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SOME ASPECTS OF THE HOST-PARASITE RELATIONSHIP BETWEEN GOATS AND GASTROINTESTINAL NEMATODES
A t h e s i s presen ted i n parti a l fu l fi l m e n t o f the requ i re m e n t s fo r t h e d egree o f Docto r o f Phi l o s ophy i n Veteri n a ry Sci e n ce a t M a s sey U n iversity
Wi l l i am Ern est Pomroy 1 9 94
1 1
ABSTRACT
Experi m e nts were conducted i nvestigat i ng t h e acqui s i t i o n , by goa t s , o f r e s i stance to Ha em onchus con tor/us a n d Trich ostron gylus colubriform is . N e i t h e r 5 .5 o r 1 4 m o n t h s o l d S a a n en goats given a t ri ck l e i n fection with H. con t ortus, which was t e rm inated with anthelmintic aft e r 10 and 1 4 weeks respectively, show e d signi ficant resi stance to a challenge i n fect i o n . Serum pepsi nogen l evels rose signi fica n t ly as a result o f i n fect i o n . Se rum gastrin levels also rose as a r e s u l t o f i n fection b u t, fol lowi ng challenge, were g e n e ra l ly higher fo r n aive goats than previous ly i n fecte d goats. There were no signi ficant corre l a t ions b etween worm counts, gastrin and peps i nogen l ev e l s a t the t i m e o f slaughter.
By con t rast, a h i g h level of resista nce to T. c olu briformis d evelop e d in 9 m o nths old Saanen goats given t rickle and two cha l l enge i n fect i o n s . Goats expo s e d only to t h e two chall enge i n fect i o n s d eveloped worm b u r d e n s i n t e rmediate b e twee n , a n d signi ficantly d i fferent from b o t h trickle - i n fecte d a n d previously u n i n fecte d goats given j u s t t h e s e c o n d challenge. Both pri m i ng i n fections were removed with anthelm i ntic. Globule l e u kocyte ( GL) cou n t s i n t h e proximal s m all i ntes t i n e of trickle - i n fecte d goats were signi ficantly h i gh e r t h a n i n goats given a s i ngle challenge i n fecti o n , w h i lst cou n t s for the group given two chall e nge i n fections were i n t e r m e d i a t e a n d n o t significantly d i ffe re n t fro m o t h e r treatments. Nematode fecun d i ty ( eggs p e r fem a l e ) a n d m al e : fe m a l e r a t i o s were also sign ificantly decreased i n the previo usly i n fected goats.
Ninety four percent o f a l l T. colubriform is w e r e fou n d i n t h e proxi mal 5 0 % o f t h e s m all i n t e s t i n e i n both young goa t s a n d older goats . Male : fe m a l e r a t i o s i ncreased a n d eggs/female nematode d ecreased w i t h distance down t h e s m a l l i n testi n e . Only a b o u t 50% of adult T. colubriform is w e r e recovered from
\
recently k i l l e d goats by opening and m assaging t h e small i nt e s t i n e u n de rI, r u n n i ng wate r .
Antipa ra site activity of intestinal m u c u s from groups o f Angora-cross goats k i l l e d 9, 18 or 2 7 days after i n fection wi t h T. colubriform is , i ncreased s i g n i fi cantly i n infect ed versus uninfected goats w i t h no d i ffe rence b e tween i n fected groups. However, the estab l i s h m e n t rate (57-67 % ) s uggests l i t t l e i m m u n i ty w a s b e i ng expressed. Following i n fect i o n , p roxi m al s m a l l i n t e s ti n a l GL cou n t s fel l wit h t i m e b u t t h e re w a s stil l a c l e a r negative relation sh i p b e tw e e n GL counts a n d w o r m b u rdens. M ucos a l m ast c e l l a n d eos in o p h i l c o u n t s s howe d no signi ficant t re n ds relat ive t o d u ra t i o n o f i n fection o r w o r m
111
b ur d e n . D i fferential cell cou n t s were m ade u s i n g a monoclonal a n t i b o dy to s h e e p m as t cells developed with d i a m i nob e nzi di n e , com b i n e d wi t h h a e m atoxy l i n a n d B i e b ri ch's scarlet. This m e thod was shown to be superior t o o t h e rs t r i e d . I n Angora-cross goats k i l l e d s e q u e n t i ally aft e r removal o f an i n fecti o n wi t h T.
