Fertilization of ova in selenium/vitamin E-treated ewes maintained on two planes of nutrition

Studies were conducted to evaluate uterine motility and fertility of ova in ewes either given or not given supplemental selenium/vitamin E (SSE or NSE, respectively). The ewes were maintained on either an adequate plane of nutrition (APN) or an inadequate plane of nutrition (IPN). In a fertility study, 60 ewes were allotted to four treatment groups, (15 ewes per group): SSE-APN, NSE-APN, SSE-IPN and NSE-IPN. A 2-ml injection, containing 10 mg of Se as selenite and 136 IU of vitamin E as alpha-tocopheryl acetate, was given IM to designated ewes (SSE) at 21-day intervals. NSE ewes were given injection of corn oil. After 150 days of SSE supplementation, ewes were checked for estrus, bred to rams and laparotomized approximately, 72 hr after the onset of estrus for determination of fertility of ova. The proportion of recovered ova that were fertilized was, for each treatment: SSE-APN (19 of 19), NSE-APN (17 of 22), SSE-IPN (five of 10) and NSE-IPN (six of 14). Fertility of ova was affected (P < .005) by plane of nutrition and tended to be affected (P < .1) by Se/vitamin E supplementation. Throughout the fertility study, ewes in the APN group maintained their body weight, while ewes in the IPN groups lost .075 kg/ewe/day. In a uterine contraction study, ewes in the SSE-APN and NSE-APN groups were laparotomized at the onset of estrus for quantitation of the directional pattern of uterine contractions. The number of total contractions for SSE-APN ewes and NSE-APN ewes during a 10-min interval was 42.7 +/- 3.5 and 33.2 +/- 2.6 (P < .05), respectively, and number of contractions moving toward the oviduct was 21.0 +/- 2.8 and 13.4 +/- 1.2 (P < .025), respectively. Se was greater (P < .001) in serum of SSE ewes than in serum of NSE ewes, while vitamin E was greater in serum of SSE-APN ewes than in that of both groups of NSE ewes.