Feed efficiencies during the growing and finishing phase of pork production have improved in the range of 25 percent over the past 15 years. Sow reproductive efficiency has shown equal improvement and the biological potential of today’s hyperprolific modern genotypes is truly staggering.
Traditionally, dietary formulation has relied on the research-based requirements set forth by scientific collaborations such as the National Research Council (NRC, 1998, 2012). Also, detailed models have been developed to accurately estimate the amino acid and energy requirements of sows. While these applications are accurate for the energy and amino acid component of sow nutrient requirements, very little research has focused on the trace mineral requirements of hyperprolific sows.
Commercial tendencies have been to increase inorganic trace mineral supplementation to allow for the greater mineral requirements of superior stock reared under commercial conditions. This increased concentration of inorganic minerals in animal diets has led to several problems, such as accidental poisoning, low absorption, reduced access to enterocytes, poor retention and high fecal excretion rates.
While research in trace element nutrition has led to the development of more bioavailable organic minerals, including trace minerals derived from chelates, some traditional nutritionists continue to use inorganics, and only feed minerals to prevent deficiency symptoms. However, recent studies have shown chelates or organic trace minerals can be included at a lower supplementation rate in monogastric diets than inorganic minerals and still provide an equivalent, if not improved effect on animal health, growth and productivity.
Mahan and Peters (Ohio State University) evaluated the effects of organic trace minerals (Bioplex) versus inorganic minerals on sow reproductive performance, sow milk compositions and weanling pig body and sow body compositions. The minerals were fed at the NRC-recommended level, the industry level and the industry level with added calcium and phosphorus. The researchers found that sows fed organic trace minerals had one more pig per litter. They also explored the effect on the transfer of trace minerals from the sow, and their work demonstrated that mineral transfer to the developing fetus is not greatly affected by mineral sources or level. However, sow tissue mineral concentration is affected by mineral level.
In 2012, Bertechini et al. evaluated the effects of diets with two levels of mineral supplementation (inorganic and organic) on the reproductive performance of sows in late pregnancy and lactation phases as well as the physiologic characteristics of piglets until weaning at 21 days of age. The researchers found increased weight at birth and at 21 days; and discovered increased iron content in the blood and liver in the piglets whose mothers were given the organic form of trace minerals.