Listen to CSU PhD student Ms Lynne Appleby here

Oregano, thyme and cloves are not usually associated with milk but Charles Sturt University (CSU) researchers hope essential oils from these plants may be useful in treating a costly problem for the dairy industry.

CSU PhD student Ms Lynne Appleby, together with CSU researchers Drs Nigel Urwin, Jan Lievaart and Professor Heather Cavanagh, are investigating if essential oils may compliment or provide an alternative to the traditional use of antibiotics in treating mastitis in dairy cows.

"Mastitis is an infection of the cows udder that is usually caused by bacteria," said Ms Appleby."It's a problem for dairy farmers because it can reduce production and affect the quality of the milk."

Mastitis is conventionally treated with antibiotics but Ms Appleby said that can be costly, sometimes ineffective, and requires careful management as milk from treated cows has to be discarded.

"There's also wider concern about antibiotic resistance developing and a global push to reduce antibiotics use in animals that are destined for the human food chain," she said.

"Previous research has shown that many essential oils of plants contain compounds that may be useful in controlling or killing many bacteria including one of the key causes of mastitis in cows, Staphylococcus aureus."

Ms Appleby's research through the Graham Centre for Agricultural Innovation and CSU School of Animal and Veterinary Sciences in Wagga Wagga is initially testing the impact of the essential oils on bacteria grown in milk in the laboratory.

"Essential oils are steam distilled from various parts of the plant; they are concentrated and usually very aromatic. They are also generally regarded as safe and are often used in both the food and cosmetic industry," she said.

"I started with more than 40 different essential oils but have narrowed it down to five: thyme, oregano, clove leaf, lemon-scented tea tree and rosalina."

Ms Appleby said the project is at an early stage and much more research is needed to understand how the oils may affect the cow and the best way to use them.

 "I have a background in plant biotechnology but my overriding goal is for a sustainable agriculture industry so if we can contribute to delivering a high quality milk product it would be a great achievement," she said.