德国牧羊犬幼犬断奶后生长曲线拟合与发育阶段划分研究

Study on Growth Curves and Development Stages of German Shepherd Puppies from 1.5 to 12 Months Old

随机抽取本地出生的1．5～12月龄德国牧羊犬，测量体重、体高、体长、胸围、荐高、胸深、管围和头长，统计各性状逐月的累积生长，以Gompertz模型拟合生长曲线并运用有序样本聚类分析方法作发育阶段的划分分析。结果表明，12月龄前各性状均未停止生长，且公犬的累积生长大于母犬。Gornpertz模型适合拟合各性状的生长曲线，拟合度（R^2）为0．971～0．998；体尺性状的拐点值均小于其2月龄均值，拐点月龄均早于1．5月龄，而体重的拐点值和拐点月龄则分别处于2～4月龄均值和3～4月龄之间；持续生长期表现为体重〉胸围〉体长〉胸深〉体高〉荐高〉头长〉管围。根据聚类结果并结合生理、行为发育等特征，1．5～12月龄犬的生长过程可分为4个阶段：1．5～2月龄、2～3月龄、3～6月龄和6～12月龄。

Eight body traits of German shepherd puppies, which born locally and were selected randomly, were measured from 1.5 to 12 months of age. Based on the data of growth, mean of each trait at each month of age were calculated, growth curves for each trait were analyzed with Gompertz model, and growth period of the puppies were divided by ordered sample cluster. The results showed that all eight traits are growing during measured period and males faster than females. The Gompertz model could fitted for all traits with 0. 971-0. 998 in indexes of fitness （R2）. The value of inflection in each conformation trait is smaller than it＇s mean at 2 months of age and the points of inflection are all before 1.5 months of age. The value of inflection in body weight is around the mean at 2-4 months of age and inflection point time is between 3 to 4 months of age. The duration of growth were ordered by body weight〉chest girth 〉 body length 〉 chest depth 〉 body height 〉 croup height 〉head length 〉 circumference of pastern. The results of ordered sample cluster indicate that, taking account of the physiologic and behavioral development, the growth period of weaned puppies can be divided into four stages： 1.5-2 month, 2-3 month, 3 -6 month and 6-12 month.