The cumulative total helminth parasite burdens of ranch calves during their first seven months of life
on the North-eastern Mountain Grassland of South Africa were determined during two consecutive
years.
Trichostrongylus axei was the most abundant nematode parasite followed by Cooperia spp. and Ostertagia
ostertagi. Haemonchus spp. occurred in relatively low numbers and its development was significantly
inhibited. The total helminth parasite burdens of the calves ranged from 681 to 7269 with a
mean of 4405.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. 
Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Logos Agvet (Pty) Ltd.  Foundation for Research Development..mn201

Louw, J.P.

The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. 
Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.The cumulative total helminth parasite burdens of ranch calves during their first seven months of life
on the North-eastern Mountain Grassland of South Africa were determined during two consecutive
years.
Trichostrongylus axei was the most abundant nematode parasite followed by Cooperia spp. and Ostertagia
ostertagi. Haemonchus spp. occurred in relatively low numbers and its development was significantly
inhibited. The total helminth parasite burdens of the calves ranged from 681 to 7269 with a
mean of 4405.Logos Agvet (Pty) Ltd.  Foundation for Research Development..mn201

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Onderstepoort Journal of Veterinary Research, 66:335-338 (1999) RESEARCH COMMUNICATION The helminths of ranch calves in the North-eastern Mountain Grassland of South Africa J.P. LOUW Onderstepoort Veterinary Academic Research Unit, Faculty of Veterinary Science, University of Pretoria Private Bag X04, Onderstepoort, 0110 South Africa ABSTRACT LOUW, J.P. 1999. The helminths of ranch calves in the North-eastern Mountain Grassland of South Africa. Onderstepoort Journal of Veterinary Research, 66:335-338 The cumulative total helminth parasite burdens of ranch calves during their first seven months of life on the North-eastern Mountain Grassland of South Africa were determined during two consecutive years. Trichostrongylus axei was the most abundant nematode parasite followed by Cooperia spp. and Os-tertagia ostertagi. Haemonchus spp. occurred in relatively low numbers and its development was signif-icantly inhibited . The total helminth parasite burdens of the calves ranged from 681 to 7 269 with a mean of 4405. Keywords: Helminth parasites, North-eastern Mountain Grassland, ranch calves The incidence and prevalence of helminth parasites of cattle in South Africa have been reported from the northern bushveld area (Horak 1978), karroid areas (Fourie & Horak 1990) and the north-eastern High-veld (Horak & Louw 1978). However, the study by Horak & Louw (1978) was conducted on irrigated pas-tures while the helminth populations of cattle kept under extensive ranching conditions may be different. The present study was conducted on a cattle and sheep ranch in the North-eastern Mountain Grass-land (Bredenkamp, Granger & Van Rooyen 1996). This ranch, Elandskloof (25°31 'S; 30°07'E), is situ-ated 1 0 km from Dullstroom and 25 km from both Belfast and Machadodorp in the Mpumalanga Prov-ince. Calves, weaned at the end of the summer graz-ing seasons and never treated with anthelmintics, were necropsied during the winters of 1997 and 1998 and their helminth parasite burdens determined. During the seven-months study periods meteorologi-cal data was obtained from Rietvallei, the weather station nearest to the ranch (Fig. 1 ). During the study Accepted for publication 27 August 1999-Editor periods of 1997 and 1998 respectively, 378 and 343,6 mm of rain were recorded. Long-term mean annual temperature for the region is 15 oc and range from -8 oc to 39 °C. Drakensberger bull calves of approximately seven months old were selected on faecal worm egg counts and transferred to the Onderstepoort Veterinary Aca-demic Research Unit of the Faculty of Veterinary Sci-ence, University of Pretoria at Onderstepoort. At this facility they were housed in pipe-frame cattle pens. One half of each pen had a roof and a concrete floor, while the other half was open and had a compacted gravel floor. The calves were fed two kilograms of a beef finishing ration daily and lucerne and eragrostis hay ad libitum. Dung was removed daily to eliminate the possibility of nematode parasite infections in the pens. For the 1997 study, eight calves were selected on faecal worm egg counts immediately after weaning on 6 June 1997 and transferred to the experimental facilities. They were slaughtered during 29-31 July 1997 and their gastro-intestinal parasites recovered for the study. 