Biochemical observations on beagle dog semen

Semen samples were collected at weekly intervals for six weeks from eight sexually mature beagles previously shown to produce normal ejaculates. Seminal plasma and sperm fractions were separated by centrifugation and the sodium, potassium, alanine and aspartate aminotransferases, acid and alkaline phosphatase concentrations in the two fractions determined. Regression analysis of the mean weekly values obtained from physical and biochemical examination of the ejaculates showed that sodium ion concentration was highest in seminal plasma. The highest levels of aminotransferases were found in sperm fractions. Those enzymes may be indices of abnormal or damaged spermatozoa. Acid and alkaline phosphatase activity was 100 times greater in seminal plasma than in sperm fractions. Phosphatase concentrations are likely to be dependent on prostate activity. Measurement of acid phosphatase in canine semen therefore may be a useful index of prostate function. The motility of the semen samples was independent of the potassium concentration in seminal plasma. However, there was some evidence of a correlation between sperm motility and the enzyme and sodium content of seminal plasma.