UNIVERSITI PUTRA MALAYSIA

GASTROINTESTINAL PARASITISM IN GOATS - BIONOMICS OF THE SUPRAPOPULATION AND INCIDENCE IN YOUNG GOATS

DAUD AHMAD BIN ISRAF ALI

FPV 1991 3

GASTROINTESTINAL PARASITISM I N GOATS - BIONOMICS OF THE S UPRAPOPULATION AND INCIDENCE IN YOUNG GOATS

By

DAUD AHMAD BIN ISRAF ALI

A Thes is Submitted in Fulfilment of the Requirements for the Degree of Master of Science in theFaculty of

Veterinary Medic ine and Animal Sc ience , Universiti Pertanian Malaysia .

November 1991

ACKNOWLEDGEMENT

The constant encouragement and c omments given by my

supervisor , Dr . Rehana Abdullah Sani is s incerely appreciated .

A warm thanks to Dr . Ridzwan Abd . Halim who not only helped a

lot with the s tatistical analys is of data but also provided the

experimental plots . A special thanks to Dr . Zamri Saad for

diagnos ing the causes of death .

Throughout the course of the work Dr . Ali Raj ion ,

En . Sharifuddin and the staff of the univers i ty's Small Ruminant

Unit have been very helpful in providing the goats for the

study . En . lslahuddin has worked very hard to maintain the

experimental plots . A special thanks to all of you .

I would also l ike to thank Mr . Lee Chu Chong , Bohari

Yaacob , Nuzolazuan I shak and Rosli Malek from the faculty ' s

paras itology laboratory and Dr . Frank Jackson from Moredun

Research Institute , U . K for their kind assistance and comments .

My s incere gratitude to the Dean of the faculty , Prof . Latif

Ibrahim for providing research faci l ities and financial

suppor t .

Last but not least a spec ial thanks to my parents , my

wife , Imah and son , Faisal who have been a source of

inspiration throughout the c ourse of study .

ii

PREFACE

This thesis comprises two parts . Part 1 describes the

testing and further modification of the Modified Parfitt ' s

Technique (MPT) which is used to recover and enumerate

infective larvae from herbage . An assessment of the

concentration of infective nematode larvae on pasture herbage

gives an indication of the infection to which graz ing animals

are exposed . The technique was then tested under field

condit ions to study the survival of infective trichostrongyle

larvae . An experiment aimed at determining the rates of

development of the various preparas itic stages i s also

included . Part 2 i s a study on the inc idence and significance

of gastrointestinal parasites in goats from b irth to nineteen

months old .

iii

TABLE OF CONTENTS

PERPUST AI<AAN UNIVERSITI PERTAN1AN MALAYSIA

Page

ACKNOWLEDGMENT i i

PREFACE iii

LIST OF TABLES iv

LIST OF FIGURES vi

ABSTRACT

ABSTRAK

CHAPTER

I

II

PART 1. BIONOMICS OF THE FREE- LIVING STAGES OF GOAT TRICHOSTRONGYLES

INTRODUCTION

LITERATURE REVIEW

Technical aspects in the Recovery of Infective Nematode Larvae from Herbage

General

Herbage Sampl ing

Separation of Larvae

vii

x

1

3

3

3

5

from Herbage . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Separation of Larvae from Debris . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Microscopical Examination of Larvae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Conditions in Microhabitats 16

Faeces 16

Soil , Mat and Herbage 20

I I I

IV

V

The Effect of Cl imate upon Development and Survival of Free-l iving Stages o f Trichostrongyles . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2

MATERIALS AND METHODS 31

The Modified Parfitt ' s Te�hnique 3 1

Spiking of Grasses 3 3

Infective Larvae 3 3

Experimental Procedures 34

Validation o f the Modified Parfitt ' s Technique 34

Improvement o f the Modified Parfitt ' s Technique . . . . . . . . . . . . . . . . . . . 3 7

Survival o f Larvae on Grass Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Development of Preparasitic Stages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

RESULTS 41

Validation of the Technique 41

Field Trial 41

Larval Loss 41

Laboratory Trials 43

Improvement of the Technique 43

Initial Modifications 43

Further Modifications 47

Survival on Grass Plots 47

Larval Development 49

DI SCUSSION 51

The Modified Parfitt ' s Technique and its Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

I

I I

I I I

IV

Preparasitic Development of Haemonchus con tortus . . . . . . . . . . . . . . . . . . . . . . . 59

