Improved productivity and quality of beef cattle based on locally available feed resources in north vietnam

Effects of length of fattening period on some slaughter and meat quality traits of bulls of Laisind and Yellow cattle fed urea-treated rice straw as roughage...26 5.. Effects of length o

Improved productivity and quality of beef cattle based

on locally available feed resources in North Vietnam

Forbedret produktivitet og kvalitet i produksjon av storfekjøtt basert på

lokalt tilgjengelige fôrressurser i Nord Vietnam

Philosophiae Doctor (PhD) Thesis Duong Van Nhiem

Department of Animal and Aquacultural Sciences Norwegian University of Life Sciences

Aas, 2012

Thesis number 2012:64 ISSN 1503-1667 ISBN 978-82-575-1100-5

Table of Contents

Acknowledgements 5

Abstract 7

Sammendrag 11

List of papers 15

Abbreviations 16

1 Introduction 17

2 Objectives 21

3 Materials and Methods 22

4 Main results 25

4.1 The current situation of beef cattle production at the farmer household level in North Vietnam 25

4.2 Effects of replacing fish meal with soy cake in a diet based on urea-treated rice straw on performance of growing Laisind beef cattle 26

4.3 Effects of length of fattening period on some slaughter and meat quality traits of bulls of Laisind and Yellow cattle fed urea-treated rice straw as roughage 26

5 General discussion 28

5.1 The current situation of beef cattle production at the farmer household level in North Vietnam 28

5.2 Effects of replacing fish meal with soy cake in a diet based on urea-treated rice straw on performance of growing Laisind beef cattle 31

5.3 Effects of length of fattening period on some slaughter and meat quality traits of bulls of Laisind and Yellow cattle fed urea-treated rice straw as roughage 33

6 Conclusions 37

7 Future perspectives 38

References 39 Papers I-III

Acknowledgements

In the first place, I would like to deeply express my special gratitude to my main supervisor, Associate Professor Jan Berg, and co-supervisors, Associate Professor Nils Petter Kjos, Professor Lars Olav Eik, and Associate Professor Nguyen Xuan Trach, for their invaluable intellectual guidance, support and continuous encouragement at all stages of my study

This research was funded by the Norwegian government through the Norwegian Programme for Development, Research and Education (NUFU) and the Quota scholarship programme All the related studies in the research were carried out in Vietnam with help and assistance from Hanoi University of Agriculture (HUA) and the National Institute of Animal Husbandry (NIAH) The data analyses and write-up

of the thesis were accomplished at the Department of Animal and Aquacultural Sciences (IHA), Norwegian University of Life Sciences (UMB) I would like to express my sincere gratitude to these institutions for their effective support during my PhD study

I wish to deeply express my thanks to the Department of Veterinary Public Health, Faculty of Veterinary Medicine, and Hanoi University of Agriculture for facilitating

me during my study

My high appreciation is also extended to Dr Vu Chi Cuong, Dr Bui Quang Tuan, Dr

Le Duc Ngoan, Dr Chumphit Loan, and Dr Timothy Olson for their invaluable advice during the preparation of experiments and data analyses

I am grateful to fellow PhD students, Nguyen Thanh Trung, Devota Mwaseba, Fanny Chimwemwe Chigwa, and Aster Abebe for their company that made me encouraged

I also wish to thank all of my Vietnamese friends in Norway for their impartial help and assistance

Finally, I am greatly indebted to my parents, my sisters for their warm love, support, and encouragement during my study I cannot adequately express the depth of my appreciation and love for my dear wife, Nguyen Thi Hai Yen, my closest friend and confident, and my darling son, Duong Xuan Dat, and daughters, Duong Thi Kim Oanh and Duong Thi Phuong Thao, who have stuck with me, encouraging me throughout the long time I was away studying in Norway You are all my love!

Aas, October 2012

Duong Van Nhiem

Department of Animal and Aquacultural Sciences

Norwegian University of Life Sciences

P.O Box 5003, N-1432, Aas, NORWAY

Email: dvnhiem@gmail.com

Abstract

The present thesis is composed of three papers reporting studies related to beef cattle production in Vietnam The first study was to investigate the current situation of household beef cattle production in North Vietnam The second study was to test a hypothesis that under subtropical conditions, like in North Vietnam, fish meal can be replaced by soy cake with no negative effects on feed intake and animal performance

of growing beef cattle fed urea-treated rice straw (URTRS) as a basal diet And, the third study was to verify a hypothesis that the cattle genotypes, Laisind and Yellow cattle, respond differently to the length of fattening on the same feeding regime

The first study (Paper I) is focused on investigation of the current situation of beef cattle production at the farmer household level in two provinces of Tuyen Quang and Vinh Phuc which represent the mountainous and lowland areas in North Vietnam, respectively Three approaches used to collect data were participatory rural appraisal, structured questionnaire, and secondary data collection Collected data were analyzed using descriptive statistics, non-parametric statistical methods, and general linear model Results showed that, most of the beef cattle were kept in a mixed crop-livestock production system Compared to a farm in the lowland area, a farm in the mountainous area owned a three-time larger farmland area and spent more time for daily cattle feeding activities In a mountainous farm, cattle contributed more to the total cash income compared to a lowland farm Most of the farms were very small-sized with one to five cattle a farm The local breed (Yellow cattle) was predominant followed by the crossbred genotype (Laisind cattle), whereas imported breeds accounted for a minority Dark coffee and yellow were the two most preferred coat

colours The top four purposes of keeping cattle in the descending order included breeding cow, assets, manure, and meat The natural mating with improved bulls was most commonly applied whereas the artificial insemination was not popular Feeding

