Veterinary Clinical Medicine-I (General and Systemic)

CLINICAL PATHOLOGY

Serum biochemistry

• Hemocon­centration, metabolic alkalosis, hypochloremia and hypokalemia.
• The severity of volvulus can be classi­fied accord­ing to the amount of fluid in the abomasum and the concentration of serum chloride and the heart rate:
  • Group 1 - abomasum distended prin­cipally with gas
  • Group 2 - abomasum distended with gas and fluid, and surgical reduction possible without removal of fluid
  • Group 3 - abomasum distended with gas and fluid, 1-29 L of fluid removed before reduction of abomasum
  • Group 4 - abomasum distended with gas and fluid, more than   30 L of fluid removed before reduction of torsion.
• Cows classified as group 3 or 4 or those having presurgical chloride levels equal to or below 79 rnEq/L (79 mmollL) or pulse rates equal to or greater than 100/min have a poor prognosis.

Urinalysis

• Paradoxic aciduria

Hemogram

• The total and differential leukocyte count --a stress reaction in the early stages, and in the later stages of volvulus there is leukopenia with a neu­tropenia and degenerative left shift

Abomasocentesis

• Centesis of the distended abomasum will yield large quantities of fluid without pro­tozoa and a pH of 2-4.
• The fluid may be serosanguineous when volvulus is present.

Prognostic Indicators

• An anion gap of 30 rnEq/L - poor prognosis and more accurate than either serum chloride or base excess values.
• The surgical and postoperative findings in cattle with abomasal volvulus are good prognostic indicators of outcome.
• Cattle with omasal-abomasal volvulus have a worse prognosis than those without omasal involvement.
• Large abomasal fluid vol­ume, venous thrombosis, and blue or black abomasal color before decompres­sion are all indicative of a poor prognosis.
• Postopera­tively decreased gastrointestinal motility is an unfavorable prognostic sign.