[HappyHippy]

It's just dawned on me that although I know they're not supposed to get citrus, that I don't actually know why  
This question comes in light of me tipping a bag of fruit from our local friendly fruit merchant in and watching in in horror as loads of grapefruit came rolling out only to be immediately snaffled by all of them   (They LOVED it, far more so than banana's, carrots, etc)
Google has revealed no answers   In fact, I found articles relating to fattening pigs on dried citrus pulp (USA) so I'm hoping someone on here can give me an answer.
Thanks folks,
Karen  

[Tiva Diva]

It gives them ulcers, apparently

[SallyintNorth]

I'm no help, I buy any past-by oranges, satsumas, etc, that I can get as Meg absolutely loves them and can peel them with her nose in a little under 20 seconds!  (She doesn't eat the peel but loves the flesh.)

A small farm I used to help out on used to get all their local Sainsbury's past-by non-meat food - a trailer-full twice a week.  I was instructed to sort onions, leeks etc out and put on the compost heap (if not edible for humans), and to put potatoes and parsnips to one side for boiling before feeding, but as far as I remember they got all the citrus in amongst everything else.  They had 4 or 5 sows and their offspring, fattening all the weaners themselves (with a lot of help from Sainsbury's!)

[SallyintNorth]

It gives them ulcers, apparently

Well I did a bit of googling and all I could find relating citrus to ulcers in pigs was in guinea pigs!

I trawled the Pig Site and it doesn't mention this at all, even though it has several whole articles on gastric ulcers in pigs and lists lots of things that can cause these ulcers.  http://www.thepigsite.com/diseaseinfo/46/gastric-ulcers

So personally I will carry on getting oranges, satsumas - and now you've put the idea in my mind, Karen, grapefruit - for Meg whenever I can!

[Tiva Diva]

When I went to Pig Paradise it was Tony York who said that citrus gives pigs ulcers. Apparently parsnips can reduce their fertility, too.
We give ours everything but citrus, parsnips leeks & onions etc. though we boil potatoes and Jerusalem artichokes first to improve the quality of nutrition. I'm not sure how much nutrition pigs get from mushrooms though ours won't eat them anyway)
I'll do a bit of research on the pigs/citrus issue and get back to the forum.

[HappyHippy]

Apparently parsnips can reduce their fertility, too.

Now I find that bizarre 
My Kunes LOVE parsnips (not in huge quantities, but they do get them) and our last litter was 10. Maybe Kunes are different to 'big' pigs - but the parsnips certainly don't seem to be affecting their fertility 
More research for me too 

[littlemisspiggy!]

i remember way reading in my 'jimmy's farm' book--- i know it was a gift!!   he got all the sqeezed pulp and peel from a jam making factory and that was fed in large quantities to his essex pigs!with other feed.. he said it made the meat very sweet and tender???

[princesspiggy]

a girl i know used to feed her horse crates of apples, really quite a lot every day for at least the 3 years i knew her, and her horse died. the post-mortem revealed alot of stomach ulcers.

[oaklandspigs]

A 2009 study on feeding cirus pulp to pigs came up with the following

"It was concluded that inclusion of citrus pulp up to 10-15% in the diet of growing pigs can modulate microbiota but lead to less firm faeces and lower carcass yield."

In other words helps against bad microbes, but gives them runny poo and doesn't add much to growth

I suspect it would also inhibit the action of Amylase in the saliva and upper stomach, where an alkaline envoronment helps the amylase break down starches, but that is just me guessing!

[Hermit]

I always thought it was something to do with arthritis  in pigs, shows you how much I know about them.

[Bioman]

So to summarize everything in moderation and all will be ok

[Bioman]

*Everything that is legal that is

[Pel]

I have a book at home that has why citrus shouldn't be used, but it does say its fine as a 5-10% inclusion. As far as I understand, your not meant to give parsnip tops and potato tops (and green potatoes), but i can't remember why. I'll find my book when I pop back home on Friday and write it down here.
Though I know someone who uses a citrus feed (i think intended for sheep and cattle) and mixes it with barley and feeds that to his pigs, all his seem to really like it and they are all breeding and doing well (to add he does give sows pig nuts too).

[HappyHippy]

I know that parsnip tops, potato tops and green potatoes are poisonous.
I always thought tomatoes were the most likely to cause arthritus (in big quantities)
It would seem that everything *legal* in moderation looks the way to go 
Thanks for all your thoughts folks
Karen