colu briform is, proxi m a l small i n t estinal GL counts increased w i t h t i m e . However, a n t i parasi te activity o f i n testi n al m u c u s was con s i s tently low. GL cou n ts in all t h ese Angora -cross goats were g e n erally higher fu rther down t h e i n t e s t i n e b eyond t h e location of a l a rge propo rtion o f t h e T. colu briform is b u rd e n .
I n Ango ra g o a t s fitted wi t h ileal can n ulae and i n fect e d w i t h T.
colubriform is , antiparasite activity o f ileal con t e n t s i ncreased signi fi ca ntly w i t h t i m e aft e r i n fection i n a l l goats. H oweve r, t h e e s t a b l i s h m e n t r a t e ( 1 0 . 6 - 6 1 .8 % ) i n dicated o n ly a moderate degree o f resi stance was b e i ng expressed a l t h o ugh a l a rge proportion of established worms were i nh i b i t e d L3 s .
IV
ACKNOW LE D G E M E NTS
Th e exp e ri m ents d escri bed i n t h i s thesis a n d the· preparation o f t h i s t h e s i s cou l d not h a v e b e e n completed w i t h o u t t h e h e l p of many p e o p l e . I w o u l d l i ke t o t h a n k :
T h e Vice-Ch a ncellor a n d U n iversity Cou ncil for permission t o u n d e r take t h i s s t u dy whilst a m em b e r of staff;
Associate-Pro fessor W.A . G . Charlesto n fo r his i nva luab le a dvice, e n cou ragem e n t and patience throughout the experim ental work and preparation o f t h i s thesis;
Professor B . W. M a nktelow fo r the oppo r t u n i ty to u n de rtake t h i s s t u dy whilst a member of s t a ff a n d for his advice d u r i ng t h e preparation o f this t h e s i s ; M s B . C . Adl ington a n d Miss S . M . Cal d e r for t h e i r extensive tec h n i cal h elp, particula rly w i t h wo rm and egg counting, and w i t h animal care;
D r P. G . C . D ouch for supply o f isolates o f Ha emonch us con tortus and Trich ostrongylus colubriformis, a n d the s heep m ast cell m onocl o n a l a n t i bo dy ( C8 ) ;
D r G . W. Reyno l d s a n d D r C. Rei d for s u rgery t o i nsert t h e i l eal can n u l a e M r R . J . S h aw fo r advice o n i m m u n ocytochem i s t ry;
Mrs P. Slack and Mrs P. Davey for assistance w i t h preparation o f h i s tological material;
D r H . Va rela-Alvarez and Professor R . M un fo r d fo r statistical a dvice ;
Mrs A. Scott fo r secretarial assistance, p a rticula rly thesis layou t a n d p r i n t i ng .
I acknowle dge, w i t h t hanks, the fi n ancial assistance of the C . A l m a B a k e r Trust, T h e Riverside Farm Research F u n d , Th e S m i t h Kli n e Ani m al H e a l t h Fou n dation a n d the Massey University Research Fun d . Wi thout thei r h el p t h i s resea rch w o u l d n o t h ave been possib l e .
Special t hanks t o m y wife L i n d a a n d m o r e recently my son Ti m o thy for t h e i r love a n d tolerance d u ri ng the period o f t h i s study.
