Now is the time for producers to be on the lookout for St John’s wort. St John’s wort is a woody weed with a distinctive yellow flower that is toxic to all grazing animals.
The toxin in St John’s wort increases the sensitivity of the skin to sunlight, resulting in severe skin damage to unprotected parts of the body. This includes pale or non-pigmented skin, and areas with less wool such as the nose, face and ears of sheep.
Initially, producers may notice swollen, droopy ears, and head shaking. As the skin becomes more damaged from the sunlight, this can progress to redness and scabbing of the face and ears. Animals also experience weight loss, reduced productivity, depression and sometimes death.
The toxin in St John’s wort can also enter the bloodstream and cross from the mother to her foetus in utero, or to her offspring at foot in her milk. This can result in the birth of weak or dead progeny, and poor performance in suckling young.
The softer, thinner skin of young animals, together with lighter fleece or hair cover, make them more susceptible to the effects of St John’s wort, compared to adult animals. In addition, suckling animals may be getting a “double dose” from the milk and from what they are grazing. St John’s wort is at its most toxic when it is flowering, usually from late October through to January, and producers should avoid grazing during this time.
Affected stock should be removed from the paddock and placed in paddocks with good shade.
Veterinary advice should be sought for severely affected animals. These animals may require treatment with antibiotics for secondary infections, and may need to kept in a darkened shed for 5-7 days.
Producers wanting more information on control options for St John’s Wort should contact the Cowra Council Biosecurity Officers on (02) 6340 270 or visit https://weeds.dpi.nsw.gov.au/Weeds/StJohnswort
If you would like further information or to chat about any animal health issues, please feel free to contact your local District Veterinarian Em Johnstone (0419 334 077) or call 1300 795 299.
Cowra News to your inbox
Sign up now for the latest news from the Cowra Area direct to your inbox.