去势对17～21月龄西门塔尔牛生长性能的影响

The Influence of Castration on Growth Performance of Simmental Cattle Aged from 17 to 21 Months

本试验旨在研究去势对西门塔尔牛日增重及体尺的影响。选取50头健康的、16月龄的西门塔尔公牛，经药物驱虫后，依据体重进行单因素配对试验设计。结果表明，17～21月龄的体重和全期平均日增重去势组均比未去势组低，差异不显著（P〉o．05）；17～21月龄，去势组与未去势组间的体高、体斜长、胸围和腰角宽的长度及其全期月增加数差异均不显著（P〉0．05）；去势后第1个月（17月龄），去势组的体高、腰角宽和坐骨端宽的月增加数均极显著低于未去势组（P〈0．01）；17～19月龄去势组的坐骨端宽比未去势组少（P〈0．05）；全期平均腹围月增加数，去势组极显著高于未去势组（P〈0．01）。结果说明，去势西门塔尔牛的全期平均日增重低于未去势西门塔尔牛；去势西门塔尔牛的生长曲线为指数曲线，未去势西门塔尔牛的生长曲线为s型；去势会短期抑制体高、腰角宽、坐骨端宽的月增长；去势能提高去势西门塔尔牛腹围的增长；西门塔尔牛在1．5岁时的体尺接近成年体尺。

The objective of the present study was to investigate the influence of castration on daily gain and body size of Simmental cattle. 50 healthy Simmental cattle （16 month） were used in a paired design of single factor by body weight. The results showed that 17 to 21 months of age, body weight and the average daily gain of castrated groups were lower than uncastrated group, re- spectively,there were no significant difference （P〉0.05）. 17 to 21 months of age, body height, body length,chest circumference and hip width＇s length and month growth of the castrated group and uncastrated group, were all no significant difference （P〉0.05）. The first months after castra- tion （17 month of age）,body height,hip width and ischial-end width＇s month growth of castrated group were extremely significantly less than uncastrated group （P〈0.01）. 17 to 19 months of age, ischial-end width of castrated group was significantly less than uncastrated group （P〈0.05）. The whole period of average month increase of abdominal perimeter,castrated group was more than in uncastrated group （P〈0.01）. The results suggested that the whole period of aver- age daily gain of castrated Simmental cattle was less than uncastrated. The growth curve of cas- trated Simmental exponential was exponential curve, and uncastrated Simmental was ＂S＂. Inhibat- ed the growth of body height,hip width and ischial-end width shortly after castration. The castra- ted would improve Simmental abdominal perimeter growth. Simmental body size at the age of 1.5 was close to the adult body size.