PART 2. INCIDENCE OF GASTROINTESTINAL PARASITES IN KIDS

INTRODUCTION

LITERATURE REVIEW

The Malays ian Goat Industry

Effects of Gastrointestinal Paras itism upon Productivity

Helminthoses in Goats

Coccidioses in Goats

Interpretation of Faecal Egg Counts

MATERIALS AND METHODS

Animals

Samples and Laboratory Techniques

Data Analysis

RESULTS

Incidence of Paras ites

Prevalence of Paras ites

Liveweight Gain

Causes of Death and Worm Counts

Relationship between Faecal Egg Counts and Total Worm Counts

Changes in Worm Populations and

62

64

64

66

68

72

77

84

84

85

86

8 9

8 9

9 4

9 7

9 9

102

Fecundity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 02

Relationship between Faecal Egg/Oocyst Counts and Age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

v DISCUSSION 109

Gastrointestinal Tract Paras ites 109

Significance of Gastrointestinal Parasitism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

Relationship between Worm and Faecal Egg Counts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

BIBLIOGRAPHY 126

APPENDIX 139

A Means and S tandard Deviations of

VITA

Variables from all Goats . . . . . . . . . . . . . . . . . .

B Means and Standard Deviations of Variables from the Goats that Survived throughout the

139

Study Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

C Means and Standard Deviations of Variables from the Goats that Died throughout the Study Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

144

Table No .

1

2

3

LIST OF TABLES

Assessment of Mean Larval Los s by the MPT using Panicum maximum Spiked with 300 L3 . . . . . . . . . . . . . . . . . . . .

Validation of the MPT on Various Grasses Spiked with 200 L3 . . . . . . . . . . . .

Validation of the MPT on Various Grasses Spiked with 300 L3 . . . . . . . . . . . .

4 Initial Modifications to the MPT and Recovery Rates using Digi taria setivalva Spiked

Page

42

44

4 5

with 200 L3 . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6

5 Further Modifications to the MPT and Recovery Rates from Panicum maximum, Setaria spl endida and Digi taria setivalva Spiked with 200 L3 . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

6

7

Recovery Rates of the MPT us ing Lukewarm water from Panicum maximum, Setaria splendida and Digi taria setivalva Spiked with 200 L3 . . . . . . . . . . . . . . . . . . .

Mean Interval for Development of Preparas itic S tages of H . con tortus under Three Different Grass Species . . . . . . . . . . . . . . . . . . . . . . . .

8 Percent Prevalence of Gastro­intestinal Paras ites in Goats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9 Distribution of Causes of Death

10

and Mean Worm Counts

C orrelation Analysis between Egg and Worm Counts , Haemonchus and Trichostrongylus Counts , and Egg Counts and TPI . . . . . . . . . . . . . . . . . . .

iv

48

50

9 8

101

103

1 1 Correlation Analysis between Egg/ Oocyst Counts and Age of Animals at Various Age Groups after Logarithmic Transformation of Counts [Log10 ( x+l ) ] . . . . . . . . . . . . . .

v

108

Figure No .

1

2

3

4

5

6

7

8

LIST OF FIGURES

Inc idence of Strongyles among Kids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison of Strongyle Egg Counts between Kids that Survived and thos e that Died . . . . . . . . . . . . . . . . . . . . .

Incidence of Coccidia among Kids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison of Oocyst Counts between Kids that Survived and those that Died

Incidence of Moneizia among Kids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison of LWG Between Animal s that Survived and those that Died . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison of Worm Burdens at Various Age Intervals . . . . . . . . . . . . . . .

Comparison of Mean Egg Production per Female Worm at Various Age Interval s . . . . . . . . . . . . . . . . . . . . . . .

vi

Page

9 0

9 2

93

95

96

100

105

106

Abstrac t of thes is submitted to the Senate of Univers iti Pertanian Malaysia in fulfilment of the requirements for the degree of Master of Science .

GASTROINTESTINAL PARASITISM IN GOATS - BIONOMICS OF THE SUPRAPOPULATION AND INCIDENCE IN YOUNG GOATS

By

DAUD AHMAD ISRAF ALI

NOVEMBER 1991

Supervisor Dr . Rehana Abdullah Sani

Faculty Veterinary Medicine and Animal S cience

The Modified Parfitt's Technique (MPT) is used to assess

the concentration of infective nematode larvae on pas ture which

gives an indication of the infection to which grazing animals

are exposed . Validation of this technique showed that it was

not successful when applied in the field and variation in

results occurred among different grass species . Using Panicum

maximum (Guinea ) , Setaria sphace la ta var splendida ( Setaria)

and Digi taria setivalva (Mardi Digit) grasses , modifications

were introduced to improve the larval recovery rate . The

soaking of herbage in lukewarm water ( 3 8oC ) instead of tap

water increased the recovery rate s ignificantly without

variation between the three grasses tested .

vii

Us ing this improved MPT , plot trials were conducted to

assess the longevity of third-stage larvae (L3 ) of goat

trichostrongyles under the forementioned grass leys . However

the technique failed to recover any L3 . Reasons for this were

low number of larvae , rainfall , and larval - grass/debris

adherence . There is a need for further investigation into thi s

technique .