of cattle was mainly based on grazing of natural grass in combination with supplementation of crop by-products There was not a modern marketing system for beef cattle The most important factors influencing beef production in order of importance were capital, market price, feed, knowledge, and service No appropriate methods of crop by-products processing were applied The shortage of feed during winter and lack of capital were the two most common concerns of the farmers This implies that a better utilization of low-cost feed resources through appropriate methods of storage and processing of crop by-products should be considered as essential to overcome the shortage of feed for cattle Beef cattle production at the farmer household level should be improved through the implementation of appropriate policies and credit programmes as well as supports for the improvement

of the marketing system

The second study (Paper II) presents results of an experiment in growing beef cattle The purpose was to investigate effects of different ratios of fish meal to soy cake as protein supplements in the diet on feed intakes and performance of growing beef cattle fed URTRS as basal diet under local conditions in North Vietnam Thirty-

six male cattle of Laisind (50% local Yellow cattle and 50% Sindhi, both Bos indicus)

diet F: 0/100 Following a 4-week adaptation period, a comparison period lasted 24 weeks The total intakes of DM, roughage, ME, and CP were 6, 7, 6, and 20% higher

in diets B-F than diet A with P values ≤ 0.05, 0.05, 0.05, and 0.001, respectively The ADG was 50% higher (P<0.001) in diets B-F than that in diet A Compared to diet A, diets B-F had lower FCRDM, FCRME, and FCRCP by 30, 20, and 30%, respectively (all

at P<0.001) There were no significant differences between diets B-F in the intakes, FCRs, and ADG The apparent digestibility of CP was 12 to 24% higher (P<0.001) in diets B-F than that in diet A There was a tendency that the apparent digestibilities of

DM, CP, and CF were increasing with increasing level of soy cake in this study The ratio of fish meal to soy cake did not significantly affect feed intakes, ADG, FCR, and the apparent nutrient digestibilities of the cattle Soy cake can therefore be used to partially or fully replace fish meal as a protein supplement in the diet of growing beef cattle fed URTRS without any negative effects on animal performance

The third study (Paper III) is focused on effects of length of fattening period

on slaughter and beef quality of the two most common cattle genotypes in Vietnam, namely Laisind and Yellow cattle The experiment was carried out in 18 bulls of Laisind and 18 bulls of Yellow cattle, both starting at around 21 to 22 months of age, with an average live weight of 209±13 kg and 139±13 kg, respectively Animals from each genotype were divided into three groups, managed and fattened alike for 6, 10, and 14 weeks, respectively The concentrate contained 17% CP (on DM), of which 25% of the supplemented protein was derived from fish meal and 75% from soy cake Urea-treated rice straw (URTRS) was used as basal diet There was a difference (P<0.001) between Laisind and Yellow cattle in live weight at slaughter (274 vs 190 kg), dressing percentage (48.3 vs 45.9%), lean meat weight (103 vs 67 kg), ADG (920 vs 680 g/d), warm carcass weight (133 vs 87 kg), percentage of bone (17.4 vs

19.4%); and in percentage of trimmed fat (4.8 vs 3.4%) There was neither significant

difference between genotypes in percentage of lean meat nor in percentage of m longissimus dorsi (LD) The length of fattening period had no significant effects on

ADG, dressing percentage, percentage of lean meat, or percentage of LD No significant interaction was present for any of the slaughter quality traits There were

no significant differences between genotypes in any of the studied quality traits The length of fattening period influenced (P<0.05) the pH, drip loss, cooking loss, and

colour (a* values) at 8 days post-mortem; the shear force of LD 12 h (P<0.05), 48 h (P<0.001), and 8 days post-mortem (P<0.001); DM content (P<0.01); and IMF

content (P<0.001) of the meat The genotype by length of fattening period interaction existed for the IMF content (P<0.001) The results suggest that in order to improve slaughter and beef quality, Laisind should be chosen rather than Yellow cattle The fattening period should be 10 weeks Grass could be replaced with URTRS as the main roughage in ration for fattening cattle if supplemented with a concentrate consisted of soy cake and fish meal with an appropriate CP content

Keywords: Laisind cattle; Yellow cattle; Household; Growth; Fattening; Fish meal;

Soy cake; Beef quality

Sammendrag

Avhandlingen er sammensatt av tre artikler som omhandler studier og forsøk relatert til produksjon av storfekjøtt i Vietnam Den første artikkelen presenterer resultater fra en spørreundersøkelse i Nord Vietnam hvor målgruppa var smågårder som produserte storfekjøtt Den andre artikkelen presenterer resultatene fra et produksjonsforsøk med storfe i vekstfasen hvor formålet var å teste hypotesen at

“soyakake” (soy cake) kan erstatte fiskemel i en rasjon basert på ureabehandlet rishalm uten negativ virkning på egenskaper som fôropptak og tilvekst Den siste artikkelen er basert på resultatene fra et produksjonsforsøk med storfe i sluttfôringsperioden Formålet var å bekrefte en hypotese at storferasene Laisind og Yellow gir ulik respons på lengde og fôring i sluttfôringsperioden

