Administration of vitamin D3 by injection or drinking water alters serum 25-hydroxycholecalciferol concentrations of nursery pigs

OBJECTIVETwo experiments were conducted to evaluate vitamin D3 administration to nursery pigs by injection or in drinking water on serum 25-hydroxycholecalciferol (25-OHD3) concentrations. METHODSAt weaning, 51 pigs (27 and 24 pigs in experiments 1 and 2, respectively) were allotted to vitamin D3 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 D3 at weaning, and iii) water administration, 5,493 IU of vitamin D3/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 D3/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 D3. RESULTSIn both experiments, serum 25-OHD3 was changed after vitamin D3 administration (p