The objective of this study was to assess the effect of feeding top-dress bioactive peptides from cottonseed (CSBP) and hydroxy seleno methionine (HSM) on the performance, immune system, and health status of Holstein cows during the prepartum period. One hundred and eighty multiparous Holstein dry cows from 21 d before the expected calving date were assigned to one of the four experimental treatments of a random-ized complete block design in a 2 × 2 factorial arrangement including 1) control group (containing inor-ganic Se recommended in NRC (2001)), 2) control plus 1.2 mg HSM, 3) control plus 300 g CSBP and 4) control plus 1.2 mg HSM and 300 g CSBP. The interaction of HSM and CSBP affected prepartum serum glucose concentration. Prepartum immune indicators and liver enzymes were not affected by the interaction of CSBP by HSM. In the postpartum period, the interaction of HSM by CSBP affected the concentration of serum glucose, cholesterol, total protein (TP), and creatine kinase (CK). Alkaline phosphatase (ALP) tended to be significant by the interaction of HSM and CSBP. The interaction of CSBP with HSM in-creased milk production. The interaction of CSBP by HSM showed that the Pe0Se1 cows had the lowest milk BHB concentration compared to other treatments. These results demonstrate that feeding top-dress CSBP and HSM could improve milk yield. Increasing total antioxidant capacity (TAC) by HSM and pep-tide separately could be helpful as a tool to pass the inflammatory period peripartum. The liver functionality index wasn’t affected by any of the experimental treatments. پرونده مقاله