Psoroptic mange is an infestation of mites of the Genus Psoroptes. Various species of this mite can infect horses, cattle, sheep, goats and rabbits.

In the larger animals, the mite prefers areas with dense hair coverage, causing inflammatory lesions, itching, hair loss, and scabbing. As scab forms, the mite cannot get at the skin, and moves to other areas of the body. If unchecked it can lead to anorexia, emaciation, anaemia, and, in some cases, death.

In rabbits, the mites start deep in the ear and may not become apparent for a comparatively long time, although you might notice the rabbit scratching at it ear, a malodorous brown discharge in the ear, or the rabbit becoming listless. Eventually the lesions may spread to other parts of the body, starting with the face.

Psoroptic mange spreads by bodily contact or through mites living (temporarily) on bedding, saddles, or even fence posts and trucks/trailers. IT can also be spread by flies, but this is usually not a problem except in laboratory settings. Treatment should be determined by your veterinarian, but include macrocyclic lactones (Avermectins), primarily ivermectin injections, and organophosphate compounds.

Psoroptes ovis* = Sheep (sheep scab), horses, cattle.
Psoroptes cuniculi = Rabbits (rabbit ear mite), goats, horses, and sheep.
Psoroptes equi = Horses
Psoroptes natalensis = Cattle and horses.
Psoroptes cervinus = bighorn sheep, elk and wapiti.
Psoroptes bovis = Cattle (cattle scabies). As far as I am aware, this last one is an 'informal' name, and probably actually refers to Psoroptes natalensis or Psoroptes ovis.

Phylum Arthropoda
Class Arachnida
Order Parasitiformes
Suborder Astigmata

* Sometimes Psoroptes communis ovis is used instead, and the variety that infects cows is called Psoroptes communis ovis var. bovis. I do not understand the implications of this alternative taxonomy, and I have not seen it used to refer to any but the sheep and cattle version of Psoroptes.