Adaptation Physiology Group, Wageningen University & Research, 6700 AH Wageningen, the Netherlands; Wageningen Livestock Research, Wageningen University & Research, 6700 AH Wageningen, the Netherlands.
Adaptation Physiology Group, Wageningen University & Research, 6700 AH Wageningen, the Netherlands.
J Dairy Sci. 2022 May;105(5):4171-4188. doi: 10.3168/jds.2021-20707. Epub 2022 Mar 2.
Based on modeling studies, a 1-yr calving interval for dairy cows is generally considered optimal from an economic point of view. Recently some dairy farmers are deliberately extending the voluntary waiting period for insemination (VWP) to extend the calving interval. Reasons to extend the VWP are to reduce the frequency of transitions such as dry-off and calving to improve health, to reduce labor associated with these transitions, and to reduce the number of surplus calves. This study aimed to evaluate yearly revenues, yearly costs, and yearly net partial cash flow (NPCF) for individual cows with a VWP of 50, 125, or 200 d based on data from a randomized control trial. The NPCF included revenues and costs for milk yield, calves born, inseminations, concentrate supply, partial mixed ration (PMR) supply, veterinary treatments, discarded milk due to veterinary treatments, culling, and labor (for milking, calving cows, inseminations, and veterinary treatments). Holstein-Friesian dairy cows (n = 153) within one herd were blocked for parity, calving season, and expected (primiparous cows) or previous (multiparous cows) 305-d milk yield. Cows were randomly assigned within the blocks to 1 of 3 VWP (VWP50, VWP125, or VWP200) in wk 6 after calving, and monitored from wk 6 after calving until wk 6 after the next calving or until culling. Revenues and costs were calculated per individual cow and expressed per cow per year. Revenues from milk and costs for PMR and concentrate contributed most to the yearly NPCF. Total yearly revenues were greater in VWP50 compared with VWP200 (€3,169 vs. €2,832), mainly because of €334 greater milk revenues. Total yearly costs were also greater in VWP50 compared with VWP200 (€1,964 vs. €1,729), mainly because of €102 greater concentrate costs. The VWP was not significantly associated with the NPCF per cow per year. A change in milk, feed, or calf price, or a change in labor costs for calving cows or for inseminations had a greater effect on the yearly NPCF of cows in VWP50 compared with cows in VWP200. To investigate variation in NPCF, cows were grouped for yearly NPCF and categorized into 3 economic classes (EC): EC1 (<€1,100/yr), EC2 (€1,100-€1,400/yr), and EC3 (>€1,400/yr). Cows in EC3 had greatest lactation production per day in the experiment (i.e., kg of milk, protein, fat, lactose), and lowest number of veterinary treatments during the experiment.
基于模型研究，从经济角度来看，奶牛的 1 年产犊间隔通常被认为是最佳的。最近，一些奶牛养殖户故意延长自愿输精等待期（VWP）以延长产犊间隔。延长 VWP 的原因是减少干奶和产犊等过渡的频率，以改善健康状况，减少与这些过渡相关的劳动力，并减少多余小牛的数量。本研究旨在根据一项随机对照试验的数据，评估 VWP 为 50、125 或 200 天的个体奶牛的年收益、年成本和年净部分现金流量（NPCF）。NPCF 包括牛奶产量、出生的小牛、配种、浓缩饲料供应、部分混合日粮（PMR）供应、兽医治疗、因兽医治疗而丢弃的牛奶、淘汰和劳动力（用于挤奶、产奶牛、配种和兽医治疗）的收入和成本。一个牛群中的荷斯坦弗里生奶牛（n = 153）按胎次、产犊季节和预期（初产奶牛）或之前（经产奶牛）305 天的牛奶产量进行分组。牛在产犊后第 6 周内按 VWP（VWP50、VWP125 或 VWP200）的 1 随机分配，并从产犊后第 6 周开始监测，直到下一次产犊后第 6 周或淘汰。收入和成本按每头奶牛计算，并按每年每头奶牛表示。牛奶收入和 PMR 和浓缩饲料成本是 NPCF 的主要贡献者。与 VWP200 相比，VWP50 的总收入更高（€3169 比 €2832），主要是因为牛奶收入高出€334。与 VWP200 相比，VWP50 的总年成本也更高（€1964 比 €1729），主要是因为浓缩饲料成本高出€102。VWP 与每年每头奶牛的 NPCF 无显著相关性。牛奶、饲料或小牛价格的变化，或产奶牛或配种劳动力成本的变化，对 VWP50 奶牛的年 NPCF 影响大于 VWP200 奶牛。为了研究 NPCF 的变化，将奶牛按每年的 NPCF 分组，并分为 3 个经济类（EC）：EC1（<€1100/yr）、EC2（€1100-€1400/yr）和 EC3（>€1400/yr）。EC3 中的奶牛在实验中的产奶量最高（即牛奶、蛋白质、脂肪、乳糖的日产量），并且在实验期间兽医治疗的次数最少。
