(Wood et al. 2008) and China (Yu et al. 2013), which may lead to multiple chronic diseases (Simopoulos 2011). Therefore, it is necessary to improve the n-3 PUFAs intake in human daily diet. Lai et al. (2006) generated hfat-1 transgenic pigs which overexpress the Caenorhabditis elegans (C. elegans) fat1 gene. Compared to the wild-type pigs, the EPA and DPA level in the transgenic pigs has increased by 15-fold and 4-fold respectively, and the n-6/n-3 PUFAs ratio decreased by 80.2 %. In the present study, we first generated mfat1 transgenic beef cattle by SCNT. A total of 20 calves were obtained in the study, and 14 out of them were transgenic positive. Importantly, the fatty acid composition analysis showed that overexpression of mfat1 gene elevatedthe contents of ALA, EPA and DHA in beef, and decreased the n-6/n-3 PUFAs ratio by 82.2 % compared to the transgenic negative calf. Our results provide evidence that new breed of cattle containing high level of n-3 PUFAs can be created in a relatively short time by using transgenic technology. However, the high neonatal mortality of SCNT animals are still problems that hindering the utilization of transgenic animals (Kang et al. 2001). In thepresentstudy,septicemia andorgandevelopmental abnormalities were the major causes of neonatal mortality (Table 2), consistent with the previous studies (Brisville et al. 2013). These abnormalities may partly result from the incomplete reprogramming of somatic cells or abnormal epigenetic modification