499 - Late-Breaking: Impact of a High Calcium Diet in Growing Labrador Retriever Puppies

An important function of feeding large breed puppies is providing appropriate amounts of calcium and phosphorus, which is used in skeletal mineralization during growth. National Research Council stated calcium requirements are 0.8-1.2%, and phosphorus 1.0-1.6%. The objective of this study was to compare a high calcium diet (Ca: 5.7%; P: 2.9%) (Nature’s Logic Canine Beef Meal Feast; Nature’s Logic) (HC) to a normal control diet (Ca: 1.6%; P: 1%) (Purina Puppy Chow; Nestle Purina) (CON) in growing Labrador Retriever puppies. Thirty-two puppies (16 HC/16 CON) were used in two 10wk modified AAFCO large breed puppy growth trials. Body weights were measured weekly, feed intake daily, and digestibility, body composition, hematology, chemistry, and bone metabolism biomarkers were measured at 8wks, 13wks, and 18wks of age. All puppies passed all AAFCO large breed puppy growth requirements, including veterinary exams, body weight gain, and bloodwork parameters. Both groups had similar average weight gains from baseline to the end of the trial. No significant differences in bone mineral density were found between HC and CON groups at any timepoint. No significant differences were found between groups after baseline for parathyroid hormone, calcitonin, or tartrate resistant acid phosphatase bone metabolism biomarkers. Total tissue mass, fat mass, and lean mass were lower in the HC group compared to CON group (P < 0.05), likely due to lower caloric content and metabolizable energy in the HC diet than expected. Calcium digestibility was significantly higher in HC diet vs CON diet (P < 0.01). Based on this data, a high calcium diet had no negative impact on major physiological parameters in growing Labrador Retriever puppies.