This work aimed to investigate the effect on redox status in dairy cows fed Origanum vulgare or Camellia sinensis extracts during the transition period. Twenty-four Jersey cows with initial overall BW 430 ± 33kg were randomly assigned to one of the following treatments: control (CO, no plant extract), green tea extract (GTE, 5 g/cow/day) and oregano extract (OE, 10 g/cow/day). Cows received the plant extracts from −21 d to +21 d relative to parturition and were fed with the same basal diet, composed of corn silage, concentrate, and pasture. Blood samples were collected by jugular vein on d −21, −6, +2, and +21 relative to parturition and further analyzed for redox status parameters. Data were submitted to variance analysis, using the Mixed procedure of SAS according to a completely randomized design, considering the effect of diet (n = 3), day of measurement (n = 4), diet by day interaction, cows as the random effect and data collected at different days as repeated measures. Treatments did not affect milk production (overall mean 16.6 ± 3.3 L/d). Cows fed GTE had lower values for dichlorofluorescein oxidation in erythrocytes (DCFE) than cows of control and OE groups. There were no significant differences between groups for dichlorofluorescein oxidation in plasma (DCFP), carbonil, thiols contents as well as superoxide dismutase (SOD), catalase (CAT), gluthatione peroxidase (GPx) and reduced gluthatione activities. Cows fed with green tea extract reduced DCFE, suggesting a slight positive effect on blood redox status. Table 1.

Item	Means			SE
	Control	Green Tea	Oregano
DCFE1	12,246b	10,288a	16,433b	719
DCFP1	4,006a	3,929a	3,749a	380
Carbonil1	1.6a	1.6a	1.7a	0.1
Thiols	0.20a	0.20a	0.20a	0.0
SOD1	16.3a	15.3a	17.3a	0.7
CAT1	1.2a	1.1a	1.2a	0.1
GPx2	0.8a	0.7a	0.8a	0.1
GSH2	0.1a	0.1a	0.01a	0.0

^a,bMeans in the same row followed by different letters are significantly different (Lsmeans, P < 0.05). ¹In nmol/mg of protein. ²In U/mg of protein.