Nogoy Kim Margarette, Zhang Yan, Lee Ye Hyun, Li Xiang Zi, Seong Hyun A, Choi Seong Ho
Department of Animal Science, Chungbuk National University, Cheongju 28644, Korea.
Co-Innovation Center of Beef Cattle Science and Industry Technology, Yanbian University, Yanji 133002, China.
J Anim Sci Technol. 2019 Jan;61(1):18-27. doi: 10.5187/jast.2019.61.1.18. Epub 2019 Jan 31.
With South Korea's limited capability of feed production because of its relatively small cultivable area, the country is pushed to depend on foreign feed imports despite the immensely fluctuating price of corn. Hence, intensive efforts to increase the total cultivable area in Korea like extending of farming to mountainous area is being practiced. Corn was planted in Goesan County, a mountainous area in the country. Grain and stover were harvested separately in three harvest periods: early-harvest (Aug 8), mid-harvest (Aug 18), and late-harvest (Aug 28). The nutrient composition such as dry matter (DM), crude protein (CP), crude fat (EE), organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF), and non-fibrous carbohydrates (NFC) was determined after harvest. Effective degradability (ED) of the major nutrients (DM, NDF, ADF, and CP) were measured through fermentation of rumen fluid from Hanwoo (Korean cattle). pH, ammonia-N concentration, volatile fatty acid (VFA) concentration, and gas production were periodically measured at 0, 3, 6, 12, 24, 48, and 72 h. Corn grain showed higher nutrient content and ED than stover. It also had higher gas production but its pH, ammonia-N, and total VFA concentration were lower than corn stover. The best nutrient composition of corn grain was observed in early-harvest (high CP, EE, NDF, OM, NFC, and low ADF). Early-harvest of corn grain also had high effective degradability of dry matter (EDDM), effective degradability of neutral detergent fiber (EDNDF), effective degradability of acid detergent fiber (EDADF), and total VFA concentration. On the other hand, the best nutrient composition of stover was observed in mid-harvest (high DM, CP, NDF, and low ADF). EDDM, EDNDF, and EDADF were pronounced in early-harvest and mid-harvest of stover but the latter showed high total VFA concentration. Hence, early and mid-harvested corn stover and grain in a mountainous area preserved their nutrients, which led to the effective degradation of major nutrients and high VFA production.
由于韩国可耕地面积相对较小，饲料生产能力有限，尽管玉米价格波动极大，该国仍不得不依赖进口饲料。因此，韩国正在大力努力增加总耕地面积，比如将农业扩展到山区。该国山区的槐山郡种植了玉米。在三个收获期分别收获谷物和秸秆：早收（8月8日）、中收（8月18日）和晚收（8月28日）。收获后测定了干物质（DM）、粗蛋白（CP）、粗脂肪（EE）、有机物（OM）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）和非纤维碳水化合物（NFC）等营养成分。通过韩牛（韩国牛）瘤胃液发酵测定了主要营养成分（DM、NDF、ADF和CP）的有效降解率（ED）。在0、3、6、12、24、48和72小时定期测定pH值、氨氮浓度、挥发性脂肪酸（VFA）浓度和产气量。玉米籽粒的营养成分和ED高于秸秆。它的产气量也更高，但其pH值、氨氮和总VFA浓度低于玉米秸秆。玉米籽粒在早收时营养成分最佳（CP、EE、NDF、OM、NFC含量高，ADF含量低）。玉米籽粒早收时干物质有效降解率（EDDM）、中性洗涤纤维有效降解率（EDNDF）、酸性洗涤纤维有效降解率（EDADF）和总VFA浓度也较高。另一方面，秸秆在中收时营养成分最佳（DM、CP、NDF含量高，ADF含量低）。秸秆早收和中收时EDDM、EDNDF和EDADF显著，但后者总VFA浓度较高。因此，山区早收和中收的玉米秸秆和籽粒保留了其营养成分，这导致主要营养成分的有效降解和高VFA产量。
