Summer Beef Series is in conjunction with Teagasc’s DairyBeef 500 campaign
An important factor to achieving the desired levels of animal performance on calf-to-beef systems during the grazing season is ensuing they are free from parasites.
Parasites can have a significant impact on animal performance, therefore it is imperative that stock are free from burdens to prevent any impact on thrive.
With the majority of dairy-beef stock now outdoors, the last number of months’ burdens have started to develop, therefore it is important to monitor and treat these to prevent any reduction in performance.
Worms
Worms are a particular issue in dairy calf-to-beef systems due to the fact the majority of the animals on the farm have very little immunity to worms due to their age profile, with stomach and lung worm been the main offenders.
Calves are particularly vulnerable to infection from stomach worms and this can result in ill-thrift and reduced growth rates.
After their first grazing season cattle generally develop sufficient immunity to prevent clinical disease, however there have been numerous cases where older animals have had high levels of worm burden therefore regular monitoring is required in older groups to ensure no issue arises.
Symptoms of stomach worms can include diarrhoea, decreased appetite and loss of weight. Stomach worms can cause severe damage to the stomach and small intestine which will cause parasitic gastroenteritis, therefore monitoring is essential to prevent such issues from arising.
Regular dung sampling to assess faecal egg counts (FEC) is an excellent way of way of identifying a worm burden in a group. Where readings in excess 200epg are recorded, treatment is advisable.
Parasite control
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).
These products have been highly effective in controlling stomach worm infection in cattle, however recent studies carried out by Teagasc showed resistance to all three classes of product.
When implementing a dosing strategy it is good practice to alternate between the different classes of drug to minimise the risk of a potential resistance build up on-farm. Taking a dung sampling a few weeks after treatment is good practice to ensure the product used gave an effective treatment.
In the case of lung worm, monitoring for clinical signs such as a husky cough or difficult breathing is the best way to identify if there is an issue.
The recent rain after the prolonged dry spell will result in high levels of infestation, therefore in the coming days farmers need to be particularly vigilant. Heavy infestations can lead to respiratory disease therefore rapid treatment is advised.
As regards treatment and control, most available anthelminthic are effective against larval and adult lungworms.
Levamisole and white drenches will take out what parasites are there on the day of treatment, but will have no residual affect and as a result shorter treatment intervals will be required whereas macrocyclic Lactones such as Ivermectins will give longer protection.
Best practice when dosing
When administering a drench to stock, particular attention needs to be payed to dose-to-weight calculations so animals receive a full dose.
Farmers should dose based on the weight of the heaviest animal in the bunch and where a large degree of weight variation exists, splitting the group into a heavier and lighter group and then dosing based on the heaviest in each group is advisable.
When choosing a product it is important to read the label and instructions carefully to ensure that you know exactly what the dose can and cannot treat. Post-treatment it is best to dose and return to dirty pasture as this will help to reduce anthelmintic resistance.
By Tommy Cox, DairyBeef 500 advisor