Perennial ryegrass (PR) is a quality and high yielding forage that tends to lack winter hardiness to persist in the upper Midwest. The objective was to evaluate yield, stand persistence, forage nutritive value, and preference of experimental populations of winter hardy PR grown in monoculture and in mixture with white clover under livestock grazing. Research was conducted in St. Paul and Grand Rapids, MN. Meadow fescue (MF), tall fescue (TF), orchardgrass (OG), a reference PR, and two experimental populations of PR were grazed every 32 days by either horses (St. Paul) or cow‐calf pairs (Grand Rapids). Prior to grazing, forage yield and quality samples were collected, and post‐grazing, fields were visually assessed for the percentage of forage removal to determine preference. Yields of all PR (6.9 to 7.6 Mg ha⁻¹) were similar, but lower compared to other cool‐season grasses (CSG). Persistence was similar among all CSG in St. Paul; however, it was lower for all PR in Grand Rapids compared to other CSG. All PR were highly preferred by both horses (≥74% removal) and cattle (≥70% removal) and were consistently among the highest for crude protein (CP; 200 g kg⁻¹), equine digestible energy (DE; 2.35 Mcal kg⁻¹) and bovine metabolizable energy (ME; 2.6 Mcal kg⁻¹), moderate for nonstructural carbohydrates (NSC; 136 g kg⁻¹), and among the lowest for neutral detergent fiber (NDF; 518 g kg⁻¹). Experimental populations of PR produced forage of high nutritive value, but yield and stand persistence may be less compared to other CSG at some locations.

中文翻译：

---

放牧条件下多年生黑麦草的产量，持久性，牧草营养价值和偏好

多年生黑麦草（PR）是优质且高产的草料，往往缺乏耐寒性，难以在中西部地区持续存在。目的是评估单种养殖和与白三叶草混合饲养的，在牲畜放牧下生长的耐寒PR的实验种群的产量，林分持久性，牧草营养价值和偏好。研究在明尼苏达州的圣保罗和大瀑布城进行。每32天，用马（圣保罗）或小牛对（大急流城）放牧草地羊茅（MF），高羊茅（TF），果园（OG），参考PR和两个实验种群PR。放牧前，收集草料产量和质量样品，放牧后，目视评估田地中草料去除的百分比，以确定喜好。所有PR的产量（6.9至7.6 Mg ha ^-1）相似，但比其他冷季草（CSG）低。圣保罗所有南玻集团的持之以恒。但是，与其他CSG相比，大急流城的所有PR都较低。所有PR均被马（≥74％去除率）和牛（≥70％去除率）高度推荐，并且始终处于粗蛋白（CP； 200 g kg ^-1），马可消化能（DE； 2.35 Mcal kg）的最高水平^-1）和牛的代谢能（ME; 2.6 Mcal kg ^-1），对于非结构性碳水化合物（NSC; 136 g kg ^-1）中等，在中性洗涤剂纤维（NDF; 518 g kg ^-1）中最低）。PR的实验种群产生了高营养价值的饲料，但在某些地方与其他CSG相比，产量和林分持久性可能更低。