Performance and milk quality of cows fed triticale silage or intercropped with oats or legumes

ABSTRACT: The use of intercropped grass legumes provides a source of sustainable animal production as these vegetables contribute to an increase in forage yield by area, and substitute inorganic nitrogen and other components. The objective of this study was to evaluate the nutritional characteristics of silages and the yield and milk quality of Holstein cows fed triticale silages in monoculture or intercropped with either oats or legumes. The crops for silage production were triticale (TS), triticale in consortium with forage pea (TSP), and triticale in consortium with oats, forage peas and vetches (TSOPV). The silages showed no differences in dry matter content. The highest crude protein (13.06 %) and ethereal extract content was observed in TSOPV, but in the case of the latter, there was little difference when compared with TS (2.35 and 2.16 %, respectively) although the ash contents of the TSOPV and TSP silages did present a difference compared to TS silage. The neutral and acid detergent fibers (NDF and ADF) and cellulose fractions of TS silage were higher (68.60, 41.46 and 38.19 %, respectively) than those in TSOPV and TSP silages, which also had higher levels of soluble nitrogen, ethanol and acetic acid. Dry matter intake was higher in both TSOPV and TSP, which also provided a higher milk yield (21.19 and 20.45 L cow d−1) compared to that of TS silage (18.74 L cow d−1). Cows fed TS also produced milk with a lower N-ureic content (15.15 mg dL−1). The inclusion of legumes with triticale provided good fermentative quality for silage and increased milk production of cows without altering their concentrations of fat and protein.

摘要：间作豆科牧草（intercropped grass legumes）可为畜牧业可持续生产提供支撑，此类作物可提升单位面积饲草产量，并替代无机氮及其他饲料组分。本研究旨在评估青贮饲料（silages）的营养特性，以及饲喂单作小黑麦（triticale）青贮料、或小黑麦与燕麦（oats）/豆科牧草间作青贮料的荷斯坦奶牛（Holstein cows）的产奶性能与乳品质。用于青贮生产的试验作物包括：单作小黑麦青贮料（TS）、小黑麦与饲用豌豆（forage pea）混播青贮料（TSP），以及小黑麦与燕麦、饲用豌豆、苕子（vetches）混播青贮料（TSOPV）。三类青贮料的干物质含量（dry matter content）无显著差异。TSOPV的粗蛋白（crude protein）含量最高，达13.06%，其乙醚提取物（ethereal extract）含量亦为最高；但与TS相比，乙醚提取物含量仅存在微小差异：TSOPV为2.35%，TS为2.16%。不过TSOPV与TSP青贮料的灰分含量（ash contents）与TS青贮料存在显著差异。小黑麦单作青贮料（TS）的中性洗涤纤维（neutral detergent fiber, NDF）、酸性洗涤纤维（acid detergent fiber, ADF）及纤维素组分（cellulose fractions）含量分别为68.60%、41.46%及38.19%，均高于TSOPV与TSP青贮料；而后两者的可溶性氮（soluble nitrogen）、乙醇及乙酸（acetic acid）含量更高。TSOPV与TSP组的干物质采食量（dry matter intake）更高，且产奶量分别为21.19 L·头⁻¹·天⁻¹与20.45 L·头⁻¹·天⁻¹，均高于TS组的18.74 L·头⁻¹·天⁻¹。饲喂TS青贮料的奶牛所产牛奶的乳尿素氮（N-ureic content）含量更低，为15.15 mg·dL⁻¹。综上，在小黑麦中搭配豆科牧草可改善青贮饲料的发酵品质，并在不改变乳脂肪与乳蛋白浓度的前提下提升奶牛产奶量。