the ration containing 25 % corn
stover. No significant difference in the potential gas production from the total degraded OM (a + b)
of rations containing 5 and 15 % corn stover was observed (P>0.05).
The level of corn stover in the rations had a negative effect on the potential gas production from
the total degraded OM (a + b) of rations when it was 25%.
3.3.2. Effects of different levels of corn stover in the rations on performance of finishing cattle
and quality of beef. (Experiment 2b)
3.3.2.1. Live weight change of cattle
The live weight change of cattle fed on three rations differing in corn stover levels is presented
in table 3.22.
Table 3.22. Live weight change of cattle
Parameter
Ration 1

(5% corn stalks)
Ration 2
(15% corn stalks)
Ration 3
(25% corn stalks)
SEM
Initial body weight (kg) 192.1 191.8 193.1 5.5
Final body weight (kg) 254.1 253.5 248.4 4.1
ADG (kg/cattle/day) 0.738
a
0.735
a
0.658
b
0.042
Values bearing different superscripts a, b, c in rows differ significantly (P <0.05).
The ADG of cattle fed on rations containing 5 and 15% corn stover was significantly different
with ADG of cattle fed on the ration containing 25% corn stover (P<0.05). No difference in ADG
between cattle fed on the ration with 5% and 15 of corn cob was found (P>0.05).
ADG of finishing cattle decreased when the level of corn stover increased from 15 to 25 % in
the ration. The reasons was that corn stover is agricultural by-products with a high fiber content;
therefore the higher level of corn stover will increase the fiber content in ration. Consequently,
animals will use more energy for fermentation of fiber in the ration and then less energy will be
retained in the body of animals leading to a low ADG.
On the other hands, when the fiber content increases, the non-structural carbohydrate (NSC) of
the rations decreases. In this experiment, the calculated NSC level decreased from ration 1 to ration
2 and ration 3 (67.4%, 58.6%, 50.5%). NSC plays a very important role in feed digestibility, feed
intake and ADG of beef and dairy cattle. Bowman et al., (2004) showed that reduced NSC in the
ration of beef cattle led to a low dry matter and protein intakes and digestive protein.
It seemed that the ration with a higher potential gas production from the total degraded OM (a +

b) when feeding cattle will give a higher ADG of cattle.
3.3.2.2. Feed intake and feed conversion ratio (FCR)
The feed intake and feed conversion ratio (FCR) of cattle fed on three rations differing in the corn
stover level are presented in table 3.23.
Table 3.23. Feed intake and feed conversion ratio (FCR) of cattle fed on three rations differing in
corn stover levels
Ration 1
(5% corn stover)
Ration 2
(15% corn stover)
Ration 3
(25% corn stover)
SEM
DM intake (kg/head/day) 5.39 5.48 5.51 0.16
DM intake as % liveweight (%) 2.42 2.46 2.50 0.10
FCR (kg DM/kg gain) 7.32
b
7.39
b
8.40
a
0.41
Energy utilization efficiency (g
gain/MJ ME)
13.91
a
13.87
a
12.65
b

0.69
Values bearing different superscripts a, b, c in rows differ significantly (P <0.05).
Although the ADG of cattle fed on rations containing 5 and 15% corn stover was significantly
different with the ADG of cattle fed on the ration containing 25% corn stover, the DM intake
(kg/head/day) and DM intake as % live weight of cattle fed on three rations differing in the corn
stover level was not significantly different. The DM intake (kg/head/day) of cattle in our experiment,
which ranged from 5.39 to 5.51 kg/head/day, was in agreement with Kearl (1982). According to Kearl
(1982), DM intake requirement of cattle weighing 200 kg, gaining 0.5 to 0.75 kg/head/day was 5.2
to 5.4 kgDM/head/day.
The FCR (kg DM/kg gain) of cattle fed on rations containing 5 and 15% corn stover was
significantly different with the FCR of cattle fed on the ration containing 25% corn stover
(P<0.05). The FCR (kg DM/kg gain) of cattle fed on rations differing in corn stover levels, which
varied from 7.32 to 7.40, was in a range published by ARC (1980), INRA (1989) and AFRC
(1993) (7.1 to 8.8 kg DM/kg gain). The FCR (kg DM/kg gain) of cattle in our experiment was also
in agreement with work by Agricultural Diversification Project, in which the FCR of cattle in the
finishing phage averaged 8.2 DM/kg gain. However, the FCR (kg DM/kg gain) of cattle in our
experiment was lower than that published by Chi Cuong Vu et al., (2007). In their experiment,
when using of 27% corn stover in finishing rations, the FCR of cattle was 10.84 kg DM/kg gain.
In general, increased levels of corn stover in the finishing rations will lead to an increase in
FCR.
3.3.2.3. Economic efficiency of beef fattening
It was found that the difference (Vietnam dong/head) between output and input was the highest
for cattle fed on ration 1 (790,682 VND/head), followed by that for cattle fed on ration 2 (753,191
VND/head). The lowest difference (VND/head) between output and input (677,818 VND/head) was
found for cattle fed on ration 3. It was concluded that using 25% corn stover in finishing rations
lowered the economic efficiency of beef fattening.
3.4. Utilization of cocoa pod using in finishing rations.
3.4.1. Effects of different levels of cocoa pod in the rations on gas volume and characteristics of
in vitro gas production of rations (Experiment 3a)
The cumulative in vitro gas production from rations differing in cocoa pod levels is presented in

