THE RELATION OF CLIMATE AND TOPOGRAPHY TO GASTRO-INTESTINAL NEMATODE WORM EGG COUNTS OF ANGORA GOATS IN THE EASTERN CAPE

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1 OnderstepoortJ. vet. Res., (1986) THE RELATION OF CLIMATE AND TOPOGRAPHY TO GASTRO-INTESTINAL NEMATODE WORM EGG COUNTS OF ANGORA GOATS IN THE EASTERN CAPE B. MCCULLOCH, R. R. DALBOCK* and H. G. KUHN, Diretorate of Veterinary Servies, Veterinary Laboratory, P.. Box 41, Grahamstown 614 ABSTRACT MCCULLOCH, B., DALBOCK, R. R. & KUHN, H. G., The relation of limate and topography to gastro-intestinal nematode wonn egg ounts of Angora goats in the Eastern Cape. Onderstepoort Journal of Veterinary Researh, 53, (1986) Haemonhus, Trihostrongylus, Ostertagia and Nematodirus wonn populations of Angora goats, based on differential egg ounts, are onsidered in relation to limatologial and topographial data. Egg ounts indiated that the estimated wonn populations in goats that experiened wet irumstanes were higher than those exposed to dry onditions. Wetness was assessed by relating spring, summer, and early autumn rainfalls to ground slope. It is proposed, that tatial anthelminti treatments of goats be based on the degree of wetness of the grazing or property. INTRODUCTION Climate, season, pasture management, grazing rotations and general weather onditions play an important role in the inidene of gastro-intestinal nematode infestations of goats and sheep. When goats and sheep graze together they are, by and large, infested with the same speies of worms, although the levels of infestation may differ (Le Jambre & Royal, 1976; Armour, 198). In a reent investigation arried out in the Eastern Cape, differential egg ounts were used to estimate the prevalene of gastro-intestinal nematodes, namely, Haemonhus, Trihostrongylus, Ostertagia and Nematodirus spp. in Merino sheep in relation to the degree of wetness on a property or grazing area (MCulloh, Kiihn & Dalbok, 1984). At the same time, omparable investigations were being arried out in Angora goats. The findings in Angora goats are desribed and ompared in this paper with the sheep data desribed by MCulloh et al. (1984). MATERIALS AND METHODS General The observations in Angora goats were arried out on 5 properties for some 12 months at a time, from November 1978 to November The properties were situated about the Eastern Cape towns of Pearston, Somerset East and Bedford, the area as a whole lying between 32 S and 33 S, 25 E and 27 E. Experimental animals Eleven different groups of goat wethers, 1 of whih ontained 128 wethers and one 112, were used. At the ommenement of eah trial, the goats in eah group were numbered and their mass individually determined, and they were then divided into 4 omparable groups based on mass. The goats used in eah trial were of uniform age. After the groups had been identified with olour tags, faeal samples were olleted from 12 goats in eah of the 4 groups, olletion being arried out in the same rank order for eah group. Thereafter, the 4 groups of goats that made up the group for eah trial were treated with a ommerially available anthelminti. Four of the II trial groups were exepted; in the 4 trials the goats had been treated just before grouping and treatment was onsidered unneessary. The anthelminti treatments whih were administered at or just before the start