Damiran Daalkhaijav, Biligetu Bill, Lardner Herbert
Department of Animal and Poultry Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada.
Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada.
Animals (Basel). 2023 Mar 14;13(6):1047. doi: 10.3390/ani13061047.
The objective of this study was to determine rumen degradation kinetics of new low-lignin alfalfa ( L.) cv. Hi-Gest360 (HiGest) in comparison with conventional alfalfa cv. AC Grazeland (Grazeland) in monoculture and binary mixtures at different maturity stages. Two cultivars of alfalfa (HiGest, and AC Grazeland) and their binary mixtures with hybrid bromegrass (HBG; cv. AC Success), grown in 2019 at two locations (Saskatoon and Lanigan), were cut at three maturity stages of alfalfa (1 = 10% bloom; 2 = 40% bloom; and 3 = 100% bloom). Rumen degradation characteristics, including rapidly degradable fraction (S), potentially degradable fraction (D), undegradable fraction (U), degradation rate (K), lag time (T), and effective degradability (ED) of each component were determined using in situ technique and were analyzed by a first-order kinetic equation described by Ørskov and McDonald with lag time. Generally, in alfalfa monoculture, S or D were decreased and U was increased without affecting K and T, resulting in decreased ED fraction with increasing stage of maturity. In binary mixtures, plant maturity stages have negligible effects on rumen degradation characteristics of CP. HiGest had higher effective degradability of DM (EDDM) as well as of NDF (EDNDF) than Grazeland. In conclusion, HiGest had greater DM and NDF rumen degradation potential relative to Grazeland. HiGest and Grazeland were different in DM and CP degradation patterns, with HiGest having higher EDDM and EDCP than Grazeland.
本研究的目的是测定新型低木质素苜蓿品种Hi - Gest360（HiGest）与传统苜蓿品种AC Grazeland（Grazeland）在不同成熟阶段的单作和二元混合物中的瘤胃降解动力学。2019年在两个地点（萨斯卡通和拉尼根）种植的两个苜蓿品种（HiGest和AC Grazeland）及其与杂交雀麦（HBG；品种AC Success）的二元混合物，在苜蓿的三个成熟阶段进行刈割（1 = 10%开花；2 = 40%开花；3 = 100%开花）。使用原位技术测定各组分的瘤胃降解特性，包括快速降解部分（S）、潜在降解部分（D）、不可降解部分（U）、降解率（K）、滞后时间（T）和有效降解率（ED），并通过Ørskov和McDonald描述的带有滞后时间的一级动力学方程进行分析。一般来说，在苜蓿单作中，S或D降低，U增加，而不影响K和T，导致随着成熟阶段的增加ED部分降低。在二元混合物中，植物成熟阶段对CP的瘤胃降解特性影响可忽略不计。HiGest的干物质有效降解率（EDDM）以及中性洗涤纤维有效降解率（EDNDF）均高于Grazeland。总之，相对于Grazeland，HiGest具有更大的干物质和中性洗涤纤维瘤胃降解潜力。HiGest和Grazeland在干物质和粗蛋白降解模式上存在差异，HiGest的EDDM和EDCP高于Grazeland。
