Vitamin D supplementation sources for hyperprolific sows in the pre-lactation phase

Context Modern pig farming has increasingly focused on hyperprolific sows to maximize productivity. However, this genetic advancement has intensified nutritional demands, particularly during late gestation, a critical phase for fetal growth and mineral metabolism. Vitamin D plays a central role in calcium, phosphorus, and magnesium regulation, with its active metabolites potentially offering improved bioavailability compared with conventional forms. Aims This study evaluated the on-top supplementation of different vitamin D sources in the diets of hyperprolific sows during the last third of gestation and to assess their effects on productive and reproductive performance as well as biochemical profile. Methods A total of 150 sows were allocated into three treatment groups: Control (no additional vitamin D supplementation), 25-hydroxyvitamin D3 (25(OH)D3), and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). Additional supplementation was provided from day 90 of gestation until farrowing. Reproductive and productive performance, blood biochemical parameters (calcium, phosphorus, magnesium, iron), and litter characteristics were recorded and statistically analyzed. Key results Vitamin D supplementation did not significantly affect sow body weight, body condition score, litter size, or piglet weight at birth or weaning. However, total litter weight was lower and birth weight variation was higher in supplemented groups. In addition, serum magnesium concentrations at farrowing were significantly (P < 0.05) reduced in supplemented sows, suggesting a metabolic interaction between vitamin D and magnesium homeostasis. Conclusions On-top supplementation of 25(OH)D3 or 1,25(OH)2D3 during late gestation did not improve the productive or reproductive performance of hyperprolific sows when basal nutritional requirements were already met. Only minor physiological effects on mineral metabolism were observed, particularly involving magnesium. Implications These findings indicate that the benefits of vitamin D supplementation in well-managed herds may be limited when baseline nutrition is adequate. For swine production systems, precision feeding strategies should consider the animals’ existing nutritional status to optimize resource use, support maternal health, and enhance piglet development.