253 A Survey of Added Trace Mineral Levels in Diets Utilized in the U.S. Swine Industry

Abstract From November 2021 to February 2022, swine nutritionists representing 29 production systems and 8 nutrition supplier companies in the United States were surveyed about added trace mineral concentration in swine diets. Respondents were asked to provide trace mineral premix concentrations, amount added to the diets outside the premix, inclusion rates, and body weight ranges associated with feeding phases. Survey participants represented 4.38 million sows, or 69% of the U.S. industry. Data were compiled into 3 nursery phases (Phase 1, weaning to 7 kg; Phase 2, 7 to 11 kg; and Phase 3, 11 to 23 kg), 3 finishing phases (23 to 55 kg; 55 to 100 kg; 100 to market), gestation, and lactation. Mainly driven by pharmacological levels of zinc and copper, trace mineral levels were, on average, 9.3 times above NRC (2012) recommendations across all nursery diets (Table). Selenium and iron were the lesser extremes being close to their requirement estimates (1.0 to 1.2). In finishing diets, trace mineral levels averaged 6.4 times the 2012 NRC recommendations. Copper and manganese contributed to that number the most, with reported values more than 10 times their requirement estimates. Zinc, selenium, and iron were on the other extreme at 1.4 to 1.8 times NRC (2012) requirement estimates. Regarding sow diets, trace mineral levels were 1.9 times the 2012 NRC recommendations on average. In gestation and lactation diets, iodine was in the upper extreme, and zinc in the lower. The only difference between gestation and lactation diets was copper ratios to NRC (2012). In gestation, it was supplemented at 1.8 times, and in lactation at 0.9 times the NRC (2012) requirements estimates. In recent years, the use of alternative zinc, copper, manganese, and selenium sources has increased. Selenium had the greatest number of nutritionists using alternative sources (Se yeast or hydroxyl-selenomethionine), with 50%, 8%, and 61% for nursery grow-finishing, and sow diets, respectively. Alternative sources of zinc (chelates or complexed with amino acids) were used the least, with 25%, 8%, and 33% for nursery grow-finishing, and sow diets, respectively. Alternative copper and manganese sources had intermediate usage reported. Different herd health status, trace mineral sources, and diet formulation philosophies with a margin-of-safety mindset are reflected in the use above requirement estimates found in trace mineral concentrations observed in all production phases. Understanding curren