Two tetraploid varieties, Astonenergy and Delphin, and two diploid varieties of perennial ryegrass (Lolium perenne), Tyrella and Glenroyal, were evaluated for voluntary dry matter intake (VDMI) and in vivo organic matter digestibility (OMD) using Texel wether sheep housed in digestibility stalls. The structural profile and leaf, stem, dead proportions of the sward were also measured. The experiment was repeated on three occasions (Time Stage (TS)): May/June 2013 (TS1), August/September 2013 (TS2) and September/October 2014 (TS3). Data from both years were analysed separately. There was no variety effect on VDMI during TS1 (1481 ± 44.4 g/day), TS2 (1621 ± 41.7 g/day) or TS3 (1223 ± 86 g/day). There was a significant interaction between TS and variety for OMD (P<0.05) in 2013. OMD declined from TS1 to TS2 for all varieties (P<0.001). This was associated with an increased content of dead material in the sward in TS2 (P<0.001). There was a significant interaction (P<0.05) between TS and ploidy for VDMI as a percentage of bodyweight (VDMI % BW) and OMD in TS1 and TS2, as diploid varieties had higher values in TS1 and lower values than in TS2. In TS3, tetraploid varieties had higher VDMI (% BW) (P<0.05) and a tendency towards higher OMD (P=0.07) when compared to diploid varieties. These results indicate that there is a season by variety (and ploidy) interaction for VDMI and OMD. Future work should use an increased number of varieties to investigate the causes and timing of this interaction.

两个四倍体品种，Astonenergy和的Delphin，以及两个二倍体品种多年生黑麦草（黑麦草），Tyrella和Glenroyal，被自愿干物质摄取（VDMI）和评价在体内使用特克塞尔阉羊有机物消化率（OMD）容纳在消化率摊位。还测量了草皮的结构轮廓和叶子，茎干，枯死率。在三种情况下（时间阶段（TS））重复了该实验：2013年5月/ 6月（TS1），2013年8月/ 9月（TS2）和2014年9月/ 10月（TS3）。两年的数据分别进行了分析。在TS1（1481±44.4 g /天），TS2（1621±41.7 g /天）或TS3（1223±86 g /天）期间，对VDMI没有变化。TS和OMD品种之间存在显着的相互作用（P<0.05）。所有品种的OMD从TS1下降到TS2（P <0.001）。这与TS2中草皮中死物含量的增加有关（P <0.001）。TS和倍性之间，VDMI与TS1和TS2中体重（VDMI％BW）和OMD的百分比之间存在显着的交互作用（P <0.05），因为二倍体变种的TS1值较高，而TS2值较低。在TS3中，四倍体变种具有较高的VDMI（％BW）（P <0.05）和具有较高OMD的趋势（P= 0.07）与二倍体品种相比。这些结果表明，VDMI和OMD存在一个按季节（和倍性）相互作用的季节。未来的工作应使用数量更多的品种来调查这种相互作用的原因和时机。