Baruselli Pietro Sampaio, de Abreu Laís Ângelo, de Paula Vanessa Romário, Carvalho Bruno, Gricio Emanuelle Almeida, Mori Fernando Kenji, Rebeis Lígia Mattos, Albertini Sofía, de Souza Alexandre Henrily, D'Occhio Michael
Departamento de Reprodução Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brasil.
Instituto Paulista de Ensino e Pesquisa, Empresa Brasileira de Pesquisa Agropecuária - EMBRAPA, Juiz de Fora, MG, Brasil.
Anim Reprod. 2023 Sep 8;20(2):e20230060. doi: 10.1590/1984-3143-AR2023-0060. eCollection 2023.
Methane emission from beef and dairy cattle combined contributes around 4.5-5.0% of total anthropogenic global methane. In addition to enteric methane (CH) produced by the rumen, cattle production also contributes carbon dioxide (CO) (feed), nitrous oxide (NO) (feed production, manure) and other CH (manure) to the total greenhouse gas (GHG) budget of beef and dairy production systems. The relative contribution in standard dairy systems is typically enteric CH 58%, feed 29% and manure 10%. Herds with low production efficiency can have an enteric CH contribution up to 90%. Digestibility of feed can impact CH emission intensity. Low fertility herds also have a greater enteric CH contribution. Animals with good feed conversion efficiency have a lower emission intensity of CH/kg of meat or milk. Feed efficient heifers tend to be lean and have delayed puberty. Fertility is a major driver of profit in both beef and dairy cattle, and it is highly important to apply multi-trait selection when shifting herds towards improved efficiency and reduced CH. Single nucleotide polymorphisms (SNPs) have been identified for feed efficiency in cattle and are used in genomic selection. SNPs can be utilized in artificial insemination and embryo transfer to increase the proportion of cattle that have the attributes of efficiency, fertility and reduced enteric CH. Prepubertal heifers genomically selected for favourable traits can have oocytes recovered to produce IVF embryos. Reproductive technology is predicted to be increasingly adopted to reduce generation interval and accelerate the rate of genetic gain for efficiency, fertility and low CH in cattle. The relatively high contribution of cattle to anthropogenic global methane has focussed attention on strategies to reduce enteric CH without compromising efficiency and fertility. Assisted reproductive technology has an important role in achieving the goal of multiplying and distributing cattle that have good efficiency, fertility and low CH.
牛肉和奶牛产生的甲烷排放占全球人为甲烷排放总量的约4.5%-5.0%。除了瘤胃产生的肠道甲烷（CH）外，养牛业还向牛肉和奶牛生产系统的温室气体（GHG）总预算中贡献二氧化碳（CO）（饲料）、一氧化二氮（NO）（饲料生产、粪便）和其他CH（粪便）。在标准奶牛系统中，相对贡献通常为肠道CH 58%、饲料29%和粪便10%。生产效率低的牛群肠道CH贡献可达90%。饲料的消化率会影响CH排放强度。繁殖力低的牛群肠道CH贡献也更大。饲料转化效率高的动物每千克肉或奶的CH排放强度较低。饲料效率高的小母牛往往较瘦，青春期延迟。繁殖力是肉牛和奶牛利润的主要驱动因素，在使牛群向提高效率和减少CH排放转变时，应用多性状选择非常重要。已鉴定出牛饲料效率的单核苷酸多态性（SNP），并用于基因组选择。SNP可用于人工授精和胚胎移植，以增加具有高效、高繁殖力和减少肠道CH排放属性的牛的比例。经基因组选择具有有利性状的青春期前小母牛的卵母细胞可被采集用于生产体外受精胚胎。预计繁殖技术将越来越多地被采用，以缩短世代间隔，加快牛在效率、繁殖力和低CH排放方面的遗传进展速度。牛对全球人为甲烷排放的相对较高贡献已将注意力集中在不影响效率和繁殖力的情况下减少肠道CH排放的策略上。辅助生殖技术在实现繁殖和推广具有高效、高繁殖力和低CH排放的牛的目标方面具有重要作用。
