Respiratory conditions

There are a number of respiratory conditions which can affect calves, young stock and adult cattle. These include pneumonia, calf diptheria, lungworm and nasal granuloma. Dairy Australia has a range of information to help dairy farmers understand the conditions which affect the respiratory system of calves, young stock and adult cattle.

Calves and young stock

Respiratory conditions that affect calves and young stock include:

Pneumonia
Calf diphtheria (also known as laryngeal necrobacillosis)
Lungworm

Adult cattle

Respiratory conditions that affect older cattle include:

Pneumonia
Nasal granuloma

Pneumonia

Symptoms

Animals are often visibly unwell
Nasal discharge and/or coughing
Laboured breathing
Animals may have a high temperature (greater than 39.5°C)
Sudden drop in milk production in lactating cows
Some animals may be found dead

Cause

Pneumonia is usually caused by a combination of viruses and bacteria. Examples of viruses involved in the cause of pneumonia include Infectious Bovine Rhinotracheitis (IBR) and Bovine Viral Diarrhoea Virus (BVDV, also known as pestivirus).

Some bacteria, such as Mycoplasma sp., can cause pneumonia on their own. Occasionally, cows that have been down with milk fever can develop aspiration pneumonia from breathing in rumen fluid.

Animals likely to be affected

Pneumonia can occur in any age group. Outbreaks may be triggered by stressful situations such as mixing of different groups of cattle, transport or crowding.

Confirming the diagnosis

Pneumonia can be often be diagnosed based on the symptoms. Dairy farmers should consult their veterinarian if they are unsure. Laboratory tests may be required to determine the exact cause of pneumonia.

Treatment

Treatment of pneumonia usually involves the administration of appropriate antibiotics and anti-inflammatories. Severe cases may require additional supportive treatments such as intravenous fluid therapy. Early detection and treatment will improve the prognosis. Some animals may need to be culled due to permanent damage to the lungs.

Risk factors

Calves

Poor colostrum management
Overcrowding
Inadequate ventilation
Stress
Mixing of different groups of animals

Older cattle

Mixing of different groups of animals
Changes in diet
Stress
Sudden changes in weather
Overcrowding

Prevention

Pneumonia may be prevented by maintaining a closed herd and preventing exposure to the risk factors above. There are vaccines available against some viral and bacterial causes of pneumonia. Good colostrum management is required to ensure protection from vaccinations given to cows are passed onto the calf. Vaccines against IBR should be used with caution in heifers intended for export.

Calf diptheria

Symptoms

Animals are often visibly unwell and have a high temperature (greater than 39.5°C)
Noisy breathing ('roaring' or 'honking' sounds)
Usually only single animals affected

Cause

Calf diptheria is an infection of the throat caused by a bacteria called Fusobacterium necrophorum. This is the same bacteria that causes footrot in cattle. It may also occasionally cause infection of the cheeks.

Animals likely to be affected

Calf diptheria occurs most commonly in weaned calves, although it may also occur in younger animals.

Confirming the diagnosis

Diagnosis is usually made based on the symptoms listed above. Dairy farmers should consult their veterinarian if they are unsure.

Treatment

Treatment involves a long course (usually two weeks or more) of an appropriate antibiotic as well as a steroidal anti-inflammatory. A breathing tube may need to be placed in severely affected animals having difficulty breathing.

Risk factors

Risk factors include feeding of 'scratchy' feeds such as straw, exposure to irritants and mild viral infections that cause inflammation of the lining of the throat.

Prevention

There are no specific preventative measures for calf diphtheria.

Lungworm

Symptoms

Sudden, sharp coughing
Increased breathing rate
Many animals may not show any other signs of disease
Severely affected animals show weight loss, lethargy and difficulty breathing

Cause

Lungworm disease is caused by a parasite called Dictyocaulus viviparous. The immature parasites live on pasture where they are consumed and migrate from the intestinal tract through the body to the lungs where they develop into maturity. Eggs are then coughed up and swallowed, hatch and travel through the intestinal tract and are deposited back onto pasture. Symptoms are caused by the presence of worms in the airways.

Animals likely to be affected

Lungworm typically affects young stock less than 10 months of age. It may occasionally occur in older cattle that have no prior immunity to lungworm.

Confirming the diagnosis

Lungworm diagnosis can be made by testing manure samples with a special laboratory technique called a Baermann test which looks for immature parasites. Counts of more than 50 larvae per gram indicate a moderate to heavy burden. Parasites can also be seen in the airways on post-mortem examination by a veterinarian.

Treatment

Treatment involves administration of a suitable anti-parasitic drench. The white drenches, 'mectins' and combination drenches tend to be most effective. There is currently no known drench resistance in the lungworm parasite.

Risk factors

Lungworm risk factors include high stocking rates, using the same paddocks to rear calves in consecutive seasons and exposure to stress, such as poor nutrition.

Prevention

In most cases, drench treatments used to control gastrointestinal worms are sufficient in also controlling lungworm. Good nutrition is also helpful, as is avoiding the use of the same paddock for calf rearing in consecutive years. Dairy Australia's Heifers on Target resources can be used to assess whether the diet is meeting the nutritional needs of young stock.

There is a lungworm vaccine available overseas, but it is not currently available in Australia.

Nasal granuloma

What to look for

Profuse yellow or orange discharge from both nostrils
Animals are usually well otherwise
Animals may have foreign material such as sticks lodged in their nostrils from scratching
Usually occurs in Jersey and Jersey-cross cattle
Chronic disease but often worsens in summer

Cause

Nasal granuloma is an allergic disease of the nostrils. It is thought that the allergen may be pollen, pasture mites or a previous viral infection.

Animals likely to be affected

Adult Jersey cattle and their crosses are most commonly affected by nasal granuloma.

Confirming the diagnosis

Nasal granuloma should be suspected in animals with a yellow or orange nasal discharge that are observed scratching their nostrils on stalky weeds, bushes and branches. The inside surface of the nostrils often has multiple raised nodules. Dairy farmers should consult their veterinarian if they are unsure.

Treatment

There is no treatment for nasal granuloma. The severity of the condition often decreases in the cooler months but worsens year on year. Affected cows often require culling for economic reasons.