Appearance of haptoglobin in serum from cows at parturition.

Haptoglobin (Hp) concentrations were evaluated in 42 cow sera at around parturition by single radial immunodiffusion using anti-cow Hp rabbit serum. At parturition, Hp was detected in 31 of 42 cows. The detection rate (74%) was significantly higher than those before (0-10%) and after parturition (5-21%). At parturition, serum concentrations of cortisol and non-esterified fatty acids were significantly higher than those before and after parturition. A significantly lower concentration of serum triglycerides at parturition, compared to the values before parturition, was also observed. From these results, Hp is considered to be associated with fatty liver development of cows, because fatty liver particularly occurs in the peripartum period.