1Department of Animal Production, Facultad de Ciencias Agrarias,Universidad Nacional del Litoral,Esperanza 3080,Argentina.
2Animal and Biomedical Sciences,Institute of Veterinary,Massey University,Palmerston North 5301,New Zealand.
Animal. 2018 May;12(5):1077-1083. doi: 10.1017/S1751731117002853. Epub 2017 Oct 26.
Milking cows once a day (OAD) is a herd management practice that may help to reduce working effort and labour demand in dairy farms. However, a decrease in milk yield per cow occurs in OAD systems compared with twice a day (TAD) systems and this may affect profitability of dairy systems. The objective of this study was to assess productive and economic impact and risk of reducing milking frequency from TAD to OAD for grazing dairy systems, using a whole-farm model. Five scenarios were evaluated by deterministic and stochastic simulations: one scenario under TAD milking (TADAR) and four scenarios under OAD milking. The OAD scenarios assumed that milk yield per cow decreased by 30% (OAD30), 24% (OAD24), 19% (OAD19) and 10% (OAD10), compared with TADAR scenario, based on experimental and commercial farms data. Stocking rate (SR) was increased in all OAD scenarios compared to TADAR and two levels of reduction in labour cost were tested, namely 15% and 30%. Milk and concentrate feeds prices, and pasture and crop yields, were allowed to behave stochastically to account for market and climate variations, respectively, to perform risk analyses. Scenario OAD10 showed similar milk yield per ha compared with TADAR, as the increased SR compensated for the reduction in milk yield per cow. For scenarios OAD30, OAD24 and OAD19 the greater number of cows per ha partially compensated for the reduction of milk yield per cow and milk yield per ha decreased 21%, 15% and 10%, respectively, compared with TADAR. Farm operating profit per ha per year also decreased in all OAD scenarios compared with TADAR, and were US$684, US$161, US$ 303, US$424 and US$598 for TADAR, OAD30, OAD24, OAD19, OAD10, respectively, when labour cost was reduced 15% in OAD scenarios. When labour cost was reduced 30% in OAD scenarios, only OAD10 showed higher profit (US$706) than TADAR. Stochastic simulations showed that exposure to risk would be higher in OAD scenarios compared with TADAR. Results showed that OAD milking systems might be an attractive alternative for farmers who can either afford a reduction in profit to gain better and more flexible working conditions or can minimise milk yield loss and greatly reduce labour cost.
奶牛每天挤奶一次（OAD）是一种牧场管理实践，可以帮助减少奶牛场的工作强度和劳动力需求。然而，与每天挤奶两次（TAD）系统相比，OAD 系统中每头奶牛的产奶量会下降，这可能会影响奶牛养殖系统的盈利能力。本研究的目的是使用全农场模型评估从 TAD 减少到 OAD 对放牧奶牛系统的生产和经济影响和风险。通过确定性和随机模拟评估了五个方案：一个 TAD 挤奶方案（TADAR）和四个 OAD 挤奶方案。OAD 方案假设基于实验和商业农场的数据，与 TADAR 方案相比，每头奶牛的产奶量分别减少 30%（OAD30）、24%（OAD24）、19%（OAD19）和 10%（OAD10）。与 TADAR 相比，所有 OAD 方案中的饲养率（SR）都有所增加，并测试了劳动力成本降低 15%和 30%的两种水平。允许牛奶和浓缩饲料价格以及牧场和作物产量随机变化，以分别考虑市场和气候变化，进行风险分析。与 TADAR 相比，方案 OAD10 每公顷的牛奶产量相似，因为增加的 SR 弥补了每头奶牛产奶量的减少。对于方案 OAD30、OAD24 和 OAD19，每公顷奶牛的数量增加部分弥补了每头奶牛产奶量的减少，与 TADAR 相比，每公顷的牛奶产量分别减少了 21%、15%和 10%。与 TADAR 相比，所有 OAD 方案中的农场每公顷每年的运营利润也有所下降，当 OAD 方案中的劳动力成本降低 15%时，TADAR、OAD30、OAD24、OAD19 和 OAD10 的每公顷农场运营利润分别为 684 美元、161 美元、303 美元、424 美元和 598 美元。当 OAD 方案中的劳动力成本降低 30%时，只有 OAD10 的利润（706 美元）高于 TADAR。随机模拟表明，与 TADAR 相比，OAD 方案面临的风险更高。结果表明，对于那些能够承受利润减少以获得更好、更灵活的工作条件的农民，或者能够将产奶量损失降到最低并大幅降低劳动力成本的农民来说，OAD 挤奶系统可能是一个有吸引力的选择。
