59 The Ash in Metacarpals, Metatarsals, and Tibia Is Better Correlated with Total Body Bone Ash Than the Ash in Other Bones of Growing Pigs

Abstract

Abstract The objective was to determine correlations between individual and total body bone ash to identify the bone that is most representative of total body bone ash. Ten gilts and 10 barrows (BW: 40.8 kg) were allotted to 2 diets. The 2 diets were formulated to contain 60% or 100% of the requirement for standardized total tract digestible (STTD) P and STTD Ca with a STTD Ca:STTD P of 1.90:1, which is believed to maximize bone ash. Body weight and the amount of feed consumed by pigs were recorded on d 14 and 28 and carcass characteristics of all pigs were determined on d 28. Metacarpals, metatarsals, femur, tibia, fibula, ribs, and all other bones from the carcass were collected separately, defatted, and ashed. The statistical model included diet as fixed effect and sex and BW within sex as random effects. Correlation coefficients between total and individual bones were determined. Overall, pigs fed the diet formulated to meet 100% of the requirement for Ca and P had greater (P < 0.05) average daily gain and gain:feed compared with pigs fed the diet with 60% Ca and P, but there was no difference in average daily feed intake (Table 1). There was no effect of dietary Ca and P on carcass characteristics of pigs. Weights of bone ash were greater (P < 0.05) for pigs fed the diet with 100% rather than 60% of the requirement for Ca and P. Correlation coefficients between the weight of total bone ash and the weight of ashed metacarpals, metatarsals, and tibia were greater than 0.950 (P < 0.05), whereas correlation coefficient for femur, fibula, and ribs were less than 0.929 (P < 0.05). In conclusion, metacarpals, metatarsals, and tibia were more representative of total body bone ash compared with femur, fibula, and ribs.