Den første artikkelen (Paper I) fokuserer på den nåværende situasjonen for produksjon av storfekjøtt hos småskala-produsenter i to ulike provinser i Nord Vietnam, Tuyen Quang i et fjellområde og Vinh Phuc i lavlandet Data ble innsamlet basert på ulike spørreskjema og innhentet statistikk fra området og analysert statistisk med beskrivende statitikk metode (descriptive statistics) ikke-parametriske metoder (non-parametric statistical methods) og regresjonsanalyse (GLM) Resultatene viste

at det meste av produksjonen av storfekjøtt foregikk på gårder hvor det var en sammensatt produksjon av husdyr og planteprodukter Sammenlignet med gårder i lavlandet, eide gårdene i fjellområdet tre ganger så stort areal og brukte mer tid på daglig fôring og stell av dyrene I fjellområdet utgjorde inntekter fra produksjon av storfekjøtt en høyere andel av totalinntektene på garden sammenlignet med gårder i lavlandet De fleste gårdene var små med en til fem storfe Den lokale rasen, Yellow, dominerte, fulgt av kryssingen Laisind, mens importerte raser utgjorde bare en mindre

del Pelsfargen “mørk kaffe” og gul var de mest ettertraktete De fire viktigste oppgitte årsakene til at man holdt storfe var produksjon av kalv, pengeverdien i et storfe, produksjon av gjødsel og kjøtt Naturlig paring med en avlsokse var mest vanlig Kunstig inseminering var ikke populært Fôring av dyrene var hovedsaklig basert på beiting av gras supplert med ulike biprodukter fra planteproduksjonen Et moderne omsetningssystem for storfe eksisterte ikke De oppgitte viktigste faktorene som hadde størst betydning i produksjonen av storfekjøtt var, i fallende grad, tilgangen til kapital, markedspris, fôr, kunnskap og service Ingen metoder for behandling av bi-produkter fra planteproduksjonen ble anvendt Mangel på fôr gjennom vinteren og mangel på kapital var de to viktigste årsakene til bekymring hos produsentene Dette viser at innføring av hensiktsmessige metoder for behandling og lagring av billige bi-produktene fra planteproduksjonen for å oppnå en bedre fôrutnyttelse, er et viktig skritt for å forbedre fôrsituasjonen Produksjonen av storfekjøtt kan også bli lettere ved bedre tilrettelegging og støtte fra myndighetene, bedre muligheter for å oppnå kreditt og forbedring av systemet for omsetning og salg

Artikkel nr to (Paper II) presenterer resultater fra et produksjonsforsøk i Nord Vietnam med storfe i vekst Hensikten med forsøket var å undersøke virkningen av ulike blandingsforhold mellom fiskemel og “soyakake” (Soy cake) som proteintilskudd i fôret på egenskaper som fôropptak og tilvekst, hos storfe som fikk en

grunnrasjon av ureabehandlet rishalm Totalt 36 okser av Bos indicus rasen Laisind

Oksene i gruppe A fikk ingen tilskudd De ulike forsøksgruppene hadde følgende blandingsforhold fiskemel/soyakake: A: 0/0; B: 100/0; C: 75/25; D: 50/50; E: 25/75; F: 0/100 Total forsøkstid var 30 uker som bestod av fire ukers tilpasningsperiode fulgt av en sammenligningsperiode på 24 uker Totalt opptak av tørrstoff, grovfôr, omsettelig energi og råprotein var 6,7, 6 og 20% høyere i forsøksgruppene B-F sammenlignet med gruppe A Forskjellen var signifikant Gjennomsnittlig daglig tilvekst var 50% høyere hos oksene i forsøksgruppene B-F sammenlignet med oksene i gruppe A Sammenlignet med forsøksgruppe A, hadde gruppene B-F 30 % høyere fôrutnyttelse, 20 % høyere utnyttelse av omsettelig energi

og 30% høyere utnyttelse av råroteinet i fôret (P<0.001) Mellom gruppene B-F var det ingen signifikant forskjell i fôropptak, energi – eller proteinutnyttelse Apparent fordøyelighet av råproteinet var 12 til 24% høyere (P<0.001) i forsøksgruppene B-F sammenlignet med gruppe A Det var en tendens til at apparent fordøyelighet av tørrstoff, råprotein og råfiber økte med økende innslag av soyakake i rasjonen Forholdet fiskemel/soyakake hadde ingen signifikant virkning på fôropptak, gjennomsnittlig daglig tilvekst, fôrutnyttelse og apparent fordøyelighet av fôrstoffer hos oksene Soyakake kan derfor helt eller delvis erstatte fiskemel som proteintilskudd i fôret til okser i vekst som får ureabehandlet rishalm som grovfôr, uten negativ virkning på egenskaper som fôropptak og vekst

Den tredje artikkelen (Paper III) fokuserte på effekten av lengde og fôring i sluttfôringsperioden på egenskaper som slakte – og kjøttkvalitet hos de to mest alminnelige storferasene i Vietnam, Laisind og Yellow Forsøket ble gjennomført med 18 okser av rasen Laisind og 18 okser av rasen Yellow Oksene ble innkjøpt fra omkringliggende gårder når de var 21 til 22 måneder gamle De hadde en startvekt på henholdsvis 209±13 kg og 139±13 kg Oksene fra begge raser ble tilfeldig inndelt i

tre grupper slik at forsøket totalt hadde seks ulike forsøksgrupper En gruppe fra hver rase ble fôret i 6, 10 eller 14 uker I forsøksperioden fikk alle oksene ureabehandlet rishalm som eneste grovfôr i tillegg til et kraftfôr som inneholdt 17% råprotein på tørrstoffbasis Kraftfôret bestod av 25% fiskemel og 75% soyakake Laisind hadde betydelig høyere levendevekt ved slakting sammenlignet med Yellow, henholdsvis

