[Haylo-peapod]

I've found a few patches of St John's Wort on our farm - fortunately in an area where the sheep are not currently grazing. Needless to say I will be endeavouring to get rid of it but since this part of the farm is a bit of a wilderness I am concerned that I may not track it all down.
 
I've never noticed it on the farm before - but then again I've only become 'tuned in' to it since earlier this year when hearing on this forum about the risks it poses to sheep. I don't know if it is on the increase but in the 4 years we have grazed sheep here we've not had a problem.... yet!
 
Consequently I'm in need of some advice from my fellow shepherds. 
 
Does anyone know how toxic St John's Wort is? How much does a sheep need to eat before it becomes a problem - a mouthful/one plant/multiple plants??? Also, is it something they normally avoid or are they quite likely to have a munch even if there is plenty of other vegetation about? 
 
Any advice gratefully received.

[omnipeasant]

I didn't know St Johns Wort was toxic, so I will watch this thread.

[tizaala]

Warning and caution:  For occasional use only. Do not exceed recommended dose except on the advice of a health professional. Do not take this herb if pregnant or while nursing except on the advice of a health professional. St. John's wort side effects include photosensitivity with prolonged exposure to sunlight. There may be an increased risk for cataract in those who use this natural antidepressant for prolonged periods and expose themselves to regular sunlight. Wear dark glasses when in sunlight. Take breaks from use, particularly in the summertime when the sun is strong. Consider other options to manage mood while off it, can also cause extreme diarrhea

[deepinthewoods]

its a herbal antidepressant and was traditionally used to cause abortion.

[goosepimple]

Hi Pea, I have a list of poisonous plants given to me when I bought our pygmy goats - its a list for pygmy goats but I would imagine it would transfer to sheep pretty much.  St John's Wort is listed as Medium in the Toxicity Level column and All Parts meaning roots leaves stems everything is poisonous - the name of the Toxin is Hypericin.  To put the 'medium' in perspective, Hyacinth is the same level as is Hydrangea and Iris although the toxin in each of those has a different name, all deemed 'medium' though.  A 'high' toxin is Laurel, Nightshade, Privet, Yew etc, the well known ones in other words. 
 
We lost a north ronaldsay sheep earlier this year to Rhodedendron which we new was poisonous and had pulled one out but didn't see the little pathetic specimen that did the deed, so I am a bit paranoid myself.  Thing is, our soay and moorit sheep had been in this part of the sheep field for ages and there had never been a problem, I did notice how much the ronaldsays browsed more than all our other sheep though, so perhaps its that some sheep may be attracted to browsing more than grazing and vice versa.  Your present sheep may not have a problem and avoid it, whereas any new intake you may have may be attracted to it.  I subsequently bought a book on poisonous plants which makes you want to burn your fields - everything looks poisonous!
 
Good luck.

[colliewoman]

It's never done me any harm, but can cause photosensitisation and can stop the contraceptive pill working for us laydees

[Beeducked]

its a herbal antidepressant and was traditionally used to cause abortion.

Which is quite interesting as it can also interact with the Pill and reduce its efficacy!