tóm tắt luận án tiến sĩ tiếng anh sử dụng một số phụ phẩm nông nghiệp để vỗ béo bò tại huyện ea kar, tỉnh đắk lắk

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 [...]... 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... 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,... 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... slaughtered (head) 3 3 3 a ab Dressing (%) 47.5 46.2 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 . 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. 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. 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