TABLE O F C O NTE NTS
ABSTRACT
ACKNOWLEDGEMENTS TABLE OF CONTENTS LIST OF FI GURES LIST O F TAB LES
C h a p t e r O ne : I nt rod u c t i o n and l i t e ratu re revi ew 1 . 1
1 . 2
1 .3
1 .4 1 . 5
Gastroi ntesti n a l nematode i n fect i o ns i n goats 1 . 1 . 1 Nematode speci es i n fecting goats
1 . 1 .2 Development of resistance to gastro i n te s t i n a l n e m atodes 1 . 1 .3 The effect o f n u t ri t io n
1 . 1 .4 Compari son b e tween s h eep a n d goats
1 . 1 .5 Peripa r t u r i e n t relaxat i o n o f resistan ce ( PPR)
The developm e n t of resi stance to Ha emonchus con tortus i n s h e e p 1 .2 . 1 Th e effect o f age
1 .2 . 2 T h e e ffect of genetic facto r s 1 .2 . 3 E ffect o f n u t rition
1 .2 . 4 " S e l f-cure"
1 .2 . 5 Population dynamics
The develop m e n t o f resistance to Trich ostron gylus colubriform is i n sheep
1 .3 . 1 The effect o f age
1 .3 . 2 The e ffect of genetic factors 1 .3 . 3 The effect of n u t r i t i o n 1 .3 . 4 Population dynamics T cells
Eosinophils
1 .5 . 1 I n t roduction
1 .5 . 2 I n fla m ma t o ry m e diators
1 .5 . 3 Eosinoph i l modulat i o n o f i nfl a m m ation 1 .5 . 4 P henotypic heterogene i ty
1 .5 . 5 Anti-hel m i nth activity
1 .5 . 6 Eosinophil responses in rum inants with gastro i n t e s t i n a l n e m atodes
Page
1 1
IV
v
IX
x i i 1
1 1 2 3 3 5 5 5 6 7 7 8
1 0 1 0 1 1 1 2 1 2 1 5 1 6 1 6 1 7 1 7 18 18 1 9
1 .6 Mast cells 20
1 . 6 . 1 I ntroduction 20
1 . 6 . 2 P h e n o typic h e te roge n e i ty 2 1
1 . 6 .3 Fixati o n and staining 24
1 .6 .4 Mast cell proliferation a n d d i ffe re n t i a t i o n 2 5 1 .6 .5 Tem p o r a l relationships b e tween m astocytosis a n d
n e m a t o d e i n fections 26
1 . 6 . 6 M a s t cell protease release 2 8
1 . 7 Glob u l e leukocytes 29
1 .7 . 1 I nt ro d u ction 2 9
1 . 7 . 2 Morphol ogy 2 9
1 . 7.3 D e rivation 2 9
1 . 7.4 Association o f glob u l e l e ukocytes with mast cells i n
the response to n e m atodes 30
1 . 8 The l e u kotri e n e s 3 1
1 .8 . 1 I n t ro duction 3 1
1 . 8 . 2 B i o logical activity 33
1 . 8 . 3 Anti-nem atode activity 33
1 . 9 Biogenic a m i n es - histamine and 5-hydroxy t ryptam i n e 3 5
1 . 1 0 Prostaglandins 37
1 . 1 1 Platelet-activating factor 37
1 . 1 2 Mucus t rappi ng 3 8
1 . 1 3 Specifi c i ty o f n ematode expulsion 39
1 . 1 4 Hypoth e s i s fo r worm expulsion 40
C h a p t e r Two : Fa i l u re o f young goats t o a c qu i re re s i stance to Haemonchus contortus
2 . 1 2 .2 2 .3 2 . 4
I nt ro d u ction
Materi als and m ethods Results
D iscuss i o n
42
42 42 46 5 9
C h a p t e r Three: Deve l o p m e nt o f re s i sta nce to Trichostrongylus colubriformis
g o a t s (Ex p e ri m e n t 3 . 1 ) 6 6
3 . 1 I nt roduction 66
3 .2 M a t e ri a l s a n d m ethods 66
3 . 3 Results 6 8
3 .4 D iscussi o n 72
C h a p t e r Fo u r: The d i st r i b u t i o n o f Trichostrongylus colubriformis i n t h e s m a l l
i n t e s t i n e (Ex p e r i m e n t 4 . 1 ) 75
4 . 1 I n t ro duction 75
4.2 M a t e r i a l s and m ethods 75
