A shift in three major issues affecting feed manufacturing for pork production has occurred simultaneously in recent years. First, high ingredient costs have resulted in increased utilization of low energy, high fiber by-product ingredients in grow-finish diets. Second, these high ingredient costs have altered the cost:benefit ratio of pelleting, causing more producers to pellet grow-finish diets. Third, feed has recently been implicated as a potential vector of Porcine Epidemic Diarrhea Virus, a virus that is known to be thermally sensitive. All three of these issues aligned to emphasize that more research is needed to assess the economic benefits of feed processing conditions in low energy, high by-product diets for grow-finish pigs. This study aimed to determine the influence of processing a low energy, high by-product diet via pelleting with a standard 45 s conditioning time, pelleting with a 90 s conditioning time, or extrusion on grow-finish pig growth performance, nutrient digestibility, and carcass characteristics. Thermal processing, regardless of type, improved gain, feed efficiency, and carcass weight without affecting feed intake. While thermal processing did not affect percentage yield, backfat, or loin depth, pigs fed thermally-processed diets had poorer fat quality than those fed mash diets. There were few differences between diets pelleted for the standard 45 s and diets that were either extruded or pelleted with long-term conditioning times, suggesting that subjecting low energy diets to harsh thermal processing conditions is neither advantageous nor deleterious to grow-finish performance compared to traditional pelleting.

Key Findings:
• Thermal processing, regardless of type, improved overall ADG and G:F, but did not affect ADFI in finishing pigs.
• Pigs fed any thermally-processed treatment had greater hot carcass weight and jowl iodine value compared to those fed the mash diet.
• There were few differences between diets pelleted for the standard 45 s and diets that were either extruded or pelleted with long-term conditioning times.
• Subjecting low energy diets to harsh thermal processing conditions is neither advantageous nor deleterious to grow-finish performance compared to traditional pelleting.