Are kumquats poisonous to horses?

[HorsesandMOARGaloar 300]

Since "kumquats" are Pinkie Pie's favourite word, I wonder if the fruits are poisonous to horses ... 

[Oblivion 20,267]

"Ingesting large quantity is toxic to horses. The fruit has a relatively high level of magnesium and ingesting a large quantity can have a laxative effect."

 

So, apparently ingesting large amounts gives horses diarrhea!

 

Source:http://www.chacha.com/question/can-a-horse-eat-kumquats