4 .3 Results 77
4 .4 Discussion 83
C h a p t e r Five: A s t u d y on the h o s t re s p o n s e o f fie l d - rea re d goa t s to i n fect i o n wi t h Trichostrongylus colubriformis a n d re p e a t a b i l i ty o f fa e c a l egg c o u n t s ove r s u c c e s s i ve i n fe c t i o n s (Ex p e r i m e n t 5 . 1 )
5 . 1 5 . 2 5 .3 5 . 4
I n t ro duction
M a t e r i a l s and m ethods Results
Discuss i o n
86
86 86 87 90
C h a p t e r Six: The u se of a m o no c l o n a l a n t i bo d y a n d t ra d i t i o n a l s t a i n i ng m e t ho d s i n c o u n t i n g m a st ce l l s a n d e o s i n o p h i l s i n i nte s t i na l m ucosa
(Ex p e ri m e n t 6 . 1 ) 9 3
6 . 1 6 . 2 6 . 3 6 .4
I n t ro duction
M a t e r i a l s and methods Results
D i scussion
93 93 98 1 03
C ha p te r Seve n : The d y n a m i c s o f l a rva l m ig ra t i o n i n h i b ito ry a c t i v i ty , m a s t c e l l a nd e o s i n o p h i l c o u n t s i n goats i n fected wi t h Trichostrongylus colubriformis
1 05 7 . 1
7.2 7 . 3 7 . 4
Introduction
M a t e r i a l s and methods Res u l ts
D i scussion
1 05 105 109 1 25
C h a p t e r E i g h t : The d y n a m i c p a ttern o f l a rv a l m i gration i n h i b i t o ry a c t i vi ty i n i l e a l c o n t e n t s o f goa t s w i t h i l e a l c a n n u l a e t h a t we re i n fected Trichostrongylus
colubriformis (Ex pe ri m e n t 8 . 1 ) 1 3 4
8 . 1 8 . 2
I nt ro duction
M a t e r i a l s and m ethods
1 34 1 3 4
8 . 3 8 . 4
Res u l ts D i scussi o n
C h a pter N i n e : G e n e ra l d i sc u s s i o n A p pe nd i c e s
Bi b l i ogra p hy
P u b l i s h e d p a p e rs b a s e d o n w o r k d e s c ri b e d i n t h i s t h e s i s
Locat i o n o f Appe n d i c e s
A p p e n d ix la A table o f exp e r i mental r e s u l t s detailing the deve lopm e n t o f resistance to H. con tortus A p p e n d ix Ib A table o f experim ental results detailing the
dev e lopm e n t o f resistance to T colubriformis A p pe n d ix 2a Fo rmulation o f pelleted r a t i o n
A p pe n d ix 2b M o d i fi e d McMaster techn i q u e for co unting strongylate eggs
A p p e n d ix 2c Peps i n digest tech n i q u e A p p e n d i x 2d Peps i nogen assay
A p p e n d ix 2e Faecal egg counts o f Experim e n t 2 . 1 A p p e n d i x 2f Faecal egg counts of Expe r i m e n t 2.2
A p p e n d ix 2g Graphs a n d statistical a n a lyses for blood para m e t e rs i n Experim en t 2 . 1
A p p e nd i x 2h Graphs a n d statistical a n a lyses fo r b lood par a m e t e rs i n Expe r i m e n t 2 . 2
A p p e n d i x 3 a Faecal egg counts fo r Expe r i m e n t 3 . 1
A p p e n d i x 3 b Graphs a n d statistical an alyses fo r serum prot e i n s i n Expe r i m e n t 3 . 1
A p p e nd i x S a Parasitological resu lts fo r Exp e r i m ent 5 . 1 A p p e nd i x 6a Gills haem atoxy l i n and eosin
A p p e nd i x 6 b Tol u i di n e b lu e
A p p e n d i x 6 c I m m u n ocytochemistry for mast cells A p p e n d i x 7 a Faecal egg counts fo r Exp e r i m e n t 7 . 1 A p p e nd i x 7 b L a rval m i g ration i n h i b i t i o n assay
