Whole semen, seminal plasma and the pre-ejaculate fraction collected from ten Angoni bulls four times a week for 6 weeks were analysed for sodium (Na+) and potassium (K+) concentrations using a flame photometer and for calcium (Ca++) and magnesium (Mg++) using an atomic absorption spectrophotometer.
Na+ concentrations (mg/100 ml) in whole semen, seminal plasma and the pre-ejaculate fraction were 320±9·9, 347±8·4 and 335±47·1, respectively. Corresponding values for K+ were 69·4±3·1, 71·4±4·5 and 152±37·8; for Ca++ were 34·0±1·4, 35·3±1·1 and 4·1±1·4 and for Mg++ were 8·8±0·06, 8·3±0·3 and 5·7±1·7.
These concentrations were compared to the cation composition in blood. Correlation coefficients were calculated.