Abstract
Copenhagen Zoo has maintained a herd of Asian elephants (Elephas maximus) since 1878. In 1999, the herd (2.3) was housed with separation of males and pairs of females. The elephants were fed concentrate, hay, vegetables, fruit, bread, sugar beets, and browse.
On the day of presentation, keepers reported that the alpha female demonstrated pronounced body wide ataxia. Due to concerns of the dry moat, the elephant was moved into an indoor enclosure. On a visual examination, the elephant was found somewhat more cooperative than usual and severely ataxic. Rectal temperature was normal (36.9°C). Auscultation demonstrated normal peristaltic sounds. Oral mucosa was pink and moist. Keepers reported that the wrapped ryegrass hay had smelled oddly when the elephants were fed in the preceding days. However, the elephants had eagerly consumed it, even before their concentrate. The hay was inspected and clearly smelled of alcohol. A tentative diagnosis of ethanol intoxication—”drunken elephant”—was made.
Elephants reportedly have a taste for alcohol and will readily eat fermented hay. The local police department was contacted for assistance. After some persuasion, they agreed to bring a Breathalyzer (Lion Alcolmeter, model S-300, Sweden) to the zoo to assess the elephant. Approximately 15 kg of hay was put into a plastic bag for 30 min to allow accumulation of any vapors. This was conducted three times and in the third attempt, enough air was trapped to process and obtained a reading over 0.1% alcohol concentration. Direct analysis of exhaled air from the elephant was unsuccessful. A blood sample was collected from an ear vein and submitted for alcohol concentration analysis to a human forensic lab (Forensic Department, University of Copenhagen, Denmark). These tests provided a result of very low alcohol content (0.0024%—legal limit for humans in Denmark driving a vehicle is 0.05%). This amount of alcohol would not account for the ataxia.
The following day, the ataxia had not changed despite diet changes that returned the elephants to normal dry hay. After reviewing the literature and considering hay composition, the diagnosis was changed to ryegrass staggers.1,2 At this time, the elephant had a normal appetite but remained confined indoors due to ataxia. After 10 days, the keepers judged that although the elephant was somewhat ataxic, it was stable enough for outside access. However, it promptly staggered and fell into the moat. The elephant was dragged from the moat by an unaffected elephant, assisted by the keepers. After another 4 days, a noticeable improvement was present in the ataxia. After 16 days, the elephant was released safely outside.
Surprisingly, 4 days after the initial case presented, a second female elephant demonstrated signs of ataxia, then the 6-ton breeding bull became ataxic the following day. This was unexpected because the suspected hay had been promptly removed from all animals’ diet. The bull was severely affected and made a slow recovery—18 days before the ataxia resolved completely.
If the mycotoxicosis had worsened, the elephants would have been treated with acepromazine or diazepam.2 In summary, the long onset of intoxication from ingestion of the fermented hay to the onset of clinical signs was surprising. The protracted recovery phase called for patience in both keepers and the veterinarian.
Literature Cited
1. Mansmann, R. A., E. S. McAllister, and R. A. Pratt. 1982. Equine Medicine & Surgery. Am. Vet. Publ., Santa Barbara, California. Pp. 1212.
2. Mayhew, J. 1999. Clinical Neurology of the Horse. Seminar Notes, Pp. 24–25.