335 Helminths of ranch calves in North-eastern Mountain Grassland of South Africa 30 ~----------------------------~ 250 25 u ~20 c.. E 2 15 >< Ill E 10 -c c:: Ill c: 5 ::§ 0 Jan Feb Mar Apr May Jun Months • Rain 97 B Rain 98 D 200 150 I ~ 100 -~ Q: 50 x--- x Max 97 o-----o Max 98 C>--<:> Min 97 +······+Min 98 FIG. 1 Meteorological data recorded at Rietvallei during 1997 and 1998 For the 1998 study, calves were weaned on 15 June 1998, kept in a kraal on the farm and fed eragrostis hay and a beef-finishing ration until six were selected and transferred to the experimental facilities on 14 July 1998. These calves were slaughtered on 12 and 13 August 1998 and their gastro-intestinal parasites recovered for the study. Immediately after slaughter at the abattoir, the calves were eviscerated and the gastro-intestinal tract from the abomasum to the rectum collected in a numbered tray. Double ligatures of string were tied between the different gastro-intestinal sections before they were transported to the parasite recovery room. The liv-ers were examined for trematodes and cestodes at the abattoir. The abomasa and small and large intestines were opened in separate buckets and thoroughly rinsed under running water. The contents were then washed on sieves, collected in labeled jars marked with the animal's number and the relevant section of the gastro-intestinal tract. For the abomasa and small intestines a sieve with 63 ~m apertures was used, while a sieve with 150 ~m apertures was used for the large intestines. To preserve the processed material, formalin to a final dilution of approximately 4% was added to all jars. The abomasal wall was digested with 3% hydrochloric acid in jars placed in a water bath operating at approximately 40 °C. After approxi-mately four hours the digested material was washed on a sieve with 63 ~m apertures and preserved in labeled jars marked with the animal's number and the identity of the material. Two 5-% aliquots of every section of the gastro-in-testinal tract were collected in honey jars. These 336 aliquots were examined under a stereoscopic micro-scope and the worms counted and identified accord-ing to the genus. Where possible, approximately 20 males of each genus and approximately 20 imma-ture worms were removed from each aliquot , mounted in !acto-phenol and the species and stages of development determined according to descriptions by Soulsby (1968). These differential counts were subsequently used to divide the total counts into spe-cies and stages of development . After removal of the aliquots, the remainder of the in-gesta was examined macroscopically in a black tray for large worm species such as Bunostomum, Oeso-phagostomum and Trichuris. These worms were counted and recorded as total counts. Worm counts and faecal worm egg counts of the calves in the two studies are presented in Tables 1 and 2. Southcott, Major & Barger (1976) found that Hae-monchus larvae are unable to survive climatological stress during spring and early summer. Horak (1978) recovered very few Haemonchus, Trichostrongylus and Cooperia from calves under extensive grazing conditions during the period from August to Novem-ber. Although the calves in the present study were only born in December, they spanned almost the entire parasitic season of each year of the study. The worm burdens are consequently an indication of the total number of worms that calves on cattle ranches in the region can accumulate in one year. The worm burdens ranged from 681 to 7 269 (mean 4 405). Worm burdens of this magnitude probably justify the deworming of calves at weaning . Deworming cattle is, however, not common practice in the region un-der study. In a survey carried out over a period of three years, Louw (1995) determined that the volume of cattle anthelmintic purchased in this region