The Effect of Maternal Supplementation of Zinc, Selenium, and Cobalt as Slow-Release Ruminal Bolus in Late Pregnancy on Some Blood Metabolites and Performance of Ewes and Their Lambs.

The aim of this study was to determine the effect of the supplementation of a slow-release bolus of zinc (Zn), selenium (Se), and cobalt (Co) at late gestation (6 week prepartum) on performance and some blood metabolites of Mehraban ewes and their lambs until weaning. Seventy pregnant ewes, 6 weeks prior to expected lambing, were randomly divided into two groups (35 heads each) including (1) control group and (2) slow-release bolus group. Blood samples of ewes were obtained on day 10 prepartum and 45 and 90 days postpartum, and milk samples were collected on day 45. Blood samples of lambs were collected on days 10, 45, and 90. Body weight at birth and weaning and average daily gain were higher and percentage of mortality and white muscle disease rate were lower in lambs whose mothers were given a bolus (P < 0.05). Slow-release bolus administration increased serum alkaline phosphatase and whole blood glutathione peroxidase activity, plasma concentrations of Zn, Se, and vitamin B12 in ewes and their lambs (P < 0.05). In addition, serum creatine phosphokinase activity of lambs whose mothers were given bolus was lower (P < 0.05). Serum concentration of T3 in bolus given ewes and their lambs was higher (P < 0.05) and serum T4 concentration was lower (P < 0.05). Zinc, Se, and vitamin B12 concentrations in milk were significantly higher in treated ewes (P < 0.05). Obtained results showed that maternal supplementation of zinc, selenium, and cobalt as slow-release ruminal bolus in late pregnancy improved some mineral status of ewes and their lambs until weaning and led to higher body weights of lambs at weaning.