Controlling worms and fluke at housing should be considered to reduce problems next spring. Sara Gregson reports...
Housing is a good time to sort out parasite problems in beef and dairy cattle, as they can be treated and cleared of infection before turnout next year, says Prof Jacqueline Matthews of the Moredun Research Institute and a member of the Control of Worms Sustainably knowledge transfer group.
She says: “There is a real risk of Type II ostertagiosis in youngstock this winter, following the summer drought and subsequent wet conditions across many parts of the country.
“This disease is caused by larvae of the stomach worm which are eaten in autumn as the days become shorter and temperatures fall. These larvae do not immediately develop into adult worms, as they would earlier in the season.
“The larvae hibernate for a few months until late winter, when they resume development after an, as yet unknown, trigger. The simultaneous emergence of a high number of stomach wall worms can cause acute disease, particularly in calves after their first season grazing. It can be fatal.”
Prof Matthews suggests the best way to avoid this is to treat youngstock at housing with a Group 3 macrocyclic lactone (ML) product to kill off the inhibited Ostertagia larvae.
This will have the added benefit that calves will not contaminate pastures with worm eggs when they go out next year.
Adult cows should not require treatment for gut worms at housing, but they may benefit if they are in poor condition. Diagnostic aids, such as blood and milk tests, can help see if treatment is needed.
Farmers should talk to their vet or suitably qualified person about which tests are most suitable and the results of any that are carried out.
There is no natural cattle immunity to liver fluke and all ages of stock can be at risk. It is important to look at several factors to assess whether treatment can be justified.
Has there been a history of infection on the farm? Have the animals been grazing wet, muddy areas where intermediate host mud snails live? What do liver fluke forecasts such as those produced by the National Animal Disease Information Service, predict?
Prof Matthews says: “The overall burden of liver fluke on pasture will be much lower in areas which suffered drought conditions this summer. But it is dangerous to assume this applies to all farms or even to all areas of a farm.
“In dry years, infective stages of liver fluke will be concentrated around permanently wet patches, such as drinking points, which of course is where the animals congregate too.”
Prof Matthews urges farmers to take an informed decision as to whether to treat for liver fluke and to test to see if treatment is necessary.
She says: “Testing can help avoid any needless treatments of animals which are not harbouring liver fluke. This saves time and money and helps protect the few medicines available to combat this parasite.”
Liver fluke treatments target different ages of the parasite so it is important to check the datasheet details of products being used. In dairy cattle, it is also crucial to check milk withdrawal dates as these differ greatly between products.
When cattle are housed, watch out for signs of lice or mange mites, such as itching, hair loss and scaly lesions. Populations increase over winter when the animals’ coats are at their thickest.
Prof Matthews says: “If you see cattle itching ask the vet to take a sample to identify exactly what you are dealing with before deciding how to treat.
“Where there is a positive diagnosis, treat all the animals in the group as young calves housed closely together are likely to spread ecto-parasites quickly.”
Northamptonshire beef and arable farmer Mark Jelley runs a sucker herd of dairy-cross cows, which are mated to a continental beef bull. The progeny is finished and marketed through ABP, with 20 heifers also being sold to a local catering butcher.
Mr Jelley discusses worming with his vet at Towcester Farm Vets and it is part of the herd health plan. Faecal egg count testing has just started to help determine the need to treat.
Last year at housing the cows and youngstock were treated with a pour-on, a Group 3 ML clear product with ivermectin as its active ingredient. This controls roundworms, lungworm and ecto-parasites, such as mites and lice.
Mr Jelley says: “Pour-on products are quick and easy to apply. However, we are looking to broaden our product use in future to include other active ingredients and application methods.”
In spring, half the young heifers go back out to finish at remote pastures where cattle handling is difficult. This year these were given an injectable Group 3 ML clear product for roundworms and lungworm.
The other heifers were kept at home and not treated. They were monitored by weighing and having their growth rates checked regularly.
Mr Jelley says: “Historically we have not had a liver fluke problem, although two of the 45 animals showed up with active liver fluke damage in the latest slaughter reports.
“We have taken on some land on as Farm Business Tenancy, which has a stream running by it, so it could have been home to some infected mud snails. We have now fenced the stream and have piped drinking water into the field.”