of eah of the 11 trials were: *Deeased Reeived 28 April 198(}-Editor An albendazole* preparation at a dosage rate of approximately 5 mg!k:g live mass: Glen Cullen 19789; Joubertskraal1979/8; Glen Cullen 1979/8; Hyndhope 198/81; Glen Cullen 1981/82 and Eildon A morantel** preparation at a dosage rate of approximately 15 mg/k:g live mass: Eildon 19789; Eildon 1979/8 and Glen Cullen 198/81. A mebendazole*** preparation at a dosage rate of approximately mg!k:g live mass: Joubertskraal 198/81. A thiabendazole/rafoxanide**** preparation at a dosage rate of approximately 63 mgtkg and 11 mg!k:g live mass respetively: Redliff 1979/8. Fallow-up anthelminti treatments Group 1 was left untreated for the duration of the investigation. All the egg ount data from these animals were used in this investigation. Groups 2 and 3 were treated with an anthelminti aording to rainfall. In the absene of a dangerous 8- week rainfall period (see Terminology below) they were left untreated. Only egg ount data from the untreated Groups 2 and 3, were used in these alulations. Group 4 was treated throughout the trial with an anthelminti at approximately 4-6-week intervals. Egg ount data per se from Group 4 were ignored. Worm egg ounts of eah of the 4 groups were determined at 4--6-week intervals. The 12 goats initially seleted from the 32 or 28 goats making up eah group were used for this purpose, faeal samples from these 12 goats being sub-grouped in set order, with 4 samples making up the 3 sub-groups for examination. Egg ounts and differential egg ounts were arried out, Nematodirus eggs being ounted separately. The 11 trials were initiated in spring from late September to early Deember. All the trials were terminated in the spring following their ineption. No speial grazing programmes were undertaken, the animals fitting into the farming proess as onvenient to the management. Statistial analysis Chi-squared assessments were effeted on geometrial arrangements of worm egg ount data by arrangements similar to those desribed in detail by MCulloh et al. (1984). *Valbazen. Smith Kline **Banminth ll, Pfizer ***Muhispe, Ethnor ****Ranizole, MSD 167

2 RELATION OF CLIMATE AND TOPOGRAPHY TO GASTRO-INTESTINAL NEMATODE WORM EGG COUNTS OF ANGORA GOATS <U Q) Ul E "' ::::J n4 Q) i : Cl ai 2 Cl E Q) u 16 1a '111' Rainfall fm Dangerous 8-week rainfall period End of April Ot. 79 Nov. De. Jan. Feb. Mar. Apr. May June July Aug. Sept. Ot. Nov. 8 AG. Ia JoubertskraaJ 1979/8 Slope,77" Veld type Karoo Minimum 4-week rainfall requirement adjusted upwards to 32 mm Annual rainfall 37 mm 118 annual rainfall qualifying date Date of anthelminti treatment <U Q) "' E -:-4 1b ---- al 5 q>,., : C)Q), ,/ ---- E , >< rn End of April..,. ' g E 12 8mm t I 'iij.. 8 :; e 4 -- Ot.8 Nov. De. Jan. Feb. Mar. Apr. May June July AG. lb Hyndhope 198/81 Slope 8,12" Veld type grass Minimum 4-week rainfall requirement 8 mm Annual rainfall 511 mm 118 annual rainfall qualifying date I Date of anthelminti treatment <U Q) E "' Q) : "' ::::J 1 8 q> 6 a. 4 Cl ai 2 1 l End April _,,""' _..,._ r=!lj = CJ-[ Ot. 8 Nov. De. Jan. Feb. Mar. Apr. May June July Aug. Sept. Ot. Nov. 81 AG. l Joubertskraal 198/81 Slope, veld type, minimum 4-week rainfall requirement-see Fig. Ia Annual rainfall 392 mm J/8 annual rainfall qualifying date 198-JJ-28 Date of anthelminti treatment AG. I Combined mean egg ounts of goats and related moving 4-week rainfall figures. Tbe moving 4-week rainfall figures are reorded on 2 propen1es over 3 oasions; on eah oasion I dangerous 8-week rainfall period was observed over the late summer and early autumn (February/ April) 168

