Abomasum displacement

A abomasum ( dislocatio abomasi ) is a slowly progressive disease that especially in dairy cows shortly after calving occurs. It is characterized by a displacement of the abomasum , which can take place either to the right or to the left.

Pathogenesis

The main causes of a displacement of the abomasum are the feeding of large amounts of concentrated feed (grain) and a lack of structurally effective crude fiber . This leads to an increase in free fatty acids during fermentation in the rumen and thus also in the abomasum. This leads to a decrease in mobility ( motility ) of the abomasum and to increased gas formation in this organ. A lack of calcium favors the decrease in motility, which is why the abomasum shift occurs mainly with the onset of milk production after birth (Ca "loss" through milk).

The abomasum expands (abomasum dilatation) and due to the increased flow rate through the ruminant stomach, the abomasum continues to fill up. When the abomasum is displaced on the left side, the abomasum moves under the rumen between the left abdominal wall and the rumen. When the abomasum is shifted to the right, the abomasum rises between the right abdominal wall and the intestinal convolute. This can lead to a rotation of the abomasum by up to 360 °. As a result, blood vessels and nerves of the abomasum can be strangled, which can lead to the death of the organ if it persists for a long time.

clinic

Symptoms of a displacement of the abomasum are apathy, reluctance to eat with a sharp drop in milk yield and weight loss. The excrement is usually greasy to pasty.

When the abomasum is displaced on the left , an externally visible expansion of the abdominal cavity to the left can occur. Often, ketosis occurs in parallel due to the metabolic imbalance . Cows with a left abomasum dislocation can survive for several months. However, the animals show a continuous decline in performance and weight loss.

When the abomasum is displaced to the right , there is an increase in the circumference of the abdominal cavity to the right and often a rumen inflation ("small-foamy fermentation"). Often the reflux of abomasum contents in the rumen leads to a shift in the pH value in the blood to the alkaline range ( alkalosis ). The animals are often extremely apathetic and painful in the abdomen.

diagnosis

The diagnosis can be made by listening to the abdominal wall with a stethoscope while tapping it vigorously with your fingers or a percussion hammer (percussion auscultation). Metallic tones are typically audible (“steel band effect”). This "ringing" is caused by liquid and gas in a highly filled hollow organ. These conditions can also apply to other organs in the same position, for example the rumen on the left (if the rumen mat is lost) or the appendix on the right (inflation).

A distinction is made between the 1st, 2nd and 3rd degree abomasum displacement, whereby the 3rd degree abomasum has risen the farthest, leaves the abdominal cavity protected by the ribs and is audible in the hunger pit. The abomasum shifted to the right can be palpated during the rectal examination , in contrast to the shift to the left.

treatment

The displacement of the abomasum on the right side is an acute emergency due to the possibility of rotation and must be treated immediately.

The displacement can occasionally be corrected by rolling the animals. As a rule, however, a surgical measure is necessary in which the vet sews the abomasum to the lower abdominal wall. This can be done without opening the abdominal cavity after rolling. With the so-called blind stitch , button stitches are placed on the abdominal wall with a long, curved needle, which fix the abomasum; With the toggle pin suture , the fixation takes place with metal toggles , which are inserted into the abomasum through a trocar . Such toggles can also be put on during a laparoscopy .

Various surgical procedures with opening of the abdominal cavity ( laparotomy ) from the right (according to Dirksen ) or left ( Utrecht method ) on the standing animal offer further possibilities . The advantage of laparotomy is that it can examine the entire abdominal cavity. This is particularly possible from the right. Since cattle are prone to fibrinous peritonitis, adhesions or adhesions within the abdominal cavity often occur . It is necessary to recognize this, because with existing adhesions a displaced abomasum may not be able to be moved back and peritonitis worsens the prognosis for the healing of the animal. In a laparotomy, the abomasum is degassed, rotated and repositioned if necessary. To fix the abomasum, the large mesh is sewn to the lateral abdominal wall approx. 10 cm from the gastric outlet.