Effects of cassava forage (manihot esculenta crantz) in diet on growth and methane production in cattle

To measure effects of dried, ensiled and fresh cassava forage in diets based on Napier grass on digestibility, body weight gain and methane production of Sindhi x Yellow cattle.. To find

Chapter 1: INTRODUCTION

1.1 Necessary of thesis

Previous studies showed that ruminants contribute 25% of total methane produced on earth due to microbial fermentation of feeds in rumen to produce volatile fatty acids (VFA), methane and carbonic… These gasses are released by eructation Some researches in Vietnam showed that each cow daily emitted into environment about 170 - 241 litters of methane depended on breed, age and productivity of animals

Some scientists reported that cassava leaf (CL) and copra meal (CM) are sources

of protein supplement as well as good by-pass feed due to their tannin and lipid Previous studies showed that supplementation of dried CL and CM in cattle diets improved body weight gain but there was few study on methane emission from rumen fermentation Therefore, we conducted the study “Effects of cassava forage

(Manihot esculenta Crantz) in diet on growth and methane production in cattle”

1.2 Research objectives

To measure in vitro digestibility and methane production of feeds and different

mixtures of Napier grass and dried cassava forage in beef cattle diet

To measure effects of dried, ensiled and fresh cassava forage in diets based on Napier grass on digestibility, body weight gain and methane production of Sindhi x Yellow cattle

To find out the appropriate ration by replacement of copra meal by dried cassava forage in diets based on Napier grass on body weight gain and methane production of

Sindhi x Yellow cattle

1.3 Research contents

The studies were conducted in following 4 experiements:

(1) Study on digestibility and methane production of some feeds and different

mixtures of Napier grass and cassava forage by in vitro gas production technique

(2) Effects of dried, ensiled and fresh cassava forage in diets on digestibility and methane production of Sindhi x Yellow cattle

(3) Effects of dried, ensiled and fresh cassava forage in diets on live weight gain and methane production of Sindhi x Yellow cattle

(4) Effects of replacing copra meal by dried cassava forage in diets on live weight gain and methane production of Sindhi x Yellow cattle

1.4 Research subjects

Studying methane production of Napier grass, ruzi grass and para grass; dried cassava forage, cotton seed meal and copra meal; mixtures of Napier grass and dried

cassava forage in cattle diets using in vitro gas production technique with Sindhi

cattle rumen fluid

Studying the uses of fresh, dried and ensiled cassava forage after harvesting on digestibility, body weight gain and methane production of Sindhi x Yellow cattle Studying the effects of replacing copra meal by dried cassava forage in diets on body weight gain and methane production of Sindhi x Yellow cattle

1.5 Location and duration

The study was conducted from October 2012 to March 2015 The experiment 1 was carried out at laboratory, department of Animal Sciences, college of Agriculture and Applied Biology, Can Tho university Experiment 2, 3 and 4 were carried out at Center for Research and Technology Transfer, Nong Lam University of Ho Chi Minh city

1.6 Findings of dissertation

Para grass, dried cassava forage and a mixture of 20% dried cassava forage and

Napier grass decreased in vitro methane production

Replacement of 20% dried, ensiled and fresh cassava forage for Napier grass in diets decreased methane emission of Sindhi x Yellow cattle

Replacement of 10% copra meal by 10% dried cassava forage in cattle diets improved body weight gain and tended to reduce methane production

1.7 Outline of dissertation

There are 3 pages of introduction, 32 pages of literature review, 19 pages of materials and methods, 52 pages of results and discussion, 1 page of conclusion and recommendation, references and index The dissertation has 46 tables, 20 figures and

188 references

Chapter 2: LITERATURE REVIEW

2.1 Rumen digestibility

Approximate 85% of feeds are digested in rumen by microbial fermentation Microbial fermentation of feeds produces VFA, NH3, amino acids and fatty acids… These products are absorbed through rumen wall, whereas carbonic and methane are released into environment by eructation Undigestibility feeds move and digest at abomasum and small intestine to supply nutrients for animals However, studies showed that 10% of energy intake are lost by rumen methane production An balance ration will improve performance and decrease methane production in cattle

