What is Cushings Disease? by Caitlin Bainum Posted: February 27, 2019 Cushings Disease also known as Pituitary Pars Intermedia Dysfunction (PPID) is one of the most common diseases in horses over 15 years old. Category: Agriculture, Farm Management, Livestock, Pests & Disease Tags: Caitlin Bainum, Equine, equine nutrition, Horse, horse care, horse diseases, Horse Herald, Laminitis, pituitary, PPID