Variation i utsöndring av blodmaskägg hos häst

Sammanfattning: Due to an increased occurrence of resistance towards anthelmintics among equine endoparasites today, it is recommended that selective therapy is performed to minimize the use of anthelmintics. Selective therapy means that only infected individuals will be treated. Faecal samples are collected and analysed to find out whether the horse should receive treatment or not. Today the faecal samples are randomly collected by the owner, which could lead to a variation in the result. The instructions concerning how and when the sample should be collected are very simple and could possibly be more precise. The purpose of this study is to examine if the instructions for faecal sampling could affect the result of the samples. Questions asked were: does the occurrence of parasites change over time; does the occurrence of parasites differ between morning and night and does the occurrence of parasites vary in a pile of dung? The hypothesises were: the occurrence of parasites change over time; the occurrence of parasites do not differ between morning and night and the occurrence of parasites do not vary in a pile of dung. The trial was split up into three sub studies. In sub study one we followed five horses during six weeks, samples were collected once weekly. Sub study two followed two horses, two times a day during fourteen days. Samples were collected both morning and night with a twelve-hour interval. During sub study three we collected three dung balls from each pile of dung, with a total of 30 piles. The dung balls were individually analysed. The modified version of the McMaster-method was used for all egg counting. The results from sub study one showed a significant difference in egg shedding in 20% of cases (3 of 15 comparisons). The difference was significant only when week one was compared with other weeks. Sub study two showed a significant difference in egg shedding between morning and night during four of fourteen days (28,6%). During three of these four days, the shedding of eggs was higher in the morning than by night. Sub study three showed that there was only a small difference in egg shedding between a dungball and the whole pile of dung. The conclusion that was made were that the instructions for collecting samples were sufficient. Concerning sub study one, we argue that the variation seen in our result is likely due to methodological errors during the first week’s samples. Thereby the hypothesis “the occurrence of parasites change over time” is rejected. Both hypothesis “the occurrence of parasites does not differ between morning night” and “the occurrence of parasites does not vary in a pile of dung” are assumed.