The calcium and phosphorus content of giraffe (Giraffa camelopardalis) and buffalo (Syncerus caffer) skeletons

Author(s)G. Mitchell, O. L. van Schalkwyk and J. D. Skinner
Year Published2005
JournalJournal of Zoology, London
Page Numbers55-61
Size96.88 KB

Osteophagia, variable serum calcium (Ca) and phosphorus (P) concentration, high serum alkaline phosphatase activity, a high growth rate, and a large skeletal mass, all suggest that Ca and P requirements and availability are finely balanced in giraffes. The mineral content of some marker bones in skeletons obtained from adult male giraffes (browsers) and adult male African buffaloes (grazers of similar body mass) were compared to assess the idea of critical Ca and P balance. Our results show that the P concentration of plasma varies more than Ca concentration, and that the Ca content of giraffe bones (0.196 ± 0.01 g/g) and buffalo (0.202 ± 0.006 g/g) varies more than P content (0.095 ± 0.002 in both). The average Ca and P content of the bones analysed was similar in both species (Ca=∼20.0%, P=∼9.5%). Giraffe skeletons, however, contain three times more Ca and P than do buffalo skeletons. This translates into a 1.5–2.0 fold higher Ca requirement for giraffes, with which they seem to cope effectively by selection for Ca-rich, dicotyledonous, browse. Sources of P to meet requirements are not obvious and a seasonal deficiency of P is a more likely cause of observed osteophagia than Ca deficiency. Giraffe rib P density, the best measure of P balance, of 0.142 ± 0.01 g/cm3 is, however, above the deficiency threshold. Bone mineral content (Ca and P) correlates well with bone density and shows only slight differences between adult males of the two species.

Key words: calcium, phosphorus, giraffe, Giraffa camelopardalis, African buffalo, Syncerus caffer, bone density

Authors: G. Mitchell, O. L. van Schalkwyk and J. D. Skinner

Journal: Journal of Zoology, London

Mitchell et al. - 2005 - The calcium and phosphorus content of giraffe (Gir.pdfDownload 
Terms and Conditions: Any PDF files provided by the GRC are for personal use only and may not be reproduced. The files reflect the holdings of the GRC library and only contain pages relevant to giraffe study, and may not be complete. Users are obliged to follow all copyright restrictions.