Hi Joyce!
First off your topic is extremely interesting. While reading your additional comments for the introduction I suggest tagging the wikipedia pages for Thiamine and Ruminant I have added them below. While reading I wanted to learn more about these so I googled them and the first pages to pop up were the wiki pages! I did not know off hand what ruminant was until you listed off other animals, maybe defining the word right after you use it for readers who do not come from a science background or who just are not familiar with these words.
I also like that you already cited your references.
I am not sure why you bolded the part where you talk about where PEM was first seen. Is it just because this is when it was basically discovered? If so do you think it is best to list this earlier? Going back to this because I read why this is in bold: I agree in taking this out.
Are there any other organic/inorganic material related/responsible for PEM? If so are you listing them or just listing the main ones?
Is listing the clinical signs going into the medical side? I am not sure I would refer to the Professor. I do like that you tagged certain symptoms. I would tag opisthotonos if that is possible, clonic convulsion, and recumbency. I am not sure what those symptoms are and because PEM is very interesting I am sure many others would be curious to what those symptoms are.
Here are the links to add if you would like: https://en.wikipedia.org/wiki/Thiamine
https://en.wikipedia.org/wiki/Ruminant
Additional comments:
If you would like to make your article longer, you could discuss treatment, current research that is focusing on treatment. The sulfur intake for recent research seems to focus on the responsibility of PEM and not the moving forward what can we do next. You can talk about common ages (I am not sure if this is too medical or opinion based.)
Best, Lila Vasquez. Good Luck!