S tudies were also conducted to establish the moulting

t imes of the pre-parasitic s tages of H . con tortus under the

three grass leys . Development to Ll and L2 took the same time

under the various grasses . Development time to L3 , however , was

longest under Mardi Digit followed by Setari a and Guinea . The

lower temperatures under Guinea aided a more rapid development

compared to the other grass species .

In order to establish the incidence and significance o f

gastrointestinal parasitism among kids , faecal samples and

l iveweights were obtained weekly for seventy-nine weeks from

forty - s ix newly born kids kept under a semi-intensive

management . S trongyle infections were detected from two months

of age and coccidia from one month . The strongyles were

identified

Infection

as

with

Haemonchus and Trichos t rongylus spec ies .

strongyles and coccidia was continuous

throughout the study period. Patent infec tions with Moni ezia

viii

occurred at eleven weeks of age and c ontinued until thirty ­

eight weeks of age .

Comparisons of egg/oocyst output and l ivewe ight gain (LWG)

of animals that survived and those that eventually died showed

a significant difference in egg output and LWG but not in

oocyst output . The prevalence of paras ites was moderate in kids

below three months of age and high among those above thre e

months . The poss ibility of reduced average daily gain (ADG) due

to paras ites was evident and the combined effects of

H.contortus and T . colubriformis significantly increased

mortality rate among the animals .

Egg and worm counts were positively correlated except for

T . colubriformis counts among animals above s ix months of age .

The use of the " total pathogenic index" (TP I ) as a diagnostic

measure is of valuable significanc e . Correlation analys is

showed suppression of eggs and oocyst production after twelve

and six months of age respectively , suggesting acquis ition of

immuni ty .

ix

Abstrak tesis yang dikemukakan kepada Senat Univers iti Pertanian Malaysia bagi memenuhi syarat - syarat ij azah Mas ter Sains.

PARASITISME GAS TROUSUS PADA KAH�ING - BIONOMIK S UPRAPOPULASI DAN INSIDENS PADA KAHBING MUDA

Oleh

DAUD AHMAD ISRAF ALI

NOVEMBER 1991

Penyelia Dr . Rehana Abdullah Sani

Fakulti Kedoktoran Veterinar dan Sains Peternakan

Teknik Modified Parfitt's (TMP) didapati tidak berj aya

mencapai matlamatnya apabila digunakan di l adang dan terdapat

perbezaan dalam keputusan apabila spesies rumput yang berlainan

digunakan .

Pengubahsuaian ke atas teknik ini dengan menggunakan

spesies - spesies rumput Pan icum maximum ( Guinea) , Setaria

sphacela t a var splendida ( Setaria) dan Digitaria setival va

(Mardi Digit) menunj ukkan peningkatan peratus perolehan yang

bermakna tanpa perbezaan di antara ketiga- tiga spe s ie s rumput

telah tercapai dengan merendam rumput di dalam air suam (38°C).

Ujikaji-ujikaj i plot dengan menggunakan TMP yang

diubahsuai , gagal mengesan larva daripada rumput. Di antara

x

sebab - sebab kegagalan ini adalah bilangan larva pada rumput

yang terlalu sedikit , huj an yang lebat dan kesukaran memisahkan

larva daripada rumput .

Kaj ian untuk menentukan j angkamasa perkembangan peringkat­

peringkat pra -paras itik cacing H . contort us di bawah rumput ­

rumput pastura menunj ukkan peringkat Ll dan L2 mengambi l masa

yang sarna di bawah rumput - rumput tersebut . Perkembangan kepada

L3 mengambil masa paling lama di bawah Mardi Digit di ikuti

dengan Setaria dan Guinea. Suhu persekitaran yang lebih rendah

di bawah rumput Guinea membantu mempercepatkan perkembangan .

Dalam kaj ian ins idens dan kepentingan parasitisma

gastrousus pada anak- anak kambing , infeks i - infeks i s trongil

dikesan s ej ak umur dua bulan dan koks idia sej ak satu bulan .

Strongil - strongil dikenalpasti sebagai spesies Haemonchus dan

Trichostrongylus . Infeks i dengan s trongil dan koks idia

berlarutan sehingga tamat tempoh uj ikaj i . Infeks i - infeks i paten

dengan Honiezia dikesan pada umur sebelas minggu dan berterusan

sehingga umur tiga puluh lapan minggu .

