In this study, the in vitro fermentation parameters of whole crop barley (WCBS-TMR) and Italian ryegrass (IRGS-TMR) silage total mixed rations were compared. A rice straw based diet (RSBD), which was a mixture of rice straw and concentrate (60:40), was used as the control. The feeds were incubated in buffered rumen fluid for 3, 6, 9, 12, 24, 48 and 72 hours at 39°C. At the end of each incubation period the following parameters were determined, total gas, pH, ammonia nitrogen (NH3-N), volatile fatty acids (VFA) and then the acetate to propionate ratio (A/P) was calculated. The dietary treatments did not affect (p>0.05) the overall production of NH3-N, gas, total VFA and all the individual VFA, with the exception of n-butyrate (p<0.001). The treatment diets significantly affected the A/P ratio (p<0.01). The control diet resulted in the lowest A/P ratios, followed by WCBS-TMR and lastly IRGS-TMR had the highest ratios. Gas production was not different between treatments, suggesting a probable similar level of digestibility when treatments are fed to animals. It can therefore be concluded from the present study that WCBS and IRGS are of almost an equivalent nutritional value when incubated in a TMR form. WCBS-TMR however resulted in lower A/P ratios than IRGS-TMR, which is indicative of a more energy efficient diet.

본 연구는 반추동물의 조사료 자원으로서 거대억새를 개발하기 위한 목적으로 수행되었다. 우리나라에서 새롭게 개발된 품종인 거대억새 1호를 완숙기 이후에 채취하여 in vitro 반추위 발효를 이용해반추위내 pH, 암모니아태 질소, 가스발생량, 휘발성 지방산 생성량 및 건물소화율을 조사하였으며,볏짚과 비교하여 평가하였다. 거대억새는 볏짚에 비하여 유의적으로 높은 반추위내 pH를 나타내었다(p<0.01). 암모니아태 질소의 경우 배양 12시간 이후에는 두 처리구간의 유의적인 차이를 나타내지 않았다 (p>0.05). 배양 6시간 이후 부터는 거대억새의 가스발생량이 볏짚에 비하여 유의적으로 낮게 나타났다 (p<0.05). 휘발성 지방산 생성량에 있어 acetate, propionate, butyrate, valerate 및 총생상량에서 볏짚이 거대억새보다 높게 나타났다. 그러나 iso-butyrate와 iso-valerate에서는 두 조사료원별 차이는 발견되지 않았다. 건물소화율에 있어 배양 12~24시간 사이의 거대억새 소화율이 볏짚에 비하여 유의적으로 나타났다. 결론적으로 거대억새의 이용성은 볏짚의 약 80% 수준인 것으로 나타났다.

Rumen fermentative characteristic is useful indicators of the quality of ruminant feed stuffs and diets. An in vitro rumen fermentation experiment was therefore carried out to compare fermentation patterns among three forage sources. These were whole crop barley (WCBS), Italian ryegrass silage (IRGS) and rice straw silages (RSS). Rice straw (RS) was the control, making the treatments 4 in total. Forages were randomly allocated to serum bottles. The incubation times were arranged 0, 3, 6, 9, 12, 24, 48 and 72h at 39℃, respectively. Each forage source was replicated 3 times per incubation time. At each sampling time, total gas and pH were measured, whilst individual volatile fatty acids (VFAs), total volatile fatty acids (TVFAs) and ammonia nitrogen (NH3-N) were determined later after storing samples at -20℃. Acetate: Propionate ratio (A/P) was then calculated. Forage source had a significant effect (P