PMC

a. DNA damage in post-thaw semen samples cryopreserved after addition of zinc (100 μM) to semen samples. a:p<0.001 compared to fresh ejaculate of respective group; b:p<0.001 compared to post-thaw control of respective group; c:p<0.001 compared to fresh ejaculate of normozoospermic subjects; b: Mitochondrial function in post-thaw semen samples cryopreserved after addition of zinc (100 μM) to semen samples. a:p<0.001 compared to fresh ejaculate of respective group; b:p<0.05 compared to post-thaw control of respective group group; c:p<0.001 compared to fresh ejaculate of normozoospermic subjects;

(a) Relative testis size (k=1.0) and ejaculate expenditure in the risk model, at r=1.0, r=0.1. (b) Relative testis size (k=1.0) and ejaculate expenditure in the intensity model.

(a) Sperm numbers (ejaculate units) in the risk model, at r=1.0, r=0.5, r=0.1. (b) Sperm numbers (ejaculate units) in the intensity model. T=100 (continuous curve); T=50, r=1.0 (dotted curve); k=β=D=1.0.

The interaction of ejaculate number and bull age on ejaculate volume (upper left panel), sperm concentration (upper right panel), and total sperm number (lower panel). Vertical bars represent s.e.m. *Asterisk represents differences between ejaculate number within each parameter (P < 0.01).