a stress, usually transport. Treatment is with oxytetracyclines and NSAIDs, and this is normally successful so more modern and expensive antibiotics are not required. There is a vaccine available.
Respiratory diseases caused by fungi and their treatment
Aspergillosis
This is extremely rare but will occur in very badly ventilated cattle sheds when mouldy straw is used. Actual hyphae will be seen in the lungs of this invariably fatal condition. A more common condition is a hypersensitivity reaction to the fungal spores which will give signs of acute respiratory distress similar to ‘fog fever’ in adult cattle. Fresh air and dexamethazone are the required treatment.
Respiratory diseases caused by parasites and their treatment
Lungworm (parasitic bronchitis)
This occurs 3 weeks after ingesting Dictyocaulus viviparus larvae. The excellent oral vaccination against this condition, which uses irradiated larvae, is sadly being neglected with the use of pour-on ivermectin-type anthelmintics. The animals at risk are 2 year old breeding heifers and, of course, adult cows. Lungworm causes devastating effects in naive adults, with very marked violent coughing. (Plate 2). Mortality may be as high as 10%. Treatment with anthelmintics, antibiotics and NSAIDs is often not very effective, with many survivors being left with irreversible lung damage.
Miscellaneous respiratory diseases, their causes and treatment
Anaphylaxis
This has a sudden onset of severe dyspnoea and muscle tremors. The rectal temperature will be raised to 42°C. The occurrence is normally linked either to a recent injection or is found in a dairy cow heavy in milk with a massively stocked udder. If the latter is the cause milking out will prompt a swift recovery. In other cases, animals should be injected with dexamethazone iv, or if pregnant with NSAIDs iv.
Fog fever
There are many theories on the aetiology of this condition of interstitial pneumonia. The theory with the most credence is that of a toxicosis resulting from the ingestion of large quantities of L-tryptophan in lush autumn grass. The disease occurs only in adults and the main sign is respiratory distress, with the rectal temperature remaining normal. It is a disease of beef suckler cows, and the affected animals tend to be separate from the rest, and are quieter than normal. Animals may be found dead or die following exercise. Care should be used in rounding up animals for treatment, which is far from evidenced based. Apart from more normal therapies, e.g. antibiotics, NSAIDs, steroids, etc., atropine and methylene blue have been advocated. In reality, the advice must be to stick to antibiotics and NSAIDs. The prognosis is guarded.
Inhalation pneumonia
This can occur when a cow is drenched carelessly with a liquid medicine, e.g. liquid paraffin or vegetable oil. It can also occur with a misplaced Agger’s pump. General anaesthetics (GAs) in adult animals are particularly hazardous. Inhalation pneumonia can occur in untreated ‘milk fever’ cases which have become bloated in lateral recumbency. The signs will vary from violent coughing to death depending on the volume of liquid inhaled. Treatment would consist of antibiotics and NSAIDs.
Diseases of the Circulatory System
Circulatory diseases with various causes and their treatment
Anthrax
This serious zoonotic disease is caused by a Gram-positive spore-forming bacterial rod called Bacillus anthracis and is notifiable in most parts of the world, including the UK. Ingestion is the most common method of infection, and there is very rapid extracellular multiplication of the bacteria, with toxin production and sudden death (although the author has seen a case that recovered which had been promptly treated after diagnosis by a colleague). Diagnosis is confirmed on staining a blood smear with McFadyen’s stain and seeing the rectangular rod-shaped bacteria with the blue-staining capsules.
Bleeding disorders
These are relatively rare and therefore represent a considerable diagnostic challenge for the clinician (Bell, 2011). In disorders of primary haemostasis, only a small amount of blood loss occurs from an injury site before a fibrin clot is formed by secondary haemostasis. Petechiae will be seen in the mucosa. In disorders of secondary haemostasis, large-volume bleeds will be seen in the body cavities. Primary disorders will cause thrombocytopenia, which is seen in acute bracken fern toxicity, acute infection with BVD virus, trichothecene mycocytosis, bovine neonatal pancytopenia (typically in calves under 1 month of age showing pyrexia and unexplained haemorrhage from the nose), ingestion of bone-marrow suppressive substances, e.g. furazolidone (now prohibited in the EU), and inherited bovine thrombopathia in Simmental cattle. Secondary disorders are seen in inherited deficiency of coagulation factor XI, Warfarin poisoning and mouldy sweet clover poisoning. Treatment is with blood transfusions (see Chapter 4).
Bovine leucosis
This is sometimes called bovine lymphosarcoma. There are two separate diseases recognized: bovine enzootic leucosis and bovine sporadic leucosis. Bovine enzootic leucosis is linked with a retrovirus and is spread by direct contact and dirty needles. It is a notifiable disease in the UK and is confirmed by agar gel immunodiffusion (AGID). The disease has been eradicated in most EU countries but is found in North America. Bovine enzootic leucosis is normally seen in older cattle, where it causes widespread tumours. There is no treatment. Bovine sporadic leucosis is seen in young growing calves, which exhibit swollen lymph nodes, salivary glands and thymuses. The disease causes rapid emaciation and death, and is confirmed at post-mortem.
Bovine petechial fever
This disease in endemic in Kenya and is caused by the blood parasite Ehrlichia ondiri. It is transmitted by an unknown arthropod vector from the bushbuck, Tragelaphus scriptus. The signs are petechial and ecchymotic haemorrhages on all the mucus membranes. There is some immunity as the disease only seems to infect animals brought into endemic areas. The treatment is with oxytetracyclines.
Cor pulmonale
This sporadic condition is right-side heart failure, normally following chronic pneumonia. The treatment is centred on the original cause of the condition together with frusemide as a diuretic.
Dilated cardiomyopathy
This is an inherited condition found in Holstein cattle. The signs are slow-developing peripheral oedema and pleural effusion, typically in 2-3 year old cattle. Diagnosis can be confirmed on ultrasonography. There is no realistic treatment and animals should be slaughtered.
Endocarditis
This is normally vegetative and caused by Arcanobacterium pyogenes. Diagnosis will be confirmed by auscultation