3 TABLE 1 Mean egg ount data (e.p.g.) of goats, reorded on 2 properties on 3 oasions, with l dangerous 8-week rainfall period observed over the late summer and early autumn months (February/ April). On l oasion the dangerous 8-week rainfall period ended in Marh and on the other 2 oasions in April Property/year Egg ounts Ot. Nov. De. Jan. Feb. Mar. Apr. May June July Aug. Sept. Ot. Nov. Joubertskraal (1979/8) Group 1 Combined Haemonhus Trilwstrongylus lo 29 Ostertagia Nematodirus Hyndhope (198/81) Group 1 Combined Haemonhus Trilwstrongylus Ostertagia Nematodirus Group2 Combined Haemonhus Trilwstrongylus 18 Ostertagia 4 Nematodirus Joubertskraal (198/81) Group 1 Combined Haemonhus Trilwstrongylus 3 Ostertagia - 2 Nematodirus = Culture failure!l'!?"?" p,.?=!='! -$

4 -.l TABLE 2 Mean egg ount data (e.p.g.) of goats, reorded on 3 properties on 8 oasions, with no dangerous 8-week rainfall period observed on any ofthe 8 oasions Property /year Egg ounts Ot. Nov. De. Jan. Feb. Mar. Apr. May June Redel iff ( 1979/8) Group I Combined 33 Haemonhus Trihostrongylus 29 Ostenagia 4 Nematodirus - 83 so 33 Eildon ( 1978n9) Group 1 Combined Haemonhus Trihostrongylus Ostertagia Nematodirus I so Eildon ( 1979/8) Group I Combined 33 Haemonhus Trihostrongylus 2 Ostenagia 13 Nematodirus so - Grou;>2 Combmed Haemonhus - Trihostrongylus Ostenagia Nematodirus - Eildon ( ) Group I Combined Haemonhus Trihostrongylus Ostenagia Nematodirus Group2 Combined 83 Haemonhus Trihostrongylus Ostenagia Nematodirus so 33 Group3 Combined Haemonhus Trihostrongylus Ostenagia Nematodirus Glen Cullen ( 1978n9) Group I Combined 33 1 so 83 so Haemonhus Trihostrongylus so Ostenagia 2 35 Nematodirus July Aug. Sept so so Ot. so Nov so r:t1 6 ><: 6-1 z Cl> 8

5 TABLE 2 Mean egg ount data (e.p.g.) of goats, reorded on 3 properties on 8 oasions, with no dangerous 8-week rainfall period observed on any of the 8 oasions Property /year Egg ounts Ot. Nov. De. Jan. Feb. Mar. Apr. May June Glen Cullen ( 1979/8) Grou_, I Combmed 67 1 Haemonhus 46 Trihostrongylus 9 1 Ostertagia 12 Nematodirus Grou_, 2 Combmed 33 Haemonhus Trihostrongylus 11 Ostertagia - 5 Nematodirus 67 - Glen Cullen ( 198/81) Groul! I Combmed Haemonhus Trihostrongylus Ostertagia - Nematodirus - Groupl Combined 33 Haemonhus Trihostrongylus Ostertagia Nematodirus 33 - Glen Cullen ( ) Group 1 Combined Haemonhus Trihostrongylus 5 Ostertagia Nematodirus GrouJ!l Comb1ned Haemonhus Trihostrongylus Ostertagia Nematodirus 5 GrouJ.»3 Combmed 33 Haemonhus 33 Trihostrongylus Ostertagia Nematodirus July Aug. Sept Ot Nov t:ll (!' (!' pp?= C:: :I: z

