Williams S N, Lawrence L A, McDowell L R, Warnick A C, Wilkinson N S
Animal Science Department, University of Florida, Gainesville 32611-0691.
J Dairy Sci. 1990 Apr;73(4):1100-6. doi: 10.3168/jds.S0022-0302(90)78769-3.
Effects of dietary P on breaking load and chemical properties of bone were evaluated in growing beef heifers. Initially, 14 weaned Angus heifers received ad libitum a low P diet (.10% P dry basis) for 270 d. Heifers were subsequently randomly allotted into two groups (7 heifers/group) and received ad libitum either .12 or .20% P (dry basis). The experimental endpoint was 245 d of the treatment phase for nonpregnant and 3 wk postpartum for pregnant heifers. Results indicate that chemical and physical properties of bovine bones are sensitive to dietary P. Mineralization of rib bones was less at .12% P (dry basis). Rib bone density (g/cm3) and mineral content expressed on a per unit volume basis (mg/cm3) were the most sensitive parameters measured. Breaking load results of 12th ribs also indicated a greater amount of mineral present in heifers receiving .20% P (153.8 vs. 114.3 kg). Vertebral bone density and mineral concentrations on a per unit volume basis were also sensitive to dietary P and clearly ranked the two dietary P amounts, whereas percentage of bone ash or mineral concentration expressed on an ash basis did not.
在生长中的肉用小母牛中评估了日粮磷对骨骼断裂负荷和化学性质的影响。最初，14头断奶的安格斯小母牛自由采食低磷日粮（干基含磷量0.10%），持续270天。随后，小母牛被随机分为两组（每组7头），并自由采食含磷量分别为0.12%或0.20%（干基）的日粮。实验终点为非怀孕小母牛处理阶段的245天以及怀孕小母牛产后3周。结果表明，牛骨骼的化学和物理性质对日粮磷敏感。干基含磷量0.12%时，肋骨的矿化程度较低。肋骨密度（克/立方厘米）和单位体积的矿物质含量（毫克/立方厘米）是所测量的最敏感参数。第12肋骨的断裂负荷结果也表明，采食含磷量0.20%日粮的小母牛体内矿物质含量更高（153.8千克对114.3千克）。单位体积的椎骨密度和矿物质浓度也对日粮磷敏感，并且能清晰地对两种日粮磷含量进行排序，而骨灰百分比或骨灰基础上的矿物质浓度则不能。