was hardly sufficient for a single treatment of 25% of the cattle population . One of the two calves infected with cestodes, har-boured Moniezia spp. and the other, Avitellina centri-punctata. Except for one calf which was not infected with Trichuris, all calves harboured Oesophago-stomum spp. and Trichuris spp. Only one calf was in-fected with Bunostomum. Trichostrongylus axeiwas the most abundant nema-tode parasite found in the calves. This was in con-trast to the other surveys carried out on cattle in South Africa. In their study Horak & Louw (1978) found that Haemonchus and Cooperia were the most abundant parasites of calves. The relatively low number of Haemonchus and Ostertagia in the ani-mals under the present study was probably due to the suppressing effect of T. axei. Turner, Kates & Wilson (1962) documented such an effect in sheep. A cross-section of approximately 0,5 mm thick was cut out of ten adult Haemonchus in the region of the junction of the oesophagus and the intestine. Each w w -...J TABLE 1 Nematode parasites recovered and faecal worm egg counts of 8 calves slaughtered in 1997 Haemonchus Animal spp. no. L4 1 100 2 190 3 5 4 5 7 35 18 85 21 255 23 0 Mean 84 a* = axei t* = falculatus r* = rugatus c* = colubriformis Ad 20 125 30 15 65 65 65 20 51 Ostertagia ostertagi L4 0 40 55 0 55 15 315 20 62 Trichostrongylus spp. Cooperie; Cooperia pectinata Ad a* t* r* c* Ad 275 330 30 0 0 140 505 4 320 60 0 0 405 215 4 750 235 660 0 40 95 435 20 0 0 55 275 1 330 165 0 0 200 1 385 2 825 0 0 30 665 465 5 595 0 0 0 140 145 920 0 0 0 20 420 2 563 64 83 4 208 TABLE 2 Nematode parasites recovered and faecal worm egg counts (Epg) of 6 calves slaughtered in 1998 Haemonchus spp. Ostertagia Tricho-Cooperia Oesophago-ostertagi strongylus punctata stomum Animal no. axei radiatum L4 Ad L4 Ad Adult Adult Adult R2 1 020 70 0 530 4 650 930 5 R11 180 340 0 480 3 740 2160 55 R12 260 50 0 350 640 570 8 R17 160 440 0 170 440 440 5 R19 640 1 610 0 840 1 340 1 360 8 R22 430 160 0 730 1 620 940 83 Mean 448 445 0 517 2 072 1 067 27 a Moniezia spp. b Avitellina centripunctata Oesophago-Trichuris punctata stomum radiatum Ad Ad 440 8 405 65 770 26 55 1 780 50 1 995 91 210 40 20 3 584 36 Trichuris Buno-spp. stomum Adult Adult 64 0 32 0 34 0 84 0 136 1 80 0 72 < 1 -L_____ Total spp. Ad 3 2 6 0 2 1 1 1 2 Cestodes spp. 0 0 2" 1b 0 0 <1 Epg on worm burden 1 346 6 117 6 792 681 2 957 7157 7 086 1 149 4 161 Total worm burden 7 269 6 987 1 914 1 740 5 935 4 043 4 648 22/7/97 33 33 133 100 200 495 266 100 170 Epg on 15/7/98 300 200 133 300 1 033 167 356 !'- :u r 0 c ~ Helminths of ranch calves in North-eastern Mountain Grassland of South Africa section was mounted upright in chilled lactophenol and the number of longitudinal cuticular ridges (syn-lophe) determined. In only two of the worms exam-ined did the number of synlophe fall within the Hae-monchus placei range. The remaining worms were all in the Haemonchus contortus range (Lichtenfels, Pilitt & Hoberg 1994). H. contortus is predominantly a sheep parasite, but the present study confirmed that it could establish itself in cattle. Such infections are, however, self-terminating because they are ster-ile in the foreign host (Southcott & Barger 1975). This phenomenon was successfully employed by Rei-necke & Louw (1991) to reduce the infectivity of sheep pastures by "vacuum cleaning" with cattle. Anthel-mintic resistance in sheep is rife in South Africa (Van Wyk, Malan & Randles 1997), but is not very common in cattle. When cattle become infected with a sheep strain of Haemonchus which also happens to be re-sistant to anthelmintics, it is likely to be mistaken for an authentic case of anthelmintic resistance in the cattle. The development of Cooperia spp. was not inhibited in the present studies. This is in agreement with what was found by Horak & Louw (1978) who postulated that inhibited development of Cooperia spp. was probably dictated by the severity of cold conditions in autumn and winter. The climate in South Africa does not appear to be cold enough to inhibit the de-velopment of this parasite. Cooperia oncophora is almost completely retarded in Canada (Smith 1974). However, in the arid northern bushveld region of South Africa Horak (1978) recorded extensive inhibi-tion of Cooperia