6 l N Sil ("") ' TABLE 3 Chi-squared evaluation of ombined, Haemonhus, Trihostrongylus and Nematodirus mean egg ount data (e.p,g,) of goats on 5 properties on II oasions, Of the II oasions, 3 (Setion I) showed I dangerous --l 8-week rainfall period over the late summer and early autumn months (February/ April) and 8 (Setion 2) showed no dangerous 8-week rainfall period, The egg ount data are in geometrial arrangement, first term/ommon ratio--16/2 (:S Property /year Combined Haemonhus Mean egg ount data (e.p.g.) in geometrial arrangement ;a-256 ;a.j28 ;a-64 ;a-32 ;a.j6 ;a-256 ;a.j28 ;a-64 ;a n Setion I Joubertskraal-1979/8 Hydhope-198/ Joubertskraal-198/ x 2 values* Setion 112 5,2 6,2 5,2 9, 9,3 4,3 Setion2 Redliff-1979/8 Eildon-1978n9 I I I 4 8 Eildon-1979/8!57! m N!54!5 Eildon-1981/82 Glen Cullen-1978n9 Glen Cullen-1979/8 Glen Cullen-198/81 Glen Cullen-1981/82 * X 2 values---1,8 (P,1); 6,6 (P,1); 5,4 (P,2); 3,84 (P,5); only signifiant values at P,5 are shown n (jad - bj - ) 2 X2 = (with Yates's orretion) (a b) ( d) (a ) (b d) ;a-)6 ;a.j I !56 Trihostrongylus ;a-64 ;a-32 ;a.j I I Nematodirus ;a-64 ;a II ;a-)6 is I F: g "r1 8 til

7 \;) TABLE 4 Chi-squared evaluation of ombined, Haemonhus, Trihostrongylus and Nematodirus mean egg ount data (e.p.g.) of 6 goat trials and 6 sheep trials arried out on the same 4 properties on the same 6 oasions. The egg ount data are in geometrial arrangement, first term/ommon ratio--16/2 Mean egg ount data (e. p. g.) in geometrial arrangement Property/year Combined Haemonhus :;:!:256 :;:!:128 :;:!:64 :;:!:32 :;:!:!6 :;:!:256 :;:!:!28 :;:!:64 :;:!:32.;;255.;;m.;;63.;;31.;;!5.;;255.;;!27.;;63.;;3i ;:!:J6 ;:!:J28.;;15.;;!27 Trihostrongylus Nematodirus :;:!:64 :;:!:32 :;:!:!6 :;:!:64 :;:!:32 :;:!:!6.;;63.;;3i.;;!5.;;63.;;31 ""15 Sheep Joubertskraal-1979/8 Hyndhope-198/81.J...H l Joubertskraal-198/ Eildon--1979/8 Glen Cullen-1978n9 Glen Cullen--1979/ ! X 2 values Sheep/goats 4,5 1,6 7, 5,6 Goats Joubertskraal-1979/8 flyndhope-198/ _ Joubertskraal- 198/ Eildon--1979/8 Glen Cullen-1978n9 Glen Cullen--1979/8 - - xz values--1,8 (P.;;,1); 6,6 (P.;;,1); 5,4 (P.;;,2); 3,84 (P.;;,5); only signifiant values at P.;;,5 are shown n <lad - bel - ) xz 2 = (with Yates's orretion) (a b) ( d) (a ) (b d) 8 I ! :1:1 I?"?"?S?= 9 C: 2

8 RELArtON OF CLIMATE AND TOPOGRAPHY TO GASTRO-INTESTINAL NEMATODE WORM EGG COUNTS OF ANGORA GOATS < 2a Q)!J 1 E -:- 8 "sq>so..., 2! '!- 4,'... : g 2...," ', 8 Q) _-_-_- -_-_- - _-_-_- -_-_ _-_-_- -_-_._-_- -_-_._-_-_- -_- -_-_-_. -_- -_._-_- -_-_._' '_,_. 16 Ot. 79 Nov. De. Jan. Feb. FIG. 2a Redliff 1979/8 Slope Jl,5 Veld type mixed Karoo and srub Minimum 4-week rainfall requirement 15 mm Annual rainfall496 mm 118 annual rainfall qualifying date Date of anthelminti treatment Mar. Apr. May June July Aug. Sept. Ot. Nov. 8 ltl Q) Ul 2b E 4 al. :!: ;- 2 _, ,, _-_- -_.. -_-_- -_- -_-_- 8 Q).><: Ul 16 Q) 125mm 5, 12...l------'=...:.:..:.: _- - -_- _-_- -_- g,i8 :; 'E 4 e o =. Ot. 78 Nov. De. Jan. Feb. Mar. Apr. May June July Aug. Sept. Ot. Nov. 79 FIG. 2b Eildon 1978n9 Slope 11,58 Veld type mixed grass and Karoo Minimum 4-week rainfall requirement adjusted downwards to 125 mm Annual rainfall565 mm 118 annual rainfall qualifying date Date of anthelminti treatment ltl Q) E -o Q)!!! :JC,. 3 o'!- 2 1 C)Ql : E Cl" Q).><: 16 Q) Q) :J 12 C)..,. :;::: E 8 >:E ltl _, :; 'E 4 e 2... _ mm -...-,_..,.--- -' Ot. 79 Nov. De. Jan. Feb. FIG. 2 Eildon Slope, veld type-see Fig. 2b Minimum 4-week rainfall requirement 119 mm Annual rainfall536 mm 118 annual rainfall qualifying date Date of anthelminti treatment Mar. Apr. May June July Aug. Sept. Ot. Nov. 8 4

