Copper, phosphorus and calcium in bovine blood and seminal plasma in relation to semen quality

The mean Cu concentration in blood plasma of bulls of 12 Holstein and 13 Czech Spotted breeds was 22.27 µmol·l^-1; P, 1.78 mmol·l^-1; Ca, 3.04 mmol·l^-1; P:Ca ratio, 0.64. The mean Cu concentration in seminal plasma of bulls was 38.17 µmol·l^-1; P, 12.07 mmol·l^-1; and Ca, 3.52 mmol·l^-1 and the P:Ca ratio was 3.31. The relationship between Cu, P and Ca concentration in blood and seminal plasma is expressed by calculated phenotypic coefficients of correlation. Highly significant positive coefficients of correlation (P<0.01) were found between the Cu, P and P:Ca ratio in blood and seminal plasma (Cu - r_p=0.36, P - r_p=0.32 and P:Ca ratio r_p=0.28). In contrast, no positive relationship between the Ca concentration in blood plasma and seminal plasma was found; the calculated coefficient of correlation was negative (r_p =-0.16). This was probably caused by the higher Ca concentration in blood plasma of bulls. Statistically significant (P<0.05) positive coefficients of correlation were found between the Cu concentration in blood plasma and the total number of sperm in ejaculate (r_p=0.33), between the Cu concentration in blood plasma and the total number of sperm with progressive motility (r_p=0.35), and between the Ca concentration and monthly value of sperm motility (r_p=0.26). Positive coefficients of correlation were found between the Cu concentration in seminal plasma and the mean monthly volume of ejaculate (r_p=0.36, P<0.01), between the Cu concentration in seminal plasma and sperm motility (r_p=0.33, P<0.05), and Cu concentration in seminal plasma and total number of sperm with progressive motility in ejaculate (r_p=0.28, P<0.05). The P concentration in seminal plasma of bulls was positively correlated with the sperm concentration in ejaculate collected on test days (r_p=0.36, P<0.01). The correlation between the P:Ca ratio in seminal plasma and the sperm concentration in ejaculate collected on test days was positive (r_p=0.39, P<0.01) and so was the correlation between the P:Ca ratio and the mean monthly sperm concentration (r_p=0.28, P<0.05). The calculated coefficient of correlation between the Ca concentration in seminal plasma and the mean monthly sperm motility was negative (r_p=-0.38, P<0.01). It can be concluded that there is a positive relationship between the Cu and P concentrations and P:Ca ratio in seminal plasma of bulls and the quality and quantity parameters of ejaculate of active stud bulls. A higher concentration of Ca in seminal plasma negatively affected mainly sperm motility in this study.