Lungworm and BRD in adult Brahman cattle
Unusual presentation:
About 10% of a mob of 250 cows showed respiratory signs and six died. The affected animals were lactating and in poor body condition.
Above: PM revealed areas of consolidation in the lungs and pleural effusion
Below: Adult lungworm in lungs (left) and trachea (right)
Time and location: September 2023, Tablelands FNQ
Case definition: Adult Brahman cows in poor body condition with coughing, increased respiratory rate, abnormal lung sounds, elevated temperatures and mortalities.
Disease mapping: Deaths occurred over a two week period. Affected cattle were in an area where stocking density was high and pasture availability was low. In May 2023 the mob had been moved from a property in western Queensland to the Tablelands in FNQ on agistment. They were treated for ticks and worms upon arrival and again in July.
Gross findings: Adult lungworms were seen in the trachea and the lungs, which were consolidated, with pleural fluid.
Field differential diagnoses: Lungworm and pneumonia
Laboratory findings:
- Diffuse, severe, bronchointerstitial pneumonia
- Adult and larvae Dictyocaulus sp
- Bacterial pathogens associated with BRDC (including Pasteurella multocida, Bibersteinia trehalose, Mycoplasmopsis bovis) were cultured from lung tissue. No Haemophilus sp was isolated.
- Diffuse periacinar hepatic necrosis, probably a result of hypoxia.
Animal / management / environment risk factors: This multifactorial pneumonia involved: naïve animals introduced to pastures containing parasites; likely immunosuppression due to overstocking, nutritional/metabolic stress of lactation; and wet/cold climatic conditions.
Recommendations:
- Immediately treat all stock with effective anthelmintic.
- Treat clinically affected animals with antimicrobial and anti-inflammatories.
- Reduce stocking density and consider supplemental feeding.
- Always take care with introduction of stock from different areas.