本試驗旨在探討去勢對綠頭鴨血液紅血球相、白血球相、睪固酮濃度及換羽之影響。選取體重相近7歲齡綠頭鴨共20隻，並且分成2個處理組；即對照組（假手術）及摘除2個睪丸（去勢鴨），每處理10隻。在褪色換羽期間進行手術，試驗期為12週，並在鴨隻手術後4、8及12週齡每處理組全部鴨隻以翼下靜脈採血，分析血液紅血球相、白血球相與血清睪固酮濃度，並在試驗結束時觀察鴨隻換羽狀況。結果顯示，公綠頭鴨經去勢不影響紅血球數目與血容比值之平均值，二個處理組間鴨之白血球總數、單核球、異嗜球、淋巴球、嗜鹼性球及異嗜酸球百分比與異嗜球／淋巴球比值均無顯著的差異。在婚羽換羽期間去勢之綠頭鴨睪固酮濃度較正常公綠頭鴨為低(p<0.05)，然而去勢不改變公綠頭鴨婚羽換羽之進行，惟其換羽速度較慢。比較公綠頭鴨與去勢綠頭鴨睪固酮濃度，顯示適量的睪固酮濃度為綠頭鴨進行婚羽換羽所必需的。
The objective of this experiment was to study the effects of castration on erythrocyte and leukocyte profile, testosterone concentration in blood and changes in molt of mallard during nuptial molting period. Twenty 7 years of age male mallards with similar body weight were randomly allotted into two groups, sham (control) and complete removal (castrated mallard) during eclipse plumage period. Ten birds of each group were fed in one floor pen for each treatment. Feed and water were ad libutum. Birds were bled from wing vein 4, 8, and 12 weeks after birds were castrated for measurements of erythrocyte and leucocyte profiles and serum testosterone concentrations. The color feather was observed at the end of experiment. Results indicated that castration did not affect red blood cell number and packed cell volume in mallard. There were no significant differences in total white blood cell number, monocytes, heterophils, lymphocytes, basophils, eosinophils and H/L (heterophils/lymphocytes) ratio between the two treatments. The castrated bird had lower serum testosterone levels than that of male mallard during nuptial molt period (p<0.05); however, castration did not handicap nuptial molt proceeding. Comparison of testosterone levels between castrated mallards and male mallards showed that lower testosterone levels slowed the regeneration rate of both head and tail feather. Thus suffice testosterone levels may be needed for molting and decreased levels during nuptial molt delayed regeneration of feathers.
