Hatfield P G, Hopkins J A, Pritchard G T, Hunt C W
Montana State University Bozeman, 59717, USA.
J Anim Sci. 1997 Dec;75(12):3353-66. doi: 10.2527/1997.75123353x.
We conducted two feedlot trials and one metabolism trial to evaluate the effect of barley level, barley bulk density, and physical form of roughage on lamb growth performance and digesta kinetics. Level of whole barley (50, 70, 90%) and type of roughage (chopped or pelleted alfalfa) were evaluated in Trial 1 (50 d period). Trial 2 (50 d) evaluated barley bulk density (heavy = 671 and light = 607 kg/m3), form of roughage (pelleted or chopped alfalfa), and level of barley (80 or 40%). The influence of treatments used in Trial 2 on digesta kinetics was evaluated in Trial 3. Gain:feed increased and DMI decreased (P < .10) linearly with increasing level of barley, and ADG and DMI were greater (P < . 10) for lambs fed pelleted vs chopped alfalfa in Trial 1. The 70% barley diet produced the highest yield grade and kidney-pelvic fat and the lowest leg score among barley levels (P < .10). Lambs fed pelleted alfalfa had heavier carcasses and a thicker body wall than lambs fed chopped alfalfa (P < .02). In Trial 2, DMI was less and gain:feed greater (P < .01) for lambs fed the heavy barley than for lambs fed the light barley and for the 80% barley diet compared to the 40% barley diet. Lambs fed pelleted alfalfa had greater dressing percentages than lambs fed chopped alfalfa. Backfat and body wall thickness were greater (P < .10) for lambs fed the 80% barley diet than for those fed the 40% barley diet. In Trial 3, retention time of barley was greater (P < .10) for lambs fed light rather than heavy barley, and retention time of alfalfa was greater (P < .10) for lambs fed chopped compared with pelleted alfalfa. Acetate:propionate ratio was greater (P < .10) for lambs fed light vs heavy barley and lambs fed the 40 vs 80% barley diets. Ruminal pH was lower (P = .05) and in situ barley digestion greater (P = .03) over time in lambs fed the 80% barley diet than in lambs fed the 40% barley diet. Feedlot lamb ADG was not always greatest with high levels of barley; however, gain:feed improved at the higher barley levels. The higher barley levels seemed to result in fatter lambs.
我们进行了两项育肥试验和一项代谢试验，以评估大麦水平、大麦容重和粗饲料物理形态对羔羊生长性能和消化物动力学的影响。试验1（为期50天）评估了整粒大麦水平（50%、70%、90%）和粗饲料类型（切碎或颗粒状苜蓿）。试验2（50天）评估了大麦容重（重 = 671 kg/m³，轻 = 607 kg/m³）、粗饲料形态（颗粒状或切碎苜蓿）以及大麦水平（80%或40%）。试验3评估了试验2中所用处理对消化物动力学的影响。随着大麦水平的增加，增重：采食量呈线性增加，干物质采食量呈线性下降（P < 0.10），并且在试验1中，饲喂颗粒状苜蓿的羔羊的平均日增重和干物质采食量高于（P < 0.10）饲喂切碎苜蓿的羔羊。在大麦水平中，70%大麦日粮产生了最高的产肉等级和肾周脂肪，腿部评分最低（P < 0.10）。饲喂颗粒状苜蓿的羔羊比饲喂切碎苜蓿的羔羊胴体更重，体壁更厚（P < 0.
02）。在试验2中，与饲喂轻大麦的羔羊相比，饲喂重大麦的羔羊以及与40%大麦日粮相比，饲喂80%大麦日粮的羔羊干物质采食量更低，增重：采食量更高（P < 0.01）。饲喂颗粒状苜蓿的羔羊比饲喂切碎苜蓿的羔羊屠宰率更高。与饲喂40%大麦日粮的羔羊相比，饲喂80%大麦日粮的羔羊的背膘和体壁厚度更大（P < 0.10）。在试验3中，饲喂轻大麦的羔羊的大麦停留时间比饲喂重大麦的羔羊更长（P < 0.10），并且与饲喂颗粒状苜蓿的羔羊相比，饲喂切碎苜蓿的羔羊的苜蓿停留时间更长（P < 0.10）。与饲喂重大麦的羔羊以及饲喂40%与80%大麦日粮的羔羊相比，饲喂轻大麦的羔羊的乙酸：丙酸比值更高（P < 0.10）。随着时间的推移，与饲喂40%大麦日粮的羔羊相比，饲喂80%大麦日粮的羔羊瘤胃pH值更低（P = 0.05），大麦原位消化率更高（P = 0.03）。育肥羔羊的平均日增重并非总是在大麦水平高时最大；然而，在较高的大麦水平下，增重：采食量有所改善。较高的大麦水平似乎导致羔羊更肥。
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