18 dietary change is usually lethal. Both phytobezoars and trichobezoars may occlude the
pylorus or intestine with like result.
Affected cattle may show signs of abdominal pain, be inappetent and pass no faeces, or scant faeces covered in mucus or blood. Rectal examination can be expected to reveal a
completely empty rectum with a dry but sticky feel. A ping and sloshing fluid may be detected upon auscultation and ballottement of a distended abdomen. With the exception of
left displacement of the abomasum, bold and early surgical intervention and often fluid therapy are required to save the animal. Successful surgery is often performed for LDA, but
the need is not so urgent.
If suitable facilities and equipment are not available, and with the possible exception of LDA, prompt euthanasia of the animal should be performed.
2.8.6 Vagal indigestion
Individual cattle may develop disturbances in rumen motility causing indigestion and fluid accumulation in the rumen. The most common cause is thought to be localised peritonitis
affecting the vagus nerve as it passes around the reticulum resulting in so-called vagal indigestion. Ballottement will detect a large fluid filled rumen. The most common cause of
localised peritonitis will be associated with penetration of the wall of the reticulum with nails, needles or short pieces of wire so called traumatic reticuloperitonitis. Outbreaks may occur
if a length of wire has been milled in the preparation of chaff. Treat with antibiotics and feed hay as a portion of the diet to try to stimulate normal rumination.
2.8.7 Ruptured urethra in steers and bulls
Diets high in grain, calcium or magnesium may cause formation of urethroliths which in steers can block the urethra leading to bladder distension and eventual urethral perforation
or bladder rupture. There may be abdominal distension from urine accumulation in the abdominal cavity if the bladder has ruptured, or subcutaneous swelling along the prepuce
and ventral abdomen if the urethra has perforated; and rectal prolapse from straining to void urine. Death follows rupture of the bladder. A ruptured urethra may resolve without
intervention if tissue sloughs and a patent urethra is established however establishing patency via surgical means increases survival and aesthetic outcome. Options for prevention
include adjusting mineral balance in or adding salt to the diet, or both. If one steer is diagnosed with urethral obstruction then all males are at risk.
Bulls may incur rupture of the urethra due to mounting behaviour. The typical subcutaneous swelling due to urine in the tissues is seen. Necrosis of subcutaneous tissues and, if the
animal survives for sufficient time, sloughing of the skin occurs. It is then not uncommon for the penis to protrude ventrally through the slough. Simple treatment is a 10cm long deep
draining incision, one on each side of and 10 cm from and parallel to the midline. It is desirable that these incisions are kept clean and open to provide adequate drainage for the
accumulated urine. The urethra has notable powers of recovery and reestablishment of normal patency is usual.
19
2.9 Knuckling
