초록
Two experiments were conducted to determine the effects of conditioning (conventional vs expander) corn- and sorghum-based diets on production traits for lactating sows and finishing pigs. In Exp. 1, one hundred sixty-eight sows (parity 1-4, PIC line C15) were fed the corn or sorghum grain diets as a meal, standard (steam) conditioned pellets, or expanded pellets to give a $2{\times}3$ factorial arrangement of treatments. Pellet durability index (PDD was similar for the sorghum- vs corn-based diets, but increased when diets were expanded pellets for both corn- and sorghum-based diets. The corn-based meal diet supported 3.3% greater litter weight gain than the sorghum-based meal diet (44.0 kg vs 42.8 kg). However, the advantage for the corn-based diet disappeared with expander processing (ie., sows fed the sorghum-based diet responded more to diets processed with the alternative processing technology). Sow weight change during lactation was similar (p>0.15) among treatments, although average daily feed intake tended to be greater (p<0.09) for the sows fed sorghum. For Exp. 2, a total of 71 barrows (average initial weight of 58.0 kg) were used in a growth assay to determine the effects of feeding com- and sorghum-based diets, as meal or pellets, after processing with a conventional steam conditioner or an expander (high-shear) conditioner. PDI was not different for the sorghum- vs corn-based diets, but increased from 84 to 95% with expander conditioning compared to conventional steam conditioning. Rate and efficiency of gain, and carcass leanness were similar for pigs fed sorghum and corn (p>0.15). Efficiency of gain was greater (p<0.04) for pigs fed the pelleted (356 g/kg) diets compared to those given the meal (348 g/kg) diets. However, efficiencies of gain were similar (p>0.11) for pigs fed the conventional- and expander-conditioned diets. Pelleting increased (p<0.01) the incidence and severity of stomach lesions regardless of grain type. In conclusion, corn-based meal diet resulted in a greater litter weight gain than the sorghum-based meal diet. However, that advantage disappeared when the diets were expanded and pelleted. Finishing pigs fed pelleted diets were more efficient than those fed meal diets.