Perbandingan hasilan telur cacing dan peningkatan berat

badan antara haiwan-haiwan yang hidup dengan yang telah mati

dalam tempoh uj ikaj i menunjukkan perbezaan yang bermakna . Tidak

terdapat perbezaan di antara kedua - dua kumpulan haiwan ini dari

segi has ilan oosista koksidia .

xi

Prevalens parasit sederhana pada anak- anak karnbing di

bawah urnur tiga bulan dan tinggi selepas urnur ini . Kernungkinan

berkurangnya purata pertambahan berat harian disebabkan kesan

paras i t telah ditunjukkan dan kornbinasi kesan-kesan H . con tortus

dan T . colubriformis rnengakibatkan kadar kernatian yang berrnakna .

Kiraan telur pada t inj a dan bilangan cacing pada saluran

gastrousus telah rnenunjukkan korelas i positif . Bagairnanapun

bagi T . colubri fo rmis, tidak terdapat korelas i di antara kedua ­

dua pernbolehubah ini bagi haiwan-haiwan yang berumur l ebih

daripada enam bulan . Penggunaan " indeks j urnlah patogenik" ( IJP)

sebagai ukuran diagnosis didapati arnat berkesan . Analisa

korelasi j uga telah rnenunjukkan pengurangan penghas ilan telur

cacing dan oosista koksidia dalarn tinj a karnbing- karnbing rnasing­

rnas ing selepas rnencapai umur dua belas dan enarn bulan . lni

rnenandakan kehadiran pelalian perolehan .

xii

PART 1

BIONOMICS OF THE FREE- LIVING STAGES OF GOAT TRICHOSTRONGYLES

CHAPTER I

INTRODUCTION

The Malays ian small ruminant industry is suffering losses

due to trichostrongylid infections , mainly haemonchosis . One

of the main options of controll ing trichostrongylosis is

grazing management s ince pastures on which animal s graze are

considered as a centre for the dispersal and exchange between

sheep and parasite populations (Crofton , 1971). For this , the

bionomic s , that is factors affecting the development and

survival of the suprapopulation ( free - living population) of

trichostrongyles has to be known .

There is virtually no s tudy reported on the bionomics of

trichos trongyles in the humid tropics . The findings in other

climatic regions cannot be applied to the humid tropics . Hence

this part of the s tudy was devoted to the bionomics of free ­

living s tages of trichostrongyles .

The first obj ective was to assess a widely acceptable

technique , the Modified Parfitt ' s Technique , used for the

recovery of third s tage trichostrongyle larvae from

herbage . Modifications , where found necessary , were applied

to the initial technique . The second obj ective was to apply

this technique to field conditions to es timate the survival

time of goat trichos trongyle larvae under three different grass

1

2

leys . The third obj ective was to determine the hatching and

moulting times of

grasses .

Haemonchus contortus eggs under these

General

CHAPTER II

LITERATURE REVIEW

Tec hnica l Aspects in t he Recovery of I nfective Nematode Larvae from Herbage

The es timation of larval populations of trichstrongyles

on pasture has become a common means of monitoring the risk of

infec tion in Europe ( Cabaret et a 1 . , 1986) . Various me thods

for the recovery , differentiation and enumeration of infective

larval s tages found on herbage have been described (Taylor ,

1939 ; Crofton , 1954 ; Donald , 1967; Heath and Maj or , 1968 ;

Bawden, 1 969 ; Heath et a1., 1970 ; Lancaster , 1970 ; Smeal and

Hendy , 1 97 2 ; Armour , 1982 ; Lee and Ikeme , 1985 ; Gettinby et

a1 . , 1 98 5 ; Cabare t et al . , 1986 ) .

According to Gettinby et a1 . ( 1 985 ) , there are three

currently used methods to assess the concentration of infective

larvae of parasitic nematodes on pasture . The first methdod

describes a technique by which recovery , enumeration and

identification of infective larvae could be achieved by manual

sampling of herbage ( Taylor , 1939) . Another method i s the

graz ing method using either animals free o f paras ites ( Tetley ,

1 9 5 9 ) o r rendered free by the use of anthelmintics (Anderson ,

1 97 3 ; Armour , 1982 ) . These animals , usually re ferred to as

" tracers" are slaughtered s oon after completion of grazing and

3

4

their worm burdens analysed . The third method , described by

Heath et a1 . ( 1970) uses oesophageal fistulated animals to

collect herbage samples .

