In recent years, more emphasis has been put on advising farmers to identify the presence of specific internal parasites in cattle before anthelmintic products are used.
The easiest way to identify the presence of specific internal parasites is by dung sampling or taking what is known as a faecal egg count (FEC).
A FEC is a test that will identify the level of worm eggs or larvae in a dung sample from livestock and can also be used to detect fluke and coccidial oocysts, according to Animal Health Ireland (AHI).
When determining the best course of action for parasite treatment in cattle, the farm vet should be consulted and an analysis of the FEC will help to determine the best course of action.
From two months after calves are turned out to grass, a regular FEC is advisable and the results can be used as part of a parasite control plan to get a better understanding of the pasture contamination pattern on the farm.
Advice on taking a livestock dung sample that will provide the farmer with an accurate result can be found here.
Young dairy-beef calves on their first season at grass will naturally enough have a very low immunity to worms and will be particularly susceptible to stomach and lungworms.
According to Teagasc, after their first grazing season, cattle generally develop sufficient immunity to prevent clinical disease however, there has being numerous cases where older animals have had high levels of worm burden so regular monitoring is required in older groups to ensure no issues arise.
Regular dung sampling to assess FEC is an excellent way of way of identifying a worm burden in a group. Where readings in excess 200epg (eggs per gram) are recorded, treatment is advisable, according to Teagasc.
When administering a dose, particular attention needs to be given to dose-to-weight calculations, so animals receive a full dose.
There are currently three classes of anthelmintic licensed for the control of stomach worms in cattle:
- Benzimidazole (white);
- Levamisole (yellow);
- Macrocyclic lactone (clear).
When implementing a dosing strategy, farmers are advised to alternate between the different classes of treatment to minimise the risk of a potential resistance build up on farm.
In the case of lungworm, monitoring for clinical signs such as a husky cough or difficult breathing will identify its presence.
Most available anthelminthic lungworm treatments are effective against larval and adult lungworm.
According to Teagasc, Levamisole and white drenches will take out what parasites are there on the day of treatment but will have no residual effect. Macrocyclic lactones such as ivermectins will give longer protection.
For all matters relating to animal health on a farm, the best advice can be sourced from the farms’ veterinary practitioner who will have a clearer picture of animal health incidents in the region and will be best positioned to offer animal health advice.