• When essential oils are supplemented in the diet, active compounds in the oils may transfer from the dam into milk.
  • In turn, these compounds may be passed on to the newborn calf and alter redox status.
  • The redox status is the balance between the presence of oxidants and antioxidants. The more antioxidants, the less risk of oxidative stress within the calf.
  • In this study, (Paris et al., 2020) calves fed milk from cows supplemented with Orego-Stim had lower reactive substances in their blood suggesting a better redox status.


  • High levels of reactive oxygen species can trigger oxidation and damage body tissues, known as oxidative stress.
  • Newborn calves are subject to high levels of oxidative stress and the redox status of the dam may impact on the health of the calf.
  • Aromatic compounds, known as phenols, from essential oils can pass into milk and may help support redox status in the calf.
  • This trial was undertaken to assess the impact of plant extracts fed to cows on subsequent redox status of their offspring.
  • Orego-Stim Powder is a high quality eubiotic composed of 100% natural oregano essential oil.



A trial was carried out at Federal University of Rio Grande do Sul, Brazil, in the hot season, from October 2015 to January 2016. 24 Jersey cows (approx. 400kg bodyweight, 2.7 lactations) were split into one of three treatments. Control (standard diet with no additives), OS (10g per day of Orego-Stim Powder) or GT (5g per day Green Tea extract), from 21 days pre-calving to 21 days post-calving. Calves received 4L of colostrum, followed by 4L per day of milk, both from their dam. Thereafter, pooled milk from the same treatment group was fed to calves in that group until weaning at 60 days. Antioxidant status of the calves were measured by assessing for the presence of oxidative stress biomarker, dichlorofluorescein (DCF) in blood samples taken on days 1, 30 and 60. Higher levels of reactive oxygen cause greater oxidation and increased presence of DCF.


  • There were no differences in bodyweight or incidence of diarrhoea between treatments.
  • Calves fed milk from cows given diets supplemented with OS had lower DCF levels in both the red blood cell and blood plasma samples (Figures 1 & 2), suggesting lower oxidative stress in these calves.
  • Supplementing cows with OS pre-calving may allow transfer of active compounds to the milk which may benefit the redox status and health of the newborn calf.