A mineral commonly used to help maintain newborn pig health and growth may not be available in the future. Because of this, Kansas State University (K-State) researchers are searching for alternatives.

Zinc plays an important role for a variety of functions in pigs, explained Jordan Gebhardt, an assistant professor in K-State’s Department of Diagnostic Medicine and Pathobiology.

“Pigs have a physiological requirement for zinc due to the functions it is involved with, including producing enzymes, immunity and nutrient metabolism,” Gebhardt said during K-State’s Swine Day on Nov. 18.

Zinc also has antimicrobial properties and can increase feed intake through brain gut peptide regulation.

In addition to the physiological requirements, higher levels of zinc in the form of zinc oxide, are often fed for the first two to three weeks after the pig is weaned from its mother to reduce the incidence of post-weaning diarrhea, and improve feed intake and growth performance, Gebhardt said.

Despite its benefits, zinc oxide is currently under scrutiny in the European Union (EU) due to concerns over heavy metal accumulation in the environment and the potential for antimicrobial resistance. Use of zinc oxide as a veterinary medicinal product will be banned by June 2022.

“Concern over heavy metal accumulation in the environment and antimicrobial resistance is very important,” Gebhardt said. “But it’s important to recognize the limited duration in which these high levels are fed. The short duration allows for dilution effect over time as that pig consumes the largest amount of feed much later in the nursery and then throughout the finishing phase.”

Dietary Changes to Achieve Growth Without Zinc Oxide

A potential move to ban the use of zinc oxide means the industry should be looking for viable alternatives now to be prepared in case of future actions, he said.

“There will not be a single change or strategy that can be incorporated to fill the void,” Gebhardt said. “We think there should be a combination of strategies, possibly including diet formulation, herd health and such management factors as weaning age, disinfecting facilities and a warm, draft-free environment.”

Gebhardt discussed four nutritional approaches that could achieve growth performance levels similar to what are seen in pharmacological levels of zinc oxide. These strategies include reduction of dietary crude protein, the use of dietary insoluble fiber shortly after weaning, the addition of various feed additives with a variety of mechanisms, and avoiding excess dietary iron which is known to promote bacterial proliferation which can further exacerbate post-weaning diarrhea.

“Nutritional approaches alone are not likely to result in the desired level of performance in a world without zinc oxide,” he said.

Other approaches may be beneficial if used in combination, he added. These include maintaining a high-health status within both the sow and wean-to-finish populations. When healthy pigs are weaned into a clean environment with few multifactorial disease issues, post-weaning diarrhea may be much less of an issue.

Additionally, increasing weaning age may be beneficial to ensure that pigs are robust at weaning, start well on feed and are set up for success in the waiting to finish period. A clean environment is critical as is having a dry, draft-free environment post weaning.

“Control of post-weaning diarrhea without the use of zinc oxide and without routinely using anti-microbials must be accomplished through a combination of management and nutritional factors. And no single silver bullet will be successful to replace zinc oxide,” Gebhardt said.

Although many of the areas he discussed include management in dietary changes, Gebhardt said there are additional areas of importance involving post-weaning diarrhea, including various aspects of genetic as well as immunological predisposing factors.

“The U.S. swine industry must remain judicious in the use of zinc oxide and incorporate where appropriate to maintain animal health and well-being. But we must avoid overuse and continue to advocate for continued access to this technology to avoid regulatory restrictions in the future, which would negatively impact the well-being of pigs in the early nursery stage by limiting the use of dietary zinc oxide,” he said

Pork Farm Journal | Jennifer Shike | November 18