274 og 190 kg, høyere slakteprosent ( 48,3 vs 45,9%), høyere produksjon av salgbart kjøtt (103 vs 67 kg), høyere gjennomsnittlig daglig tilvekst (920 vs 680 g/dag), høyere slaktevekt (133 vs 87 kg), lavere beinprosent i slaktet (17,4 vs 19,4%) men mer avpusset fett i slaktet, henholdsvis 4,8 og 3,4% av slaktevekt Det var ingen

forskjell mellom rase i mengde salgbart kjøtt eller mengde ytrefilét (longissimus dorsi) målt i prosent av slaktevekt Lengde av sluttfôringa hadde ingen signifikant

effekt på gjennomsnittlig daglig tilvekst, slakteprosent, prosent salgbart kjøtt eller ytrefilét i slaktet Det var ingen signikante samspilleffekter rase x lengde av fôring for noen slaktekvalitetsegenskaper Det var ingen signifikant forskjell mellom rase i noen av de målte kjøttkvalitetsparametre Lengde av sluttfôringen påvirket kjøttets

pH, drypptap, koketap og farge 8 dager etter slakting (post-mortem), mørhet (skjærekraft) av ytrefilét 12 timer -, 48 timer - og 8 dager post-mortem og innhold av

tørrstoff og intramuskulært fett (IMF) i ytrefilét Det var samspill mellom rase x lengde av fôring for IMF (P<0.001) Resultatene fra forsøket viser at for å forbedre slakte - og kjøttkvaliteten, bør rasen Laisind brukes framfor Yellow

List of papers

The present thesis is based on the following papers:

I The current situation of beef cattle production at the farmer household level in

North Vietnam (Manuscript)

II Effects of replacing fish meal with soy cake in a diet based on urea-treated rice

straw on performance of growing Laisind beef cattle Accepted in Tropical Animal Health and Production

III Effects of length of fattening period on some slaughter and meat quality traits of

bulls of Laisind and Yellow cattle fed urea-treated rice straw as roughage

(Manuscript)

EAA Essential amino acid

FAO Food and Agriculture Organisation

FCR Feed conversion ratio

FCRCP Feed conversion ratio for crude protein

FCRDM Feed conversion ratio for dry matter

FCRME Feed conversion ratio for metabolizable energy

GDP Gross domestic products

GSO Vietnam General Statistic Office

HUA Hanoi University of Agriculture

IHA Department of Animal and Aquacultural Sciences

LD m longissimus dorsi

MARD Ministry of Agriculture and Rural Development

NIAH National Institute of Animal Husbandry

NRC National Research Council

1 Introduction

Vietnam covers an area of 331,000 km2 stretching for more than 1,600 km along the eastern edge of the Southeast Asian mainland The population is 87.84 million people, of which approximately 70% are farmers living in rural areas where agricultural production provides the major source of income and livelihood The livestock sector contributes around 20% of agricultural gross domestic products (GDP) which contribute to 21% of the total GDP in 2010 (GSO, 2011) According to Nin et al (Nin et al., 2003), more than 92% of the animal producers in Vietnam employ only household labours in livestock management compared to 62% in general agriculture, and own 0.77 hectares of farmland in average

Concerning cattle production in Vietnam, there have been a number of studies

on current situation and farming systems (Hung and Binh, 2004; Duong, 2008; Ngoan and Giang, 2008; Huyen et al., 2009; Quan et al., 2009) Phung and Koops (2003) and Phung (2009) reported the reproductive performance of cows Tuyen et al (2008) and

Vu and Thanh (2008) studied the situation in cattle feedlot A study on some parameters of beef quality in Vietnam was carried out by Luc et al (2009) Results of studies in cattle feeds and feeding have also been reported by several authors (Trach

et al., 2001b; Ba et al., 2005; Khang and Wiktorsson, 2006; Huyen et al., 2010; Thang

et al., 2010; Tra, 2011)

The Laisind (Vietnamese local Yellow cattle x Red Sindhi, both Bos indicus)

and Vietnamese local Yellow cattle (hereafter referred to as Yellow cattle) are the most common genotypes of cattle in Vietnam Red Sindhi was imported from Pakistan in the 1920s Compared to the Yellow cattle, Laisind is 30 to 35% heavier in

adult live weight and the percentage of lean meat in the carcass is 5 to 8% higher (Su and Binh, 2002; Cai, 2007) Both genotypes are well adapted to the local environmental conditions of Vietnam (Su and Binh, 2002; Cai, 2007; Trach et al., 2007)

According to the Department of Animal Husbandry (2006), household farms keep about 90% of the total cattle population in Vietnam, whereas the remaining are raised by commercial farms Ten years ago, Perkins (2002) reported that beef shared only 5% of the total meat production of the country and did not meet the demand of domestic consumption To fill the gap beef has been imported, especially to satisfy the needs for high quality beef for restaurants and supermarkets in the big cities However, according to Indexmundi (2012b, a), beef and veal production in Vietnam had been steadily increasing from 1998 to 2008, but slightly lowering down during recent years Nevertheless, the domestic consumption of beef and veal has been increasing a lot since 1997 to 2012 Consequently, the gap between demand and supply has been becoming bigger

During the last decades, there has been a policy of the Vietnamese government

to support beef production, including subsidy for crossbreeding of cattle, for grass production, providing low-interest credit and loan, and support for breeding programmes However, it seems more efforts are required to improve beef cattle production at the farmer household level to satisfy the increasing demand for beef

