Pigs can benefit from being fed oregano, study shows

Feeding lactating sows oregano essential oil helps maintain body condition and can also improve weights and reduce mortality when fed in piglet creep diets, leading to reduced use of antimicrobials, research has demonstrated.

Oregano essential oil contains compounds carvacrol and thymol, which have proved both antimicrobial and anti-oxidant functions in animals.

About the research

Researchers at Nottingham Trent University carried out trials in conjunction with animal health company Anpario on a commercial, indoor sow herd.

In total, 62 multiparous sows across two batches were randomly allocated a control diet or Oregano Stim powder at a rate of 500g/t from seven days prior to farrowing until weaning (around 33 days).

Sows were fed manually twice daily to intake. Feed intake and refusal was measured daily by weighing any leftover feed.

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All piglets were ear-tagged at birth and any cross fostering was carried out within the treatment group.

At two weeks of age, all piglets were offered creep feed containing 1kg/t of the oregano feed until around one week post weaning when they were fed a standard commercial diet.

In both sow and piglet diets gut health additives were removed for the trial period – including zinc oxide.

All piglets that retained their ear tags were weighed 10 weeks post-farrowing (340 piglets per treatment group) and up to slaughter (30 pigs per group at first thinning).

Body condition of sows was also monitored regularly: when they moved to the farrowing crates, at farrowing and at weaning.


The trial found:

  • Piglets fed the oregano diet had improved average daily weight gain from birth (240g in the control group compared with 245g in the other)
  • Finisher weights higher by 0.6kg and 3.4kg respectively.
  • Piglets born from sows fed the oregano feed had lower incidence of health problems, resulting in a 4.2% decrease in therapeutic treatments compared with the control group.
  • Mortality was reduced. The control group’s pre-weaning mortality was 14.3% compared with 10.9% in the sow group fed oregano.
  • Sows supplemented with oregano maintained higher body condition score at weaning (3.5 on average in comparison to 3.0 in the control group) and this continued until weaning.
  • There was no significant difference in feed intake in either sows or piglets, although sows fed oregano ate more consistently. 

Paper co-author Heidi Hall, also Anpario’s swine global technical manager, said: “There is increasing pressure on the pig industry to reduce antimicrobial usage while maximising animal health and performance.

Therefore, identifying sustainable alternatives is of growing interest. 

“In order to reduce the reliance upon antimicrobials at weaning, such as zinc oxide, pig farmers need to be able to produce more robust piglets.

The weaning and nursery period is a critical time for developing and enhancing piglet health to ensure long-term optimal performance,” she added.