What role does green tea and oregano play in cow diets?

The study: Impact of oregano and green tea extracts on transitioning cows

The research, which was carried out in Brazil by E.F. Vizzotto et al., looked at plant extracts oregano and green tea and their impact on the transitioning Jersey cow. The extracts were fed to Jersey cows from approximately 21 d before calving to 21 d after calving and milk production, milk composition, and blood metabolites were evaluated. In addition, the study investigated immunological and antioxidant attributes.

The research involved 24 Jersey cows with 441 ± 27 kg of BW, 3.5 ± 0.3 of body condition score (BCS), and 2.7 ± 1.8 lactations that were selected at approximately 28 d before the expected parturition date and were randomly assigned to 3 treatments with 8 cows each:

• without plant extracts in diet (control – CON)
• addition of 10 g per day of oregano extract (OR)
• and addition of 5 g per day of green tea extract (GT)

The researchers assessed feed intake, BW, BCS, blood metabolites, hemogram as well as oxidative stress biomarkers from approximately 3 weeks prepartum to 3 weeks postpartum (transition period) while milk production and composition were evaluated during the first 3 weeks of lactation, according to the research paper.

The results

Plant extracts did not change BW, BCS, and DM intake (DMI) throughout the transition period, but OR increased in approximately 20% total digestive nutrients and metabolisable energy intake on days 15 and 16 postpartum compared with CON. In the prepartum, OR increased in 48% platelets count compared to the CON, while GT augmented in 142% eosinophils compared with CON. Oregano extract reduced the levels of reactive species in the erythrocytes in 40% during prepartum and postpartum compared with CON, while GT reduced its levels in 24 and 29% during prepartum and postpartum, respectively, when compared with CON. In the postpartum period, OR increased in 60% the carbonylated protein content compared with CON, while GT reduced in 45% the levels of reactive species in plasma compared with CON. During the postpartum, both extracts increased in 33% the concentration of reduced glutathione when compared with CON. Moreover, GT tended to decrease feed efficiency in 11% when compared with CON; OE reduced milk pH and somatic cell count when compared with CON.

Oregano and green tea extracts improved antioxidant defence system

According to the research paper, oregano and green tea extracts improve several biomarkers of antioxidant defence system reducing free radicals in Jersey cows during the transition period. Since feed intake was similar and milk production level was moderate for all cows, such positive effects were not enough to improve milk production, milk composition and blood metabolites pattern.

Feeding oregano extract at 10 g per cow per day reduces some oxidative stress markers in Jersey cows during the transition period without adverse effect on animal’s performance such as feed intake, milk production, and feed efficiency. Feeding green tea extract at 5 g per cow per day reduces some oxidative stress markers in Jersey during the transition period but it impaired feed efficiency.

The research, ‘Supplementation with green tea and oregano extracts on productive characteristics, blood metabolites, and antioxidant status of Jersey cows during the transition period’ was carried out by E.F.Vizzottoa, C.B.Stivanin, M.de Paris, L.T.Passos, D.Wernckea, C.P.Klein, V.Stone, C.Matté, M.B.Zanela, V.Fischer: https://doi.org/10.1016/j.animal.2020.100032

For the full paper and more info, visit Sciencedirect