Rice straw is one the most common crop by-products in Vietnam Improved utilization of rice straw will effectively contribute to overcoming the shortage of feed for ruminants in general and cattle in particular (Trach, 1998) Urea-treated rice straw (URTRS) has been utilized as a roughage source in ruminant feeding in tropical and subtropical areas (Doyle et al., 1986; Dolberg, 1992; Chenost and Kayouli, 1997) Although URTRS has a higher crude protein (CP) content compared to the untreated form (Shen et al., 1998; Khang and Dan, 2001; Ahmed et al., 2002), when fed alone it does not meet the minimum CP requirement, 10% and 15% of dry matter (DM) for growing and fattening cattle, respectively, under tropical conditions (Kearl, 1982) Supplementation of protein sources to diet of cattle fed URTRS is therefore necessary

to improve animal performance

Soybean meal and fish meal are the two most common supplemental sources

of protein for livestock (FAO, 2011a, b; Miles and Jacob, 2011) Fish meal contains between 60 and 72% CP of the DM, in which escape protein (EP) is about 60% of CP Especially, fish meal is a good source of the essential amino acids (EAA) lysine, methionine, cysteine, and tryptophan; the EAA index is as high as 68% of CP (Michael, 1995; Santos et al., 1998) Among oilseed meals, soybean meal is most similar to fish meal in terms of nutritional characteristics According to Michael (1995) and Hempel (1997), compared to fish meal, soybean meal usually has a lower content of EP (35 vs 60% of CP) but a higher content of ruminally degradable protein (RDP) (65 vs 40% of CP) The RDP may improve the digestibility of nutrients (Khandaker and Tareque, 1997; Arroquy et al., 2004; Bohnert et al., 2011) The CP content of soybean meal ranges from 41 to 55% of the DM depending on processing technique Soybean meal has a higher EAA index compared to fish meal, 71 vs 68 (Michael, 1995)

However, the use of fish meal as a supplemental source of protein for animals has been limited, even banned in some countries in recent decades (Cooke and Nelson, 2001) Reasons for this include the relatively high cost of fish meal compared

to other sources, concerns related to the sustainability of fish stocks and the negative perception of feeding animals with protein derived from animal sources due to the mad cow disease crisis Vegetable protein sources such as soybean meal should be fed

as alternatives to fish meal Study II was therefore carried out to test if deoiled soybean meal, called soy cake, can be used as partial or full replacement of fish meal without any negative effects on animal performance during the growth phase of cattle Based on results obtained in Study II, the best soy cake to fish meal ratio was selected for use during the finishing phase of cattle in Study III

Beef cattle slaughter quality characteristics are affected by many factors such

as breed, sex, age, length of fattening period, and feeding regime (Purchas, 2003; Cuvelier et al., 2006b; Vu and Thanh, 2008; Warren et al., 2008) Beef quality characteristics are dependent on similar factors in addition to pre-slaughter handling, and ageing extent (Mandell et al., 1997; Purchas, 2003; Cuvelier et al., 2006a; Vieira

et al., 2007) However, breed may be considered as one of the most important factors affecting slaughter and meat quality of beef cattle Although cattle slaughter and meat quality may be affected by length of fattening period, different genotypes may respond differently to length of fattening period Study III was therefore conducted to

(3) To verify a hypothesis that different cattle genotypes (Laisind vs Yellow cattle) respond differently to the length of fattening on the same feeding regime (Study III)

3 Materials and Methods

Study I was conducted to investigate the current situation of beef cattle production at the farmer household level in Tuyen Quang and Vinh Phuc provinces, which represent the mountainous and lowland areas, respectively, in North Vietnam The three approaches used to collect data were participatory rural appraisal for baseline information, structured questionnaire, and secondary data collection for additional information The information from the participatory rural appraisal stage was used for the preparation of the questionnaire for the formal survey Two districts were selected from each province From each selected district, two typical communes were selected In each selected commune, 30 farms were randomly selected from the total list of household beef cattle farms In total, 240 household beef cattle farms were selected for the investigation Leaders of the selected farms were interviewed using the structured questionnaire The daily management practices were also observed and recorded The collected data were grouped as follows: (i) Household information including age, gender, ethnicity, and education level of the household leader, sources

of income, and farmland area; (ii) Farming system including cattle herd size, management system, breed of cattle, purposes of keeping cattle, breeding practices, coat colour preference, and time devoted to feeding out cattle; (iii) Feed and feeding

In Study II, the effect of different ratios of fish meal to soy cake as protein supplements on feed intake and performance of Laisind cattle fed URTRS as a basal diet was assessed

Thirty-six Laisind bulls at around 12 months of age, start weight 124±12 kg, were used in the experiment Following a 4-week adaptation period, a comparison period

lasted 24 weeks All the animals were given URTRS ad libitum, 4 kg elephant grass,

and 0.9 to 1.4 kg concentrate Diet A was the control diet with concentrate consisting

of equal amounts of whole cassava meal and corn meal only The other five diets (B

to F) were protein-supplemented diets consisting of the same level of CP (17 % of

concentrate) but different ratios of the two protein sources, viz fish meal with 64%

CP of DM and soy cake with 51% CP of DM, based on CP content as follows: diet A: 0/0; diet B: 100/0; diet C: 75/25; diet D: 50/50; diet E: 25/75; and, diet F: 0/100 Recommendations for the nutrient requirements for growing beef cattle in tropical countries (Kearl, 1982) were followed The animals were expected to gain 500 g/d The level of concentrate was adjusted every two weeks during the experiment period

to satisfy the need of CP and metabolizable energy (ME) An apparent digestibility trial was carried out during week 12 in the comparison period The measurements included feed intake, average daily gain (ADG), feed conversion ration (FCR), and apparent digestibilities of DM, CP, and crude fibre (CF)