Cassava leaf contains 18.3–24.5% crude protein, full of essential amino acids and minerals Cassava leaf also contain quite high toxic compounds such as condensed tannin (2.7– 4.4%) and hydrogen cyanide (325–399 mg/kg in dried and ensiled cassava leaf and 911–1,426 mg/kg in fresh cassava leaf) If feeding at high amount of fresh cassava leaf, it will affect animal health By recommendation, the appropriate level of additional cassava leaf in ruminant diet is 20% The researches in cattle showed that supplementation of cassava leaf and copra meal has improved dry matter intake, feed digestion and body weight gain, but reduces protozoa population and methane production

2.2 Effect of diets on rumen methane production

Studies showed that supplemental diets of cassava leaf or copra meal reduce methane emission because condensed tannin and lipid content in diet reduce amount

of protozoa and decrease rumen methane production

Tannin: Addition of 20% cassava leaf or 0.4% condensed tannin in diet often

reduces ruminal protozoa population of cattle and buffaloes, which relates to decrease methane emission Ruminal protozoa involve in rumen methane production, and protozoa may produce hydrogen and provide this gas for activity of rumen methanogen bacteria Methanogen bacteria and protozoa live symbiotically in rumen, and therefore, reducing of protozoa population may affect activity of rumen

methanogen bacteria

Lipid: Supplementing lipid in diet often decreases methane emission, which

depends on kinds of lipid However, supplementation of lipid at 6 - 8% in diet will cause negative effects on dry matter intake and digestibility of carbohydrates On the other hand, lipid reduces rumen protozoa population, and some fatty acids are toxic to methanogen bacteria or hydrogenation of unsaturated fatty acids leads to decline methane production

Chapter 3: MATERIALS AND METHODS

3.1 Research methods

3.1.1 Experiment 1: Study on digestibility and methane production of feeds and

mixtures of Napier grass and cassava forage by in vitro gas production technique

The objectives of this experiment were to determine in vitro digestibility and

methane production of some feeds such as Napier grass, ruzi grass, guinea grass, para grass, cassava forage, cotton seed meal, copra meal, and mixtures of Napier grasss grass and cassava forage in cattle diet

The experiment was carried out from October 2012 to March 2013

Table 3.1: Nutrient composition of feeds used in experiment 1

DM: dry matter, OM: organic matter, CP: crude protein, NDF: neutral detergent fiber, Ash: total minerals

In vitro gas production technique was followed the method of Menke and Steingass (1988) Preparation of media solution for in vitro gas production was a

mixture of solutions: macro-mineral solution, micro-mineral solution, buffer solution, resazurin solution and reducing solution The media solution was incubated at 39°C, stirred and gassed carbonic until solution turns blue to pink pH value of media solution before incubation ranges from 7.0 to 7.3

Rumen fluid was used from 03 fistulated cattle fed the same diet based on natural grass and rice straw Rumen fluid was collected before morning feeding and kept in thermos flasks It was then transported to laboratory, filtered through muslin fabric into pre-warmed thermos flasks and incubated at 39°C Rumen fluid was gassed further with carbonic to make anaerobic condition, tighly closed and incubated for experiments

The experiment was conducted as a completely randomized design with 5 replicates The treatments included (1) forages such as para grass, ruzi grass, guinea

grass and Napier grass; (2) protein-supplemented feeds such as cassava forage, cotton seed meal and copra meal; (3) mixtures of replacing Napier grass for cassava forage

at 0, 10, 20 and 30% in diet (DM basis) Two replicates of blank solution were also included in this study The blank solution contained only rumen fluid and media solution without substrates Measured gas from blank solution was used to correct the exact calculation of gas production

Parameters: Digestibility of DM and OM, total gas volume, methane and carbonicconcentrations, methane and carbonicvolumes at 48 h post incubation

3.1.2 Experiment 2: Effects of dried, ensiled and fresh cassava forage in diet on digestibility and methane production of Sindhi x Yellow cattle

