Periparturient oxidative and inflammatory status and their relation to energy metabolism and performance in transition dairy cows.

Interactions among metabolic, oxidative, and inflammatory states are expected to influence cow health and physiology during the transition period. However, the interrelation remains to be elucidated. In this study, 66 lactations from 57 individual multiparous Holstein Friesian cows with a complete profile of oxidative and inflammatory status-related variables at both -7 and 21 d relative to calving were involved under similar transition management. Blood samples were collected at -7 (7 d before the expected calving date) and 3, 6, 9, and 21 DIM to analyze metabolic markers, including BHB acid (BHBA), nonesterified fatty acids, and insulin. Additionally, oxidative variables (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 Hp and SAA, and albumin-to-globulin ratio (A:G) were assessed in the blood of -7 and 21 d relative to calving. Initially, 5 oxidative variables (GSSG [%], GPx, SOD, MDA, and ORAC) at 21 DIM were subjected to fuzzy c-means clustering, delineating 2 groups: lower antioxidant ability (LAA_80%, n = 27) and higher antioxidant ability (HAA_80%, n = 14), with 80% referring to the cut-off value for cluster membership. Twenty-five lactations with membership values below this threshold were excluded. Subsequently, using k-medoids clustering on 3 APP (Hp, SAA, and A:G) at 21 DIM, clinically healthy cows were categorized into 2 groups: those exhibiting an acute phase response (APR, n = 13) and those without this response, termed non-APR (n = 41). Cows that developed one or more clinical diseases during the transition period (n = 12) were considered as a distinct group. A modest association was observed between compromised antioxidant ability and enhanced inflammatory status at a systemic level. Clinically diseased cases manifested increased GPx activities compared with clinically healthy cases, independent of their inflammation levels. A limited association was noticed between oxidative status at -7 and 21 d relative to calving. However, at -7 d relative to calving, the non-APR group exhibited reduced SAA levels in comparison to both the APR and diseased groups. Energy metabolic stress was more pronounced in the LAA_80% group than in the HAA_80% group, characterized by elevated BHBA concentrations during the transition period. Between 5 and 21 d of lactation, a decline in milk yield was observed in the LAA_80% group. Moreover, the LAA_80% group displayed increased milk fat percentages. Nevertheless, the detrimental effects of the transition period were relatively muted when clinical symptoms were absent in the APR group. Notably, the clinically healthy cows produced more milk than the diseased cows. During the transition period, the diseased cases exhibited elevated BHBA concentrations. These findings highlight the heterogeneity in the oxidative and inflammatory status of dairy cows during early lactation. Cows with impaired oxidative status require close monitoring, whereas those with higher antioxidant ability and no clinical symptoms appear capable of managing elevated inflammatory responses.