Study III was carried out to compare the effect of length of fattening period on some slaughter and beef quality traits of Laisind and Yellow cattle fed URTRS as a basal diet A total of 18 bulls of Laisind and 18 bulls of Yellow cattle, both starting at around 21 to 22 months of age, with an average live weight of 209±13 kg and 139±13 kg, respectively, were allocated into 6 groups according to a 2x3 factorial design with two cattle genotypes and three lengths of fattening period (six weeks, W6;

ten weeks, W10; and fourteen weeks, W14) The animals were offered URTRS ad libitum and the same type of concentrate Recommendations for the nutrient

requirements for growing beef cattle in tropical countries (Kearl, 1982) were followed

in this experiment The amount of concentrate was adjusted every two weeks to cover the need of energy and protein for an ADG of 750 g/d Parameters measured were live weight, feed intake, FCR, ADG, carcass traits as warm carcass weight, dressing percentage, lean meat weight, percentage of lean meat, percentage of bone, percentage

of trimmed fat, and percentage of m longissimus dorsi (LD), and meat quality traits

as pH, drip loss, cooking loss, colour, shear force, DM, and intramuscular fat (IMF) content of LD

2956 m2) and spent more time for cattle feeding (7.3 vs 4.4 h/d in winter and 6.3 vs 4.1 h/d in summer, respectively) In a mountainous farm, cattle contributed more to the total cash income compared to a lowland farm, 12.6 vs 7.1%, respectively Most

of the farms (93%) were small-sized with one to five cattle each Local breed (Yellow cattle) was predominant followed by a crossbred genotype (Laisind cattle), 59.2 vs 38.3% respectively, whereas imported breeds accounted for a minority (2.6%) Dark coffee and yellow were the two most preferred coat colours (index 0.528 vs 0.438, respectively) The top four purposes of keeping cattle in a descending order were breeding cow, assets, manure, and meat (index 0.322, 0.204, 0.196, and 0.112, respectively) The natural mating with improved bulls was most commonly applied whereas the artificial insemination was not popular, 89 vs 11%, respectively The cattle were mainly (85% of the farms) fed by grazing of natural grass in combination with supplementation of crop by-products and concentrate The most common crop by-product was rice straw which was normally stored after being sun-dried No appropriate methods of crop by-products processing were applied Most of the farms (96 to 99%) faced shortage of feeds, especially forage during the winter from November to February All the marketed cattle were sold at farm to other farmers,

collectors, or traders The farmers considered the most important factors influencing beef cattle production in order of importance as capital, market price, feed, knowledge, and service Difficulty in capital was also usually encountered by most of

DM (FCRDM), ME (FCRME), and CP (FCRCP)by 30, 20, and 30%, respectively (all at P<0.001) There were no significant differences between diets B-F in the intakes, FCRs, and ADG The apparent digestibility of CP was 12 to 24% higher (P<0.001) in diets B-F than that in diet A There was a tendency that the apparent nutrient digestibilities were increasing with increasing level of soy cake in this study

4.3 Effects of length of fattening period on some slaughter and meat quality

carcass weight (133 vs 87 kg), percentage of bone (17.4 vs 19.4%); and in percentage of trimmed fat (4.8 vs 3.4%) There was neither significant difference between genotypes in percentage of lean meat nor percentage of LD The length of fattening period had no significant effects on ADG, dressing percentage, percentage

of lean meat, or percentage of LD No significant interaction was present for any of the slaughter quality traits There were no significant differences between genotypes

in any of the studied quality traits The length of fattening period influenced (P<0.05)

the pH, drip loss, cooking loss, and colour (a* values) at 8 days post-mortem; the shear force of LD 12 h (P<0.05), 48 h (P<0.001), and 8 days post-mortem (P<0.001);

DM content (P<0.01); and IMF content (P<0.001) The genotype by length of fattening period interaction existed for the IMF content (P<0.001)

5 General discussion

5.1 The current situation of beef cattle production at the farmer household level

in North Vietnam

According to FAO (2001), the farmland area per capita in the Red River Delta

is lowest among all regions of the country and the mountainous farmers generally own more farmland area than the lowland farmers In the current study, the difference between the two provinces in farmland area might partially explain the differences in some of the major characteristics of beef cattle production

Mixed crop-livestock production systems are popular in developing countries Economic activities in livestock in such a mixed production system are mostly undertaken by smallholders (Costales et al., 2007) In a study conducted in Son La province in Vietnam, Huyen et al (2010) reported that all of the surveyed household cattle farms kept other animals A similar result was found in the present work However, compared to the lowland province, the mountainous province had higher percentage of mixed farms, 97 vs 63%, and more types of animals per farm These differences may be due to differences in the natural conditions, especially feed resources, between the two provinces

respectively A majority of the herd were the local (Yellow) cattle, followed by the crossbred genotype Laisind (50% Vietnamese local Yellow cattle and 50% Sindhi,

both Bos indicus) Imported breeds were rare Breeding cows accounted for a highest

percentage in the herd This result is similar to those found in other studies (Hung and Binh, 2004; Duong, 2008)

The four top purposes of cattle raising were breeding stock (ranked highest), followed by assets, manure, and meat Nearly half of the respondents considered breeding cows to be the most important reason to keep cattle because of the higher profitability compared to other types of cattle A similar result was found in another study (Hung and Binh, 2004) Although draught power and manure production were not considered to be the first purpose of keeping cattle, most of the farms (218/240) mentioned manure production and nearly half (109/240) considered draught power to

be one of the main purposes This result is in agreement with a previous study by Huyen (2011) who reported that small farms in Son La province kept cattle mainly for draught power and manure production

Although more than half (56%) of the family members were the formal labour force (from 18 to 60 years old), most of the cattle grazing and feeding activities were undertaken by children (younger than 18 years) and old people (older than 60 years) Thus, cattle raising can be considered to be a means of social upliftment in addition to

a source of additional income of the family All the labour force involved was from the family members so that the farm did not employ external labourers This is in line with other studies (Nin et al., 2003; Costales et al., 2007)