table 3.24.
Table 3.24. Cumulative in vitro gas production from rations differing in cocoa pod levels
Ration Cumulative in vitro gas production at different time of incubation (ml/200mg
DM)
3 h 6 h 12 h 24 h 48 h 72 h 96 h
25% cocoa pod 7.82
a
14.84
a
37.63 58.22 64.10 67.64 71.15
30% cocoa pod 6.15
ab
13.12
a
35.86 56.45 63.61 67.16 70.36
35% cocoa pod 5.24
b
10.26
b
34.12 55.82 63.16 66.75 70.00
SEM 0.84 1.18 1.03 1.24 1.06 1.91 1.68
Values bearing different superscripts a, b, c in columns differ significantly (P <0.05).
After 3 hour incubation, the cumulative in vitro gas production of rations differing in the
percentage of cocoa pod started to be different. However, the cumulative in vitro gas production of
rations containing 25 and 30% of corn stover was still similar. The similar trend was observed in the
cumulative in vitro gas production of rations after 6 hour incubation.
After 24 to 96 hours of in vitro incubation, however, no significant difference in the cumulative
in vitro gas production was found among rations differing in percentage of cocoa pod (P< 0.05). It
indicated that levels of cocoa pod from 25 to 35% in the finishing rations did not affect the
cumulative in vitro gas production of rations.

The characteristics of in vitro gas production of rations differing in cocoa pod levels are
presented in table 3.25.
Table 3.25. Characteristics of in vitro gas production of rations differing in cocoa pod levels
Ration a + b (ml) c (%/h) RSD
25% cocoa pod 68.97 0.075 3.076
30% cocoa pod 68.53 0.073 2.903
35% cocoa pod 68.27 0.070 3.462
SEM 1.56 0.002 0.197
As can bee seen from table 3.25, the potential gas production from the total degraded OM (a +
b) of rations containing 25, 30 and 35% cocoa pod was not different (P>0.05). No significant
difference in the potential gas production from the total degraded OM (a + b) of rations containing
25; 30 and 35% cocoa pod was observed (P>0.05).
It appeared that levels of cocoa pod ranging from 25 to 35% in the rations had no negative
effect on the potential gas production from the total degraded OM (a + b) of rations.
3.4.2. Effects of different levels of cocoa pod in the rations on performance of finishing cattle
and quality of beef. (Experiment 3b)
3.4.2.1. Live weight change of cattle
The live weight change of cattle fed on three rations differing in cocoa pod levels is presented
in table 3.26.
Table 3.26. Live weight change of cattle fed on three rations differing in cocoa pod levels
Ration 1
(25% cocoa pod)
Ration 2
(30% cocoa pod)
Ration 3
(35% cocoa pod)
SEM
Initial body weight (kg) 207.6 207.0 206.8 7.3
Final body weight(kg) 267.0 264.9 263.8 7.4
ADG (kg/cattle/day) 0.707 0.689 0.679 0.024

Although the level of cocoa pods increased (25, 30 and 35% in ration 1, 2 and 3), the ADG of
cattle fed on three rations was not significantly different (P>0.05). As analysis in the previous
section on in vitro gas production: levels of cocoa pod ranging from 25 to 35 % in the rations had
no negative effect on the potential gas production from the total degraded OM (a + b) of rations.
This may be a reason explaining the similarity in ADG of cattle fed on three rations differing in
cocoa pod levels
Our finding in this experiment was in agreement with a publication of the International Cocoa
Organization - ICCO (2000). In this publication, ICCO reported that cocoa pod can replace maize in
beef cattle rations at a level of 45% without any negative effect on ADG. The work done by Wood
and Lass (2001) also indicated that 50% cocoa pods in the cattle rations had no negative effect on
cattle performance.
The ADG of cattle in our experiment was higher than that of Brahman crosses fed on the ration
containing 50% cocoa pod (0.5 kg/head/day) (Wong et al., 1986).
3.3.3.2. Feed intake and feed conversion ratio (FCR)
The feed intake and feed conversion ratio (FCR) of cattle fed on three rations differing in the
cocoa pod level are presented in table 3.27.
Table 3.27. Feed intake and feed conversion ratio (FCR) of cattle fed on three rations differing in
the cocoa pod levels
Ration 1
(25% cocoa
pod)
Ration 2
(30% cocoa
pod)
Ration 3
(35% cocoa
pod)
SEM
DM intake (kg/head/day) 5.37 5.43 5.53 0.11
DM intake as % liveweight (%) 2.26 2.30 2.35 0.09

FCR (kg DM/kg gain) 7.60 7.88 8.15 0.34
Energy utilization efficiency (g
gain/MJ ME)
13.59 13.43 13.33 0.60