Sanchez M P, Ferrand M, Gelé M, Pourchet D, Miranda G, Martin P, Brochard M, Boichard D
Génétique Animale et Biologie Intégrative, INRA, AgroParisTech, Université Paris Saclay, F-78350 Jouy-en-Josas, France.
Institut de l'Elevage, F-75012 Paris, France.
J Dairy Sci. 2017 Aug;100(8):6371-6375. doi: 10.3168/jds.2017-12663. Epub 2017 Jun 16.
Genetic parameters for the major milk proteins were estimated in the 3 main French dairy cattle breeds (i.e. Montbéliarde, Normande, and Holstein) as part of the PhénoFinlait program. The 6 major milk protein contents as well as the total protein content (PC) were estimated from mid-infrared spectrometry on 133,592 test-day milk samples from 20,434 cows in first lactation. Lactation means, expressed as a percentage of milk (protein contents) or of protein (protein fractions), were analyzed with an animal mixed model including fixed environmental effects (herd, year × month of calving, and spectrometer) and a random genetic effect. Genetic parameter estimates were very consistent across breeds. Heritability estimates (h) were generally higher for protein fractions than for protein contents. They were moderate to high for α-casein, α-casein, β-casein, κ-casein, and α-lactalbumin (0.25 < h < 0.72). In each breed, β-lactoglobulin was the most heritable trait (0.61 < h < 0.86). Genetic correlations (r) varied depending on how the percentage was expressed. The PC was strongly positively correlated with protein contents but almost genetically independent from protein fractions. Protein fractions were generally in opposition, except between κ-casein and α-lactalbumin (0.39 < r < 0.46) and κ-casein and α-casein (0.36 < r < 0.49). Between protein contents, r estimates were positive, with highest values found between caseins (0.83 < r < 0.98). In the 3 breeds, β-lactoglobulin was negatively correlated with caseins (-0.75 < r < -0.08), in particular with κ-casein (-0.75 < r < -0.55). These results, obtained from a large panel of cows of the 3 main French dairy cattle breeds, show that routinely collected mid-infrared spectra could be used to modify milk protein composition by selection.
作为“PhénoFinlait”项目的一部分，对法国3个主要奶牛品种（即蒙贝利亚尔牛、诺曼底牛和荷斯坦牛）主要乳蛋白的遗传参数进行了估计。利用中红外光谱法，对20434头头胎泌乳奶牛的133592份测定日产奶样品中的6种主要乳蛋白含量以及总蛋白含量（PC）进行了估计。泌乳平均值以奶（蛋白含量）或蛋白（蛋白组分）的百分比表示，采用包含固定环境效应（牛群、产犊年份×月份和光谱仪）和随机遗传效应的动物混合模型进行分析。遗传参数估计在各品种间非常一致。蛋白组分的遗传力估计值（h）通常高于蛋白含量。α-酪蛋白、α-酪蛋白、β-酪蛋白、κ-酪蛋白和α-乳白蛋白的遗传力为中度到高度（0.25 < h < 0.72）。在每个品种中，β-乳球蛋白是遗传力最高的性状（0.61 < h < 0.86）。遗传相关性（r）因百分比的表示方式而异。PC与蛋白含量呈强正相关，但与蛋白组分几乎在遗传上独立。蛋白组分通常呈相反关系，κ-酪蛋白与α-乳白蛋白之间（0.39 < r < 0.46）以及κ-酪蛋白与α-酪蛋白之间（0.36 < r < 0.49）除外。在蛋白含量之间，r估计值为正，酪蛋白之间的r值最高（0.83 < r < 0.98）。在这3个品种中，β-乳球蛋白与酪蛋白呈负相关（-0.75 < r < -0.08），尤其是与κ-酪蛋白（-0.75 < r < -0.55）。这些结果来自法国3个主要奶牛品种的大量奶牛，表明常规收集的中红外光谱可用于通过选择来改变乳蛋白组成。
