PPID:

https://cvm.msu.edu/vdl/client-education/guides-for-pet-owners/equine-endocrinology-pituitary-pars-intermedia-dysfunction-ppid#:~:text=What%20is%20PPID%3F,less%20than%2010%20years%20old.

EMS:

https://ceh.vetmed.ucdavis.edu/health-topics/equine-metabolic-syndrome

Overview of EMS:

https://www.merckvetmanual.com/metabolic-disorders/equine-metabolic-syndrome/overview-of-equine-metabolic-syndrome