Displacement of the abomasum in dairy cows: risk factors and pre-clinical alterations

Abstract

Displacement of the abomasum (DA) in dairy cows is a disorder described since the fifties of the previous century. Since then, a considerable amount of research concerning DA is conducted. The normal, healthy abomasum is positioned in the ventral part of the abdominal cavity. As a result of accumulation of gas (mainly methane and carbondioxide) the abomasum will float in the abdominal cavity; the displacement of the abomasum is present. The DA can occur to the left (90% of the cases), or to the right side. DA occurs most of the cases in the first four weeks after calving. The annual incidence of DA is increasing; up to 5 percent of the newly calved cows will get DA. There is suggested that this is only a small part of the total amount of animals experiencing difficulties with DA, since a practitioner will examine not every cow. In a field trial there are differences found between herds without DA and herds with high incidence of DA. Nutrition and cow management, both in the dry period as well as the milking period, are of major importance in the risk of DA. Experimental research reveals that prior to DA cows have a decreased feed intake, of the ingested feed a relative high proportion consists of concentrates, and they produce less milk. The position of the abomasum is higher prior to the development of DA. Prior to DA osmotic pressure of the rumen fluid is higher in DA cows. The following blood alterations were found in cows prior to DA; lower calcium, glucose, and insulin concentrations, and higher concentrations of free fatty acids and ketone bodies. However, it is hard discriminate whether the pre-clinical alterations can be considered as causal factors of DA, or the alterations are part of a complex leading to DA.