Temperate grass and legume yield and quality are markedly reduced during hot, dry summer months in the southern USA; therefore, browse species could add feed options for small ruminants during this season. Our objective was to compare total biomass yield and forage nutritive value of two browse species, leguminous bristly locust ( Robinia hispida ) and smooth sumac ( Rhus glabra ), as well as a leguminous shrub known as sericea lespedeza ( Lespedeza cuneate ), during summer months (June, July, August and September). Plants were sampled monthly during growing-seasons in 2012 and 2013 to determine biomass yield (foliar, shoot, and total above ground) and foliar nutritive value [crude protein (CP), acid detergent fiber (ADF), acid detergent lignin (ADL), and condensed tannins (CT)]. There was a species × harvest time interaction for foliar biomass yield ( P = 0.0125). This interaction was likely due to low yield in June for bristly locust compared with sericea lespedeza and smooth sumac, but in all other months (July, August, and September) yields were similar for each species. Bristly locust had the highest CP (16.9%), followed by sericea lespedeza (14.8%), and smooth sumac (12.3%). Acid detergent fiber and ADL were similar between bristly locust (ADF 38.5%; ADL 24.1%) and sericea lespedeza (ADF 38.4%; ADL 23.1%), but was lower for smooth sumac (ADF 22.1%, ADL 6.3%; P < 0.05). Condensed tannins, an anti-nutritive yet anti-parasitic phenolic compounds, were highest in smooth sumac, intermediate in bristly locust, and lowest in sericea lespedeza. Plant foliar percentage (ratio of foliar to shoot mass), was highest in smooth sumac (55.1%), followed by sericea lespedeza (47.7%), and bristly locust (42.6%). Overall, smooth sumac had the highest foliar biomass and lowest ADF and ADL; however, this species had the lowest CP and highest CT. Consequently, average foliar biomass yield of all three browse species in our study far exceeded forage yield from dominant forage species [tall fescue ( Schedonorus arundinaceus ) and bermudagrass ( Cyanodon dactylon )] in this region and may provide high-yielding, low input, anti-parasitic fodder for small ruminants during this period in the Southeastern U.S.

中文翻译：

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浏览刺槐、光滑漆树和胡枝子对小型反刍动物的潜力

在美国南部炎热干燥的夏季，温带草和豆科植物的产量和质量显着下降；因此，浏览物种可以在本季节为小型反刍动物增加饲料选择。我们的目标是比较两种浏览物种，即豆科刺槐（ Robinia hispida ）和光漆树（ Rus glabra ），以及一种被称为胡枝子（ Lespedeza cuneate ）的豆科灌木在夏季的总生物量产量和饲料营养价值。 （六月、七月、八月和九月）。在 2012 年和 2013 年的生长季节每月对植物进行采样，以确定生物量产量（叶面、地上部和总地上部分）和叶面营养价值 [粗蛋白 (CP)、酸性洗涤纤维 (ADF)、酸性洗涤木质素 (ADL)和缩合单宁 (CT)]。叶面生物量产量存在物种×收获时间相互作用（ P = 0.0125）。这种相互作用可能是由于 6 月份刚毛刺槐的产量低于胡枝子和光滑漆树，但在所有其他月份（7 月、8 月和 9 月），每个物种的产量相似。刺槐的 CP 最高（16.9%），其次是胡枝子（14.8%）和光漆树（12.3%）。刺槐（ADF 38.5%；ADL 24.1%）和胡枝子（ADF 38.4%；ADL 23.1%）的酸性洗涤纤维和 ADL 相似，但光滑漆树的酸性洗涤纤维和 ADL 较低（ADF 22.1%，ADL 6.3%；P < 0.05） ）。缩合单宁是一种抗营养但抗寄生虫的酚类化合物，在光漆树中最高，在刺槐中居中，在胡枝子中最低。植物叶面百分比（叶面与枝条质量之比），在光滑漆树中最高 (55.1%)，其次是胡枝子 (47.7%) 和刚毛刺槐 (42.6%)。总体而言，光滑漆树具有最高的叶生物量和最低的 ADF 和 ADL；然而，这个物种的CP最低，CT最高。因此，我们研究中所有三种浏览物种的平均叶面生物量产量远远超过了该地区优势牧草物种 [高羊茅 ( Schedonorus arundinaceus ) 和狗牙根 ( Cyanodon dactylon )] 的牧草产量，并可能提供高产、低投入、抗- 这一时期美国东南部小反刍动物的寄生饲料