Mycobacterium avium subspecies paratuberculosis (MAP) is a cause of contagious and typically fatal enteric disease, primarily affecting ruminant and pseudoruminant species. During a MAP outbreak in a captive collection, six of nine adult Mishmi takin (Budorcas taxicolor taxicolor) showed marked weight loss over 1-3 mo, followed by an acute deterioration. Fecal culture and microscopy failed to identify MAP shedding. Necropsy findings included grossly normal intestines and marked enlargement of mesenteric lymph nodes. Histological findings included multibacillary granulomatous enteritis, mesenteric lymphadenitis, and periportal hepatitis. MAP was confirmed by culture of intestinal and lymph node tissues from the index case. Results of antemortem serological testing using an indirect ELISA (ID SCREEN® Paratuberculosis Indirect) were corroborated by findings at necropsy or survival of the outbreak. Mishmi takin appear to show high MAP susceptibility and a rapid disease course compared with domestic ruminant species.