Post Treatment Skeletal Mineral Accretion in Malnourished, Growing Animals

Abstract

Cases of rickets and other conditions of malnutrition in growing animals have been uncommon in recent years, but the popularity of raw and homemade diets in companion and exotic animals have resulted in an increased number of cases presented to veterinary clinics and teaching hospitals.Growing animals, including four puppies, two cougars, two jaguars and one serval, fed non‐commercial diets were diagnosed radiographically with multiple fractures and/or folding fractures. All animals were undersized, exhibited lameness of varying degrees, or were beginning to exhibit neurological signs. A review of diets indicated that they were either imbalanced in calcium:phosphorus or were deficient in calcium. Dual energy X‐ray absorptiometry (DEXA) scans were performed prior to correction of nutrition imbalances and were followed up with scans at intervals of 30 days and/or 60 and 90 days. Upon discharge, animals were fed commercial growth diets appropriate for their species and were administered calcium carbonate (250 mg PO q 24 h). DEXA scans performed at 30 days showed a significant accretion of bone mineral at fracture sites, with insignificant increase in bone mineral density of long bones. Subsequent radiographs and DEXA scans showed increased cortical bone density, bone healing, and remodelling of fracture sites. It appears that the initial period following correction of mineral malnutrition may involve preferential directing of dietary calcium towards sites of bone injury, without significant improvement in overall bone mineral deficits. The appropriateness of calcium supplementation during correction of calcium malnutrition and normalization of calcium ‘set point’ is not well documented. Additionally, an optimal dose of calcium supplementation that will maximize calcium accretion without a negative feedback response is desired. When treating cases of malnutrition, it is prudent to limit activity during the first 4–6 weeks of treatment to protect the animal from further injury until general increases in bone mineral density occur.