去势对育成期雄水貂生长发育及毛皮质量的影响

对不同d龄（55、85、115、145）去势雄水貂的生长发育及毛皮质量的研究结果表明：55d龄去势的雄水貂在打皮时（205d龄）体重和体长均极显著低于未去势者（P＜0．01）；毛皮质量有所提高，但55d龄去势的雄水貂皮张长度明显降低（P＜0．05）；说明水貂去势不宜早于85d龄．组织学研究结果表明：去势雄性水貂骺板P区软骨细胞数目较多，D区较窄，细胞肥大过程延迟,钙化及骨化速度降低；骺板宽度变化的测定表明：雄性水貂骺板融合时间在145d龄左右，55、85d龄去势雄性水貂骺板融合延迟40d以上．骺板融合的延迟虽然使55d龄去势雄性水貂挠骨长度相对于体长增加，55、85d龄去势雄性水貂挠骨长度相对于体重增加，但是并没有使骨骼绝对长度增加．115d龄以后去势对雄性水貂骺板融合没有影响．对不同日龄去势雄水貂血清睾酮水平亦进行了测定分析．

EFFECT OF CASTRATION ON THE GROWTH DEVELOPMENT AND PELT QUALITY OF MALE MINK(MVSTELA VISON)

The study on different age(55, 85, 115 and 145 days old)castrated male minks showed that the bodylength and weight of 55 d castrated minks were lower than those of the entire minks which were slaughtedfor pelt(P<0. 01). The pelt quality of castrated minks was slightly better. However, the pelt length of 55 dcastrated minks was shortened significantly (P<0. 05). This suggests that it is not suitable to castrate maleminks ho fore 85 d. In castrated minks the number of cartilage cells increased in P-zone and the width ofDzone narrowed, hypertrophy of the cells was delayed, calcification and ossification were decreased. Theradius epiphyseal plate of entire minks closed in about 145 d, but the plate closure of 55 or 85 castrated minkswas retarded over 40 days. Though the retarded plate closure caused the increase in the ratio(lr/lb)of the 55d castrated minks and the increase in the ratio(lrlmb)of the 55 or 85 d castrated minks, the delay could notabsolutely increase the bone length. The plate closure could not retard in minks castrated after 115 d. Thetestosterone levels in serum were also studied by RIA for the entire and different age castrated male minks.