Wolfová M, Wolf J, Kvapilík J, Kica J
Institute of Animal Science, PO Box 1, CZ 104 01 Prague-Uhríneves, Czech Republic.
J Dairy Sci. 2007 May;90(5):2442-55. doi: 10.3168/jds.2006-614.
A bioeconomic model for dairy cattle production was used to estimate economic values of 18 traits for dairy sires in purebred Holstein and Czech Fleckvieh populations. Economic values were defined as partial derivatives of the profit function with respect to each trait in a closed production system with dairy cow herds and integrated fattening of bulls. All revenues and costs associated with cows calving in the herds within one year and with their progeny were discounted at 5% per annum back to the date of calving. Calculations were carried out for the situation in the Czech Republic in 2005 (scenario 1: market quotas for milk yield and fat percentage) and for the expected situation in 2015 (scenario 2: free market). The relative economic importance of each trait was expressed as a ratio of the standardized economic value of that trait (its marginal economic value multiplied by its genetic standard deviation) to the standardized economic value of 305-d milk yield, with average fat and protein percentages. In addition to milk yield, somatic cell score was the second most important trait, achieving 32% to 43% of the value for milk yield in both scenarios. The relative importance of milk components differed notably between scenarios. The relative importance was approximately zero for protein and from -14 to -23% for fat percentage in scenario 1, but changed to 38% for protein and 27 to 31% for fat percentage in scenario 2. In both scenarios and for both breeds, the relative economic values for somatic cell score and length of productive life of cows were similar to those for fat and protein percentages in scenario 2. The smallest relative economic values (less than 4% of the relative importance of milk yield) were for birth weight, conception rate of heifers, and carcass traits. In conclusion, relative emphasis among traits in the breeding objective for Czech dairy cattle should be reassessed according to the expected situation after shifting to a free market economy in 2015.
利用奶牛生产生物经济模型估算了纯种荷斯坦牛和捷克弗莱维赫牛群体中18个种公牛性状的经济价值。经济价值被定义为在奶牛群封闭生产系统以及公牛综合育肥系统中，利润函数对每个性状的偏导数。与牛群中一年内产犊母牛及其后代相关的所有收入和成本均按每年5%的贴现率贴现至产犊日期。针对捷克共和国2005年的情况（情景1：牛奶产量和乳脂率的市场配额）以及2015年的预期情况（情景2：自由市场）进行了计算。每个性状的相对经济重要性表示为该性状的标准化经济价值（其边际经济价值乘以其遗传标准差）与305天产奶量标准化经济价值的比值，产奶量的平均乳脂和乳蛋白率。除了产奶量，体细胞评分是第二重要的性状，在两种情景下其价值均达到产奶量价值的32%至43%。不同情景下，乳成分的相对重要性差异显著。在情景1中，蛋白质的相对重要性约为零，乳脂率的相对重要性为-14%至-23%，但在情景2中，蛋白质的相对重要性变为38%，乳脂率的相对重要性为27%至31%。在两种情景下以及两个品种中，体细胞评分和母牛生产寿命的相对经济价值与情景2中乳脂和乳蛋白率的相对经济价值相似。出生体重、小母牛受孕率和胴体性状的相对经济价值最小（低于产奶量相对重要性的4%）。总之，捷克奶牛育种目标中各性状的相对侧重点应根据2015年转向自由市场经济后的预期情况进行重新评估。
