Department of Dairy Science, University of Wisconsin, Madison 53705; Department of Animal Science, Food and Nutrition (DIANA), Facoltà di Scienze Agrarie, Alimentari e Ambientali, Università Cattolica del Sacro Cuore, 29100 Piacenza, Italy.
Department of Animal Science, Food and Nutrition (DIANA), Facoltà di Scienze Agrarie, Alimentari e Ambientali, Università Cattolica del Sacro Cuore, 29100 Piacenza, Italy.
J Dairy Sci. 2020 Nov;103(11):10898-10916. doi: 10.3168/jds.2020-18157. Epub 2020 Sep 18.
A linear programming model that selects the optimal cropping plan and feeds allocation for diets to minimize the whole dairy farm feed costs was developed. The model was virtually applied on 29 high-yielding Holstein-Friesian herds, confined, total mixed ration dairy farms. The average herd size was 313.2 ± 144.1 lactating cows and the average land size was 152.2 ± 92.5 ha. Farm characteristics such as herd structure, nutritional grouping strategies, feed consumption, cropping plan, intrinsic farm limitations (e.g., silage and hay storage availability, water for irrigation, manure storage) and on farm produced forage costs of production were collected from each farm for the year 2017. Actual feeding strategies, land availability, herd structure, crop production costs and yields, and milk and feed market prices for the year 2017 were used as model inputs. Through optimization, the feeding system was kept equal to the actual farm practice. The linear program formulated diets for each animal group to respect actual herd dry matter intake and fulfill actual consumption of crude protein, rumen-degradable and rumen-undegradable fractions of crude protein, net energy for lactation, neutral detergent fiber, acid detergent fiber, forage neutral detergent fiber, and nonfiber carbohydrate. Production levels and herd composition were considered to remain constant as the nutritional requirement would remain unchanged. The objective function was set to minimize the whole-farm feed costs including cash crop sales as income, and crop production costs and purchased feed costs as expenses. Optimization improved income over feed costs by reducing herd feed costs by 7.8 ± 6.4%, from baseline to optimized scenario, the improved was explained by lower feed costs per kilogram of milk produced due to a higher feed self-sufficiency and higher income from cash crop. In particular, the model suggested to maximize, starting from baseline to optimized scenario, the net energy for lactation (+8.5 ± 6.3%) and crude protein (+3.6 ± 3.1%) produced on farm, whereas total feed cost (€/100 kg of milk) was greater in the baseline (20.4 ± 2.3) than the optimized scenario (19.0 ± 1.9), resulting in a 6.7% feed cost reduction with a range between 0.49% and 21.6%. This meant €109 ± 96.9 greater net return per cow per year. The implementation of the proposed linear programming model for the optimal allocation of the nutritional resources and crops in a dairy herd has the potential to reduce feed cost of diets and improve the farm feed self-sufficiency.
开发了一个线性规划模型，用于选择最佳的作物种植计划和饲料分配方案，以最大限度地降低整个奶牛场的饲料成本。该模型实际上应用于 29 个高产荷斯坦-弗里森奶牛场，这些奶牛场采用全混合日粮饲养方式，奶牛存栏量平均为 313.2±144.1 头，土地面积平均为 152.2±92.5 公顷。从每个农场收集了 2017 年的农场特征，如牛群结构、营养分组策略、饲料消耗、作物种植计划、内在农场限制（如青贮和干草储存可用性、灌溉用水、粪便储存）以及农场生产的饲料生产成本。2017 年的实际饲养策略、土地可用性、牛群结构、作物生产成本和产量、牛奶和饲料市场价格用作模型输入。通过优化，饲养系统与实际农场实践保持一致。线性规划为每个动物群体制定了饲料配方，以尊重实际牛群干物质摄入量，并满足实际粗蛋白、瘤胃可降解和不可降解粗蛋白、泌乳净能、中性洗涤纤维、酸性洗涤纤维、饲料中性洗涤纤维和非纤维碳水化合物的消耗。考虑到生产水平和牛群组成保持不变，因为营养需求不会改变。目标函数设定为最小化整个农场的饲料成本，包括现金作物销售收入作为收入，以及作物生产成本和购买饲料成本作为支出。通过降低牛群饲料成本，优化从基准到优化方案提高了收入超过饲料成本，从基准到优化方案降低了 7.8±6.4%，这是由于饲料自给率提高和现金作物收入增加，导致每公斤牛奶的饲料成本降低。特别是，模型建议从基准到优化方案，最大限度地提高农场生产的泌乳净能（+8.5±6.3%）和粗蛋白（+3.6±3.1%），而总饲料成本（每 100 公斤牛奶的欧元）在基准方案（20.4±2.3）中大于优化方案（19.0±1.9），导致饲料成本降低 6.7%，范围在 0.49%至 21.6%之间。这意味着每头牛每年的净利润增加了 109±96.9 欧元。在奶牛群中实施最佳营养资源和作物分配的线性规划模型具有降低日粮饲料成本和提高农场饲料自给率的潜力。