Feeding of the cattle was mainly based on grazing of natural grass in combination with supplementation of crop by-products Among crop by-products, rice straw was most commonly used Rice straw was normally dried and stored Neither

silage nor alkaline treatment of straw was applied in the surveyed areas Meanwhile, most of the farms (96 to 99%) faced scarcity of feed during winter, mainly observed

in grass and crop by-products, including rice straw This implies that if appropriate methods of storage and processing of crop by-products were applied the shortage of feeds would be partially relieved

Huyen et al (2010) reported that most of the surveyed farms applied a controlled natural mating method for cattle, whereas artificial insemination accounted for a small proportion A similar result was found in the present work A great majority of the breeding bulls in the current study areas were of crossbred breeds, mainly the genotype Laisind, while imported breeding bulls were rare Reasons for not accepting artificial insemination with large-framed bulls were the unfamiliarity and the afraidness of calving difficulty and danger for cows due to potential big size

of calves This should be hindering genetic improvement progress in the local cattle population

The most important factors influencing beef production in order of importance were capital, market price, feed, knowledge, and production services However, knowledge was considered most important by the farmers in Tuyen Quang This might be due to the less opportunity for mountainous farmers to get access to training courses compared to other areas More extension activities, including farmer training, are thus warranted for the mountainous areas in the country

More than half (54%) of the farms expressed that they would not invest more

in cattle production mainly due to difficulties to get capital and lack of feed resources Only one fourth of the farms had loans from relatives and/or banks for cattle production and a similar number of farms were satisfied with the availability of capital Most of the loan was used to buy breeding calves If having easy access to low-interest credit sources, most of the farms (86%) would prefer investing in the crossbred cattle production This implies that in order to improve beef cattle productivity by promoting crossbred cattle, low-interest credit sources should be highly taken into account

5.2 Effects of replacing fish meal with soy cake in a diet based on urea-treated rice straw on performance of growing Laisind beef cattle

A forage based diet for ruminants when supplemented with protein sources is normally better balanced in amino acid composition and the absorption of protein is therefore enhanced leading to higher digestibilites of nutrients as compared to the non-supplemented diets (Sewell, 1993; Michael, 1995; Akey, 2011) In this experiment, the basal diet did not contain sufficient contents of CP and ME to satisfy

a minimum requirement for an ADG of 500 g/d according to Kearl (1982) and NRC (2000) When the basal diet was supplemented with the concentrate of diet A, which contained 6.8% CP, the CP content of the total ration was 9.1% of the DM which is lower than the requirement for an ADG of 500 g/d which is 11.3% of the DM (Kearl, 1982; NRC, 2000)

The cattle supplemented with protein gained 500 g/d as expected which was much higher than those not supplemented with protein (330 g/d) The cattle with

higher potential for production consume more feed In this study, the supplementation

of protein resulted in a higher intake of roughage, higher ADG, and lower FCR McCollum (1997) demonstrated that forage intake increased 30% by the dairy cow with supplementation of CP at 0.18% of the body weight Obeid et al (2006) reported that digestibility of CP increased linearly when the dietary CP level varied from 9 to 15% in diet for young Zebu bulls In a study on cattle grazing oats pasture, Arelovich

et al (2003) found that performance of animal is improved by supplementation of EP The protein-supplemented diets were similar in DM, ME, CP, and with only small difference in the estimated level of supplemental EP, between 4.0 and 6.8% of the

DM in concentrate This could explain the lack of differences between these diets in intake of URTRS, ADG and FCR which is in agreement with other studies (Michael, 1995; Polan et al., 1997; Wagner et al., 2010) Sewell (1993) reported that there was

no response from adding EP (blood meal and corn gluten meal) vs soybean meal to steers fed 1.4 kg corn grazing fescue pastures

The higher digestibilities of the DM in the protein-supplemented diets were due to the higher CP level compared to the control diet This result is supported by several studies such as those by Obeid et al (2006) and Valadares et al (1997) The tendency that the apparent nutrient digestibilities were increasing with increasing level of soy cake in this study might be explained by an increased concentration of RDP This is supported by other authors (Khandaker and Tareque, 1997; Arroquy et

with a study by Atwal and Erfle (1992) which showed no significant difference in digestibilities of DM, CP, and ADF between diets consisting of soybean meal (16% CP), fish meal (16% CP), and soybean meal plus fish meal (20% CP) for dairy cows

Due to the lower FCR in protein-supplemented diets, the feed cost expressed

as total expenditure for feed per kg live weight gain (LWG) was 20 to 35% lower compared to control diet 22000 vs 30000 VND/kg LWG, respectively This difference might be of importance for farmers or producers when adding protein to diet of growing cattle Due to a higher price of fish meal compared to soy cake, it was expected that the diets with more fish meal and less soy cake would be more costly than those with more soy cake and less fish meal However, the supplemental protein sources used in this study accounted for a small part of the total ration cost compared

to the other feeds The difference in feed cost was therefore small since there were no significant differences in FCR and ADG between protein-supplemented diets

5.3 Effects of length of fattening period on some slaughter and meat quality traits of bulls of Laisind and Yellow cattle fed urea-treated rice straw as roughage

The differences between Laisind and Yellow cattle in total DM intake, FCR, ADG, live weight, carcass weight, and lean meat weight are in line with other studies (Su and Binh, 2002; Cai, 2007; Trach et al., 2007) reporting that Laisind cattle in general are better than Yellow cattle in performance Higher total DM intake and intake of URTRS observed in Laisind were due to the bigger size compared to Yellow cattle However, when calculated as % of animal live weight, intakes of total DM and URTRS, as DM, were 20% and 40% higher respectively in Yellow cattle than in

