Study of Calcium Metabolism in Captive Elephants by Means of Feeding Trial Involving Both Calcium and Vitamin D Supplementation
American Association of Zoo Veterinarians Conference 2009
Willem Schaftenaar1, DVM; Linda van Sonsbeek2; Johannes P.T.M. van Leeuwen3, PhD; Johannes. H. van der Kolk2, DVM, PhD, DECEIM
1Rotterdam Zoo, Rotterdam, The Netherlands; 2Department of Equine Sciences, Medicine Section, University of Utrecht, Utrecht, The Netherlands, 3Department of Internal Medicine, Medical Center, Erasmus University, Rotterdam, The Netherlands


Hypocalcemia in elephants is a concern that needs attention. Cases of calcium-responsive dystocia have been reported anecdotally and the number of bone fractures in hospitalized working elephants in Thailand is relatively high.2,3 A feeding trial in 4 Asian elephants at the Rotterdam zoo showed that an increase in the calcium concentration of the roughage resulted in a significant rise in blood calcium levels.1,4 The results of a follow-up study in 5 European zoos, including 12 Asian elephants and 6 African elephants are discussed in this presentation. Blood calcium levels taken during periods in the summer in which normal food was supplemented with either calcium or vitamin D were compared. The study was repeated in the winter in order to determine the influence of low UV light on blood calcium levels. The following parameters were measured in heparinized plasma and/or whole blood: ionized calcium, total calcium, phosphate, 1,25(OH)2vitD, and 0,25(OH)vitD. In addition, the plasma levels of markers for bone formation (bone alkaline phosphatase—BAP), and for bone resorption (N-terminal of telopeptide of collagen I—NTx), were measured to find out whether the induced changes in ionized calcium, total calcium and phosphate could be related to an increase/decrease of mineral exchange between blood and bones.

Results indicate that Asian elephants depend more on dietary calcium concentration than African elephants. The latter species, however, seems to profit more from vitamin D supplementation in the food.


The authors would like to thank the zoo veterinarians and elephant keeper staff of Amsterdam Zoo, Antwerp Zoo, Hannover Zoo, Safaripark Beekse Bergen and Rhenen Zoo for their close cooperation during the feeding trials and the staff of the Department of Internal Medicine, Erasmus University Medical Centre, Rotterdam, The Netherlands.

Literature Cited

1.  van der Kolk, J.H., J.P. van Leeuwen, A.J. van den Belt, R.H. van Schaik, and W. Schaftenaar. 2008. Subclinical hypocalcaemia in captive Asian elephants (Elephas maximus). Vet. Rec. 162:475–479.

2.  Mahasawangkul, S., and T. Angkawanich. 2007. Elephant Health Status in Thailand—The Role of Elephant Hospitals and Mobile Elephant Clinics. EU-Asia Link Project Symposium “Managing the Health and Reproduction of Elephant Populations in Asia” Elephant Hospital, National Elephant Institute, Forest Industry Organization, Lampang, Thailand. Pp. 32–37.

3.  Sanyathitisaeree, P. N. Yartbantoong, S. Thongthipsiridej, and W. Theeraphan. 2007. Elephant Health Problems: An Accumulative Case Report from the Kasetsart University Veterinary Teaching Hospital—Kamphaengsaen. EU-Asia Link Project Symposium “Managing the Health and Reproduction of Elephant Populations in Asia” Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand. Pp. 41–48.

4.  Thitaram, C., P. Pongsopawijit, N. Thongtip, T. Angkawanich, S. Chansittivej, and W. Wongkalasin. 2006. Dystocia following prolonged retention of a dead fetus in an Asian elephant (Elephas maximus). Theriogenology. 66:1284–1291.


Speaker Information
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Willem Schaftenaar, DVM
Rotterdam Zoo
Rotterdam, The Netherlands

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