Plan now for effective parasite control in cattle

Date published: 21 November 2024

There has been a welcome relief in weather conditions recently allowing farmers one last opportunity to boost forage stocks and extend their grazing season. However, over the coming weeks any remaining livestock will be housed. Now is an ideal time to consider parasite control prior to housing.

Parasites are a major cause of underperformance in livestock, and in some cases can result in death. Jonathan Brown, CAFRE Beef and Sheep Adviser highlights that “It is estimated that the cost of raising a beef or dairy calf to finishing or breeding condition is increased by at least 30% if that animal harbours even a moderate burden of gastrointestinal parasites.”

The main parasites that need to be targeted are lungworms, stomach worms and liver fluke along with external parasites such as biting and sucking lice and mites. By formulating and implementing an effective parasite plan now, livestock performance will not be compromised over the winter period.

Young cattle have no resistance to lung and stomach worms, so must be treated as a priority. Choosing the correct product and getting the best results in return are key factors in ensuring the highest level of cattle performance at least cost whilst reducing the risk of anthelmintic resistance.

Roundworms are parasites, which can live in many parts of an animal. They are usually found in the gastrointestinal tract. Roundworms can deprive an animal of nutrients by eating tissue, sucking blood, or eating stomach contents.

Stomach worms are a type of roundworm that live in the abomasum of cattle. The most common stomach worm in the UK is Ostertagia ostertagi. Type II Ostertagia (winter) is usually seen in yearlings, following their first grazing season. Larvae that are eaten in September do not go through normal development but instead remain dormant in the gastric glands of the animal. If these are not eliminated there is the potential for thousands of larvae to simultaneously develop to adults and emerge in early spring. To pre-empt this a wormer that is effective against inhibited larvae should be used at housing. In general adult cattle over two years of age will have built up a natural immunity to worms, however any symptoms such as poor thrive, weight loss or reduced appetite should be investigated further and advice sought via your vet.

Lungworms, infect the airways of cattle and can cause parasitic bronchitis, also known as ‘hoose’. Livestock should be treated with either a white, yellow or clear drench. It is important that farmers know what developmental stage of the stomach or lungworm they are trying to target. This will help to assess if re-dosing will be required to ensure that eggs, larvae and adult worms will be controlled.

Liver fluke is influenced by the climate and thrives in warm wet weather - similar to what we have experienced this autumn. It takes three months for fluke to develop in the liver of livestock. This is why it is of utmost importance to understand which stage you are treating. The first month they are called ‘early immature’, the second month they are called ‘immature’ and the third month they are known as ‘adults’.

By dosing for fluke at the time of housing, you will potentially only kill off the adult fluke. However, by waiting for approximately six weeks after housing treatment will be much more effective. Products which are triclabendazole-based will kill all stages of fluke, however, cases of resistance to these products are becoming common due to overuse.

Housing provides the ideal environment for external parasites such as lice and mites to thrive. All ages of livestock have no resistance to these parasites. Signs of scratching/ hair loss are early indicators of a problem which will lead to poor performance and discomfort. Treatment with a pour on product is normally effective to control this issue.

To aid parasite control, it is advisable to clip animal’s backs and tails at housing. This reduces the cover for parasites to live in, reduces sweating, and keeps animals cleaner.

Consultation with your vet is paramount to ensure parasite control at housing is an integral part of your year-round health plan. Caution must also be given to ensure dosing equipment is correctly calibrated and used, and product label dosage rates are adhered to. For further advice on all aspects of herd management contact a CAFRE Beef and Sheep Adviser via your local DAERA Direct office.