Acknowledgments
This work was funded by the National Natural Science Foundation of China (31260616), Herbivorous Livestock Technology System in Gansu Province, and Integrated Experimental Demonstration Project of Disease Prevention and Control and Biosafety Technology for Healthy Pig Breeding (20201007-2). We thank all staff members from Gansu Agricultural University and Lanzhou Veterinary Research Institute who provided support for this study. Great gratitude goes to linguistics Prof. Ping Liu from Huazhong Agriculture University, Wuhan, China for her work at English editing and language polishing.