There is no evidence that ragwort is a risk to dogs.
On 11 May 2002 Dr Germaine Greer, the well known and respected academic and journalist, Wrote the following in her Daily Telegraph column "Country Diary"
"THE ragwort fuss shows no sign of abating. If the first torrent of letters to the Weekend editor had betrayed careless reading, the succeeding waves gave no sign whatsoever of first-hand acquaintance with my column. Though I said that I was well aware that Senecio jacobaea is a serious threat to the health of horses, she was asked in the testiest tones whether the silly woman (in other words me) knew that hundreds of horses and even dogs died of ragwort poisoning every year.
As a matter of fact I don't know this, and I doubt whether anyone else does.
On Saturday 6 October 2012 The Skegness standard newspaper published a story containing the following text.
"A CONCERNED resident is urging dog walkers, children and passers-by to be mindful of potentially harmful ‘ragwort weed’ which is alleged to be growing in nearby Skegness fields."
This is one of a number of such stories that appear in the press. See See Ragwort and dogs for a full rebutal.