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The importance of lungworm control in cattle

Cattle lungworm is a cause of serious respiratory disease in youngstock as well as in adult cattle. However, taking a proactive approach to prevention and rapidly treating outbreaks can lessen the negative impact on herd productivity and help to reduce your long-term costs.

Lungworm infections typically occur in cattle from July onwards and, depending on climate conditions, the disease can be seen as late as November.

It can cause significant losses in a dairy herd, due to:

  • reduced milk yield
  • reduced fertility rates
  • dead or culled animals
  • the cost of veterinary treatment
  • affected cows will be more susceptible to other respiratory diseases.

It’s not too late to plan your approach to lungworm control this year

If you have already turned your cattle out and haven’t vaccinated them against lungworm, talk to your vet or animal health advisor at Mole Valley Farmers, or ideally both. They will be able to give advice about strategic lungworm treatments and grazing management techniques to protect your cattle against lungworm and other productivity-limiting parasites.

Practice pasture management

Warm, wet weather provides optimal conditions for lungworm. Populations of infective larvae can establish very quickly on pasture. Studies have shown that, just 30 days after an animal has been infected with a low dose of 200 lungworm larvae, 2.5 million infected larvae can be shed onto the pasture, due to the parasite’s fast, direct lifecycle.

Rotating paddocks, strip grazing and use of silage aftermath later in the season can be effective measures to reduce pasture larvae load and worm challenge faced by cattle.

“Cattle gain immunity to lungworm infections through vaccination pre-turnout or low levels of natural exposure on pasture,” explains Sioned Timothy, Technical Manager at Boehringer Ingelheim Animal Health UK “Youngstock and immunologically naive cattle are at greatest risk of respiratory disease caused by lungworm. Worm control strategies should allow some exposure to occur, as this will trigger an immune response, but prevent a high lungworm challenge that could cause clinical disease.

“Maintaining this fine balance between exposure and immunity is crucial and the precise strategy should be developed for each individual farm with your vet and Mole Valley Farmers animal health advisor.”

Be alert to signs of disease

Lungworm should always be considered as a potential cause of coughing in grazing cattle. However, early infection can be difficult to spot and may only be recognised once a full outbreak occurs

. Lungworm can sometimes be confused with Infectious Bovine Rhinotracheitis (IBR), especially in older cattle, but affected animals will typically have a deep, harsh cough and may exhibit laboured breathing. Severely affected cattle may extend their head and neck in an ‘air hunger’ position.

Affected cattle may rapidly lose condition and if lactating, show a sudden drop in milk production. They may also be seen resting more often and eating and drinking less than normal.

Some animals may remain asymptomatic, with studies showing that up to 10% of cattle may be subclinical carriers of lungworm. These animals contribute small numbers of larvae to the pasture but function as a reservoir of infectivity.

Treat disease rapidly

Where lungworm is confirmed, the whole herd or group must be treated, ideally with an anthelmintic that offers prolonged activity against Dictyocaulus viviparus. Preventing immediate reinfection helps the animal’s lungs to recover and prevents further damage during the treatment phase.

Anthelmintics with a zero-milk withhold period, such as those containing eprinomectin, can allow lactating cows to be treated for lungworm, without the loss of milk sales. Severely affected cattle will require veterinary assessment and supportive treatment to relieve pain and inflammation and treat secondary infections. The importance of lungworm control in cattle

References 1. Vercruysse J, Janssens PG, Vercruysse J, Jansen J (1989) Dictyocaulosis. Worms and Worm Diseases Samson Stafleu, Alphen aan den Rijn/Brussel, pp 210-222 1. Eysker M, Classens EW, Lam TGM, Moons MJ, Pijpers A (1994) The prevalence of patent lungworm infection in herds of dairy cows in the Netherlands. Veterinary Parasitology 53 (3-4) 263-267

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