Fenger F, Casey I A, Buckley C, Humphreys J
Animal and Grassland Research and Innovation Centre, Teagasc, Moorepark, Co. Cork, P61 P302 Ireland; Department of Chemical and Life Sciences, South East Technological University, Waterford, X91 K0EK Ireland; Thünen Institute of Organic Farming, 23847 Westerau, Germany.
Department of Chemical and Life Sciences, South East Technological University, Waterford, X91 K0EK Ireland.
J Dairy Sci. 2023 Nov;106(11):7750-7768. doi: 10.3168/jds.2023-23362. Epub 2023 Aug 23.
The area adjacent to the milking parlor, accessible for grazing by lactating dairy cows (i.e., the grazing platform [GP]), can be limited on fragmented pasture-based dairy farms. Such farms, with a moderate overall farm stocking rate, typically have a much higher stocking rate of dairy cows on the GP. This study quantified the effects of farm fragmentation on milk and herbage production and profitability in a whole-farm systems-scale study over 3 yr (2017-2019). Four systems, each with an overall farm stocking rate of 2.5 cows/ha but with different grazing platform stocking rates (GPSR), were examined. The proportions of the overall farm area within the GP were 100%, 83%, 71%, and 63% in each of the 4 systems, respectively. Hence, the 4 systems had a GPSR of 2.5, 3.0, 3.5, and 4.0 cows/ha. The GP was used for grazing and silage (ensiled herbage) production, and the non-GP portion of each GPSR system was used solely for silage production. Concentrate supplementation per cow was the same across all GPSR systems; approximately 10% of the annual feed budget. All systems were compact spring-calving with 24 cows per system. We discovered a lower proportion of grazed herbage in the diet with higher GPSR. All silage produced on the non-GP areas was required to support higher GPSR on each of the systems. Annual herbage production and milk production per cow were not different between GPSR systems, resulting in similar milk production per hectare of the overall system area. The economic implications of different GPSR on fragmented farms were modeled in 2 scenarios: (1) quantifying the cost associated with different levels of farm area fragmentation; (2) investigating the optimum GPSR on fragmented pasture-based dairy farms, depending on variable criteria. A greater level of farm fragmentation lowered the profitability of pasture-based dairy production. Costs of production increased with higher GPSR and longer distances between GP and non-GP areas. At a fixed GP area, it was most profitable to increase GPSR up to 4 cows/ha on the GP when milk price was high, land rental price was low, and shorter distance existed between GP and non-GP areas.
在以牧场为基础的碎片化奶牛场中，挤奶厅附近可供泌乳奶牛放牧的区域（即放牧平台[GP]）可能会受到限制。这类农场总体养殖密度适中，但放牧平台上奶牛的养殖密度通常要高得多。本研究在一项为期3年（2017 - 2019年）的全农场系统规模研究中，量化了农场碎片化对牛奶和牧草产量以及盈利能力的影响。研究考察了4种养殖系统，每种系统的农场总体养殖密度均为2.5头/公顷，但放牧平台养殖密度（GPSR）不同。4种系统中，放牧平台占农场总面积的比例分别为100%、83%、71%和63%。因此，这4种系统的放牧平台养殖密度分别为2.5、3.0、3.5和4.0头/公顷。放牧平台用于放牧和青贮饲料（青贮牧草）生产，每个放牧平台养殖密度系统的非放牧平台部分仅用于青贮饲料生产。所有放牧平台养殖密度系统中每头奶牛的精饲料补充量相同；约占年度饲料预算的10%。所有系统均为紧凑型春季产犊，每个系统有24头奶牛。我们发现，随着放牧平台养殖密度的增加，日粮中放牧牧草的比例降低。为了支持各系统更高的放牧平台养殖密度，非放牧平台区域生产的所有青贮饲料都是必需的。不同放牧平台养殖密度系统之间，每头奶牛的年牧草产量和牛奶产量没有差异，导致整个系统每公顷的牛奶产量相似。在两种情况下对碎片化农场中不同放牧平台养殖密度的经济影响进行了建模：（1）量化与不同程度农场区域碎片化相关的成本；（2）根据可变标准研究以牧场为基础的碎片化奶牛场的最佳放牧平台养殖密度。农场碎片化程度越高，以牧场为基础的奶牛生产的盈利能力越低。生产成本随着放牧平台养殖密度的增加以及放牧平台与非放牧平台区域之间距离的延长而增加。在固定的放牧平台面积下，当牛奶价格高、土地租赁价格低且放牧平台与非放牧平台区域之间距离短时，将放牧平台养殖密度提高到4头/公顷是最有利可图的。
