Regrinding large particles from milled grains improves growth performance of pigs

Abstract

The effects of grain type (barley [B] or sorghum [S]); particle size (ground grain [G] or ground grain from which the coarse fraction had been separated and re-ground, then added back to the fine fraction [R]), and diet form (mash [M], or pellet [P]), on average daily intake (ADI), body weight gain (BWG) and feed conversion ratio (FCR, feed:gain as fed) in grower pigs were measured over a period of four weeks. Ninety-six pure-bred Large White pigs of average weight 20.2±1.07kg were assigned to 8 treatments, with12 pigs per treatment. FCR was significantly affected (P<0.05) by grain type, particle size and feed form. Barley-based diets were more efficiently utilised than sorghum-based diets (FCR difference 4.14%). Regrinding the coarse fraction for both barley and sorghum diets significantly (P<0.001) reduced (improved) FCR (6.57%). Pelleting diets significantly (P<0.05) reduced (improved) FCR (3.56%) compared with the mash diets. The lowest efficiency of feed use for barley-based diets was for the ground, mash diet (FCR 2.038) and highest was for the reground, mash diet (FCR 1.88). The lowest efficiency of feed use for sorghum-based diets was for the ground, mash diet (FCR 2.195) and the highest for the reground, pelleted diet (FCR 1.919). There was no effect of treatment on ADI or BWG (P>0.05) for barley-based diets, but these measures were significantly higher (P<0.05) for mash than pelleted sorghum-based diets. This study showed that regrinding the coarse fraction of cereal grains and feeding as a mash diet gave similar efficiency of feed use by pigs as pelleting the non-reground grain. Thus, regrinding the coarse fraction of grains could be an alternative method to pellet processing for maintaining energy delivery to growing pigs. The optimal processing choice may differ according to the grain type, with regrinding and pelleting resulting in the highest efficiency of feed use for sorghum-based, but not barley-based diets.