Pneumonia Respiratory distress dyspnoea

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2.1.5 Reduced grooming of the nose with the tongue

Reduced grooming of the nose and resulting accumulation of nasal secretions in the nares occurs in sick cattle. It may be an early sign of systemic disease.

2.1.6 Oesophageal and gastrointestinal obstruction

Oesophageal and gastrointestinal obstruction are discussed under the syndrome Abdominal distension below.

2.2 Respiratory distress dyspnoea

Dyspnoea occurs when breathing is affected by physical, physiological or environmental factors, either alone or in various combinations. Dyspnoea is most often associated with disease of the respiratory tract such as airway obstruction, pneumonia, tracheitis, bronchitis, or alveolitis. Pulmonary congestion, pleural effusions, hypoxaemia, neuromuscular dysfunction and abdominal distensionthoracic compression may also cause dyspnoea. Exertion will cause temporary dyspnoea. Heat stress is a common cause of dyspnoea in breeds not tropically adapted. Dyspnoea accompanied by coughing is indicative of tracheobronchial disease. The most likely differential diagnoses in shipboard cattle with respiratory distress include: • pneumonia • heat stress • bloat causing compression of diaphragm • physical exertion • hypoxia from engine exhaust gases, or exposure to toxins in feed nitratenitrite, cyanide

2.2.1 Pneumonia

Pneumonia is a common and serious disease in long voyages where there are combinations of crowding, heat or cold stress and inadequate ventilation. The extent of disease is usually only fully appreciated when deaths occur or lungs of slaughtered animals are examined at destination. A number of viral, bacterial and mycoplasmal pathogens may act individually or combine to cause disease. In feedlots, the recognised pathogens are bovine herpesvirus 1, bovine respiratory syncytial virus, bovine coronavirus, bovine viral diarrhea virus, Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, Arcanobacterium pyogenes, Salmonella spp., and Mycoplasma spp. – the same situation likely applies in shipboard cattle. Stress with or without viral infections suppresses host defenses allowing proliferation of commensal bacteria in the upper respiratory tract and subsequent extension to the lower respiratory tract to cause pneumonia which can extend to pleurisy. Fever, inappetance and depression in the absence of obvious respiratory signs may be indications of early to advanced pneumonia. Nasal discharge may be present. The earliest cases of heat stress may be animals with pneumonia. Cattle with pneumonia deteriorate very quickly in hot humid conditions as normally functioning lungs are an important means of shedding heat load. Misdiagnosis of presence or absence of pneumonia based on auscultation and percussion of the thorax is notoriously common. Unlike normal cattle, close observation will usually detect 10 a distinct breathing effort that may be fast or slow, but usually shallow because of pleuritic pain. Treat suspected cases with antibiotics, isolate in a well ventilated area if practicable and maintain hydration. Low stocking rates, good ventilation and vaccination against respiratory pathogens can markedly reduce morbidity and mortality from pneumonia.

2.2.2 Heat stress