12 during transport and loading. They are unlikely to cause lameness but are unsightly. No
treatment is required - draining blood from these can delay and complicate healing and is best avoided.
2.3.4 Mycoplasma bovis, Histophilus somni, Chlamydophila spp
These pathogens may infect ship board cattle. They may cause respiratory disease and arthritis and with Mycoplasma bovis, also mastitis. Lameness and joint swelling from arthritis
may be the dominant manifestation. Early and prolonged treatment with long acting oxytetracycline is recommended.
2.4 Diarrhoea
Diarrhoea is the passage of faeces with high water content. It may be accompanied by blood as dysentery, fresh blood as in haemorrhage, clotted or digested as in melaena or by fibrin
coagulated in clots or plaques. Diarrhoea may be osmotic if osmotically active nutrient enters the intestine, as happens with nutrient overload. It may be secretory if endotoxin injury
causes the small intestine to secrete electrolytes and fluid, as happens in enterobacterial infections. It may be malabsorptive if the effective absorptive epithelium of the ileum and
colon is reduced by atrophy or erosion.
The most likely causes of diarrhoea in shipboard cattle include: • indigestion associated with dietary changes
• salmonellosis • rumen acidosis
• bovine virus diarrhoea virus infection
2.4.1 Indigestion associated with dietary changes
Indigestion is the most common cause of diarrhoea in shipboard cattle, usually associated with the feeding of a new batch of pellets. Cattle have watery faeces but otherwise appear
healthy with normal or slightly depressed appetite. Multiple animals in multiple pens will be affected. The diarrhoea usually resolves in a few to several days as rumen flora adapt.
Substituting chaff or hay for part of the pellet ration speeds recovery. Prevent by adapting cattle to the shipboard ration before the voyage.
2.4.2 Rumen acidosis
In live export cattle, rumen acidosis usually follows excessive consumption of pellets containing high concentrations of grain. High levels of lactic acid form in the rumen that kill
essential gut microflora, damage the mucosal lining, and draw in body fluid. This leads to rumen stasis and dehydration. Usually only mild forms occur with watery faeces
accompanied by temporary inappetance. In severe cases there will also be dehydration, weakness and depression with some animals dying. The only practical treatment on ship is
to replace pellets with hay or chaff and maintain adequate fluid intake. Bicarbonate infusions into the rumen might be considered in early cases.
2.4.3 Salmonellosis
Individual cattle but sometimes multiples, suffering fever, depression, dehydration and putrid diarrhoea or dysentery will probably have salmonellosis. Some cattle die in one or two days,
others with moderate intestinal injury may have a protracted course before recovery or
13 death. Prompt treatment with antibiotics and maintaining adequate hydration are important
for full recovery. Isolate if practical and implement hygiene to prevent spread to other cattle and humans.
2.4.4 Bovine viral diarrhoea virus infection BVD
BVD infection is usually a mild infection of young cattle. Virulent strains cause high fever, nasal discharge, lacrimation, oral ulcerations, diarrhoea, eruptive lesions of the coronary
band and interdigital cleft and sometimes haemorrhaging. High morbidity and moderate mortalities may result. BVD infection of pregnant cows may result in abortion, delivery or
normal and immune calves, and in some cases birth of persistently infected PI animals that may show no signs of illness and yet are capable of being life lone shedders of the virus. PI
animals usually become illthrifty and die before two years of age.
Malignant catarrhal fever can resemble BVDV because of oral and muzzle erosions but cases are usually older, are in single animals and have bilateral corneal opacity. The muzzle
and oral erosions of bovine papular stomatitis can look similar but diarrhoea is not a feature unless they have intercurrent ostertagiasis.
If active BVD infection is suspected in cattle, provide nursing and treat severely affected cattle with antibiotics to prevent pneumonia.
Control programs generally involve testing to detect and cull PI animals and vaccination.
2.5 Eye discharge Watery eyes