Laisind This indicates that Yellow cattle have a higher relative feed intake capacity and are more adapted to eat low quality roughage than Laisind cattle The increasing

of FCR and tendency of decreasing ADG with increasing length of fattening period were also expected, although the differences between lengths of fattening period were not significant in the present study A slightly better feed utilization efficiency, as opposite to FCR, in Laisind compared to Yellow cattle might be an explanation for the small difference in ADG between the two genotypes The significant genotype x length of fattening period interaction for the total DM intake was due to the fact that the DM intake of Laisind increased whilst that of Yellow cattle decreased with increasing length of fattening period This might also explain the higher ADG of Laisind (920 g/d) compared to Yellow cattle (680 g/d) and higher than the expected (750 g/d)

An average live weight of 190 kg at slaughter and dressing percentage of 45.8% of Yellow cattle were higher than those (which was 155 kg and between 40 and 44%, respectively) reported by Cai (2007) and Trach (2007) This difference might be due to the better feeding in the present experiment compared to the previous works

Prolongation of the fattening period increased the live weight at slaughter and carcass weight but with little change of the dressing percentage The percentage of bone decreased whilst the percentage of trimmed fat increased with increasing length

There were no significant differences between genotypes in any of the beef quality traits in the present study This is in agreement with findings by Luc et al (2009) who did not find any significant difference between Laisind and Yellow cattle

in values of pH, drip loss, cooking loss, and colour values However, a significant

difference in shear force of LD at 48 h post-mortem between Laisind and Yellow

cattle was found in the reported study but not in the present study The difference of results concerning shear force between these two studies could not be clearly explained

The lower total drip loss and cooking loss at 8 days post-mortem in 10W (P

<0.05) compared to 6W might be explained by the higher DM content of 10W muscle relative to 6W There is a negative correlation between total cooking loss and tenderness according to Gullet et al (1996) This might be an explanation for the lower shear force value of LD in 10W compared to 6W

It is well documented that the content of IMF is increased when cattle are fattened longer (Alderson, 1994; Purchas, 2003; Bruns et al., 2005) The higher contents of IMF from cattle fattened for 10 weeks and 14 weeks compared to 6 weeks were expected and might partially explain the differences between these groups in the shear force The higher content of IMF which was found in 10W compared to 14W was unexpected and probably a result of the higher content of IMF of Yellow cattle in 10W compared to other five subgroups However, the highest content of IMF found in 10W of Yellow cattle could not be explained in this study According to Handley (2010), the marbling score of beef from young bulls is graded as “practically devoid” when the IMF content is less than approximately 3% That means LD from the cattle

in the current study was very lean This result is consistent with several other studies

(Seideman, 1985; Wheeler et al., 1994; Highfill et al., 2011), which have shown that

Bos indicus in general is leaner than Bos taurus breeds

The feed cost was similar for both Laisind and Yellow cattle (29000 VND/kg LWG) but increased slightly with increasing length of fattening period, from approximately 26000 to 29000, and further to 32000 VND/kg LWG for 6, 10, and 14 weeks, respectively Assuming that the price of feed as well as of beef did not change over time, the difference between feed cost to and income from one kg LWG would decrease with increasing length of fattening period due to increased feed cost However, a longer fattening period enhances the carcass weight and possibly improves some meat quality parameters In the present study, although 10W was lower than 14W in some of the slaughter quality traits, it may be compensated by the higher meat quality and the lower feed cost

6 Conclusions

It can be concluded from the survey that household beef cattle production in both mountainous and lowland areas in North Vietnam is generally extensive in small scales with few technical interventions applied There are therefore possibilities to improve beef production through genetic improvement programs, nutritional measures as well as improved production services and extension activities

With reference to Paper II, the conclusion is that supplementation of a low protein diet with protein sources improves feed intake and enhances the ADG of growing beef cattle, reducing the FCR and feed cost Since the ratio of fish meal to soy cake does not significantly affect feed intakes, ADG, FCR, and the apparent nutrient digestibilities of cattle, soy cake would therefore be able to be used as a partial or full replacement of fish meal in diet for growing beef cattle with a basal diet

of URTRS without any negative effects on animal performance

From Paper III, it is concluded that in order to improve slaughter and beef quality, Laisind cattle should be chosen rather than Yellow cattle The fattening period should be 10 weeks Grass could be replaced with URTRS as the main roughage in ration for fattening cattle if supplemented with a concentrate consisted of soy cake and/or fish meal with an appropriate CP content

7 Future perspectives

From the present work, a general view of household beef cattle production in the study areas was shown However, a comprehensive study on economics and value chain analysis involving all stages of beef production and marketing chain has not been carried out This is therefore an area for future research

In the cattle growing experiment, no differences found among the protein supplemented diets might be due to the small difference in protein composition, i.e

EP and RDP, among these diets Future studies on the effect of fish meal to soy cake ratios should try with larger differences in protein composition For example, an experiment should be carried out with diets of 20% CP (vs 17% in the present study)

in cattle fed untreated instead of urea-treated rice straw Different basal diets other than rice straw should be tested in similar experiments The cattle fattening study did not analyze the sensorial and nutritional qualities of meat These areas should be covered in future studies Both growing and fattening experiments were carried out using relatively small number of animals per treatment Future studies in growing and fattening cattle should include more animals per treatment This will increase the probability of detecting differences between treatments and therefore producing more

confidence in applying findings of experiments

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