Survey of Lesions in Hoofed Stock
American Association of Zoo Veterinarians Conference 2007
Robert E. Schmidt, DVM, PhD, DACVP; Drury R. Reavill, DVM, DABVP (Avian), DACVP
Zoo/Exotic Pathology Service, Greenview, CA, USA


Records of hoofed-stock submissions to the Zoo/Exotic Pathology Service were studied, and the types of lesions, causes, and organs involved were characterized.


Any animal with hooves has been considered an ungulate; however, the use of the name “ungulate” has been inconsistent. It was originally used to refer to the orders Artiodactyla (even-toed) and Perissodactyla (odd-toed)—the so-called “true” ungulates, but over time the term expanded to seven different extant Mammalian orders, some of which had no hooves. Recent advances in molecular biology/taxonomy, relying on genetic code similarities, indicate that the grouping was artificial. As a result, ungulate is now considered to have no taxonomic significance, and the definition is once again descriptive: a mammal with hooves.


The records of the Zoo/Exotic Pathology Service were examined to characterize the types of lesions seen in material submitted from animals considered hoofed stock. These animals comprised 5.1% of mammalian submissions (10159 mammals, of which 514 were considered hoofed stock). Thirty-eight species were identified, and this paper presents the etiologies (if determined), morphologic diagnoses, and organs in the species submitted.


The most common species represented made up approximately 70% of the submissions. These included gazelles (all types) (20.6%), impala (8.9%), nyala (7.5%), kudu (all types) (6.9%), antelope (other types) (6.1%), sitatunga (5.5%), waterbuck (4.1%), giraffe (3.8%), dik-dik (3.5%) and ibex (2.9%).

The most common etiologic diagnosis was ‘undetermined’ (56.6%). Others included bacterial infection (11.3%), mycobacterial infection (8.1%), congenital disease (5.2%), nutritional/metabolic disorder (4.3%), neoplasia (2.9%), protozoal infection and physical (1.7%), secondary (0.9%), virus (0.6%) and mycotic, toxic, allergy, and none/normal tissue (0.3%).

The 10 most common morphologic diagnoses as a percent of animal submissions were enteritis (18.8%), pneumonia (11.9%), thymic hypoplasia (9.8%), nephritis (all types) (4.6%), septicemia and striated muscle degeneration including skeletal and cardiac muscle (3.5%), lymphoid hyperplasia of lymph nodes (2.6%), renal mineralization and cholangiohepatitis (1.7%) and vacuolar hepatopathy (1.4%). A large number of other diagnoses made up the remaining 40.5%.

Organ/organ system involvement was as follows: gastrointestinal system (24.3%), respiratory system (16.5%), hematopoietic/lymphatic (13.3%), urinary tract (11.6%), whole body (11.0%), liver/pancreas (7.8%), skin/subcutis (5.2%), musculoskeletal (4.3%), cardiovascular (3.2%), reproductive (1.7%), central/peripheral nervous system (1.2%) and endocrine (0.9%).


Without population data, it is difficult to determine if the numbers of each species represented is indicative of a greater propensity for problems, or simply a reflection of the overall population of these animals in zoos. For submissions with a possible etiology determined, bacterial diseases were the most common overall and the most common infectious condition. Generic identification of the organisms would depend on correlation with any cultures taken at necropsy. Congenital lesions and lesions considered most likely nutritional/metabolic were the most common noninfectious conditions. Enteritis of all types was the most common morphologic diagnosis, and the gastrointestinal system was the most commonly affected organ system. The category of ‘secondary’ as an etiologic diagnosis refers to lesions such as amyloidosis, soft tissue mineralization following renal disease, and peritonitis after traumatic perforation of the gastrointestinal tract.


Speaker Information
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Robert E. Schmidt, DVM, PhD, DACVP
Zoo/Exotic Pathology Service
Greenview, CA, USA

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