星草營養成分及消化率變動之研究

星草（Cynodon plectostachyaum Schum.）的耐逆境力強，做為芻料利用的缺點在於夏季生長快速造成老化及莖桿粗大，若能加以適當的放牧或收穫管理，在進口乾草價格高漲的今天，可能成為國產芻料的來源之一。本研究以四種割期的連續刈割處理，探討星草的營養成分變化。星草的粗蛋白質、中洗纖維、酸洗纖維含量及試管真消化率均隨著季節呈現規律的變動，粗蛋白質含量在10%-26%之間，試管真消化率在60%-87%之間，季節的影響大於割期，高溫下營養價值快速下降，低溫下營養價值易維持但生產量低。為探討不同生產量時的營養價值狀況，本研究進而將樣品依產量由低至高分成四組，與進口百慕達草（C. dactylan L.）12個樣品進行營養價值與消化介量的比較。四組星草的粗蛋白質（分別為23.6%、17.8%、15.8%、13.1%）均顯著高於進口百慕達草（9.6%），雖然進口百慕達草的酸洗纖維含量較低，但其經96小時消化後之不可分解部分（30.5%）僅與最高產組（26.4%）差異不顯著，但高於其他三組（分別為8.7%、10.9%、18.4%），瘤胃利用率則與次高產組相當。本研究結果顯示，在適當割期下（因季節而異），星草可獲得可接受的乾物產量，且營養價值不低於一般進口百慕達草。

關鍵字

星草；百慕達草；牧草品質

並列摘要

Stargrass (Cynodon plectostachyum (Schum.) Pilger) has a great tolerance to environmental stress. However, being a forage, it lacks quality stability which drops off quickly and becomes tough stems after vigorous growth in summer. The grass is expected to be a feasible source for local forage through appropriate grazing and good harvest management. Stargrass was harvested at 35, 45, 55 and 65 day intervals and the nutritive values were determined. The crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and in vitro true digestibility (IVTD) rhythmically varied with the seasons. The ranges of crude protein and IVTD were 10% - 26% and 60%-87%, respectively. Season effect on forage quality was more intensive than the cutting interval. The nutritive value tended to decrease under high temperature, and was easily maintained under low temperature which would cause low productivity. We grouped the stargrass into four according to their yields and then compared the nutritive values and parameters of digestibility kinetics with twelve imported bermudagrass. All the stargrasss groups had higher CP contents than bermuda hay. Although the bermuda hay was low in ADF content, its indigestible pool was similar to the highest yield group and significantly higher than the other three sets. The results showed that stargrass had acceptable yield with appropriate cutting interval and season with the nutritive value not lower than the imported bermuda hay.

並列關鍵字

Cynodon plectostachyum ； C. dactylon ； Quality

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