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

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

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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

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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.

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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:

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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 croplivestock 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 smallsized 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

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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. Thirtysix male cattle of Laisind (50% local Yellow cattle and 50% Sindhi, both Bos indicus)
at around 12 months of age with an average live weight of 124±12 kg at start were
used in six groups of the experiment. Six diets named A, B, C, D, E, and F used in the
experiment were similar in CP level, except for diet A with no protein
supplementation, but different in fish meal/soy cake ratio 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,

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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.

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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.

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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

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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
(Yellow x Sindhi), ble kjøpt inn fra omkringliggende gårder og satt inn i forsøket ca
12 måneder gamle og med en startvekt på ca 124 ± 12 kg. Oksene ble tilfeldig delt
inn i seks forsøksgrupper kalt gruppe A, B, C, D, E og F. Alle oksene i hver gruppe,
med unntak av gruppe A, fikk proteintilskudd med likt innhold av råprotein, men med
ulik sammensetning, dvs ulikt blandingsforhold mellom fiskemel og soyakake .

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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

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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

Sluttfôringsperioden bør være 10 uker.

Laisind

brukes

framfor

Yellow.

Gras kan bli erstattet av ureabehandlet

rishalm som eneste grovfôr til sluttfôring av okser hvis fôrrasjonen blir supplert med
et kraftfôret som består av soyakake og fiskemel med et tilfredsstillende innhold av
råprotein.
Nøkkelord: Laisind, Yellow, tilvekst, sluttfôring, fiskemel, soyakake, kjøttkvalitet.

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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).

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Abbreviations

ADF

Acid detergent fibre

CF

Crude fibre

CP

Crude protein

CWE

Carcass weight equivalent

DM

Dry matter

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

IMF

Intramuscular fat

LD

m. longissimus dorsi

LWG

Live weight gain

MARD

Ministry of Agriculture and Rural Development

ME

Metabolizable energy

NIAH

National Institute of Animal Husbandry

NRC

National Research Council

NUFU

Norwegian Programme for Development, Research and Education

RDP

Ruminally degradable protein

UMB

Norwegian University of Life Sciences

URTRS

Urea treated rice straw

VND

Vietnamese Dong

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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

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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.
Prior to implementing any new techniques and methods to improve beef cattle
productivity and quality, knowledge and insights into the current situation of beef
cattle production are necessary. A first step in the present study was therefore a
survey of the current situation (Study I).

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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).

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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
test if Laisind and Yellow cattle respond differently to length of fattening period on
the same feeding regime.

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2. Objectives

(1) To investigate the current situation of household beef cattle production in North

Vietnam (Study I);

(2) 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 URTRS as a basal diet (Study II); and

(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).

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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
management system including feed resources, types of grazing land, feeding regimes,
processing techniques and storage for crop by-products and other sources of feed,
shortage of feeds by type and month; (vi) Marketing system for beef production; and,
(v) Influencing factors and constraints related to the beef production.

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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;

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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.

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4. Main results
4.1. The current situation of beef cattle production at the farmer household level
in North Vietnam

Results presented in Paper I show that most beef cattle (in 80% of the farms)
were kept in mixed crop-livestock production systems. Compared to a farm in the
lowland area, a farm in the mountainous area owned a larger farmland area (8365 vs.
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,

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