• Orego-Stim Liquid, when provided at a dose of 2ml per calf per day in the milk, significantly increased visits to the milk feeder.
  • The inclusion of Orego-Stim in the milk also significantly increased visits to the concentrate feeders, even though there was no Orego-Stim included in this feed.
  • Orego-Stim has been shown to be an effective appetite enhancer in pre-weaning dairy calves.


  • Orego-Stim is a high quality eubiotic containing 100% natural oregano oil.
  • Oregano is a known flavouring compound and aids with palatability in feeds.
  • A recent trial (Duthie et al., 2019) found that healthy calves made more visits to milk and concentrate feeders than diseased calves.
  • Growth data is presented in a separate Trial Summary titled “Enhanced growth of calves fed Orego-Stim”.



An independent trial was carried out at the AgriFood and Biosciences Institute (AFBI) in Northern Ireland, to assess the efficacy of Orego-Stim Liquid on calf growth and health.  70 Holstein-Friesian dairy calves were assigned to one of two treatments from birth until 70 days of age. Treatments were: Control – no additive and Orego-Stim- 2ml/calf/day of Orego-Stim Liquid added via the milk. Groups were balanced for sex and birth weight.  All calves were offered sufficient colostrum to ensure adequate transfer of immunity (IgG) from dam to calf.  From 5 days of age, calves were housed in straw pens and offered reconstituted milk replacer at 150g/litre and fed up to 6 litres per day via automatic milk feeders until day 35, when allocation was stepped down until weaning at 56 days of age.  Calf starter feed and water was available ad libitum throughout. Every visit to any feeder was recorded and timed.  Any incidence of scour or pneumonia was recorded daily.

Table 1. Effect of Orego-Stim on voluntary visits to the milk and concentrate feeders for dairy calves

  Unit Control Orego-Stim®
Visits to milk feeder n/day 10.74b 11.41a
Visits to concentrate feeder n/day 6.13b 6.68a
Speed of concentrate consumption g/s 0.576b 0.627a

a, b in the same row denotes p<0.001. Adapted from Craig et al., 2019, unpublished.


  • Calves offered Orego-Stim liquid made more visits to the milk feeders and concentrate feeders versus control calves (p<0.001, Table 1).
  • Even though no Orego-Stim was included in the concentrate feed, calves fed Orego-Stim via the milk visited the concentrate feeders more often compared with control calves (p<0.001, Table 1).
  • Speed of concentrate consumption was also increased by 8.8% in calves receiving Orego-Stim in the milk (p<0.001, Table 1), though there was no significant overall increase in concentrate intake.