Kok Akke, van Middelaar Corina E, Mostert Pim F, van Knegsel Ariëtte T M, Kemp Bas, de Boer Imke J M, Hogeveen Henk
Animal Production Systems group, Wageningen University & Research, Wageningen, the Netherlands.
Adaptation Physiology group, Wageningen University & Research, Wageningen, the Netherlands.
PLoS One. 2017 Oct 27;12(10):e0187101. doi: 10.1371/journal.pone.0187101. eCollection 2017.
Shortening or omitting the dry period of dairy cows improves metabolic health in early lactation and reduces management transitions for dairy cows. The success of implementation of these strategies depends on their impact on milk yield and farm profitability. Insight in these impacts is valuable for informed decision-making by farmers. The aim of this study was to investigate how shortening or omitting the dry period of dairy cows affects production and cash flows at the herd level, and greenhouse gas emissions per unit of milk, using a dynamic stochastic simulation model. The effects of dry period length on milk yield and calving interval assumed in this model were derived from actual performance of commercial dairy cows over multiple lactations. The model simulated lactations, and calving and culling events of individual cows for herds of 100 cows. Herds were simulated for 5 years with a dry period of 56 (conventional), 28 or 0 days (n = 50 herds each). Partial cash flows were computed from revenues from sold milk, calves, and culled cows, and costs from feed and rearing youngstock. Greenhouse gas emissions were computed using a life cycle approach. A dry period of 28 days reduced milk production of the herd by 3.0% in years 2 through 5, compared with a dry period of 56 days. A dry period of 0 days reduced milk production by 3.5% in years 3 through 5, after a dip in milk production of 6.9% in year 2. On average, dry periods of 28 and 0 days reduced partial cash flows by €1,249 and €1,632 per herd per year, and increased greenhouse gas emissions by 0.7% and 0.5%, respectively. Considering the potential for enhancing cow welfare, these negative impacts of shortening or omitting the dry period seem justifiable, and they might even be offset by improved health.
缩短或省略奶牛的干奶期可改善泌乳早期的代谢健康，并减少奶牛的管理过渡。这些策略的实施成功与否取决于它们对产奶量和农场盈利能力的影响。了解这些影响对于农民做出明智的决策很有价值。本研究的目的是使用动态随机模拟模型，研究缩短或省略奶牛干奶期如何影响畜群水平的产量和现金流，以及每单位牛奶的温室气体排放。该模型中假设的干奶期长度对产奶量和产犊间隔的影响源自商业奶牛多个泌乳期的实际表现。该模型模拟了100头奶牛群中个体奶牛的泌乳期、产犊和淘汰事件。对畜群进行了5年的模拟，干奶期分别为56天（传统）、28天或0天（每组50个畜群）。部分现金流根据出售牛奶、犊牛和淘汰奶牛的收入以及饲料和饲养幼畜的成本计算得出。温室气体排放采用生命周期方法计算。与56天的干奶期相比，28天的干奶期在第2至5年使畜群的产奶量降低了3.0%。0天的干奶期在第2年奶产量下降6.9%之后，在第3至5年使奶产量降低了3.5%。平均而言，28天和0天的干奶期分别使每组畜群每年的部分现金流减少1249欧元和1632欧元，温室气体排放分别增加0.7%和0.5%。考虑到提高奶牛福利的可能性，缩短或省略干奶期的这些负面影响似乎是合理的，甚至可能被改善的健康状况所抵消。
