In situ degradability of crude protein in whole crop rice silage.
2004
Ishida, M. | Ito, G. | Ando, S. | Hosoda, K. | Matsuyama, Y. | Nishida, T. | Yoshida, N.
In situ degradability of crude protein (CP) in head and straw from four of whole crop rice silage was determined to examine the effect of rate of grain escaped from digestion and composition of head on CP degradability of the silage. Ground samples in the polyester bags were incubated in the rumen of two ruminal fistulated Holstein steers. Disappearance rate of CP (p) at given incubation time (t) of each sample were fitted to the exponential model of p=a+bx(1-exp(-ct)) to determine faster digestion fraction (a), slower digestion fraction (b) and digestion rate (c). Degradibility of CP in whole crop rice silage at various rates of grain escaped from digestion and those at various compositions of head were calculated. "a" fraction of head (34.5%) was significantly lower than that of straw (40.8%) although "b" fraction of grain (52.9%) and straw (40.6%) were not significantly different. The constant rate of "c" of head (0.151/hr) was much higher than that of straw (0.023/hr). It was estimated that the degradability of CP was decreased by 0.4 points when the rates of grain escaped from digestion increased by 1 point and that the degradability was increased by 0.2 points when the composition of head increased by 1 point. These results showed that the rate of grain escaped from digestion and the composition of head affected degradibility of CP in whole crop rice silage.
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