Milk and meat from cattle and buffaloes contribute 45% of the global animal protein supply, followed by chickens (31%), and pigs (20%). In 2016, the global cattle population of 1.0 billion head produced 6.5 billion tons of cows' milk, and 66 million tons of beef. In the past century, cattle breeding programs have greatly increased the yield per animal with a resultant decrease in the emissions intensity per unit of milk or beef, but this has not been true in all regions. Genome editing research in cattle to date has focused on disease resistance (e.g. tuberculosis), production (e.g. myostatin knockout; production of all-male offspring), elimination of allergens (e.g. beta-lactoglobulin knockout) and welfare (e.g. polled or hornlessness) traits. Modeling has revealed how the use of genome editing to introduce beneficial alleles into cattle breeds could maintain or even accelerate the rate of genetic gain accomplished by conventional breeding programs, and is a superior approach to the lengthy process of introgressing those same alleles from distant breeds. Genome editing could be used to precisely introduce useful alleles (e.g. heat tolerance, disease resistance) and haplotypes into native locally-adapted cattle breeds, thereby helping to improve their productivity. As with earlier genetic engineering approaches, whether breeders will be able to employ genome editing in cattle genetic improvement programs will very much depend upon global decisions around the regulatory framework and governance of genome editing for food animals.

中文翻译：

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基因组编辑在牲畜中的应用：牛。

来自牛和水牛的牛奶和肉占全球动物蛋白供应量的45％，其次是鸡（31％）和猪（20％）。2016年，全球10亿头牛的生产量为65亿吨牛奶和6600万吨牛肉。在过去的一个世纪中，牛育种计划极大地提高了每只动物的产量，从而降低了单位牛奶或牛肉的排放强度，但并非在所有地区都如此。迄今为止，对牛的基因组编辑研究集中在抗病性（例如结核病），生产（例如肌肉生长抑制素；全男性后代的生产），消除过敏原（例如β-乳球蛋白基因敲除）和福利（例如轮询或无角）性状上。 。建模揭示了使用基因组编辑将有益等位基因引入牛品种如何能够维持或什至加速常规育种程序实现的遗传增益速率，并且是从远距离品种渗入相同等位基因的漫长过程的一种极好的方法。基因组编辑可用于将有用的等位基因（例如耐热性，抗病性）和单倍型精确引入本地适应当地的牛品种，从而帮助提高其生产力。与早期的基因工程方法一样，育种者是否能够在牛的遗传改良计划中采用基因组编辑将在很大程度上取决于围绕食用动物基因组编辑的监管框架和治理的全球决策。