A p p e n d ix 7c Co rrelat i o n o f LMI wit h wo r m , eosinophi l , mast cells a n d glob u l es l e ukocyte counts fo r Expe r i m e n t 7 . 1 A p p e n d i x 7 d Correlation o f total wo rm cou n t with mast cell,
eosi nophils and globule l e u kocy t e co unts i n Exp e r i m e n t 7 . 1
A p p en d i x 7 e Correlation o f two diffe re n t cou nt i ng techn i ques for glob ule l e u kocytes in Expe r im ent 7 . 1
A p p e n d i x 7 f Correlation o f globule l e ukocy t e counts (using
the m onoclonal antibody) w i t h m ucosal mast cell a n d eosinophil counts i n Expe r i m e n t 7 . 1
A p p e n d i x 8 a Comparison o f larval m i g r a t i o n i n hi b i ti o n ( LM I ) b etwee n days followi ng t h e fi r s t a n d seco n d challenge A p p e n d i x 8 b Correlation of various param e t e rs fo r goats i n
Expe r i m e n t 8 . 1
1 55 1 65 1 7 2 1 73 1 74 1 75 1 77 1 79
1 8 1 204 226 2 2 8 2 3 4 2 3 7 2 3 8 2 3 9 2 4 2 2 4 4 245
247 248
249 250 252
1 3 8 1 45 1 5 0 1 55 253 303
LIST O F F I G U R ES
F i g u r e 1 . 1 . The 5-li poxyge n a s e pathway of l eukotri e n e syn t h es i s ( from Lam a n d Aus t e n , 1 992) .
Page 32 F i g u r e 2 . 1 . Faecal egg cou nt s ( m ea n ± s . e . ) fro m Exper i m e n t 2 . 1 . 49 F i g u r e 2 . 2 . Faecal egg cou n t s ( m e a n ± s . e . ) fro m Expe r i m e n t 2 . 2 . 4 9 F i g u r e 2 . 3 . Packed cell vo l u m e s ( m ean ± s. e . ) from Exp e r i m ent 2 . 1 . 5 1
F i g u r e 2 . 4 . Packed cell vol u m es ( m ean ± s . e . ) from Exp e r i m e n t 2 . 2 . 5 1 F i g u r e 2 . 5 . Serum pepsi nogen values ( m ean ± s . e . ) fro m Expe r i m en t
2. 1 . 55
F i g u r e 2 . 6 . Serum pepsinogen values ( m ean ± s . e . ) from Exper i m en t
2 . 2 . 55
F i g u r e 2 . 7 . Serum gastri n values ( m ean ± s . e . ) from Exp e r i m e nt 2 . 1 . 57 F i g u r e 2 .8 . Se rum gastrin val ues ( m ean ± s . e . ) fro m Exp e r i m e n t 2 . 1 . 57
F i g u r e 3 . 1 . Faecal egg cou n t s ( ± range) of Experim e n t 3 . 1 . 69 F i g u r e 4 . 1 . The distributi o n o f t h e propo rtion o f wo rm counts by t h e
proportion of small i ntesti nal length fo r you n g goats
( n = 10) in Expe r i m e n t 4 . 1 . 78
F i g u r e 4 . 2 . The d i s t r i b u t i o n of t h e propo rtio n o f worm counts b y the proportion of s m a l l i n testinal length fo r o l d e r goats
( n = 8 ) in Expe r i m e n t 4 . 1 79
F i g u r e 4 . 3 . The m ean d i s t r i b u t i o n o f t h e propo rtion o f worm counts b y t h e propo rtion o f s m a l l i ntestinal l e ngth for young goats
(n = 1 0 ) and o l d e r goats (n = 8 ) in Exp e r i m e n t 4 . 1 . 80 F i g u re 4 . 4 . Scatterplot o f eggs per female for t h e y o u n g goats i n
Expe r i m e n t 4 . 1 . 82
Figure 4 . 5 . Scatterplot o f eggs p e r female for t h e o l d e r goats i n Experiment 4 . 1 .
F i g u r e 6 . 1 . Tissue fixed i n I FAA and stained with"tol u i d i n e b l u e (430 x m agni fication ) .
