The cold spell of weather in the last week has turned most milking cows and cattle in for housing full-time, which means parasites need to be treated for and controlled during winter.
The College of Agriculture, Food and Rural Enterprise (CAFRE) has offered advice on controlling parasites in your herd.
The dry and mild weather up to now has allowed farmers to keep cows and young stock out grazing, which has given some relief on silage stock for the potentially long winter.
However, now is an ideal time to consider parasite control prior to housing or just as cows are coming in for housing on a full-time basis as parasites are a major cause of underperformance in livestock, and in some cases can result in death.
CAFRE beef and sheep advisor, Jonathan Brown highlighted 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.
If a plan is put in place now, the performance and productivity of these animals won’t be hindered over the winter months.
Worms
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 is the key to ensure the highest level of cattle performance while reducing the risk of anthelmintic resistance.
Roundworms are parasites which can live in many parts of an animal and are usually found in the gastrointestinal tract, and 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 and the most common stomach worm in the UK and Ireland is called Ostertagia ostertagi.
Type II Ostertagia (winter) is typically seen in yearlings following their first grazing season, and is where larvae that are eaten in September do not go through normal development but instead remain dormant in the gastric glands of the animal.
If they are not eliminated, there is the potential for thousands of larvae to simultaneously develop to adults and emerge in early spring.
Controlling parasites
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 you should ask your vet for advice.
Lungworms infect the airways of cattle and can cause parasitic bronchitis, also known as ‘hoose’ and 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, as this will help to assess if re-dosing is be required to ensure that eggs, larvae and adult worms are controlled.
Liver fluke is influenced by the climate and thrives in warm wet weather, which is similar to what we have experienced this autumn.
It takes three months for fluke to develop in the liver of livestock, which 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, but, by waiting for approximately six weeks after the housing treatment, it will be much more effective.
Products which are triclabendazole-based will kill almost 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 and no matter what the ages of your livestock are, there is no resistance to these parasites.
Signs of scratching / hair loss are early indicators of a problem which will lead to poor performance and discomfort and so treatment with a pour on product is normally the most effective way to control this issue.
To aid parasite control, it is advisable to clip animal’s backs and tails at housing, as doing so reduces the cover for parasites to live in, reduces sweating, and keeps animals cleaner.
Caution must also be given to ensure dosing equipment is correctly calibrated when being used, and that the product label dosage rates are adhered to.
