The effect of two levels of hemospermia on stallion fertility.

Theriogenology

PubMedID: 27268295

Turner CE, Walbornn SR, Blanchard TL, Varner DD, Brinsko SP, LaCaze KA, Teague SR, Love CC. The effect of two levels of hemospermia on stallion fertility. Theriogenology. 2016;.
Hemospermia can occur consistently or intermittently in stallion ejaculates and may cause a reduction in the fertility of the affected ejaculate. It is unknown what amount of blood in an ejaculate leads to subfertility. This study investigated the effect of higher and lower levels of hemospermia (50% and 5%, respectively) on fertility using 24 reproductively normal mares inseminated over three consecutive estrous cycles with fresh extended semen. Mares inseminated with a 5% blood-contaminated ejaculate became pregnant at the same rate (75% per cycle; 18 of 24) as the mares inseminated with blood-free (control) semen (75% per cycle; 18 of 24). The ejaculates containing 50% blood were sterile (0% per cycle, 0 of 24). We concluded that it is the amount of blood, not the mere presence of blood, in an ejaculate that impacts fertility.