Elephants Elephants - Wildpro - Twycross Zoo

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we can conclude that all the diets surveyed in 2001 were providing sufficient
calcium in the diets.
The recommended level of phosphorus in horse diets by the NRC is 0.17%.
The average phosphorus content in the diets analysed in this survey was 0.3%.
As with calcium, phosphorus is not completely absorbed from the diet and an
estimate of 35% absorption is applied when calculating the diet for horses.
The results of our analysis show that adequate phosphorus is provided in the
diets fed to elephants in all cases; however, individual collections should
check their diet analyses to ensure not only that the calcium and phosphorus
content is sufficient, but also that the Ca:P ratio is correct. A maximum
tolerable limit for dietary phosphorus has been suggested for horses of 1%,
(National Research Council 1989) and all diets fall well below this limit.
Sodium
Wild elephant diets have been recorded as containing 0.01-1.67% sodium
(Ullrey et al 1997) and wild elephants are known to seek sodium rich water
and soil (Dierenfeld 1994). It is perhaps because of this that five out of 15 of
the responding collections supplemented their elephant diets with salt (only
one of these collections was included in the full diet analysis). The average
sodium content in the diets analysed was 122g (0.3%). This is more than the
recommended amount of 75-100g in the daily diet (Dierenfeld 1994), but is
well below the maximum tolerance for sodium in horses of 3% (National
Research Council 1989).
Iron
The amounts of iron in the analysed diets varied widely between the
collections, and ranged from 0.23-42.93 mg/kg diet. Collections whose diets
contained the highest levels of dietary iron were supplemented with vitamin
and mineral compounds such as El-E-Vite or Selenavite, plus concentrated
pellets. Those diets with low iron content either did not include mineral
supplements, or did not increase mineral supplementation in proportion to
the amount of food consumed. Forage and browse of wild elephants have
been shown to contain 152-368 mg/kg iron (Ullrey et al 1997). The
recommended level for dietary iron for horses is 40mg/kg (National Research
Council 1989). It is expected that the majority of dietary iron for elephants
would be provided by the forage consumed; in the absence of analysed data it
is impossible to confirm this. The maximum tolerable level of dietary iron for
horses had been estimated at 1,000 mg/kg. Iron intake may be made up by
consumption of soil in elephants kept on pasture.
Zinc
A deficiency of zinc in the diet is known to cause inappetance, reduced
growth rate, parakeratosis (scaling of the skin) and alopecia (hair loss) in foals
(National Research Council 1989). Deficiencies have also caused
hyperkeratosis (hard, thickened skin) in an Asian elephant around its toenails
and elbows. The diet of this elephant contained 22 mg/kg zinc; recovery was
observed within weeks when the diet was supplemented with 2g zinc per day
(Dierenfeld 1994).
Various analyses of natural elephant diets have shown them to contain 20-52
mg/kg zinc (Ullrey et al 1997) and the recommended zinc intake for horses is
40 mg/kg. (National Research Council 1989). These levels are much higher