Worm burdens in animals at pasture are an inevitable fact of farming in Ireland.
As temperatures increase, the time for worm eggs to develop into infective larvae shortens and when we move into June and July, there is an abundance of larvae on pasture.
Worming is essential to break the life cycle of gutworms where cattle are grazing infected pastures.
Treatments should aim to limit disease and minimise pasture contamination.
Hoose (lungworm) is an added complication in cattle. The best on-farm test for lungworm are the farmers' own ears.
Affected cattle should be treated as early as possible, because severely affected animals may either not respond or symptoms may be exacerbated, as dead or dying larvae block the lower airways and alveoli.
The low infection threshold for disease and the potential for rapid increase of infective larvae on pastures means that outbreaks are unpredictable.
Consequently, the use of clean grazing strategies is less reliable than for other roundworm species.
Clean grazing strategies include:
Strategies to reduce the risk of anthelmintic resistance include:
To identify which parasite control plan suits their system, farmers should consider the following:
Is help available to gather stock multiple times throughout the grazing season?
Using products with licensed persistency (prolonged activity after treatment) can provide for labour-saving solutions by increasing the dosing interval. For example, Cydectin 1% injection and pour-on and Dectomax injection and pour-on all have five weeks persistency for gutworm and up to sis weeks persistency for lungworm. This means dosing interval can be increased to every eight weeks (versus five weeks for ivermectin-based products). Cydectin 10% long-acting injection protects cattle against re-infection with gut and lungworm for up to 120 days, meaning one treatment is generally sufficient until four to five weeks pre-housing.
Is wormer resistance a concern?
Will the cattle be set stocked throughout the grazing season?
Answering these questions can help farmers identify an effective parasite control programme with their adviser.
Once the most appropriate option has been identified, farmers can be guided to a suitable protocol in the dosing chart and treatment dates, which will depend on turnout and housing dates, can be filled in on the chart.
The dosing chart can be downloaded from the following link on the Zoetis website.
With the start of the grazing season under way, now is the time for farmers speak to their prescriber and plan their grazing and worming strategies for the season.
All Cydectin® products contain moxidectin. All Dectomax® products contain doramectin.
Duration of persistency: Cydectin 1% injection, Cydectin Pour-On and Dectomax Pour-On: Ostertagia five weeks, Dictyocaulus six weeks; Dectomax 10mg/ml injection Ostertagia & Dictyocaulus: five weeks; Cydectin 10% Long acting injection Ostertagia & Dictyocaulus: 120 days.