6 Jan 2020
Adding oregano oil to waste milk fed to Holstein dairy calves “significantly” reduces amount of Escherichia coli bacteria resistant to the cephalosporin antibiotic cefquinome.
James Westgate
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The levels of Escherichia coli bacteria resistant to a fourth-generation cephalosporin antibiotic can be significantly reduced by adding an oregano essential oil to calf diets, according to new research.
Partha Ray and Caroline Rymer, researchers at the University of Reading, undertook a trial to determine the effect of supplementing natural oregano essential oil (Orego-Stim Liquid) in waste milk fed to dairy calves, on the population of antimicrobial resistant bacteria in their faeces.
Holstein male calves were offered either waste milk treated with Orego-Stim Liquid for 10 days or a control diet of the same waste milk source without its addition. After the initial 10 days, all calves were fed the same ration of untreated waste milk and concentrates until weaning.
The results of the study are said to be “very promising”, offering a potential solution in helping to reduce the presence of antimicrobial-resistant bacteria.
In the faeces of calves fed waste milk with no Orego-Stim Liquid, 44.1% of E coli present were resistant to the cephalosporin antibiotic (cefquinome).
However, in calves fed waste milk supplemented with Orego-Stim Liquid until day 10, this was significantly reduced to 12.6% of total E coli being resistant to cefquinome.
Dr Ray, lecturer in dairy animal science at the University of Reading, said: “Oregano essential oil supplementation not only reduced the abundance of cefquinome-resistant E coli, but also delayed the emergence of resistance to cefquinome.
“We are conducting further studies to understand the mechanism underlying the effect of Orego-Stim Liquid feeding on antimicrobial resistance in the gut of young cattle.“
Dr Rymer, associate professor of animal science at University of Reading, added: “Feeding supplements that have antimicrobial activity may themselves encourage the development of antimicrobial resistance.
“It was, therefore, very pleasing that there was no evidence feeding Orego-Stim Liquid increased the resistance of E coli to any of the antibiotic classes tested. It was even more promising that resistance to the critically important cefquinome was reduced.”
