A dysregulated inflammatory response contributes to the occurrence of disorders in cows during the transition period from pregnancy to lactation. However, a detailed characterization of clinically healthy cows that exhibit enhanced inflammatory response during this critical period remains incomplete. In this experiment, a total of 99 individual transition dairy cows and 109 observations (18 cows monitored in 2 consecutive lactations), submitted to similar transition management were involved to evaluate the relationship between elevated inflammatory response and metabolic, oxidative status as well as transition outcomes. Blood was taken at -7, 3, 6, 9 and 21 d in milk (DIM) and concentrations of metabolic parameters (glucose, β-hydroxybutyric acid (BHBA), nonesterified fatty acids (NEFA), insulin, insulin-like growth factor 1 (IGF-1) and fructosamine) were analyzed. Additionally, oxidative parameters (proportion of oxidized glutathione to total glutathione in red blood cells (GSSG (%)), the activity of glutathione peroxidase (GPx) and of superoxide dismutase (SOD), concentrations of malondialdehyde (MDA) and oxygen radical absorbance capacity (ORAC)) and acute phase proteins (APP) including haptoglobin (Hp), serum amyloid A (SAA) and albumin-to-globulin ratio (A:G) were determined in the blood of 21 DIM. The 3 APP parameters were used to group clinically healthy cows into 2 categories through k-medoids clustering, i.e., a group showing an acute phase response (APR, n = 39) and a group not showing such a response, i.e., non-APR (n = 50). Diseased cases (n = 20) were handled in a separate group. Lower SAA and Hp concentrations as well as higher A:G were observed in the non-APR group, although for Hp differences were observed from the APR group, not from the diseased group. Only one of the 5 oxidative parameters differed between the groups, with the non-APR group exhibiting lower GPx activity compared with the diseased group. The non-APR group showed the highest IGF-1 levels among the 3 groups, and lower NEFA concentrations compared with the diseased groups. The diseased group also showed reduced dry matter intake and milk yield compared with clinically healthy cows, regardless of their inflammatory status. Moreover, the APR group exhibited temporarily lower activity levels compared with the non-APR group. These findings highlight that cows with a lower inflammatory status after 21 DIM exhibited better metabolic health characteristics, productive performance as well as activity levels. Nevertheless, the detrimental effects of a higher inflammatory status in the absence of clinical symptoms are still relatively limited.
Keywords: acute phase protein; metabolic status; productive performance; transition period.
The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).