effect of vasectomy on the testosterone levels and testicular structures in bucks for long term

This study was conducted on 12 adults local crossbreed bucks to investigate the long-term effect of the vasectomy on testosterone levels, sexual efficiency, and testicular structures. the bucks were divided into 4 groups according to the duration after the surgery. following surgery, testosterone hormonal fluctuations were observed in association with stressed factors such as operation pains. initially, surgical discomfort increased sexual arousal time during the first week post-operation. as healing progressed, arousal time gradually declined by the fourth week.  however, ejaculate volume showed a continuous decline throughout the study. a similar pattern of decline, followed by an absolute lack, is noted in sperm motility in all the bucks by the end of the fourth week. testosterone levels evaluated by enzyme-linked immunosorbent assay (elisa), demonstrated fluctuations. post operation testicular parenchyma sections during the first month indicated injury to seminiferous tubules due to increase in the count of leydig cells. by the second month tubules had  separated and shrunken, accompanied by a decline in leydig cells. during the 3rd month, the seminiferous tubules disappeared, and the interstitial tissue extended with renewed proliferation of the leydig cells. however, by the fourth month, the interstitial tissue suffered from mild shrinkage, and leydig apoptosis were evident. in conclusion, vasectomized bucks demonstrated the suitability to use the males for teasers at the first period. but the libido declined during the second period due to the scrotal pains. then these pains  became chronic and less severe  in the third month, which improved the sexual desire.