16 occur in a group of cattle. Treatment options include adding hay or chaff to the pellet ration,
a change of pen or pen mates, and antibiotics and anti-inflammatory drugs if underlying disease is suspected or other efforts are ineffective. If illthrift is becoming widespread, check
the quality of water, especially for rust, and the quality of feed, especially for fuel, lubricant, fumigant or mould contamination.
2.7.2 Pestivirus see Bovine viral diarrhea virus – 2.4.4
Consider persistent infection with pestivirus in individual illthrifty cattle that have not undergone preshipment screening.
2.7.3 Chronic toxaemia or pain
Treat with antibiotics and anti-inflammatory drugs depending on the underlying condition that is suspected and monitor closely the response. It is possible that long and costly courses of
treatment may be required to achieve improvement, and relapse may occur upon withdrawal of treatment.
2.8 Distended abdomen
Abdominal distension when viewed from the front or rear of the animal may be unilateral, bilaterally symmetrical, asymmetrical or more prominent in the dorsal or ventral half
depending on cause.
Passing a stomach tube, auscultation with percussion and ballottement to detect areas of gas and fluid, insertion of a trochar and examination of faeces may assist in deciding cause
and level of urgency to intervene.
Of the many causes of abdominal distension, those that should be given greater consideration in shipboard cattle include:
• frothy bloat • free gas bloat
• advanced pregnancy • vagal indigestion
• oesophageal obstruction with a fruit, vegetable or milled feed • ruptured urethra in steers
• gastrointestinal accidentobstruction such as displaced abomasum or a bezoar phytobezoar or trichobezoar
2.8.1 Frothy bloat
Feeding fine or dusty feeds may cause bloat in multiple cattle. A stable foam, difficult to eructate, forms in the rumen. Compression of the thorax causes respiratory distress and
asphyxiation if severe. The problem, if mild, is treated by adding chaff or hay to the feed or painting bloat oil on the flank which is licked off by the patient.
The problem if more than mild will need to be treated with products that break down the foam by modifying surface tension. The resulting free gas layer is more readily eructated.
Specific products for oral or intrarumenal via a cannula or large bore needle administration are available.
Life threatening distension is treated by venting the rumen through a small hole in the left flank made with a knife or trochar and cannula.
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2.8.2 Free gas bloat
Inflammation such as from warts or penetrating wire or a foreign body such as plastic or string in the area around the oesophageal groove can interfere with eructation and cause
free gas bloat. Usually only individuals are affected. Resolution may require antibiotics, or surgery to create a rumen fistula, or the passage of time, or all three. Consider inserting a
commercially available plastic, self-retaining cannula. The accompanying trochar is not usually robust enough to penetrate the skin so it is best to make an incision with a scalpel at
the intended place of cannula insertion.
Make a vertical incision through skin and underlying fascia of a length equal to twice the diameter of the cannula body. With the trochar in place in the lumen of the cannula, sharply
thrust through the abdominal and rumen walls. With the trochar still firmly in place, screw the cannula in so that the spiral flange holds the rumen firmly against the abdominal wall.
The trochar is then removed and the gas allowed to escape. Gas escape is best controlled in order to avoid a sudden fall in blood pressure that accompanies the sudden fall in intra-
abdominal pressure. The cannula can remain in place for as long as necessary, which may be as long as two weeks.
A stomach tube passed down the oesophagus into the rumen can be used to relieve free gas bloat. However, severely distended cattle have been known to drop dead when this has
been done.
2.8.3 Advanced pregnancy
