Strong relationships between mediators of the acute phase response and fatty liver in dairy cows

The objective of this study was to investigate the relationship between activation of acute phase response and fatty liver in transition dairy cows. Fatty liver was induced in dairy cows by feeding 8 kg of cracked corn 1 mo before the expected day of parturition. Liver and blood samples were obtained at days -4, 3, 8, 12, 14, 22, 27, and 36 postpartum. Cows that developed fatty liver (n = 4) reached peak total lipids in the liver at day 12 postpartum with 11.4% (wet wt.) compared with 6.6% in control cows (n = 4). Cows with fatty liver had greater plasma tumor necrosis factor-alpha (TNF-alpha), nonesterified fatty acids (NEFA), and lower lactate concentrations than did control cows at day -4. During highest concentrations of total lipids in the liver, for at least one time-point, fatty-liver cows had greater concentrations of plasma serum amyloid A (SAA), haptoglobin, and NEFA and lower concentrations of calcitonin gene-related peptide (CGRP), prostaglandin E2 (PGE2), cortisol, and TNF-alpha than did control cows. Concentrations of total lipids in the liver at 12 d postpartum were correlated (a) positively with plasma TNF-alpha, SAA, and NEFA and negatively with plasma CGRP before calving, (b) positively with plasma SAA, haptoglobin, and NEFA and negatively with plasma PGE2, CGRP, total cholesterol, and glucose at days 3, 8, and 12 postpartum, and (c) negatively with concentrations of plasma glucose, lactate, and total bilirubin after day 12 postpartum. In conclusion, this study indicates that the acute phase response occurs in cows with fatty liver as well as strong relationships between mediators of immune response and fatty liver.