spp. in cattle almost throughout the year. Drought, rather than cold, therefore seems to be the more important environmental trigger in South Africa for Cooperia spp. to slow down its develop-ment in the host in order to escape unfavorable con-ditions in the environment. The development of Hae-monchus was significantly inhibited in the present study. Although worm egg counts in animals with mixed infections are probably species dependant, it is clear from Tables 1 and 2 that there was no correlation between faecal worm egg counts and actual worm burdens. This publication appears to be the first record of the helminth parasite populations of calves reared un-der ranching conditions on the North-eastern Moun-tain Grassland of South Africa. The information should be invaluable to stock farmers in this impor-tant cattle ranching region. ACKNOWLEDGEMENTS This study was made possible by the financial sup-port of Logos Agvet (Pty) Ltd and the Foundation for 338 Research Development. The use of the facilities and equipment of the University of Pretoria is gratefully acknowledged. The temporary and full-time personnel of the Onder-stepoort Veterinary Academic Research Unit, Mr J.C. Kotze, Ms S. Meyer and Mss Eunice Petlele and Karen Louw are sincerely thanked for their techni-cal assistance. REFERENCES BREDENKAMP, G.J. , GRANGER, J.E. & VAN ROOYEN , N. 1996. North-eastern Mountain Grassland, in Vegetation of South Africa, Lesotho and Swaziland, edited by A.B. Low & A.G. Rebelo. Pretoria: Department of Environmental Affairs and Tourism. FOURIE, L.J. & HORAK, I.G. 1990. Parasites of cattle in the south-western Orange Free State. Journal of the South Afri-can Veterinary Association, 61 :27-28. HORAK, I.G. 1978. Parasites of domestic and wild animals in South Africa. XI. Helminths in cattle on natural pastures in the Northern Transvaal. Onderstepoort Journal of Veterinary Re-search, 45:229-234. HORAK, I. G. & LOUW, J.P. 1978. Parasites of domestic and wild animals in South Africa. VI. Helminths in calves on irrigated pastures on the Transvaal Highveld. Onderstepoort Journal of Veterinary Research, 45:23-28. LICHTENFELS, J.R. , PILITT, P.A. & HOBERG, E.P. 1994. New morphological characters for identifying individual specimens of Haemonchus spp. (Nematoda: Trichostrongyloidea) and a key to species in ruminants of North America. Journal of Para-sitology, 80:107-119. LOUW, J.P. 1995. Anthelmintic sales in the Highveld region of Eastern Transvaal. Journal of the South African Veterinary Association, 66:66-70. REINECKE, R.K. & LOUW, J.P. 1991. Disinfestation of irrigated sheep pastures by alternating grazing with cattle. Journal of the South African Veterinary Assocation, 62:156-157. SMITH, H.J. 1974. Inhibited development of Ostertgia ostertagi, Cooperia oncophora and Nematodirus helvetianus in parasite-free calves grazing fall pastures. American Journal of Veteri-nary Research, 35:935-938. SOULSBY, E.J.L. 1968. Helminths, Arthropods & Protozoa of domesticated animals. London: Balliere Tindall & Cassell. SOUTHCOTT, W.H. & BARGER, I.A. 1975. Control of nematode parasites by grazing management- II. Decontamination of sheep and cattle parasites by varying periods of grazing with alternate host. International Journal of Parasitology 5:45-48. SOUTHCOTT, W.H. , MAJOR, G.W. & BARGER, I.A. 1976. Sea-sonal pasture contamination and availabi lity of nematodes for grazing sheep. Australian Journal of Agricultural Research, 27:277-286. TURNER, J.H., KATES, K.C. & WILSON, G.l. 1962. The inter-action of concurrent infections of the abomasal nematodes, Haemonchus contortus, Ostertagia circumcincta and Trichos-trongylus axei (Trichostrongylidae) in lambs. Proceedings of the Helminthological Society of Washington, 29:210-216. VANWYK, J.A., MALAN, F.S. & RANDLES, J.L. 1997. How long before resistance makes it impossible to control some fie ld strains of Haemonchus contortus in South Africa with any of the modern anthelmintics? Veterinary Parasitology, 70:111-112. 

The helminths of ranch calves in the North-eastern Mountain Grassland of South Africa

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The helminths of ranch calves in the North-eastern Mountain Grassland of South Africa

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