Supplementing 25-Hydroxy-Vitamin D3 to Sows Enhances Milk and Blood Parameters, with Extended Benefits to Their Offspring

The objective of this study was to evaluate the effects of 25-hydroxy-vitamin D₃ (25OHD₃) supplementation on reproductive performance, nutrient digestibility, lameness score, milk composition, and blood profiles in sows, as well as the performance and blood profiles of their offspring. From day 110 of gestation to 21 days of weaning, a total of 30 multiparous sows (Landrace × Yorkshire) were randomly assigned to one of three dietary treatments, with ten sows per treatment. The dietary treatments were: (1) CON, basal diet; (2) TRT1, CON diet plus 1114 IU 25OHD₃/kg (13.92 µg 25OHD₃/kg feed); and (3) TRT2, CON diet plus 2227 IU 25OHD₃/kg (27.84 µg 25OHD₃/kg feed). The reproduction performance and nutrient digestibility of sows were not affected by 25OHD₃ supplementation. However, the inclusion of graded levels of 25OHD₃ in the sow diet had significantly reduced their farrowing time (<i>p</i> < 0.001) compared to those fed the CON diet. Also, sows fed 25OHD₃ produced significantly higher (<i>p</i> < 0.05) number of piglets compared to the CON group. Piglets from supplemented sows exhibited greater (<i>p</i> < 0.05) average daily gain and weaning body weight. Moreover, colostrum protein content was higher (<i>p</i> < 0.05) in sows fed 25OHD₃ compared with the CON group. Similarly, the concentration of 25OHD₃ in colostrum and milk at weaning was markedly (<i>p</i> < 0.001) elevated. Furthermore, serum 25OHD₃ levels were significantly higher (<i>p</i> < 0.05) in both sows and piglets, and piglet serum immunoglobulin G (IgG) concentrations were also elevated (<i>p</i> < 0.05) in the supplemented groups. In summary, dietary 25OHD₃ in the sow diet not only improves their reproductive performance and milk quality but also enhances piglet growth, immunity, and overall vitality, suggesting that 25OHD₃ is a valuable nutritional strategy for optimizing sow productivity and promoting healthier offspring.