This study was carried out to investigate the relationships between blood electrolyte (Na+, K+, Cl-, Ca++, inorganic P, and Mg++) concentrations and ECG parameters obtained from cows with RPT, vagal and simple indigestion and ruminal acidosis and the significance of this parameters in the diagnosis and prognosis of the forestomach diseases.

78 cows, consisting of 18 cows with acute RPT, 15 with chronic RPT, 13 with vagal indigestion, 12 with simple indigestion, 10 with rumen acidosis and 10 control ageing between 2-14 years old, brought to our polyclinics for examination were used.

The diagnosis of forestomach diseases were made by using conventional clinical and laboratory methods.

Cl- concentrations by Schales schales method, Na+ and K+ concentrations by flame fotometry, inorganic P concentrations by Wayner diagnosis kits, Ca++ and Mg++ concentrations by atomic absorbtion spectrophotometry were determined.

ECG's of these cows were examined using BA (base apex) lead.

In spite of the fact that some of the cows with RPT had tendency to hypokalemia, hyponatremia, hypochloremia and hypocalcemia, it was found that these tendencies did not effect the ECG parameters. However it was found that inflammation reaction appeared in cows with acute RPT caused some morphological changes in ECG parameters, sinus tachycardia, sinus arrhythmia.

Hypokalemia, hypochloremia and hypocalcemia were found in more than half of the cows with vagal indigestion, which was found to cause a non-physiological increase in amplitude mean of only S wave of ECG parameters.

Some of the electrolyte changes observed in some of cows with simple indigestion were not considered as serious changes, and these changes did not alter the ECG parameters.

Hyperkalemia, hyponatremia, hypocalcemia were found in the significant number of the cows with rumen acidosis in addition, hypocalcemic and hyperphosphoremic tendencies were found in some cows. These changes were considered as evidence for the development of metabolic acidosis in cows with rumen acidosis. Sinus tachycardia, sinus arrhytmia and extrasystols did also contribute to metabolic acidosis.

The changes in heart arrhytmia of cows with acidosis caused significant (p<0,05) changes in the means of P and T wave amplitudes, PRa and QTa intrevals, PRs and STs segments of ECG parameters. Extension of QTc interval and increase in P and T waves were found to be correlated with hypocalcemia and hyperkalemia, respectively.