盤固草乾草倉儲期間品質變化之研究

本研究為探討盤固草（Digitaria decumbens, Pangolagrass）圓形乾草包在不同割期、打包時不同含水率及儲存期間之品質變化，以瞭解最適當儲存條件期能保持乾草品質。試驗方法為盤固草於第一期及第二期乾草調製時分別以低含水率（15～20%）、中含水率（21～25%）及高含水率（26～30%）等三種不同處理，予以打包運回倉庫儲存。儲存期間每隔一、二、四及六個月取樣分析乾物率、CP、ADF、NDF、Ca、P、K、Mg及試管乾物消化率，並評鑑外觀色澤、香味及有無長黴等。試驗結果，第一期乾草儲存六個月後低、中及高含水率處理，其含水率分別減少7.4%、9.6%及14.3%；第二期乾草分別減少4.1%、10.8%及18.9%，顯示乾草打包時含水率愈低其儲存期間草包重量損失相對減少。第一期乾草儲存期間之CP含量高低起伏變動不一，低、中及高含水率等處理自儲存開始至六個月期間分別為6.9～5.2%、4.9～7.3%及5.3～7.9%之間變動，有顯著差異（P＜0.05）。第二期乾草儲存期間CP含量變化比較一致，低、中及高含水率等處理自儲存開始至六個月期間分別為8.2～9.3%、7.8～9.0%及7.4～10.1%之間，各處理在儲存期間無顯著差異（P＞0.05）。第一、二期乾草之ADF含量變化大致具相同趨勢，即低含水率乾草變化最少。第一期及第二期草之中含水率乾草中之ADF增加含量分別為8.8%及4.3%，高含水率乾草之ADF增加量分別為12.1%及3.7%。中洗纖維含量變化與酸洗纖維含量變化相似，隨著儲存時間之增長而含量升高。儲存期間植体中礦物元素Ca及P有變化，K及Mg變化不明顯。乾物消化率方面，由第一、二期草所分析IVDMD結果發現，含水率15%以下的低含水率乾草之消化率變化最小，且最穩定。外觀色澤、香味以低含水率組最佳，其次為中含水率組，而高含水率組其色澤呈黑褐色、嚴重白黴，品質不佳。綜合本試驗結果，在台灣夏季高溫多濕季節，以大型圓形乾草打包，其乾草含水率須低於15%以下，才能保持乾草儲存品質。

關鍵字

盤固草乾草；含水率；牧草品質

並列摘要

The objective of this study was to determine the optimal moisture content of pangolagrass (Digitaria decumbens) round bale hay stored for a longer period. Pangolagrass was harvested to make hay at the 1_(st) and the 2_(nd) cuts and baled with 3 levels of moisture, namely, low (15-20%), medium (21-25 %) and high (26-30%). The percentage of dry mater (DM), the content of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), Ca, P, K, and Mg and In vitro dry matter digestibility (IVDMD), visual color, odor and molding of hay were determined in 1,2,4 and 6 months after storing, respectively. The results showed that the contents of the crude protein were 5.2-6.9%, 4.9~7.3% and 5.3~7.9% at low, medium and high levels of moisture between beginning and 6 months after storing for the 1_(st) cut, respectively, and those were 8.2~9.3%, 7.8~9.0% and 7.4~10.1% for the 2_(nd) cut respectively. Significant differences (p＜0.05) were observed among different storing periods for the 1_(st) cut, while no significant difference was found for the 2_(nd) cut (p＞0.05). The changes in both contents of ADF and NDF for the 1_(st) and the 2_(nd) cut hays were similar during 6 months of storage. It showed that both ADF and NDF contents were increased with storage period and the hay with less moisture content at the beginning of storage had less change in ADF and NDF content during storing. The concentrations of Ca and P were significantly changed for both 1_(st) and 2_(nd) cuts during storing, however, the changes were not similar. The in vitro dry matter digestibility (IVDMD) of the hay with low level moisture changed little and was more stable than those with higher levels of moisture during storing. In addition, less changes were observed in color, odor and visible mold in the hay with low level moisture during storage. These results indicated that pangolagrass round bale hay with moisture content of less than 15% could be stored and in good forage quality 6 months after storing.

並列關鍵字

Pangolagrass (Digitaria decumbens) ； Moisture contents ； Forage quality

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