Evans J L, Fish R E, Lelkes Z B, Trout J R
J Dairy Sci. 1976 Oct;59(10):1838-41. doi: 10.3168/jds.S0022-0302(76)84446-3.
Hydroxyproline, calcium, magnesium, phosphorus, and alkaline phosphatase values were determined in serum over 24 h in Holstein cows. The cows represented two age groups and three percents of diet calcium. Hydroxyproline followed a cyclic pattern dipping at 0800 and 1600 h after milking at 0500 and 1530 h. Phosphorus showed a 24 h rhythm peaking at 1600 h. No other time effects were demonstrated. Hydroxyproline and alkaline phosphatase were both lower in the older cows, indicating a decreased calcium mobilization from bone with age. There was a correlation coefficient of only .20 between serum calcium and hydroxyproline. The calcium concentration in serum was maintained within a narrow range presumably as a result of homeostatic mechanisms involving bone resorption, i.e. the release of calcium and hydroxyproline may indicate the degree of homeostasis required to maintain serum calcium.
对荷斯坦奶牛24小时内血清中的羟脯氨酸、钙、镁、磷和碱性磷酸酶值进行了测定。这些奶牛代表了两个年龄组，以及三种日粮钙水平。羟脯氨酸呈现出一种周期性模式，在05:00和15:30挤奶后的08:00和16:00时下降。磷呈现出24小时节律，在16:00时达到峰值。未显示出其他时间效应。老龄奶牛的羟脯氨酸和碱性磷酸酶均较低，表明随着年龄增长，骨骼中钙的动员减少。血清钙与羟脯氨酸之间的相关系数仅为0.20。血清中的钙浓度维持在一个狭窄的范围内，这可能是由于涉及骨吸收的稳态机制，即钙和羟脯氨酸的释放可能表明维持血清钙所需的稳态程度。
