Young hazel & tannins?

Hi - I regularly feed my buns hazel and hawthorn twigs/leaves from our garden - but was flipping through a copy of 'Green Foods for Rabbits and Cavies' (great book!) which said to avoid feeding hazel buds/young leaves because they have high tannin levels...

Has anyone else heard of this, or seen any supporting info that indicates the tannin levels of young hazel are unsafe for rabbits? I can only find reference to witch hazel being high in tannins. (And something about hazel and bramble tannins killing off gastrointestinal nematode worms in goats..!)

Hazel is a really handy forage over winter/early spring so I'm hesitant to avoid it unnecessarily

Tannins can be bad (poisonous/reduce appetite) - but also good e.g they can help with parasites and digestion - they are sometimes given as an additive and there is more than one type of tannin just to add to the confusion!

Young leaves have a higher tannin content - which is probably the route of the advice.

Without a lot of science it's tough to know where the line is. It's not instant poison if they eat a young leaf but possibly not the best idea as a staple diet. The tannin levels reduce as the leaves age though so if you collect your forage over summer rather than spring it should help avoiding the issue. I've a feeling, but don't quote me that the leaves drying out helps too.

Thank you Tamsin! I will go for collecting and drying...

I feed mine a few young hazel twigs most days when it's in season. When I was at the vet this week, he asked if my rabbits ate a lot of bark because they have tannin stains on their teeth. Apparently this is what wild rabbit's teeth look like - so it makes me think that they would probably get a lot more tannins in their diet naturally.

I know that tannins can impair protein uptake, but then a lot of pet rabbits get too much protein anyway. I've seen various studies which looked at supplementing rabbit's diets with tannins: some said there was no effect and some said it reduced growth rates which might be bad in a rabbit grown for meat, but not so bad in a pet rabbit prone to obesity. It's probably one of those foods where you should see how your rabbit responds to it - and feed with a variety of other things.

Brilliant thanks! I've never had a problem with it but I don't feed vast quantities, particularly as they are very good hay eaters. Interesting stuff!