St. Louis Zoological Park, Forest Park, St. Louis, MO, USA
Speke’s gazelle (Gazella spekei) originates from the dry, open bushland of eastern Ethiopia and Somalia. They have formed part of the St. Louis Zoological Park’s animal collection since the mid-1960s. The gazelles were born in the collection or were derived from the same breeding line, with the exception of three animals from Qatar. Over 120 Speke’s gazelles have been necropsied at the zoo, and tissues en bloc have been collected and stored from the majority of cases since 1970. Analysis of the necropsy records revealed that the cases fell into six age categories: 1) aborted fetuses and stillborn calves; 2) neonates up to 2 weeks old; 3) adolescents from 2 weeks to 1 year old; 4) young adults from 1–2 years old; 5) adults from 2–4 years old; and 6) aged adults greater than 4 years old, proportionally the largest group.
Within defined age groups, cause of death followed a distinct pattern. With abortion in early gestation, the dam was not always identified, while late abortion occasionally followed restraint for treatment of an unrelated medical or surgical problem. In neonates, poor mothering and congenital limb deformities were the main problems. Limb deformities and injuries were seen also in young adults. In the former cases, despite apparently favorable surgical outcomes, often the gazelles declined weeks to months later, and at gross examination of the carcass, aspiration pneumonia was suspected. Approximately one-third of the deaths in young adults occurred in heifers peripartum and were associated with prolonged labor with malpresentation or pregnancy toxemia. The widest range and least specific lesions were seen in adults 2–4 years old. Aged animals frequently died in renal failure and often showed signs of chronic arthritis. Review of histological material has shown that amyloidosis, not restricted to the renal system, is a frequent finding. Ongoing studies are aimed at identifying the extent and form of the deposits, which are thought to be most consistent with the form of amyloid seen following prolonged inflammation and synthesis of acute phase reactants.