Bawden ( 1969) was abl e to obtain a mean recovery of 90 . 4%

with his apparatus . However as stated by Smeal and Hendy

( 1972 ) , the cost o f the sieve and filtering apparatus would

prohibi t its constant use . Parfitt ( 1955) reported that when a

known number of larvae was p laced on grass , his technique

yielde d an average of 43% . Durie ( 1959) tested his technique by

adding known numbers of l arvae to sediment obtained by washing

samples of pasture which were free of infective larvae .

Recoveries ranged from 61% to 94% with an average of 74% .

Gettinby et a1 . ( 1985) observed a three to nine fold

increase in recovery rates from oesophageal fistulated animals

compared to manual sampling . However Cabaret et a1 . ( 1986 )

observed that ewes ingested on average less infected herbage

than would be predicted from a random sample collected on

pasture.

It is acceptabl e that throughout the labourious, time

consuming process of separating larvae and subsequent

enumeration , there will be a considerable loss of larvae .

However these losses can be minimized by modification of the

current techniques . In general the techniques employed in the

5

recovery of infect ive

aspects :

nematode larvae combine four major

* Sampling of the herbage

* Separating the larvae from the herbage

* Separating the larvae from the debris

* Microscopical examination of the larvae

Herbage Sampling

The first and mos t important aspect in recovering

infective nematode larvae is the sampling of the herbage . The

method employed should be able to pick up as many infective

larvae as poss ible . Various methods of sampling herbage have

been described . Taylor ( 1 9 3 9 ) preferred a double z igzag ( "W" )

fashion and collections made at about one hundred different

places by pinching two or three pinches of grass from four

places at each spo t . Plucking should be as close to the ground

as pos s ible without uprooting the grass .

Lee and Ikeme ( 1985) only used a single zigzag and

collection made at every fifth s tep . They preferred cutting

the top c lusters of herbage in front and on both s ides so as to

s imulate the graz ing behaviour of the animals . Smeal and Hendy

( 19 7 2 ) preferred to follow Taylor ' s method . Lancas ter ( 1 9 7 0 )

also preferred Taylor ' s method but s tated that "N " shaped

transects are more convenient for a single collector . He s tated

6

that there was no apparent di fference between results obtained

by either method of sampl ing .

According to Crofton ( 19 54) , Taylor ' s method , in theory ,

was inefficient due to the low number of traverses . He claimed

that only if larvae were numerous and randomly distributed

would Taylor ' s method be sufficient . However , larvae are

ne ither numerous nor randomly distributed in relation to the

total number of pinches . Therefore , it seems obvious that the

samples must be either greatly increased in number or s ize ,

which in either case increases bulk and makes the recovery more

difficult ( Crofton , 1954) .

The various methods for the recovery of infective

larvae have been subj ected to various tests in order to

validate the technique . However , mos t of the workers (Donald ,

1967 ; Heath and Major , 1968 ; Bawden , 1969 ; Lancaster , 1970 ;

Smeal and Hendy , 197 2 ; Lee , 1985) based their results on

" spiked" herbage (herbage to which larvae have been added after

sampling) and not with natural populations . They did not take

into account the effec t of grass characteristics upon recovery

rates .

Bawden ( 19 6 9 ) was able to obtain a high recovery rate with

his apparatus but again , his results were based on " spiked"

herbage and he failed to mention an appropriate herbage

sampling me thod. Therefore , it is expected that his technique

7

would give a low recovery rate if the herbage contained

natural populations of larvae . This is due to the fact that

there is a closer association between natural larval population

and debris particles ( Lancaster , 1970 ; Lee , 1985} .

Bryan and Kerr ( 19 88) concluded that manual pasture

s ampling based on observed grazing behaviour seems the only

method which mee ts all criteria . Lee and Ikeme ( 19 8 5 ) also

noticed the importance of manual sampling and tried to s imulate

animal grazing habits . Generally it has been accepted that from

the s ingle plant , sheep and cattle eat leaf in preference to

s tem (Arnold and Dudzinski , 1 978) and goats tend to nibble at­

the shoots and leaves of growing plants and rejec t the s tems

( Devendra and McLeroy , 1982 ) .

Since ruminants are selective in their grazing hab i ts ,

the importance of contamination and availability of infective

larvae has been recently highlighted .

claimed that sampling herbage us ing

Gettinby et a1 . ( 1985)

oesophageal fistulated

sheep gave a three to nine fold increase in infective larvae

recovery compared to manual collection through a zig- zag

route. However , Morley and Donald ( 1980) s tated that the

c ontamination of the pasture with infective larvae may s imulate

availability after a single shower of rain .

According to Gettinby et a 1 . ( 19 85 ) , manual collection of

herbage leads to substantial underestimation . Therefore the