Scaglia G, Swecker W S, Fontenot J P, Fiske D, Fike J H, Abaye A O, Peterson P R, Clapham W, Hall J B
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg 24061-0306, USA.
J Anim Sci. 2008 Aug;86(8):2032-42. doi: 10.2527/jas.2007-0407. Epub 2008 Apr 11.
Small cow-calf operations are common in the Appalachian region. Tall fescue [Lolium arundinaceum (Schreb.) S. J. Darbyshire] is the dominant forage in these systems for direct grazing as well as for stockpiling. The present study was conducted from 2001 to 2005. A total of 108 Angus and Angus crossbred cows were allotted randomly to 6 forage systems and then to 3 replicates within each system. In brief, system 1 had a stocking rate of 0.91 ha/cow in a Middleburg 3-paddock (A, B, and C) system. System 2 was similar to system 1 except for a stocking rate of 0.71 ha/cow. A stocking rate of 0.71 ha/cow also was used in systems 3 through 6. All A paddocks had tall fescue, whereas B paddocks had tall fescue/white clover (Trifolium repens L.) except in system 6, which had tall fescue/lespedeza [Lespedeza cuneata (Dum. Cours.) G. Don]. System 3 evaluated a 2-paddock (A and B) rotational grazing system, and system 4 evaluated a 3-paddock (A, B, and C) rotational grazing system, with paddock C containing orchardgrass (Dactylis glomerata L.) and alfalfa (Medicago sativa L.). Systems 5 and 6 differed from system 2 in the areas of paddocks B and C as well as in the forage mixtures used. In paddock C, system 5 had switchgrass (Panicum virgatum L.) and system 6 had tall fescue and birdsfoot trefoil (Lotus corniculatus L.). System 1 had the greatest average herbage availability from weaning until breeding (P < 0.05) with the least amount of hay fed (P = 0.03) when compared with the remainder of the systems. Differences (P > 0.05) in percentage of ground cover were not detected among systems. There was no year x system interaction effect on the cow or calf performance variables evaluated and no treatment effect on cow performance variables. There was a treatment effect on calf performance variables. System 2 produced the greatest adjusted weaning weight, kilograms of calf weaned per hectare, and kilograms of calf per kilograms of cow at weaning (P < 0.05). Numerical ranking for total calf production per hectare from the greatest to least was system 2, 6, 3, 5, 4, and 1. Systems evaluated did not affect cow performance although differences in calf performance and overall productivity of the systems were observed.
小型奶牛养殖在阿巴拉契亚地区很常见。高羊茅[Lolium arundinaceum (Schreb.) S. J. Darbyshire]是这些养殖系统中用于直接放牧和储备的主要草料。本研究于2001年至2005年进行。总共108头安格斯牛和安格斯杂交母牛被随机分配到6种草料系统中,然后在每个系统内再分为3个重复。简而言之,系统1在米德尔堡三牧场(A、B和C)系统中的载畜率为0.91公顷/头。系统2与系统1类似,只是载畜率为0.71公顷/头。系统3至6也采用了0.71公顷/头的载畜率。所有A牧场都种植高羊茅,而B牧场种植高羊茅/白三叶(Trifolium repens L.),但系统6种植的是高羊茅/胡枝子[Lespedeza cuneata (Dum. Cours.) G. Don]。系统3评估了一个两牧场(A和B)轮牧系统,系统4评估了一个三牧场(A、B和C)轮牧系统,其中C牧场种植鸭茅(Dactylis glomerata L.)和苜蓿(Medicago sativa L.)。系统5和6在B和C牧场的面积以及使用的草料混合物方面与系统2不同。在C牧场,系统5种植柳枝稷(Panicum virgatum L.),系统6种植高羊茅和百脉根(Lotus corniculatus L.)。与其他系统相比,系统1从断奶到配种期间的平均牧草可利用量最大(P < 0.05),干草饲喂量最少(P = 0.03)。各系统之间未检测到地被覆盖率百分比的差异(P > 0.05)。在评估的奶牛或犊牛性能变量方面,未发现年份×系统交互效应,对奶牛性能变量也没有处理效应。对犊牛性能变量有处理效应。系统2产生了最大的校正断奶体重、每公顷断奶犊牛千克数以及断奶时每千克母牛的犊牛千克数(P < 0.05)。每公顷犊牛总产量从高到低的数值排名为系统2、6、3、5、4和1。尽管观察到系统在犊牛性能和整体生产力方面存在差异,但所评估的系统对奶牛性能没有影响。