Evaluating increasing levels of sodium diformate in diets for nursery and finishing pigs on growth performance, fecal dry matter, and carcass characteristics.

Two studies were conducted to evaluate the effects of sodium diformate in swine diets. For Exp. 1, 360 barrows (DNA 200 × 400; initially 5.9 ±â€…0.06 kg) were used in a 38-d study. At weaning, pigs were randomly assigned to pens with five pigs per pen. Each pen was allocated to one of six treatments with 12 pens per treatment. Treatments were formulated to provide none, 0.40%, 0.60%, 0.80%, 1.00%, or 1.20% sodium diformate added at the expense of corn. Diets were fed in three phases: phase 1 from weaning to day 9, phase 2 from days 9 to 24, and phase 3 from days 24 to 38. From days 0 to 24 (phases 1 and 2), increasing sodium diformate increased (linear, P = 0.001) gain-to-feed (G:F). However, sodium diformate did not affect average daily gain (ADG) or average daily feed intake (ADFI). From days 24 to 38 (phase 3) and overall (days 0 to 38), there was no evidence of differences due to increasing sodium diformate for any growth response criteria. There was no evidence for differences in fecal dry matter (DM) on day 9. However, fecal DM decreased (linear, P < 0.05; quadratic, P = 0.097) as sodium diformate increased on day 24. In Exp. 2, 2,200 pigs (Duroc sire [PIC 800 or DNA 600] × PIC Camborough; initially 24.2 ±â€…0.30 kg) were used in a 117-d growth trial. Pens of pigs (25 pigs per pen) were randomly assigned to one of four treatments with 22 pens per treatment. Treatments were formulated with additions of none, 0.25%, 0.50%, or 0.75% sodium diformate. Diets were fed in six phases from 24 to 141 kg. For period 1 (days 0 to 32), ADFI tended to decrease then increase (quadratic, P = 0.081) with increasing sodium diformate, whereas G:F increased then decreased (quadratic, P < 0.001) with increasing sodium diformate. For period 2 (days 32 to 60), there was no evidence for differences in ADG or ADFI; however, there was a tendency for G:F to increase then decrease (quadratic, P = 0.093) with increasing sodium diformate. From days 60 to 93, increasing sodium diformate increased (linear, P < 0.01) ADG and ADFI. From days 93 to 117, increasing sodium diformate increased (linear, P < 0.05) ADG, ADFI, and G:F. Overall (days 0 to 117), pigs fed increasing sodium diformate had increased (linear, P < 0.01) ADG and a tendency for increased (linear, P = 0.075) ADFI; however, there was no evidence for differences in G:F. There were no treatment differences for any carcass characteristic. In summary, increasing sodium diformate may increase G:F in the early nursery and improve ADG after day 60 (approximately 82 kg) in the finishing period.