Parasite detection in extensively hold Gotland ponies

Abstract: Horses are herbivores that spend almost all day grazing. While grazing they are infected by different endoparasites through ingestion of infective eggs or larvae on pasture. The most significant equine endoparasites in Sweden are the equine roundworm Parascaris equorum, small (Cyathostominae) and large strongyles (Strongylus spp), the tapeworm Anoplocephala perfoliata and the pinworm Oxyuris equi. For many years have horses been dewormed on regularly basis, which has resulted in the development of resistance to many anthelmintic classes. Because of the problems with resistance it is since 2007 necessary to have a prescription on anthelmintics and faecal sampling is also recommended. Endoparasites can cause different clinical signs such as weight loss and diarrhea. Therefore it is important to deworm horses with large worm burdens. Depending on what kind of parasite the horse is infected with is there different appropriate anthelmintics. There are three major anthelmintics: benzimidazoles, tetrahydropyrimidines and macrocylic lactones. In this study was the purpose to evaluate how the parasite prevalence is affected by extensive holding of horses on the same pasture for a year. Moreover the horse grazing and defection behavior was evaluated. Twelve one year old stallions of the breed Gotland ponies were held in three enclosures with four horses in each. The horses were kept outside all year round without extra feeding and were included in a bigger project called “russprojektet”. In this master thesis was among others faecal samples analyzed for the equine roundworm Parascaris equorum, large and small strongyles as well as the tapeworm Anoplocephala perfoliata. The result showed a significant difference between the amount of strongyle eggs during different seasons but no significant differences were seen between horses or enclosures. In addition, it was seen that the horses grazed in an unstructured pattern and that no sign of toilets were observed.