9 m 2d Ql U> 1 E 8 ::I q> Ql 6 " a. 4 : Ol C1i Ol 2 E 16.:.!. U> Ql Ql 12 3: ::I I Ol Ql ,._ '..., :;: E 8 Ol = m.s ;;; 4 e mm Ot.81 Nov. De. Jan. AG. 2d Eildon 1981/82 Slope, veld type-see Fig. 2b Minimum 4-week rainfall requirement mrn Annual rainfall48 mrn 118 annual rainfall qualifying date Date of anthelminti treatment Feb. Mar. Apr. May June July B. MCCULLOCH, R. R. DALBOCK & H. G. KUHN ;'... "'"'/ ,.,.,.,. Aug. Sept. Ot. Nov. 82 m 2e Ql.l!l 1 E8o " ::I q> 8 6 : Ol Ql 4 E 2. ;o,,' /...,'...,' -...,..., ,,...,' ' _.,,,..._ 18 r :.t. U> a> a> 125mm J ,,g>E g>.s8 4 - Ot. 78 Nov. De. Jan. Feb. Mar. Apr. AG. 2e Glen Cullen 1978n9 Slope 14,68 Veld type mixed grass and Karoo Minimum 4-week rainfall requirement adjusted downwards to 125 mrn Annual rainfall714 mrn 118 annual rainfall qualifying date Date of anthelminti treatment May June July Aug. Sept. Ot. Nov. 79 m 21 E 1oo,/', i q>... 4,"'...," , -. Q),... / ' "/ ', "',... 8 Ql,._-_-_-_-_-_-_-_-_-_ _-_-_-_-_ _-_-_-_-_._-_-_-_-, _" mm 4 Ot. 79 Nov. De. Jan. Feb. Mar. Apr. May June FIG. 2f Glen Cullen Slope, veld type, minimum 4-week rainfall requirement--see Fig. 2e Annual rainfall 595 mrn 1/8 annual rainfall qualifying date Date of anthelminti treatment July Aug. Sept. Ot. Nov. 8

10 RELATION OF CLIMATE AND TOPOGRAPHY TO GASTRO-INTESTINAL NEMATODE WORM EGG COUNTS OF ANGORA GOATS <tl Q) Ill 2g E --:-4 " 5 (.) q. 2 :. C) (1,),..,.,/ E ar- o ! >< Ill lb "f 6, ;;::: Ol = E 8 <tl :;. 4 Ot. BO Nov. De. Jan. Feb. Mar. Apr. May June July Aug. Sept. Ot. Nov. 81 FIG. 2g Glen Cullen 198/81 Slope, veld type, minimum 4-week rainfall requirement-see Fig. 2e Annual rainfall 578 nun 1/8 annual rainfall qualifying date Date of anthelminti treatment <tl Q).l!l 1 E --:- 8 2h "2 5 6 (.) q. 4 "" :E-2, <1> """... _ >< Ill 16 lb (I: 125mm "f 6,12..r---...::..:_;:..:_; 8 rt-jl, :; 4. CJ Ot. 81 Nov. De. Jan. Feb. Mar. Apr. May June July Aug. Sept. Ot. Nov. 82 FIG. 2h Glen Cullen Slope, veld type, minimum 4-week rainfall requirement-see Fig. 2e Annual rainfali499 nun 118 annual rainfall qualifying date Date of anthelminti treatment FIG. 2 Combined mean egg ounts of goats and related moving 4-week rainfall figures. The moving 4-week rainfall figures are reorded on 3 properties over 8 ocasions; on no oasion was a dangerous 8-week rainfall period observed Chi-squared assessments were also effeted on the geometnally grouped egg ount data reorded from 6 of the 11 goat trials and on 6 of 16 sheep trials (MCulloh et al., 1984), whih were arried out over the same periods of time on the same properties. Terminology Desriptive terms, suh as slope, 118 annual rainfall qualifying date, 4-week rainfall figures, minimum 4- week rainfall req_uirement and dangerous 8-week rainfall period, are desnbed by MCulloh et al. (1984). Topographial onsiderations--slope alulations On one property, a alulation of the ground slope from the lowest to the highest point of the grazing area was an adequate expression of the overall position. On the other 4 properties, 3 slopes were alulated and mean values utilized. REsULTS Angora goat trials Moving 4-week rainfall figures pertaining to the trials are reorded (Fig. 1 & 2), as are faeal worm egg ounts of Group 1 (Fig. 1 & 2, Tables 1 and 2). Faeal worm egg ounts of Group 4 and Groups 2 and 3 are exluded, unless Groups 2 and 3 ould be onsidered supplement to Group 1 (Tables 1 and 2), as happened from time totlme. 