*Develop papules on the muzzle, external nares and in the [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]]; the [[Oesophagus - Anatomy & Physiology|oesophagus]] and [[Stomach and Abomasum - Anatomy & Physiology|forestomachs]] may also be affected. | *Develop papules on the muzzle, external nares and in the [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]]; the [[Oesophagus - Anatomy & Physiology|oesophagus]] and [[Stomach and Abomasum - Anatomy & Physiology|forestomachs]] may also be affected. |