The objective of this experiment was to determine effect of dried, ensiled and fresh cassava forage in Napier grass diet on DM intake, nutrient digestibility, nitrogen retention, rumen fluid parameters and methane production of Sindhi x Yellow cattle

The experiment was carried out from March to June 2013

Nutrient composition of feeds and diets are presented in Table 3.2 and 3.3

Table 3.2: Nutrient composition of feeds used in experiment 2

The experiment was conducted as a 4 x 4 Latin square design Four treatments were control without replacing of Napier grass by cassava forage (CF-0), replacing of Napier grass by 20% dried cassava forage (DCF-20), replacing of Napier grass by 20% ensiled cassava forage (ECF-20) and replacing of Napier grass by 20% fresh cassava forage (FCF-20)

Each experimental period lasted for 21 days including the first 14-day for adaptation to experimental diets Animals were then kept in cage floor for 7-day to collect the data of feed intake, feces and urine At the end of 3 days of each

experimental period, cattle were located into respiration chambers to determine volume of methane emission

Table 3.3: Diet formulation and nutrients of experiment 2 (% DM)

Air samples inside respiratory chambers were collected for every 30 minutes At every sapling time points, air samples were collected for one minute and kept in 2 m3gas collecting bags When bags were full of air, it would be measured for methane concentration using Gasmet equiment (Model DX 4030, Gasmet Techologies Inc., Finland) Similarly, this process was repeated during each sampling period

Parameters: feed and nutrient intakes, nutrient digestibility, pH, N-NH3, numbers of rumen bacteria and protozoa, daily volume of cattle methane emission

3.1.3 Experiment 3: Effects of dried, ensiled and fresh cassava in diet on body weight gain and methane production of Sindhi x Yellow cattle

The objective of experiment was to determine effect of dried, ensiled and fresh cassava forage in Napier grass diet on body weight gain, feed conversion ratio, economic effect and methane production of Sindhi x Yellow cattle

The experiment was carried out from July 2012 to December 2013

Chemical composition of feeds are presented in Table 3.4 and 3.5

Table 3.4: Nutrient composition of feeds used in experiment 3

The experiment was conducted as a completely randomized design with 4 treatments and 5 replicates Four treatments were control without replacing of Napier grass by cassava forage (CF-0), replacing of Napier grass by 20% dried cassava forage (DCF-20), replacing of Napier grass by 20% ensiled cassava forage (ECF-20) and replacing of Napier grass by 20% fresh cassava forage (FCF-20)

Table 3.5: Diet formulation and nutrients of experiment 3 (% DM)

CF-0: control without replacing cassava forage for Napier grass, DCF-20, ECF-20, FCF-20: replacing

20% dried, ensiled, fresh cassava forage for Napier grass in diet; ME: metabolizable energy

Parameters: Feed and nutrient intakes, feed conversion ratio, weight gain, economic effect and methane emission

3.1.4 Experiment 4: Effect of replacing copra meal by dried cassava forage in diet on body weight gain and methane production of beef cattle

The objective of experiment was to determine effect of replacing copra meal by dried cassava forage in diet on body weight gain, feed conversion ratio, economic effect and methane production of Sindhi x Yellow cattle

The experiment was carried out from March 2014 to March 2015 Chemical composition of feeds and diets are presented in Table 3.6 and 3.7

Table 3.6: Nutrient composition of feeds used in experiment 4

Table 3.7: Diet formulation and nutrients of experiment 4

The ratio of concentrate:roughage was 30:70 The levels of replacing copra meal

by dried cassava forage were at 0, 5, 10, 15 and 20% while rice bran was kept at 10%

in diets The formulation of concentrate is presented in Table 3.8

Table 3.8: Formulation and nutritional values of concentrate (% DM)

Item Feed ingredients of concentrate (%)

All parameters in this experiment were similar to those in experiment 3

3.2 Statistical analysis

Experimental data were analyzed variance by ANOVA procedure of General Linear Model and regression of Minitab 16.0 Significant differences among treatment means were assessed by Tukey's multiple comparison tests after a significant F-test Overall differences between treatment means were considered to be significant at P<0.05

