As the summer grazing season is now in full swing farmers are being urged to consider dosing strategies for dairy beef animals.
According to Teagasc, ensuring cattle are free from parasites plays a crucial role in animal performance in calf-to-beef systems.
Due to its grass-based nature, dairy beef systems can be particularly exposed to outbreaks of stomach worms and lungworm.
Farmers are advised to closely monitor the parasitic burden among their herd during the summer grazing period.
Worms
Teagasc has said that calves are especially vulnerable to stomach worms, which can cause reduced growth rate.
Although cattle develop immunity to prevent clinical disease after their first grazing season, there has been numerous cases of older animals with high levels of worm burden.
Farmers should be vigilant for symptom of stomach worms, which can include diarrhoea, decreased appetite and loss of weight.
As the name suggests, these worms can cause severe damage to the stomach and small intestine in cattle, leading to parasitic gastroenteritis.
In order to determine the level of worm burden in a herd, farmers can ask their vet to carry out a faecal egg count (FEC) test to determine if dosing is required.
In order to avoid worm resistance building up on farms, farmers should take dung samples to see if a worm dose is warranted or not.
Teagasc advises that where readings in excess 200epg are recorded, treatment is necessary.
Control of stomach worms on dairy calf to beef farms is usually achieved by the administration of anthelmintic doses.
There are currently three classes of anthelmintic licensed for the control of stomach worms in cattle – benzimidazole (white), levamisole (yellow) and macrocyclic lactone (clear).
Although these products are highly effectively in controlling infections, Teagasc research has shown resistance to all three classes of product.
Therefore, when farmers undertake a dosing strategy, it is advisable to alternate between the different classes of drug to minimise the risk of a potential resistance build up on farm.
For lungworm, Teagasc said that farmers should look out for animals having a husky cough or difficult breathing.
Heavy infestations of lungworm can result in respiratory disease or pneumonia.
Most anthelmintics available on the market are effective against larval and adult lungworms.
Levamisole and white drenches will kill whatever parasites are there on the day of treatment, but will have no residual affect.
On the other hand, Macrocyclic Lactones such as ivermectins will give longer protection.
Dosing
When farmers are administering a drench to stock, they should be aware of dose-to-weight calculations, so animals receive a full dose.
Teagasc said that farmers should dose based on the weight of the heaviest animal in the bunch.
If there is a large variation in weights, divide the animals into a heavier and lighter group and then dosing based on the heaviest in each group.
When choosing a product, it is important that farmers read the label and instructions carefully to determine what the dose can and cannot treat.
Teagasc added that it is best to dose and return to dirty pasture post treatment, as this will help to reduce anthelmintic resistance.