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We have feed ponderosa pine needles to our male goats and they love them. It's my understanding they can cause a doe goat to miscarriage, so we don't give them any.
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I have Boer's that sometimes eat cedar and juniper. It is not their preferred browse, but I think it's just a goat thing to sample a little of this and a little of that. Because they do not choose to eat much of it, I would assume that that indicates it might not be a good option to feed in large quantities.