Résumé:
The dry period is known for its suitability for antimicrobial control of staphylococcal
intramammary infections (IIMs). The present work aims to prospectively study the use of
essential oils (aromatherapy) at the drying off for the control of staphylococcal mastitis in the
conditions of Algerian dairy farms. This study is based on the collection of information
regarding the current use of antibiotics, phytotherapy, and aromatherapy during the dry period
via a questionnaire survey. Then, an in vitro evaluation of the efficacy of some essential oils
of Lamiaceae (Thyme, Oregano, Mint) on Staphylococcus strains isolated from the milk of
cows suffering from recurrent mastitis was carried out to select the essential oil(s) to be tested for their in vivo antimicrobial activities. Our survey identified noncompliance with
recommended zootechnical practices during the dry period as a risk factor for poor udder
health and non-effectiveness of antibiotic therapy at drying off (DCT). The latter is a common
practice and is selective in 86.49% of cases, regardless of the health status of the udder. In
addition, self-medication, anarchic and selective use of some molecules, mainly ß-lactams
with cefalexin as the most infused intramammary antibiotic (40.54%), were noted. This
survey confirmed interesting perspectives on the possibility of using phytotherapy and
aromatherapy as complementary or palliative approaches to control mastitis and reduce
antibiotic use. The study of the antibacterial activities, in vitro and in vivo, of three essential oils from three plants of the Lamiaceae family (Mentha, Origanum and Thymus) against
bacteria causing mastitis has shown their very significant effects on different strains of
Staphylococcus aureus. The highest inhibition diameter was obtained with the essential oil of
Thymus munbyanus (41.07 mm). The lowest minimum inhibitory concentration (MIC) was
recorded with the essential oil of Origanum vulgare (0.01%). The application of this oil in
vivo on udders of cows with subclinical mastitis showed a significant (P<0.001) decrease in
total aerobic mesophilic bacteria (TAMB) and a non-significant (P>0.05) decrease in
coagulase-positive staphylococci (CPS). The use of essential oils seems to be a promising
option for the actors of the Algerian dairy sector to join the ""One Health"" concept.
