Kinetics of ruminal passage rate of particles of signal grass silage, maize and intercropped

The purpose of this study was to evaluate the kinetics of ruminal passage rate of particles from the subsequent associations: corn and signal grass; corn, signal grass and Calopogônio; corn, signal grass and Macrotiloma; and corn, signal grass and Estilosantes. It was used four crossbred holstein-zebu cattle with the rumen tubed in order to determine the the kinetics of ruminal passage rate of particles. The feces were collected at the times zero (immediately after addition of fibers complexed with chromium), 1, 2, 4, 6, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 56 , 64, 72, 80, 88, 96, 120, 132, 144 and 192 hours. The profile parameters of passage rate estimative were adjusted according to robust regression procedures. The average time of particles retention in the raft (ATPR1); the average time in the rumen liquid phase (ATRLP2) and the average time of total ruminal retention (ATTRR) were adjusted for the passage kinetics and estimated with the NLIN procedure of SAS. From the observed results, may be suggested that the transference rate λ has an inverse behavior to the escape rate κ, the τ average values, the average retention time and average particles retention time in the rumen liquid phase (ATRLP2) were not statistically different. The feed characteristics after the raft escape and reach to ATRLP2, were very similar; (ATTRR), related to treatments, were not statistically different (P<0,05). There were observed small TMRR numerical differences in different foods. The corn and signal grass; corn, signal grass and calopogônio; corn, signal grass and macrotiloma, corn, signal grass and estilosantes silage fibers had similar rates ofλ, k, ATPR1, ATRLP2 and ATTRR. Therefore, the the kinetics of ruminal passage rate of particles is similar. Thus, the choice of the system should be based on other factors, such as viability of the management ease and silage cost.

本研究旨在评估以下组合饲粮颗粒的瘤胃通过率动力学：玉米与信号草（signal grass）、玉米+信号草+距瓣豆（Calopogônio）、玉米+信号草+硬皮豆（Macrotiloma）以及玉米+信号草+柱花草（Estilosantes）。本试验选用4头安装瘤胃瘘管的荷斯坦-瘤牛杂交肉牛，以测定颗粒的瘤胃通过率动力学。分别于0小时（铬标记纤维复合物添加后即刻）、1、2、4、6、8、12、16、20、24、28、32、36、40、44、48、56、64、72、80、88、96、120、132、144及192小时采集粪便样本。通过率估算的轮廓参数通过稳健回归（robust regression）程序进行校正调整。颗粒在瘤胃漂浮相（raft）的平均滞留时间（ATPR1）、瘤胃液相平均滞留时间（ATRLP2）以及总瘤胃平均滞留时间（ATTRR）均针对通过率动力学进行校正，并通过SAS软件的NLIN程序进行估算。基于观测结果可知，转移速率λ与逃逸速率κ呈负相关关系；τ平均值、平均滞留时间以及瘤胃液相颗粒平均滞留时间（ATRLP2）均无统计学差异。饲粮在脱离漂浮相并进入瘤胃液相后，其特性极为相似；不同处理组的总瘤胃平均滞留时间（ATTRR）均无统计学差异（P<0.05）。观测发现不同饲粮间的TMRR数值差异较小。玉米+信号草、玉米+信号草+距瓣豆、玉米+信号草+硬皮豆以及玉米+信号草+柱花草青贮纤维的λ、κ、ATPR1、ATRLP2及ATTRR均无显著差异。因此，不同处理组的瘤胃颗粒通过率动力学特征相似。综上，饲粮系统的选择应基于其他考量因素，例如管理可行性与便捷性以及青贮饲料的成本。