6 Mean undifferentiated faeal worm egg ounts are shown as ombined ounts, mean Haemonhus, Trihostrongylus and Ostertagia egg ounts being differentiated, while the mean Nematodirus ount is listed separately (Tables 1 and 2). Where one dangerous 8-week rainfall period ourred over the late summer and early autumn months (February/April), ombined egg ounts tended to be higher in subsequent months than those reorded in the absene of an equivalent dangerous 8-week rainfall period (Fig. 1, Table 1 and Fig. 2, Table 2, respetively). Haemonhus and Trihostrongylus egg ounts predominated and made up the greater part of the ombined egg ounts. As in the ase with the ombined egg ounts, the Haemonhus ounts were favourably influened by wet onditions during the late summer and early autumn months. The position with regard to the Haemonhus ounts was more learly defmed than that of the ombined ounts (Table 3: Setion 1/Setion 2). There were no distint indiations that the Trihostrongylus ounts were influened by wet or dry onditions (Table 3: Setion 1/Setion 2). Nematodirus egg ounts were low throughout. There were no signs that the Nematodirus ounts were favoured by wet or dry onditions (Table 3: Setion 1/Setion 2). Ostertagia ounts were very low durin the period of observation and no trends ould be determmed.

11 B. MCCULLOCH, R. R. DALBOCK & H. G. KUHN Angora goat and Merino sheep trials Comparisons of wonn egg ounts reorded in the 6 goat trials and 6 sheep trials (MCulloh et al., 1984), whih were arried out over the same periods of time and on the same properties, namely Joubertskraal 1979/8, Hyndhope 198/81, Joubertskraal 198/81, Eildon 1979/8, Glen Cullen and Glen Cullen 1979/8, showed that ombined Haemonhus and Trihostrongylus egg ounts were only slightly lower in goats than in sheep (Table 4). DISCUSSION The area under onsideration is representative of the heart of the Angora goat industry in South Afria. Fanners were asked to supply some 15 Angora goats and/or 15 Merino shee.p for gastro-intestinal nematode survey purposes, provision of both goats and sheel?. for onurrent trials being a partiularly valuable ontribution. Haemonhus ontortus infestations are partiularly favoured by wet summer weather onditions. The same riteria of rainfall, ground slope, 1/8 annual rainfall qualifying date, 4-week rainfall figures, minimum 4- week rainfall requirement and dangerous 8-week rainfall period assessments et., as employed in the sheep trials (MCulloh et al., 1984), were used in the assessment of wetness and in the evaluation of the goat trials. On the properties where the goat trials were held (Fi. 1 & 2), onditions were often onsiderably drier m spring and summer than those on whih the sheep trials took plae (MCulloh et al., 1984; Fig. 1, 2, 3 & 4). The rainfall patterns of the goat trials showed only limited variation; only 3 out of 11 trials showed dangerous 8-week rainfall periods and on the 3 oassions the dangerous 8-week rainfall periods were reorded from the late summer. Notwithstanding, the ombined and Haemonhus eg ounts of the goats were in general, as in the ase w1th sheep, favourably influened by wet onditions in the late summer and early autumn (Table 3: Setion 1/Setion 2). However, withm the limits of the goat trials, there were no indiations that the Trihostrongylus egg ounts were favoured by wet onditions nor the Nematodirus egg ounts by dry onditions, as was observed in the sheep trials. Results from work in the pastoral