Effect on Perinatal Mortality of a Single Selenium Injection To Sows and Gilts

Selenium treatment of pregnant sows and gilts was conducted as a double-blind placebo-controlled study in 5 commercial herds with a total of 350 sows and gilts (Danish Landrace, Yorkshire and Landrace-Yorkshire crossbreeds). At 3–6 weeks before farrowing the animals were injected once intramuscularly with either Na-selenite (0.05 mg Se per kg) or placebo. Blood samples were taken immediately before treatment and once again at 3–6 weeks after farrowing, to evaluate the Se status. The productivity of the sows and gilts was recorded.Within herds there was no pretreatment difference in Se status between the two treatment groups, while a considerable variation was seen among herds. After farrowing there were only minor differences in Se status between the treatment groups, whereas the variation among herds persisted.Overall, no effect of the Na-selenite injection was seen, in that there was no difference in number of liveborn, stillborn, and weaned piglets between the treatment groups. The number of days from weaning to oestrus and the number of oestrous cycles per pregnancy were not influenced by the Na-selenite treatment.