New research suggests that dogs tolerate up to 70.000 IU of Vitamin A without ill effects / toxicity as their metabolism is different from the human. The common amount of Vitamin A in dog food (pr. 100 gr) ranges from 10 - 17.000 IU
The statements that cod liver oil does not include Omega 3 are wrong. The ratio between Omega 6 & 3 should be 1:5 and there should preferably have Omega 8 too
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