A survey of equine gastrointestinal parasites in the Wagga Wagga district of NSW

Abstract

Animal Production in Australia 1998 Vol. 22 A SURVEY OF EQUINE GASTROINTESTINAL PARASITES IN THE WAGGA WAGGA DISTRICT OF NSW Y.M. BROCKWELLA, P. ECKEA and P. ROLFEB A B School of Agriculture, Charles Sturt University, Wagga Wagga, NSW 2678 Veterinary Research Consulting, Teen Ranch, Cobbity Rd, Cobbity, NSW 2570 Virtually all grazing horses harbour gastrointestinal parasites which are major factors in the aetiology of equine gastroenteric disease (Duncan and Love 1991). Adequate control of these parasites is necessary to ensure the successful growth and health of horses, but this is often not very well managed. The first step in improved internal parasite control is the identification of the parasites present. Therefore the objective of this study was to determine the species of gastrointestinal parasites, detectable by faecal egg count and differentiation of third stage larvae, present in normal adult horses grazing non-irrigated pasture in the Wagga Wagga district during autumn and winter. Fresh faecal samples were collected from 500 horses and subjected to faecal egg counts and larval differentiation to determine the level and species of parasitic infection present respectively. The egg count technique was a modified McMaster technique (Anon 1988). Parascaris equorum eggs were able to be identified at this stage, while larval cultures were necessary to allow identification of the strongyle species. The faecal culture technique also followed that of Anon (1988) and the third stage larvae were identified according to the key of Soulsby (1965) with Cyathostomum spp. replacing Trichonema spp. (Lichtenfels 1975). Seven species and three genera were identified: Parascaris equorum, Trichostrongylus axei, Gyalocephalus capitatus, Oesophagodontus robustus, Strongylus equinus, S. edentatus, S. vulgaris, Cyathostomum spp., Poteriostomum spp., and Triodontophorus spp. Table 1. Prevalence of equine gastrointestinal parasites Parasite Number of horses (*) Percentage Parasite edentatus capitatus equiinus robustus equor u m Number of horses (*) 18 18 8 7 5 Percentage 3.6 3.6 1.6 1.4 1 Cyathostomum spp. 3 Poteriostomum spp. 1 T. axei Triodontophorus spp. S. vulgaris *An individual horse may have 58 71.6 S. 05 21 G.. 87 17.4 S. 64 12.8 O. 57 11.4 P. more than one parasite present Cyathostomum spp. was the most prevalent parasite occurring in over 70% of surveyed horses, and was the sole parasite detected in 34% of horses. The magnitude of Cyathostomum spp. infection ranged from 20 to 4,140 larvae per gram of faeces. The variation in parasite burdens found in this study may be attributed to the varying management practices in use on the properties surveyed, however the high prevalence of Cyathostomum spp. indicates they are of major importance and one of the equine gastrointestinal parasites to be targeted in future control programs. We wish to acknowledge the financial support of MSD Agvet and the assistance provided by the parasitology department of Elizabeth Macarthur Agricultural Institute. ANON. (1988). Report of the Working Party for the Animal Health Committee of the Standing Committee on Agriculture. Tech. Rep. Series no. 28. (CSIRO: Melbourne). DUNCAN, J.L. and LOVE, S. (1991). Equine Vet. J. 23, 226-228. LICHTENFELS, J.R. (1975). Proc. Helminthol. Soc. Wash., 42, (special issue) 92pp. SOULSBY, E.J.L. (1965). Textbook of Veterinary Clinical Parasitology. (Blackwell Scientific Publications: Oxford). 334