Figure 6 . 2 . Tissue fixed i n fo r m a l i n and stai n e d w i t h tolui d i n e blue (430 x magn i ficatio n ) .
F i g u r e 6 . 3 . Tissue fixed i n fo r m a l i n , prob e d with t h e m o n oclonal
MABC8, stai n e d with d i a m i n ob enzi d i n e and cou nte rsta i n e d w i t h Weiger t ' s h a e m a toxy l i n and B i e b rich's scarlet
(430 x magni ficati o n ) .
Figure 6 . 4 . Ti ssue fixed i n I FAA, probed with t h e m onoclonal MAB C 8 , s t a i n e d w i t h d i a m i nobenzidine a n d co unterstai n e d with Weigert's haem atoxy l i n a n d B i e b ri ch ' s sca r l e t (430 x m agni ficatio n ) .
F i g u r e 6 . 5 . Tissue fixed i n for m a l i n, stain e d with h a e m a t oxyl i n and eosin and o b se rv e d with fluorescence m icrosco py (2 1 5 x m agni ficati o n ) .
F i g u r e 6 . 6 . Tissue fixed i n fo r m a l i n, stai n e d with h a e m atoxyl i n a n d eosin a n d o b s e rved with fluo rescence m i c roscopy (430 x
82
96
96
97
97
99
m agni ficati o n ) . 99
F i g u r e 7 . 1 . Experi ment 7 . 1 : LMI-in dex (mean ± s . e . ) o f goats i n
Part A. 1 1 1
Figure 7 . 2 . Experim ent 7 . 1 : L M I - i n dex (mean ± s . e . ) o f goats i n
Part B. 1 1 1
Figure 7 . 3 . Experi ment 7 . 1 : Mucosal mast cell cou n t s ( m ean ± s . e . )
o f goats i n Pa rt A . 1 1 3
F i g u r e 7 . 4 . Experiment 7 . 1 : Mucosal mast cell counts ( m ean ± s . e . )
of goats i n Part B . 1 1 3
Figure 7 . 5 a . Experi m e n t 7 . 1: Glob ule leukocyte co u n t s ( m ean ± s . e . )
o f goats i n Part A; s t a i n e d using a monoclon a l antibody. 1 1 5
Fig u r e 7 .5b . Exper i m e n t 7 .2 : Glob ule l e u kocyte counts ( m ean ± s . e . )
o f goats i n Pa rt A; s t a i n e d with H & E . 1 1 5
Fig u r e 7 . 6 a . Exper i m e n t 7 . 1 : Globule l e u kocyte counts ( m ean ± s . e . )
o f goats i n Pa rt B ; stained using a m onoclonal antibody. 1 1 7
F i g u r e 7 . 6 b . Experim e n t 7 . 1 : Glob ule l e u kocyte counts ( m ean ± s . e . )
o f goats i n Part B ; s t a i n e d w i t h H & E . 1 1 7
Figure 7 . 7 . Experi m e n t 7 . 1 : Eosinophi l cou n t s ( m ean ± s . e . ) o f goats i n Part A.
Figure 7 . 8 . Experi m e n t 7 . 1 : Eosinoph i l cou n t s ( m ean ± s . e . ) o f goats i n Par t B .
F i g u r e 7 . 9 . Experi m e n t 7 . 2 : Globule leukocyte counts ( m ean ± s . e . ), stained using H & E.
F i g u r e 7 . 1 0 . Experi m e n t 7 . 3 : Glob ule leukocyte counts ( m ean ± s . e . ) , stained u s i n g H & E .
F i g u r e 8 . 1 . LMI-index o f i n t e s t i n a l con tents o f goats ( n = 6 ) i n fect e d w i t h 35,000 T colubriformis on Day 0 a n d again on Day 4 8 aft e r b ei ng treated with ivermect i n o n Day 2 8 .
