Normal fertility in ewes after cervical insemination with frozen–thawed spermatozoa supplemented with seminal plasma

Abstract

The effect of seminal plasma (SP) on the motility, capacitation status, penetration through cervical mucus and fertility of frozen–thawed ram spermatozoa was examined. In the presence of SP, motility of frozen–thawed spermatozoa was better (P<0.001) and there were more uncapacitated and less acrosome-reacted cells in comparison with controls (P<0.001). Frozen–thawed spermatozoa were also better able to penetrate cervical mucus after addition of SP. Addition of SP increased the percentage of ewes pregnant after insemination of frozen–thawed (39/94, 41.5% v. 51/92, 55.4%; P<0.05) but not fresh spermatozoa (34/55, 61.8% v. 42/58, 72.4% for 0 v. 30% SP in the resuspension medium). Moreover, SP improved pregnancy rates after cervical (14/50; 28% v. 25/49; 51%; P<0.05) but not intrauterine insemination (25/44; 56.8 v. 26/43; 60.5%) with frozen–thawed spermatozoa. In a second experiment, pregnancy rates were 30/45 (66.7%), 9/37 (24.3%) and 24/40 (60.0%) for ewes inseminated with frozen–thawed spermatozoa in the uterus (control), cervix without SP and cervix after supplementation with SP, respectively (P<0.01 for unsupplemented v. supplemented spermatozoa). These experiments demonstrate that impaired function of cryopreserved spermatozoa can be overcome by addition of SP, resulting in normal fertility after cervical AI.