Beck Matthew R, Garrett Konagh, Marshall Cameron J, Gregorini Pablo
Conservation and Production Research Laboratory, USDA-ARS, Bushland, TX 79012, USA.
Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln 7647, New Zealand.
Transl Anim Sci. 2024 Jul 10;8:txae103. doi: 10.1093/tas/txae103. eCollection 2024.
The current experiments were conducted across two lamb finishing seasons (2019 [experiment 1; ] and 2020 [experiment 2; ]). In both experiments lambs were provided a monotonous () diet (annual ryegrass [ L.] during 2019 and perennial ryegrass [ L.] and white clover [ L.] during 2020) or a diverse () diet composed of spatially separated strips sown to chicory ( L.), plantain ( L.), perennial ryegrass, lucerne ( L.), and dock (). During Exp1, the DIV lambs had a stocking rate () of either 80, 95, 100, or 110 m/lamb/wk, whereas the MON lambs had a 100 m/lamb/wk SR. In Exp2, the SR aimed to allocate the MON lambs with twice the forage allowance (kg DM/lamb/d) as DIV lambs. In Exp1, all lambs provided DIV had a greater ( < 0.01) average daily gain (; + 130%) than MON rams, independent of the SR. Accordingly, DIV had greater ( < 0.05) hot carcass weight (; + 26%) and aged carcass weight (; + 27%) compared with MON, across all SR. The 80 m/lamb/wk SR tended to have a greater ( = 0.10) dressing percentage and had similar ( = 0.29) drip loss percentage to the MON lambs, while the other DIV lamb SR all had greater ( < 0.05; +12%) dressing percentages and lower ( < 0.05) drip loss percentage than MON lambs. In Exp2, DIV lambs had greater ( < 0.01) ADG (+37%), HCW (+15%), and dressing percentage (+6%) compared with MON lambs. This improved animal performance occurred despite being offered 57% less ( = 0.01) dry matter (), 56% less ( < 0.01) digestible DM, and 57% less ( = 0.02) metabolizable energy per lamb per day. Ultimately, these experiments demonstrate that providing growing lambs a functionally diverse diet improves animal growth performance and carcass weight compared with a monotonous diet of annual ryegrass or a mixed sward containing perennial ryegrass with white clover.
当前的实验在两个羔羊育肥季节进行（2019年[实验1；]和2020年[实验2；]）。在两个实验中，给羔羊提供单一（）日粮（2019年为一年生黑麦草[L.]，2020年为多年生黑麦草[L.]和白三叶草[L.]）或由播种在空间上分开的条带中的菊苣（L.）、车前草（L.）、多年生黑麦草、紫花苜蓿（L.）和酸模（）组成的多样化（）日粮。在实验1中，多样化日粮组羔羊的饲养密度（）为每只羔羊每周80、95、100或110平方米，而单一日粮组羔羊的饲养密度为每只羔羊每周100平方米。在实验2中，饲养密度旨在为单一日粮组羔羊分配的饲料供应量（千克干物质/只/天）是多样化日粮组羔羊的两倍。在实验1中，所有提供多样化日粮的羔羊的平均日增重（；+130%）均高于单一日粮组羔羊（<0.01），与饲养密度无关。因此，在所有饲养密度下，与单一日粮组相比，多样化日粮组的热胴体重（；+26%）和成熟胴体重（；+27%）更高（<0.05）。每只羔羊每周80平方米的饲养密度的屠宰率倾向于更高（=0.10），且滴水损失率与单一日粮组羔羊相似（=0.29），而其他多样化日粮组羔羊的饲养密度的屠宰率均高于单一日粮组羔羊（<0.05；+12%），滴水损失率低于单一日粮组羔羊（<0.05）。在实验2中，与单一日粮组羔羊相比，多样化日粮组羔羊的平均日增重更高（<0.01；+37%）、热胴体重更高（+15%）和屠宰率更高（+6%）。尽管每只羔羊每天提供的干物质（）减少了57%（=0.01）、可消化干物质减少了56%（<0.01）和代谢能减少了57%（=0.02），但动物性能仍得到了改善。最终，这些实验表明，与一年生黑麦草单一日粮或包含多年生黑麦草和白三叶草的混合草皮单一日粮相比，为生长中的羔羊提供功能多样的日粮可提高动物生长性能和胴体重。
