McCullock Katelyn, Hoag Dana L K, Parsons Jay, Lacy Michael, Seidel George E, Wailes William
Livestock Marketing Information Center, Colorado State University, Fort Collins 80523.
J Dairy Sci. 2013 Oct;96(10):6366-77. doi: 10.3168/jds.2013-6672. Epub 2013 Aug 9.
The use of sexed semen in the dairy industry has grown rapidly. However, high costs and low fertility have limited the use of this potentially valuable tool. This study used simulation to evaluate 160,000 combinations of key variables in 3 spheres of influence related to profit feasibility: (1) market (e.g., milk and calf prices), (2) dairy farm management (e.g., conception rates), and (3) technology (e.g., accuracy of sexing). These influential variables were used to determine the most favorable circumstances in which managers or technicians can effect change. Three distinct scenarios were created to model 3 initiatives that a producer might take with sexed semen: (1) using sexed semen on heifers, (2) using sexed semen on heifers and a fraction of the genetically superior cows, and (3) using sexed semen on heifers and a fraction of the genetically superior cows, and breeding all other cows with beef semen. Due to the large number of management, market, and technology combinations, a response surface and interpretive graphs were created to map the scope of influence for the key variables. Technology variables such as the added cost of sexed semen had relatively little effect on profitability, defined as net present value gain per cow, whereas management variables such as conception rate had a significant effect. Milk price had relatively little effect within each scenario, but was important across scenarios. Profitability was very sensitive to the price of dairy heifer calves, relative to beef and dairy bull calves. Scenarios 1 and 2 added about $50 to $75 per cow in net present value, which ranged from $0 to $200 and from $100 to $300, respectively. Scenario 3 usually was not profitable, primarily because fewer excess dairy replacement heifers were available for sale. Dairy heifer price proved to be the most influential variable, regardless of scenario.
在奶牛养殖业中，性别分选精液的使用迅速增加。然而，高成本和低受胎率限制了这种潜在有价值工具的应用。本研究采用模拟方法评估了与盈利可行性相关的3个影响领域中160,000种关键变量组合：(1)市场（如牛奶和犊牛价格）、(2)奶牛场管理（如受胎率）和(3)技术（如性别分选准确率）。这些影响变量用于确定管理者或技术人员能够实现变革的最有利情况。创建了3种不同情景来模拟生产者使用性别分选精液可能采取的3种举措：(1)对小母牛使用性别分选精液；(2)对小母牛和一部分遗传上优良的母牛使用性别分选精液；(3)对小母牛和一部分遗传上优良的母牛使用性别分选精液，并对所有其他母牛使用肉牛精液进行配种。由于管理、市场和技术组合数量众多，创建了响应面和解释性图表来描绘关键变量的影响范围。性别分选精液的额外成本等技术变量对盈利能力（定义为每头奶牛的净现值增益）影响相对较小，而受胎率等管理变量则有显著影响。牛奶价格在每种情景中影响相对较小，但在不同情景间很重要。相对于肉牛和奶牛公牛犊，奶牛小母牛犊的价格对盈利能力非常敏感。情景1和情景2每头奶牛的净现值分别增加约50至75美元，范围分别为0至200美元和100至300美元。情景3通常不盈利，主要是因为可供出售的多余奶牛替代小母牛较少。无论情景如何，奶牛小母牛价格被证明是最具影响力的变量。
