What is it?
Dictyocaulus viviparous is a parasitic roundworm which directly affects the lungs causing tissue damage and inflammation. It has a severe effect on both beef and dairy production, affecting welfare, BCS, impaired growth rates, milk production and a risk of secondary bacterial infections. Deaths can be seen as early as 1-2 days post-symptoms. While cases tend to peak around September, they are unpredictable and can occur anytime from June to December. Losses in growing cattle are estimated to be between £50-£100 per head, and dairy cows can experience a fall in milk production of up to £3 per cow per day.
Which cattle are most at risk?
The disease commonly affects calves in their first grazing season or those who lack previous exposure and have thus developed no immunity against the disease. Usually, autumn-born calves during their first grazing season the following summer or spring-born calves during their second season at grass.
Lungworm larvae do not survive for long periods on pasture and are normally killed by dry summers and cold winters. Adults may be asymptomatic carriers and a cause of spread. It is also thought lungworm larvae can be spread by other means such as an animal’s feet, vehicle wheels, boots and possibly even on the wind. Thus, outbreaks of lungworm can be unpredictable, so vaccination before turnout protects a herd from walking into a potential minefield.
Lungworm Prevention
Cattle can produce an immune response to lungworm larvae and adult worms, forming some immunity. This immunity can wane after a few months unless cattle are exposed to low-level contamination on the pasture.
Vaccination is the most predictable method of building herd immunity to protect against lungworm.
Cattle over 8 weeks of age entering their first grazing season can be vaccinated for lungworm by giving two doses of an oral vaccine, four weeks apart. The vaccine contains irradiated lungworm larvae which stimulates immunity. Cattle then need to be turned out onto low-level infected pasture no sooner than 2 weeks after the second dose, which allows them to boost their immunity naturally.
If you would like more information on the vaccine and how it could help protect your herd, please contact one of our Farm Vets.
