Cattle in some parts of the world graze pastures that consist of tall fescue that may contain ergot alkaloid contamination. Those ergot alkaloids are associated with reduced reproductive rates in cattle. Our objective was to determine if ergot alkaloids [dihydroergotamine (DHET), ergonovine (EN), and ergotamine (ET)] directly affect bovine sperm characteristics. Spermatozoa were collected from mature Angus (n = 2) and Balancer (n = 4) bulls. Within bull, treatments were structured as a 3 × 5 factorial with three alkaloids (DHET, EN, and ET) and five concentrations of each alkaloid (0, 33, 66, 100, or 200 µM). Spermatozoa (25 × 10 6) were incubated (39˚C) in 1 mL of modified sperm medium. Sperm motility characteristics were evaluated using CASA (Hamiliton Thorne IVOS, Beverly, MA) at 0, 3, and 6 h after initial alkaloid exposure. Initial sperm motility was (69% ± 1.1%) and declined (P = 0.01) to (35% ± 2.6%) at 6 h. Sperm motility decreased (P < 0.05) with increasing concentrations of DHET and ET, but not EN. As concentration of ET or DHET increased all CASA sperm characteristics were altered. The interaction of alkaloid concentration and incubation length affected sperm velocity and head size; exposure to 200 µM of ET or DHET for six hours decreased (P < 0.05) both characteristics. Our results demonstrate that ergot alkaloids (ET and DHET) can directly alter bovine sperm motility and morphology, which adds to our understanding of how ergot alkaloids may hinder cattle reproductive rates.

Our purpose was to determine the impact of ascorbic acid and α-tocopherol on bovine sperm motility following short-term storage or cryopreservation. Semen was collected from mature Angus bulls (n = 4). The experimental design was a randomized complete block, with bull serving as block, and treatments were structured as a 4 × 4 factorial with four concentrations of ascorbic acid (0, 5, 10, 20 mM) and four concentrations of α-tocopherol (0, 0.05, 0.5, 5 mM). Sperm motility characteristics were evaluated using computer assisted sperm analyses at 0, 4, and 8 h of incubation (39˚C) and post-cryopreservation. Initial sperm motility was (79.6% ± 1.6) and decreased to (6.1% ± 1.6%) after cryopreservation. Cryopreserved spermatozoa had lower (P < 0.05) post-thaw qualities when compared with fresh collections and for spermatozoa that had been incubated for 4 h at 39˚C. In contrast, most of the motility characteristics of spermatozoa that were incubated for 8 h at 39˚C were similar to those of post-thaw spermatozoa. Sperm motility, hyperactivity, and velocity characteristics were not affected (P > 0.1) by α-tocopherol. Addition of 20 mM ascorbic acid to storage media decreased (P < 0.05) sperm velocity traits, but the addition of 5 or 10 mM ascorbic acid did not alter sperm velocity. Sperm cell oxidation following cryopreservation/post-thaw was affected by an interaction (P < 0.05) between concentrations of ascorbic acid and α-tocopherol. Stepwise regression models predicted (P < 0.05) post-thaw motility and velocity characteristics of cryopreserved spermatozoa. Our results suggest that adding ascorbic acid and α-tocopherol was not beneficial for short-term storage of spermatozoa; however, our results were inconclusive with regards to inclusion of ascorbic acid and α-tocopherol in egg yolk-based cryopreservation media.