Pashu Sandesh, 10 April 2019
Dr. Arun Kumar, Dr. Rashmi Saini, Dr. Rajat Verma,Dr. Manish Kumar Verma
Abomasum of adult dairy cow is a sac-like elongated organ lying on the lower right quadrant of the abdominal cavity extending from its abomasal attachment to the area of the eleventh or tenth rib. Abomasal displacement in cattle is found throughout the world. It is seen most commonly with increasing tendency in regions with intensive cattle breeding and husbandry. Abomasal diseases of dairy cattle are mostly associated with stress of situations, nutritional disorders and metabolic disturbances. These diseases include LDA, RDA, abomasal volvulus (AV), abomasal ulcer and impaction. Abomasal displacement is one of the several conditions which causes post-calving digestive upset and may lead to confuse diagnosis of digestive and metabolic diseases in cattle.
A number of factors have been implicated in the etiology of abomasal displacement. The primary causative factor in abomasal displacement appears to be atony or hypotony of the abomasums. Dairy cattle with high milk production and being fed large quantities of grain, where exercise is limited may have abomasal atony. Other contributing factors decreased abomasal motility include metabolic disorders (hypocalcemia and ketosis), concurrent diseases as mastitis and metritis, changes of intra-abdominal organs especially in late pregnancy and genetic predisposition. Sudden change in the feed before calving, in preparation for lactation or as a result of ownership promotes abomasal displacement and induces improper adjustment of flora and fauna. It is mention that there were loss of cholinergic excitatory and an increase of nitroxergic inhibitory tone, also decreased contractility of the antral muscles. It is stated that a sudden onest of ruminal stasis, lack of appetite and fall in milk yield was also characteristic of acute intestinal obstruction, simple indigestion and abomasal displacement. LDA is more frequent than RDA in cows. ketosis recorded in concurrent with LDA than RDA. LDA is characterized by partial or complete displacement of the dilated abomasum between the rumen and left abdominal wall. There is a high incidence in the period from 3-6 weeks after calving. In addition to this, there is a high incidence of LDA in winter due to higher frequency of calving and inactivity.
Clinical findings of abomasal displacement include inappetence, sometimes complete anorexia, marked drop of milk yield, varying degrees of ketosis and tinkling sounds on auscultation. Abomasal displacement is characterised by dehydration and metabolic alkalosis due to continuous secretion of hydrochloric acid, sodium, potassium and chloride into the abomasum which becomes gradually distended and does not evacuate its contents into the duodenum. Serum biochemical changes associated abomasal displacement included severe decrease in serum chloride, sodium, potassium, calcium and glucose. Also, there was significant increase in serum total proteins, urea, lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase.
By ultrasonography, the abomasum wall can be visualised as a narrow echogenic line. Parts of abomasal folds are occasionally visible as elongated echogenic sickle shaped structures. The ingesta are visualised ventrally and appeared echogenic to hypoechogenic. In cows with LDA, the rumen displaced by the abomasum more dorsally and the abomasum is seen between the left abdominal wall and the rumen. In RDA, the liver was displaced medially from the right abdominal wall.
The first step in the treatment of abomasal displacement depends on the correction of complication of ketosis and hypocalcaemia by intravenous administration of glucose 25% and calcium. Moreover, intravenous injection of isotonic saline (0.85%) and isotonic potassium chloride (1.1%) are indicated to overcome metabolic alkalosis. Mechanical reposition of the displaced abomasum may also be successful.
Dr. Arun Kumar, Dr. Rashmi Saini, Dr. Rajat Verma,
Dr. Manish Kumar Verma
College of Veterinary and Animal Sciences,
G.B. Pant University of Agriculture and Technology, Pantnagar