Chapter 4: RESULTS AND DISCUSSION

4.1 Experiment 1: Study on digestibility and methane production of feeds and

mixtures of Napier grass and cassava forage by in vitro gas production technique

4.1.1 Digestibility and methane emission of para grass, ruzi grass, guinea grass

and Napier grass by using in vitro gas production technique

Table 4.1: In vitro digestibility, volume and concentration of methane and carbon dioxide

production of grass at 48 hours

Item

Treatment

MSE

P

Para grass

Ruzi grass

Guinea grass

Napier grass

DM digestibility, % 51.6a 54.2a 47.0b 53.3a 0.81 <0.01

OM digestibility, % 52.9a 55.5a 48.2b 54.1a 0.83 <0.01

Total gas, ml/0.2 g DM 27.7b 32.5a 25.5b 35.1a 0.87 <0.01 Methane, % 7.07b 10.8a 12.4a 12.4a 0.40 <0.01 Carbon dioxide, % 71.7 73.6 70.3 72.3 0.91 0.13 Methane, ml 1.95d 3.52b 3.15c 4.37a 0.62 <0.01 Carbon dioxide, ml 19.8b 23.9a 17.9b 25.4a 0.65 <0.01

Total gas, ml/g OMD 297c 321b 300c 366a 2.90 <0.01 Methane, ml/g OMD 21.0c 34.9b 37.2b 45.7a 0.75 <0.01 Carbon dioxide, ml/g OMD 213c 237b 211c 265a 1.97 <0.01

OMD: organic matter digestibility, DM: dry matter, OM: organic matter a, b, c, d Means within rows with differing superscript letters are significantly different (P<0.01)

Table 4.1 showed that in vitro dry matter digestibility (DMD) and organic

matter digestibility (OMD) at 48 hours of guinea grass was lowest 48.2% (P<0.05)

Because it contains high NDF and low CP In vitro dry matter and organic matter digestibility at 48 hours of para grass, ruzi grass, guinea grass and Napier grass were

more than 47%

Total gas, methane and carbon dioxide volume (ml/g OMD) at 48 hours of para grass and guinea grass were lowest while ruzi grass and Napier grass had the highest value (P<0.01) Para grass has considerable potential to reduce methane emission

4.1.2 Digestibility and methane emission of dried cassava forage, cotton seed

meal and copra meal using in vitro gas production technique

Table 4.2: Digestibility, volume and concentration of methane and carbon dioxide emission

at 48 hours of dried cassava forage, cotton seed meal and copra meal

DCF: dried cassava forage, CSM: cotton seed meal, CM: copra meal OMD: Organic matter digestibility, DM: dry matter, OM: Organic matter a, b, c Means within rows with differing superscript letters are significantly different (P<0.01)

Table 4.2 showed that DMD and OMD at 48 hours of dried cassava forage (DCF), cotton seed meal (CSM) and copra meal (CM) were significantly different (P<0.01) Dry matter digestibility of DCF was lowest 48.6% DCF would be a good

cattle bypass source feed Organic matter digestibility at 48 hours of DCF, CSM and

CM were more than 50% It was a very good feed to supply protein for cattle

Total gas, methane and caborbon dioxide volume (ml/g OMD) were lowest at 48 hours of DCF, next was CSM and highest was CM It was significantly different

(P<0.01) Low in vitro digesitbility of DCF could be cause low total gas and methane

volume Moreover, DCF would be a good source feed which contains rumen bypass nutrients It limited rumen fermentation, total gas emission On the other hand, DCF contained condensed tannin 3.04% (Table 3.2) which reduced rumen protozoa to make low methane emission

Total gas and methane volume of CM were highest due to high NDF content of

CM (56.3%), it was lower in DCF and CSM with 44 and 41,4%, respectively (Table 3.1) NDF digestion produced more acetic acid and caused increasing methane volume Because bacteria fermented cellulose and produced more hydrogen for bacteria to synthesize methane