• Calves offered Orego-Stim in their milk had a greater proportion of Actinobacteria in their gut. These bacteria have been previously reported to be associated with healthy calves.
  • These calves also had higher levels of Ruminococcus bacteria, which is associated with lower Cryptosporidia
  • When offered to calves, Orego-Stim Liquid helps to support and maintain gut health, as indicated by an increase in beneficial bacteria and decline in potentially harmful bacteria.


  • Firmicutes are a group of bacteria that generally make up most of the human and animal microbiome, they are also associated with obesity in humans.
  • Actinobacteria are associated with optimum health and are also used in the development of many pharmaceutical products associated with both human and animal use.
  • This study was undertaken to determine the effect of Orego-Stim Liquid on the microbiome and antimicrobial resistance (AMR) in the gut of dairy calves. (See also TS 22223701).
  • Orego-Stim is a consistent, high quality eubiotic containing 100% natural oregano essential oil.



A pilot study was carried out at the University of Reading in the UK. Ten male Holstein dairy calves were assigned to one of two treatments within 48 hours of birth; Control with no supplements in the milk, Orego-Stim with 10ml/calf/day of Orego-Stim Liquid added to the milk. The milk used was unsaleable, waste milk from the University dairy herd.  Orego-Stim was included in both the morning and evening feeding (5ml in 2.5 litres milk) for the first 10 days only.  All calves then received the same milk and concentrates until weaning at day 60.  Calves were individually housed until 21 days of age and then housed together in a straw pen until the end of the trial at day 78.  Faecal samples were taken on days 0, 3, 10, 21 and 60 (weaning) for analysis of the microbial profile in the gut.

Figure 1. The proportion of the two most abundant groups of bacteria in the faeces of dairy bull calves. (* p0.05; ** p≤0.01. Adapted from Ray et al., 2020). Figure 2. The proportion of three kinds of bacteria in the faeces of dairy bull calves. (~ p0.10; * p≤0.05. Adapted from Ray et al., 2020).
  • Calves fed Orego-Stim had a significantly higher abundance of Actinobacteria (Figure 1) which is associated with a high health status.
  • Higher levels of Arthrobacter in control calves (Figure 2) were associated with increased antimicrobial resistance and greater Cryptosporidia
  • Orego-Stim supplemented calves had higher levels of Ruminococcus (Figure 2), which was associated with lower Cryptosporidia (See also TS 22223001).