Uterine Contractions and Electrical Activity in Ewes Treated with Selenium and Vitamin E1

The effects of selenium (Se) and vitamin E (E) on uterine contractions and electrical activity were investigated in 40 yearling Dorset ewes. Control ewes were deficient in Se and E, while remaining ewes received periodic injections of Se, E or Se + E. The number of contractions of the uterine horns was recorded for a 10 min interval in anesthetized estrous ewes. Contractions recorded as moving were visible as constrictions that moved lengthwise along the horn toward the oviduct, cervix, or in neither direction (to be defined later). Number of contractions migrating toward the oviduct was greater (P<0.01) in Se- and Se + E-treated ewes (41.6 and 43.2, respectively). Total number of contractions was greater (P<0.05) in Se- and Se + E-treated ewes (75.7 and 73.5, respectively) than in control ewes (58.5). In estradiol-17β (E2-17β)-treated ovariectomized ewes, number of contractions migrating toward the oviduct was twofold greater (P<0.01) in Se- and Se + E-treated ewes (30.6 and 30.4, respectively) than in control and E-treated ewes (15.8 and 12.2, respectively). An electromyographic record was constructed for each uterine horn of E2-17β-treated ovariectomized ewes for the determination of mean amplitude of electrical activity, number of electrical spikes per minute, and velocity of uterine contractions. Mean amplitude for the two hours combined was greater (P<0.01) in Se- than in E-treated ewes; however, mean amplitude in these groups was not different from mean amplitude of control ewes. Velocity of contractions was greater (P<0.05) in Se- and Se + E-treated ewes (17.9 and 18.9 mm/sec, respectively) than in control and E-treated ewes (11.0 and 8.0 mm/sec, respectively). These results indicate that selenium is more important than vitamin E in influencing uterine motility and contraction velocity but does not appear to influence the number of electrical spikes per minute or the mean amplitude of these spikes.