Changes in prevalence and abundance of parasitic invasions in sheep at various physiological stages

Abstract

The aim of the study was to determine the degree of parasitic invasion at various physiological stages, as well as tracing the dynamics of parasitic invasions in a flock of sheep kept in the combined indoor-pasture management system. The observations were performed on 224 mother ewes of the synthetic SCP prolific meat line over the course of two years. The animals were kept in the combined indoor-pasture management system with uniform feeding and environmental conditions and were under continuous animal husbandry and veterinary supervision. The ewes participating in the experiment were not wormed in the year preceding the experiment and during the observations. The experiment involved parasitologic tests aimed at the determination of abundance and prevalence of invasions of gastrointestinal parasites in mother ewes. The study material was faeces collected from the rectum in the following stages: pregnancy (November), day 2, 28, 42 and 56 after lambing, drying off (day 100 after lambing) and rest (between dry-off and mating). In the analysis of the results of the study it can be noted that, in most cases, the highest prevalence and abundance levels are observed in the infertility period. Moreover, the period of pregnancy and lambing was a crucial one. On the other hand, the lowest abundance and prevalence levels in the majority of cases were observed on day 28 and 42 after lambing. The results of the study should be taken into consideration during the development of prevention strategies limiting parasitic invasions in sheep flocks. Adjusting chemotherapy to the most important periods of parasitic invasions will enable a more efficient fight against parasites. It should also reduce the excessive use of chemical preparations, which is crucial due to the increasing resistance of parasites. Apart from the aforementioned actions, farmers should pay attention to supporting immunity by means of feed, especially in the periods of highest vulnerability to invasions. Such actions should lead to the reduction of losses caused by parasitic invasions in sheep flocks.