Document Type : Research Paper
Assistant Professor, Department of Animal Science, College of Agriculture, Isfahan University of Technology, Iran
Ph.D. Candidate, Department of Animal Science, College of Agriculture, Isfahan University of Technology, Iran
Associate Professor, Department of Animal Science, College of Agriculture, Isfahan University of Technology, Iran
In this study, the metabolic and antioxidative differences, BW changes and performane of12 primiparous (parturition BW 643±48 kg BW) and 15 multiparous (parturition BW 773±65 kg) cows were investigated during transition period. Blood sample for antioxidative and metabolic parameters on d -14, +1, and +21 (relative to parturition), DMI throughout the entire period, BW and BCS on d -21, +1, and +21 and milk yeild were measured. In prepartum, both groups had similar DMI, but DMI and milk yield were greater in multiparous than primiparous cows in postpartum. BW and BCS were decreased in both primiparous and multiparous cows during transition period, but multiparous cows tended to have more BW loss and negative energy balance after parturition. Concentrations of non-esterified fatty acids, beta hydroxy butyrate, and cholesterol were similar, but glucose level was lower in multiparous than primiparous cows. Regarding antioxidative status, primiparous cows had lower antioxidative status as malondialdehyde concentration at parturition was higher and that of total antioxidative status at postpartum were lower than multiparous cows. Regarding performance related parameters, mlondialdehyde level could be an apropriate index of energy balance, health and performance status. It is concluded that primiparous cows were under more oxidative stress during transtion period, but metabolic load and negative energy balance were more sever in multiparous cows.