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The period from late pregnancy to lactation is crucial for successful farrowing and lactation. Sows with elevated levels of calcium in their bloodstream are at a reduced risk of experiencing birthing difficulties. Diets that provide a negative dietary anion cation difference (DCAD) and supplement with a vitamin D metabolite 25-OH-D3 (calcidiol) may increase calcium availability at parturition and enhance piglet survival and performance.
Method: This factorial study assessed the effects of DCAD, calcidiol (50 µg/kg), and parity (parity 1 or >1) and their interactions. Large White and Landrace sows (n = 328), parity 1 to 8 were randomly allocated in blocks to treatment diets from day 103 of gestation until day 3 postfarrow: 1) negative DCAD without calcidiol (-2 mEq/kg DCAD + no CA), n = 84, 2) negative DCAD with calcidiol (-2 mEq/kg DCAD + CA) n = 84, 3) positive DCAD without calcidiol (68 mEq/kg DCAD + no CA), n = 81, and 4) positive DCAD with calcidiol (68 mEq/kg DCAD + CA), n = 79. Negative DCAD diets were acidified with an anionic feed (2 kg/t) and magnesium sulfate (2 kg/t).
Results: Before farrowing, all negative DCAD sows had lower urine pH than all sows fed a positive DCAD. The percentage of sows with stillborn piglets was not affected by DCAD, calcidiol, or parity alone but sows fed the negative DCAD + CA diet had a 28% reduction in odds of stillbirth compared to the negative DCAD + no CA diet and even lesser odds to the positive DCAD + CA diet. At day 1 after farrowing, blood gas, and mineral and metabolite concentrations were consistent with feeding a negative DCAD diet and that negative DCAD diets influence energy metabolism, as indicated by increased glucose, cholesterol, and osteocalcin concentrations and reduced nonesterified free fatty acids and 3-hydroxybutyrate concentrations. In the subsequent litter, total piglets born and born alive was greater for positive DCAD diets compared to negative DCAD diets; and there was an interaction between DCAD, calcidiol, and parity.
Conclusion: The results suggest that feeding a negative DCAD diet could influence stillbirth, subsequent litter size, and metabolic responses at farrowing.
Weaver AC, Braun TC, Braun JA, Golder HM, Block E, Lean IJ. Effects of negative dietary cation–anion difference and calcidiol supplementation in transition diets fed to sows on piglet survival, piglet weight, and sow metabolism. Journal of Animal Science. 2024; 102: skae027. https://doi.org/10.1093/jas/skae027