Effect of parenteral supplement with sodium selenite on lamb mortality and hematic values of selenium

In the livestock region of the southeast of the State of Tlaxcala and the mountain area of the State of Puebla, the mortality of the lambs from birth to 60 d of age was 62%. The lambs had symptoms of nutritional myopathy and the main finding at necropsy was nutritional muscular dystrophy (NMD), due to selenium (Se) deficiency. Se levels in blood serum, forage and soil were 0.02 mug mL(-1), 0.05 mug g(-1) and 0.023 mug g(-1). Soil pH was 5.8. Se concentration in blood serum for different groups of ages was extremely low: Group(i) 0-2 months, 0.020+/-0.0023 mug mL(-1); (ii) 3-8 months, 0.021+/-0.0023 mug mL(-1); (iii) 9-18 months, 0.024+/-0.0022 mug mL(-1); (iv) 19-30 months, 0.024+/-0.0019 mug mL(-1); older than 30 months, 0.018+/-0.0016 mug mL(-1); (p>0.05). Forty five lambs from 3 to 7 d postpartum, born from Se-deficient ewe, were divided in three groups to compare the effectiveness of Se injection. Group C1: Control; C2: 0.25 mg Se kg(-1); C3: 0.5 mg Se kg(-1). The concentration of blood Se increased quickly, 20 d after beginning the treatment, 44% in C2 and 163% in C3 (pless than or equal to0.01). The application of Se (0.25 and 0.5 mg Se kg(-1))increased blood Se concentration in lambs and both doses were effective to prevent white muscle disease lesions and to improve lamb survival until weaning.