Following the label storage instructions
Failure to do so may result in degradation of the drug and decreased deworming effectiveness over time. For example, for best results, Flukiver® must be stored at temperatures below 30°C, should be protected from light exposure and should be discarded after 3 months following opening.
Pasturemanagement to prevent reinfection
Dewormers, provided they are working properly, kill the parasites inside the animal. However, most dewormers are only short acting and do not provide ongoing protection from re-infection. So, if sheep remain on pastures that are heavily contaminated with infective L3 larvae after they have been dewormed, they will continue to ingest larvae, which take just 2-3 weeks to develop into adult worms. Consequently, if animals continue to be in poor condition or have clinical signs several weeks after dewormer administration it may be due to re-infection. In these circ*mstances, it is important to move sheep on to less contaminated pastures.
If all the issues above are monitored, it may be that the parasite is resistant to the dewormer used. Anthelminthic resistance occurs when gastrointestinal roundworms undergo genetic changes that allow them to survive exposure to dewormers. This is now a major problem in western Canada and is discussed in more detail in the next section.
For more information go to the Sustainable Control of parasites (SCOPS) website.
