65 Technologies and practices to improve feed and nutrient utilization by pigs

Abstract Feed is a major contributor to pig production’s environmental impact. Various production practices used within the pork ecosystem allow for improvements in nutrient utilization that can reduce on-farm emissions from swine manure and reduce indirect swine-related emission from the feed supply chain. A literature review was conducted on current and potential technologies and practices to improve feed efficiency and nutrient utilization through feed formulation, feed processing, and feeding management. Nutrient utilization by pigs can be improved by more closely meeting the nutrient requirements for maintenance, growth and reproduction, which reduces nutrient excretion. For example, N excretion can be reduced by 8 and 3.7% for every percentage unit reduction in crude protein (CP), respectively, for growing pigs and lactating sows. Similarly, reducing excess trace minerals or replacing inorganic Cu, Zn, and Mn with lower additions of organic sources can reduce excretion by, respectively, 28-42, 38-53, and 12-20%. In addition, adoption of feeding strategies that allow pigs’ requirements to be more precisely met can lower N and P excretion by at least 11%. Feed formulation can also help improve feed efficiency and nutrient utilization through ingredient selection and use of feed additives that enhance nutrient digestibility. Exogenous carbohydrase and protease can improve feed efficiency by 1.8%, while phytase can enhance P digestibility by 30 to 50%. At the feed mill, physical and thermal processing - can improve nutrient digestibility. Feed efficiency can be improved by 1% for every 100-micron reduction in particle size and up to 8% with pelleting. At the farm, feeding practices such as reducing overfeeding of developing gilts and sows, increasing meal frequency, and minimizing feed wastage can also improve feed utilization. For example, feed wastage is estimated to represent 5 to 6% of total feed disappearance, and feeder type can reduce this by 1 to 10%. Lastly, non-nutritional strategies to improve feed efficiency should be considered, including genetic selection, managing thermal environment, and improving herd health. Current genetic selection results in a reduction in greenhouse gas production by 0.5-1.5% per year. Likewise, compared to healthy pigs, disease challenged pigs have 6.25, 7.9, 7.4, 5.8, and 5.8% greater climate change potential, soil and water acidification potential, eutrophication potential, cumulative energy demand, and land application requirements, respectively. Currently, the swine industry primarily focuses on feed and management practices that optimize growth and minimize production cost. The challenge to future swine production will be to find emerging technologies that further reduce environmental impacts while still optimizing performance and production costs. Interactions between current and future technologies and practices should be evaluated to precisely determine their life cycle effects within the pork ecosystem.