Evaluating effects of sodium diformate on finishing pig performanceEvaluating effects of sodium diformate on finishing pig performance
Research has shown feeding potassium diformate increases average daily gain, feed efficiency.
July 11, 2024

By Katelyn Gaffield, Mike Tokach, Robert Goodband, Jason Woodworth, Joel DeRouchey and Jordan Gebhardt. Kansas State University
Formic acid is an organic acid commonly used as an acidifier in swine diets. Formic acid has been shown to lower the pH of the stomach, increase the apparent total tract digestibility of protein, and significantly alter intestinal microbial concentrations and diversity. Formic acid is frequently fed in the form of calcium, sodium or potassium salts. There have been multiple studies on feeding potassium diformate which resulted in increased average daily gain and feed efficiency. However, there is currently limited research analyzing the effects of various levels of the formic acid salt, sodium diformate, fed throughout the finisher phase. Therefore, the objective of this study was to investigate the effects of increasing levels of sodium diformate in grow-finish diets on growth performance and carcass characteristics.
Animals, diets and procedures
A total of 2,200 pigs (Duroc sire (PIC 800 or DNA 600) × PIC Camborough; initially 53.4 ± 0.66 pounds) were used to conduct a 117-day growth trial at a commercial research grow-finish site located in south-central Minnesota. Pens of pigs (25 pigs per pen) were randomly assigned to one of four dietary treatments in a randomized complete block design with 22 replicates per treatment. Dietary treatments were corn-soybean meal-based with the addition of none, 0.25, 0.50 or 0.75% Formi NDF (ADDCON Nordic AS, Porsgrunn, Norway). This product is a combination of 57% sodium formate and 38.5% formic acid. All diets were manufactured at Bixby Feed Mill, Inc. (Blooming Prairie, Minnesota). Diets were fed in six phases from 53 to 75, 75 to 145, 145 to 195, 195 to 245, 245 to 265 and 265 to 310 lb. Nutrients for all treatment diets were formulated to meet or exceed the NRC requirements for growing-finishing pigs in each appropriate weight range.
Pens of pigs were weighed every two weeks and feed disappearance was measured to determine ADG, average daily feed intake and feed-to-gain ratio. Two weeks prior to the end of the experiment, four pigs per pen were weighed and marketed. The remaining pigs were weighed and marketed at the completion of the study. Pigs were transported to a USDA-inspected packing plant. Hot carcass weight, loin depth and backfat measurements were collected. Carcass yield was determined using the pen average HCW divided by the pen average final live weight. A proprietary equation from the packing plant was used to calculate the percentage lean.
For the economic analysis, high- and low-priced scenarios were used to calculate total feed cost, feed cost per lb of gain, total revenue and income over feed cost per pig. Feed cost per pig was determined by total feed intake × diet cost ($/lb). Feed cost per lb of gain was determined as the total feed cost divided by total gain per pig. Revenue per pig was calculated for both low- and high-priced scenarios as total gain × carcass yield × $0.60/lb carcass price, or total gain × carcass yield × $0.88/lb carcass price, respectively. Finally, IOFC was determined as total revenue minus total feed cost per pig. All economic analyses were determined on a per pigs placed basis.
Results
For the overall period (d 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 (P > 0.10) in feed efficiency. Increasing sodium diformate increased (linear, P = 0.005) final BW on d 117.
For carcass characteristics, no evidence for differences (P > 0.10) was observed for HCW, carcass yield, backfat, loin depth or lean percentage due to increasing sodium diformate. There were also no differences (P > 0.10) in removals and mortalities observed from increasing sodium diformate in the diet.
For economics on a per pig placed basis, increasing sodium diformate in the diets increased (linear, P < 0.001) feed cost and feed cost per lb of gain in both low and high price ingredient scenarios. However, there was a tendency for a quadratic effect (P = 0.059) of revenue, with pigs fed 0.25% sodium diformate generating the greatest revenue in both the low and high price scenarios. The revenue was greatest for the 0.25% sodium diformate treatment due to increased market weight compared to the control treatment, while having numerically lower mortality than the other sodium diformate treatments. However, mortality in this study was low compared to industry standard. Due to the increased feed cost and quadratic response in revenue, pigs fed increasing sodium diformate had a quadratic (P < 0.05) response in IOFC, with pigs fed no sodium diformate having the greatest IOFC.
In conclusion, these data suggest that feeding increasing levels of sodium diformate improved ADG and ADFI after approximately 180 lb in the grow-finish period. However, due to the increased feed cost, it is currently not economical to feed sodium diformate throughout the entire grow-finish period. Therefore, further research is needed to investigate the addition of sodium diformate only in the late finisher phase to understand if pigs will have similar improvements in growth performance with reduced overall feed cost.
Funding, wholly or in part, was provided by the National Pork Checkoff. The authors appreciate Quality Technology International, U.S. distributor of Formi NDF, for the donation of test materials and Holden Farms, Northfield Minnesota for facility use.
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