Lipid mobilization, insulin resistance and oxidative stress as metabolic adaptation processes in dairy cows during the periparturient period

This study aimed to evaluate several biochemical changes in dairy cows during the periparturient period. It was carried out on 38 multiparous Holstein/Friesian crossbreed dairy cows 3-11 years old. On the basis of clinical examination and assessment of BHBA concentration in blood, cows were classified to 4 groups, control healthy cows include 16 animals, subclinical ketosis include 10 animals, cows with retained placenta include 6 animals and clinical mastitis include 6 animals. The plasma level of BHBA showed a significant increase (p<0.05) at 2 weeks postpartum in subclinical ketosis than other groups. The plasma level of NEFA showed a significant increase (p<0.05) at 2 weeks antepartum in retained placenta and 2 weeks postpartum in subclinical ketosis than other groups. The plasma level of MDA showed a significant increase (p<0.05) at 2 weeks antepartum in retained placenta and 2 weeks postpartum in SCK than other groups. The plasma level of glucose showed a significant decrease (p<0.05) at 2wks postpartum in subclinical ketosis group, TAC showed a significant decrease (p<0.05) at 4wks antepartum in retained placenta group and insulin showed a significant decrease (p<0.05) in all groups after parturition. RQUICKI showed a significant decrease (p<0.05) at 2wks antepartum in retained placenta group and 2wks postpartum in subclinical ketosis group compared with groups. It could be concluded that the periparturient period induced biochemical changes, insulin resistance and oxidant injury which could be implicated in the pathogenesis of the diseases during the periparturient period of dairy cows. The extreme reduction in insulin level and RQUICKI could be considered important risk factors for induction metabolic diseases in dairy cows beside reduction of oxidative stress indices.