Coughing Cattle

At this time of year and throughout summer, if you have animals on pasture coughing you should be suspicious of lungworm. Mobs of young calves can be severely affected due to reduced immunity and exposure to high larval loads on pasture, particularly if the same grazing area has been used for growing young stock in the past.

Like intestinal worms, lungworm larvae are ingested from pasture, but then migrate from the intestines, travel through the bloodstream to the lungs where eggs are coughed up or swallowed and excreted into faeces. Lungworm larvae can survive for a long time on pasture and their spread is facilitated by attaching to fungal spores in mushrooms growing in cow pats. A perfect storm can occur following wet weather, long drenching intervals and if calves are being reared on the same paddocks over multiple years

Why worry about lungworm?

A few animals affected may just be the tip of the iceberg as worms become lodged in airways leaving them struggling to breathe. Unlike intestinal worms, only a small number of worms are required to produce clinical disease. Outbreaks can occur when naïve animals with no immunity are exposed to worms for the first time.

Typically, adult cattle have developed immunity, but this is not always the case. Heifers grazing on a run-off block with a continuous drenching program remain naïve and face problems later when they enter the milking herd, as they may not have received enough natural challenge to develop immunity

How will I know if my cattle are affected with lungworm?

Frequent coughing, especially after exercise
Increased breathing rate when resting
Discharge from nose or drooling
Extended head and neck or gasping for air
Reduced milk yield in adult cows
Sudden death
Youngstock may continue to eat but have poor coat and condition

If I suspect lungworm infection, what should I do?

Thankfully, ‘mectin-based’ drenches are highly effective against lungworm and there are no current reports of resistance. Best results are achieved early in the course of disease before structural damage to the lungs occurs and to limit further larval contamination on pasture. The choice of product depends on duration of action and ease of administration.

Clinical signs may worsen after drenching as killed worms accumulate and block airflow in airways.

Also consider:

Removal from affected pasture
Anti-inflammatories are useful to reduce the reaction to larvae in severe cases
Severely affected calves may need re-hydration

Young stock (safe options for under 120kg)

Injectable options

Eclipse E (Eprinomectin, Levamisole), available with B12 + selenium. Levamisole targets Cooperia worms while Eprinomectin is particularly good at killing Ostertagia, so the two active ingredients will kill the two most important parasites in young calves. Provides persistent activity against lungworm.

Dose rate: 1mL/35kg, given under the skin

Oral drenching options

Turbo Advance (Eprinomectin, Levamisole) + cobalt + selenium

A good safe option for calves under 120kg

Dose rate:1mL/10kg, given orally

Turbo Initial (Eprinomectin, Levamisole, Diclazuril) + cobalt + selenium.
Provides cover against intestinal parasites plus protects against coccidia.
A good safe option for weaned calves grazing on pasture and coming off coccidiostat-treated meal before they develop immunity to coccidia.

Dose rate: 1mL/10kg, given orall

Regular drenching intervals for young stock is important for lung worm control.

Adult Cattle

Pour-on-options

Most ‘mectin-based’ drenches (eg. Eclipse pour-on, Eprinex, Arrest C) are effective against adult and immature stages of lungworm but will not have persistent activity against subsequent pasture challenge