Where this is not possible, infection should be suppressed with the use of anthelmintics. The cost of control varies according to the persistency. Wormers based on the ingredients benzimidazole and levamisoles are effective but involve regular dosing every three weeks, as these products have no residual activity. Alternatively, avermectins are significantly more expensive but are persistent and can be justified when labour is limiting. Dosing is required less frequently at typically three, eight and 13 weeks.
Anthelmintics work best if the animal has been fasted for a few hours before dosing.
If you are turning stock to clean pasture, as in second cut aftermaths, house stock for 12 hours after dosing as this will reduce the infection carried to the clean pasture. Calving index is one of the most common and basic measures of herd fertility. Now, when the entire herd is calved, is an appropriate time to establish the calving index for the past season. List all the cows which calved down this past season and note the last calving date and also the previous calving date for each cow. Use a calendar to calculate the number of days between the 2 dates.