title: Nutritional status of adult ewes during early and mid-pregnancy. 2. Effects of supplementation with selenised yeast on ewe reproduction and offspring performance to weaning.
abstract: The objective of this study was to determine the effects of selenium (Se) supplementation of mature ewes in the period from day -14 to day 90 post mating on Se status, productivity and viability of ewes and their offspring. Multiparous crossbred ewes (n = 82) were randomly assigned to receive a standard dried grass-based diet (control) or dried grass diet supplemented with 1 g of selenised yeast (Selplex®), providing 0.5 mg Se per ewe per day. After day 90 post mating, all ewes were offered grass-based diets supplemented with a standard multivitamin and mineral mix, up to lambing. Ewes that were fed additional Se had increased (P < 0.001) activity of glutathione peroxidase enzyme (GPx) and increased plasma Se concentrations throughout the treatment period. At lambing, GPx activity of supplemented ewes was higher (P < 0.001) than that of controls. Twenty-four hours after birth, lambs of ewes given Se had higher (P < 0.001) concentration of Se in plasma, greater (P < 0.001) activity of GPx and better (P < 0.01) immune status. Lambs of ewes that received supplementation showed a faster progression to stand than control lambs (P < 0.05), independent of maternal behaviour which was not affected. Supplementation reduced perinatal lamb mortality (0.04 v. 0.17; P < 0.05). However, overall mortality from birth to weaning was unaffected (P > 0.05). Supplemented ewes weaned lambs on average 2 kg heavier than control ewes, due to the higher (P < 0.05) growth rates achieved by their offspring. In conclusion, for ewes with a marginal Se status, an organic source of Se supplemented throughout pregnancy, compared with supplementation only in the last trimester, positively affected measures of lamb viability and survival.
authors.affiliation: 1Queen's University Belfast, University Road, Belfast BT7 1NN, Northern Ireland, UK.
authors.forename: C
authors.initials: C
authors.lastname: Muñoz
authors.forename: A F
authors.initials: AF
authors.lastname: Carson
authors.forename: M A
authors.initials: MA
authors.lastname: McCoy
authors.forename: L E R
authors.initials: LE
authors.lastname: Dawson
authors.forename: N E
authors.initials: NE
authors.lastname: O'Connell
authors.forename: A W
authors.initials: AW
authors.lastname: Gordon