Rickets in alpacas (Lama pacos) in New Zealand.

Rickets was diagnosed in two weaner alpacas from a flock showing ill thrift and lameness during the winter of 1992. Both animals had abnormally shaped ribs with occasional healing fractures, irregular thickening of growth plates and metaphyseal haemorrhages. The mean serum phosphorus concentrations of the alpacas fell during June and July, even though lambs grazing the same pasture had normal serum phosphorus concentrations and the phosphorus concentration of the pasture was considered adequate. Vitamin D deficiency may also have contributed to the osteodystrophy. The alpacas had a thick fleece during the winter, and diurnal Vitamin D, synthesis resulting from solar irradiation is likely to have been minimal, especially considering the reduced sunshine hours recorded during the 1992 winter. Surviving alpacas recovered after treatment with monosodium phosphate and an oral Vitamin D supplement. It is possible alpacas are more susceptible to deficiencies of phosphorus and Vitamin D than other grazing animals in New Zealand.