Section snippets Experimental basis Ethical approval: The experimental proposals and procedures for the care and treatment of cattle were approved by the Animal Care and Use Committee of Jilin Agricultural University (approval number: JLAU-2022-018). The experiments were conducted on a commercial farm in Shizuishan City, Ningxia, China, from April to June 2023. Lactating primiparous and multiparous (two or three parities) Holstein dairy cows were included in the study.
