1College of Animal Science and Technology, Northeast Agricultural University, Haerbin, China
College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
*Corresponding author's e-mail: ylqu007@126.com
Online published on 15 March, 2019.
One hundred twelve China Holstein cows with similar body weight and lactation stage were selected. The average daily milk yield of one half was 20.34±1.61kg and the other was 25.41±2.97kg. In each herd, the cows were randomly assigned to two groups. The control diets(I and II) werethe originaldairyfarm diets, and the testdiets (I and II) werethe corresponding control diets adjusted by CPM-Dairy (Cornell-Penn-Miner Dairy System). The diagnosis for the two original diets showed the ME and MP balance were greater than the cow requirement. The rumen peptide balance also showed the same tendency. Both test diets had lower CP (%/DM) than the corresponding Control diet by 1.60% and 2.5%, respectively. However, both the RUPs(%/CP) were increased a little in the twotest diets. The MPallowed daily milk yieldof Control diet Iwas greater than the actual dailymilkyield and ME allowed dailymilkyield (P < 0.05), but they didn't present significant difference in Test diet I (P > 0.05).
CPM, Dairy cows, Lactating performance