1 1 9
1 1 9
1 22
1 23
1 4 1 F i g u r e 8 . 2 . Comparison o f s a m ples o f i n t e s t i n a l contents o n d ay 5 9 . 1 42 Figure 8 . 3 . Comparison o f t h e LMI- i n dex o f intesti n al m ucus collecte d
a t necropsy with LMI-index o f i n testinal contents collect e d
2 days pre-slaughte r . 1 43
Figure 8 . 4 . Globule leukocyte counts ( m ean ± s . e . ) o f s e c t i o n s taken at m e t re i nt e rvals down the small i n t est i n e . 1 4 4
Tab l e 1 . 1 Tab l e 1 .2 .
Tab l e 2 . 1 . Tab l e 2 . 2 .
Tab l e 2 . 3 . Tab l e 2 . 4
Tab l e 2 . 5
Tab l e 3 . 1 .
Tab l e 3 . 2
Tab l e 4. 1 .
Tab l e 5 . 1 .
Tab l e 5 . 2 . Tab l e 5 . 3
L I S T O F TAB LE S
Recorded roles or fu nctions of T H2 cyt o k i n e s .
Mo rphological a n d functional characteri s t i cs o f rodent m ast cells.
H. con tortus b u rdens for Experi m e n t 2 . 1 .
Statistical a nalysis o f two sample T-t est o f t h e total worm coun t s o f Expe r i m e n t 2 . 1 .
H. con tortus b u rdens i n Expe riment 2 .2.
Correlations b etween faecal egg coun ts, pepsinogen val u e s Page
1 6
22 47
48 50
and gastri n values at the end of the t rickle i n fect i o n s . 58
Correlations b etween total worm cou n ts , p e ps inogen val u e s a n d gastr i n v a l u e s at t h e t i m e o f slaugh t e r . 5 9
T. colubriform is w o r m counts, eggs p e r fem a l e , m a l e: fema l e ratios and fi n a l egg cou n ts o f
Groups 1 , 2 a n d 3 . 70
Correlation coeffici ents at the t i m e of sla ugh t e r for
goats with a n egg cou n t > 0 epg. 7 1
M ultiple com parison of m a l e : female r a t i o fo r all
goats ( n= 1 8 ) . 8 1
Spearman r a n k correlations b etween egg cou nts fo r 3 successive i n fect i o n s .
Arithmetic m ean egg counts for t h e t h re e i n fections.
Correlations b etwee n parasitological p a r am e t e rs fol lowi ng t h e t h i rd i n fect i o n .
88 89
89
Tab l e 6 . 1 . Comparison o f m ean cell cou nts ( n = 5 ) per m m2 fo r d i ffe rent fixative/stain com b i n ations.
Tab l e 6 . 2 . Correlation coeffici ents between m e a n',cell counts using
1 00
d i ffe rent fixative/stain com b i n ations ( n = 8 ) . 1 0 1 Tab l e 7 . 1 Experim e n tal schedule fo r Exper i m e n t 7 . 1 . 1 0 6
Tab l e 7 . 2 . Wo rm coun ts, estab lishment and eggs p e r fem al e for
Experi m e n t 7 . 1 . 1 1 0
Tab l e 7 .3 a . S tepwise regression analysis o f t o t a l w o r m counts
o f goats i n Groups B2, B3 and B4, Exper i m e n t 7 . 1 . 1 20
Tab l e 7 .3b . Stepwise regression an alysis o f LMI - i n dex o f small intestinal m ucus o f goats i n Groups B2, B3 a n d B4,
Experi m e n t 7 . 1 . 1 2 1
Tab l e 7 . 4 . Correlations o f various parasitological parameters
with GL counts fo r Experiment 7 .3 ( n = 29 ) . 1 24 Tab l e 7.5 .
Tab l e 8 . 1
Experi m e n t 7 . 4 - LMI- i ndex o f small i n t esti n al con tents a t v a ryi ng i n t e rvals of storage at -20°C.
Faecal egg counts, worm cou nts, eggs per fem a l e worm and larval m igration inhib i t o ry activity of i n t estinal m ucus and ileal con tents o f goats challenged with 35,000 T. colu briform is, given anthelm i n tic treatment a ft e r 28 days, rechallenged as b e fore aft e r 20 days and k i l led afte r a fu rther 28 days.
1 2 4
1 3 9
