I went down the back of an unused paddock and found some thistles there. Most are still in bud, but some are starting to spread seed (we are in New Zealand summer). Husband has been rostered to work 76 hours this week, and cutting thistles with a baby is not the easiest. I am wondering if I should let the goats in to eat the buds and stop the rest going to seed and spreading, but I am worried that they will eat the mature seed and then spread that in their droppings. Will goats eat seeding thistles, and will the seeds be viable at the the other end, or will they probably digest them?
good question, and it got me looking. I found a paper in New Zealand Plant Protection on a study testing seed viability in goat feces. They aren't thistles that i am familiar with, but if you are from new zealand you probably know them...californian thistle, scotch thistle, and variegated thistle. (i wonder if scotch thistle is what we call canadian thistle? for some reason they didn't feel inclined to include the scientific names, grumble)
Anyway it looks pretty promising. Here's from the study:
interest is their efficiency at destroying thistle
species, since goats are known to eat their flower
and seed-heads. The present results suggest that
94% of all viable seeds of Californian thistle
are destroyed by their passage through goats.
Destruction is even more pronounced for Scotch
thistle (96%) and variegated thistle (99.5%), as
shown in Table 1."
I think I'd go for it, especially if most are still in the bud stage. If you were worried about it maybe you could contain them to that paddock for a period after they've grazed the seed heads, to let everything 'run through'?
What brilliant news and thanks for finding the paper Kari. Yes scotch thistle is indeed canadian thistle, sometimes called creeping thistle. Right, my goats need to be moved this summer into the south field.
Oh sure, it's a tiny ad, but under the right circumstances, it gets bigger.
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