Lopez-Villalobos N, Garrick D J, Holmes C W, Blair H T, Spelman R J
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
J Dairy Sci. 2000 Jan;83(1):164-72. doi: 10.3168/jds.S0022-0302(00)74867-3.
The effects of selection and crossbreeding on the New Zealand dairy industry net income were evaluated with a deterministic model over a 25 yr planning horizon. Several mating strategies involving Holstein-Friesian, Jersey and Ayrshire cattle were evaluated. These strategies were straight breeding, upgrading to Holstein-Friesian, upgrading to Jersey, upgrading to Ayrshire, use of the best bulls irrespective of breed and two- and three-breed rotational crossbreeding. Industry productions of milk, fat, protein, and lactose were calculated assuming that 12,000 kg of dry matter per hectare was utilized from 1,224,911 hectares of pasture. Profitability was the difference between income (international sale of whole milk powder, casein, butter, and beef from salvage animals) and costs (farm expenses, milk collection, manufacture, and marketing). Casein and whole milk powder were valued at NZ$8.345 and NZ$3.306/ per kilogram, respectively, over 25 yr. Butter was valued at NZ$2.995/kilogram for base year production levels and NZ$0.45/kilogram for marginal increases in production. Upgrading to Holstein-Friesian resulted in the highest industry net income (NZ$1119 million) followed by straight breeding (NZ$1086 million) and two-breed rotational Holstein-Friesian x Jersey (NZ$1076 million). However, if the marginal value of extra butter production was assumed equal to the average base value, then upgrading to Jersey resulted in the highest industry net income (NZ$1185 million) followed by two-breed rotational Holstein-Friesian x Jersey (NZ$1177 million) and use of the best bulls (NZ$1173 million). Future costs and prices of dairy products have major impact on mating strategies.
在25年的规划期内，使用确定性模型评估了选育和杂交育种对新西兰乳业净收入的影响。评估了几种涉及荷斯坦-弗里生牛、泽西牛和艾尔郡牛的交配策略。这些策略包括纯种繁育、升级为荷斯坦-弗里生牛、升级为泽西牛、升级为艾尔郡牛、不论品种使用最佳公牛以及两品种和三品种轮回杂交。假设从1224911公顷牧场中每公顷利用12000千克干物质，计算了该行业的牛奶、脂肪、蛋白质和乳糖产量。盈利能力是收入（全脂奶粉、酪蛋白、黄油的国际销售以及淘汰动物牛肉的销售）与成本（农场开支、牛奶收集、加工和销售）之间的差额。在25年期间，酪蛋白和全脂奶粉的价值分别为每千克8.345新西兰元和3.306新西兰元。黄油的基础年生产水平价值为每千克2.995新西兰元，产量边际增加部分价值为每千克0.45新西兰元。升级为荷斯坦-弗里生牛带来了最高的行业净收入（11.19亿新西兰元），其次是纯种繁育（10.86亿新西兰元）和两品种轮回杂交荷斯坦-弗里生牛×泽西牛（10.76亿新西兰元）。然而，如果假设额外黄油产量的边际价值等于平均基础价值，那么升级为泽西牛带来了最高的行业净收入（11.85亿新西兰元），其次是两品种轮回杂交荷斯坦-弗里生牛×泽西牛（11.77亿新西兰元）和使用最佳公牛（11.73亿新西兰元）。乳制品未来的成本和价格对交配策略有重大影响。
