Administration of vitamin D 3 by injection or drinking water alters serum 25-hydroxycholecalciferol concentrations of nursery pigs

Two experiments were conducted to evaluate vitamin D administration to nursery pigs by injection or in drinking water on serum 25-hydroxycholecalciferol (25-OHD ) concentrations. At weaning, 51 pigs (27 and 24 pigs in experiments 1 and 2, respectively) were allotted to vitamin D treatments. Treatments in experiment 1 were: i) control (CON), no vitamin administration beyond that in the diet, ii) intramuscular (IM) injection of 40,000 IU of vitamin D at weaning, and iii) water administration, 5,493 IU of vitamin D /L drinking water for 14 d postweaning. Treatments in experiment 2 were: i) control (CON), no vitamin administration, and ii) water administration, 92 IU of d-α-tocopherol and 5,493 IU of vitamin D /L drinking water for 28 d postweaning. The lightest 2 pigs within each pen were IM injected with an additional 1,000 IU of d-α-tocopherol, 100,000 IU of retinyl palmitate, and 100,000 IU of vitamin D . In both experiments, serum 25-OHD was changed after vitamin D administration (p