areas of Sukumaland, Tanzania, by MCulloh & Kasimbala (1968), indiated that goats and sheep were equally suseptible to H. ontonus wonn infestation, but that goats were less suseptible than sheep to Trihostrongylus olubriformis wonn infestation. In a survey arried out by I.e Rihe, Efstathiou, AI tan & Campbell (1973) in Cyprus, it was noted that mature goats had lower wonn infestations than adult sheep. Observations made on sown pastures in Australia by I.e Jambre & Royal (1976), showed, after a 4-month period of a trial using 15 month old Angora goats and Merino sheep of the same age that the goats arried signifiantly more H. ontortus, T. olubriformis and other wonns than the sheep. Assessments of the relative suseptibility of goats and sheep to gastro-intestinal nematodes are at variane. Inferenes are that the preferenes of goats to browse shrubs and bushes, suh as thorn-bush, are responsible at times for the lower infestations aorded to goats. The generally higher growth levels of browse to graze ould be of importane. Silangwa & Todd (1964) observed that only 2-3 % of the infetive trihostrongylid larvae plaed in a position to migrate vertially did so, and that of this perentage less than 1 % attained heights greater than 127 mm. Browse was readily available on the veld utilized for this present work. A omparison of the goat and sheep wonn egg ounts in the 6 respetive goat and sheep trials onduted over the same periods of time on the same properties would indiate that egg ounts were only slightly lower in goats than in sheep (Table 4). It would seem reasonable to antiipate that under veld onditions in the Eastern Cape these differenes would be of limited importane in tenns of gastro-intestinal nematode ontrol, and that ontrol in Angora goats ould be based on tatial anthelminti treatments related to dangerous 8-week rainfall periods, as appeared warranted in Merino sheep (MCulloh et al., 1984). ACKNOWLEDGEMENTS We are grateful to the South Afrian Mohair Growers' Assoiation for their help in initiating the trials, to the Diretor of Veterinary Servies for permission to publish and to various members of the fanning ommunity for providing the animals and failities required for the programme. Our thanks are also due to the laboratory staff assoiated with the work, espeially Miss H. A. Amos and Mrs T. P. Fry and to Dr C. van N. Jonker for his support throughout. REFERENCES ARMOUR, J., 198. The epidemiology of helminth disease in farm animals. Veterinary Parasitology, 6, LE JAMBRE, L. F. & ROYAL, W. M., A omparison of worm burdens in grazing Merino sheep and Angora goats. Australian Veterinary Journal, 52, LE RICHE, P. D., EFSTATHIOU, G. C., ALTAN, Y. & CAMPBELL, J. B., A helminth survey of sheep and oats in Cyprus. Part 11. Age distribution and the severity of infetion with gastro-intestinal parasites. Journal of Helminthology, 47, MCULLOCH, B. & KASIMBALA, S., The inidene of gastrointestinal nematodes of sheep and goats in Sukumaland, Tanzania. British Veterinary Journal, 124, MCULLOCH, B., KOHN, H. G. & DALBOCK, R. R., The relation of limate and topography to worm egg ounts of gastro-intestinal nematodes of sheep in the Eastern Cape. Onderstepoort Journal of Veterinary Researh, 51, SILANGWA, S.M. & TODD, A. C., Vertial migration oftrihostrongylid larvae on grasses. Journal of Parasitology, 5,