Department of Veterinary Clinical Sciences, Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.
Theriogenology. 2013 Feb;79(3):502-7. doi: 10.1016/j.theriogenology.2012.11.005. Epub 2012 Dec 4.
As other European donkey breeds, Martina Franca could be considered an endangered breed because of the population number (48 jackasses and 515 jennies in 2011). To increase donkey population and breed biodiversity preservation, several research projects on donkey reproduction have been performed; however reproductive seasonality has been only partially investigated in jackasses. For this reason the aim of this study was to investigate the effect of seasons and of long (spring to summer; SS) and short (autumn to winter; AW) day length periods, on reproductive physiology of Martina Franca jackasses, in particular on: (1) testicular morphometric characteristics, (2) behavior, through the evaluation of the reaction time, and finally, (3) semen characteristics. Seven adult and reproductively mature Martina Franca jackasses were enrolled. For each jackass, a morphometric evaluation of both testes was performed once for every season, before the first seasonal collection. Semen was collected, by artificial vagina, weekly for a whole year (52 collections per donkey); at each collection the reaction time was recorded and a complete semen evaluation was performed immediately after collection. No differences in testicular measures were observed neither between left and right testis nor during the four seasons. A lower reaction time was observed in spring and summer compared with autumn and winter and during the period SS compared with AW. Total volume was significantly higher in winter compared with all the other seasons; gel-free volume was higher in winter compared with summer and autumn. Mean sperm concentration was significantly lower in winter compared with spring and summer and in AW compared with SS. Total and progressive motility and membrane integrity did not show any significant difference between season and between SS and AW. A lower average path velocity was observed in autumn compared with spring and summer, and in summer a higher straight line velocity compared with spring and autumn, and a lower curvilinear velocity compared with winter were found. No differences in amplitude of lateral head displacement, beat cross frequency, straightness and linearity were observed neither between seasons nor in SS versus AW. Seminal pH did not show any seasonal difference; also sperm morphology did not show any significant difference during the whole year. This study demonstrated that under our climatic and management conditions Martina Franca donkey stallions do not show significant differences in testicular morphometric characteristics during the year, even if a certain seasonal influence exists on reaction time and some seminal parameters. Considering the variable temperature and photoperiod during the four seasons where the study was performed, this lack of substantial differences could be related to a characteristic of the Martina Franca breed.
与其他欧洲驴品种一样，由于数量（2011 年 48 头公驴和 515 头母驴），Martina Franca 驴也被认为是濒危品种。为了增加驴的数量和保护品种的生物多样性，已经进行了多个关于驴繁殖的研究项目；然而，对驴的季节性繁殖仅进行了部分研究。因此，本研究的目的是研究季节以及长（春季至夏季；SS）和短（秋季至冬季；AW）日照时间对 Martina Franca 公驴生殖生理学的影响，特别是：（1）睾丸形态计量学特征，（2）通过评估反应时间的行为，最后，（3）精液特征。招募了 7 头成年且具有繁殖能力的 Martina Franca 公驴。对每头公驴，在每个季节的第一次季节性采集之前，对每个季节的两个睾丸进行一次形态计量学评估。通过人工阴道每周对精液进行一次采集，全年采集 52 次（每头驴 52 次采集）；每次采集时记录反应时间，并在采集后立即进行完整的精液评估。睾丸测量值在左右睾丸之间以及四个季节之间均无差异。春季和夏季的反应时间比秋季和冬季短，SS 期比 AW 期短。与所有其他季节相比，冬季的总容积明显更高；与夏季和秋季相比，无凝胶体积在冬季更高。冬季的平均精子浓度明显低于春季和夏季，AW 期的平均精子浓度明显低于 SS 期。总活力、前向运动活力和膜完整性在季节之间和 SS 与 AW 之间没有显著差异。秋季的平均路径速度比春季和夏季低，夏季的直线速度比春季和秋季高，冬季的曲线速度比夏季低。在季节之间和 SS 与 AW 之间，头部侧向位移振幅、摆动交叉频率、直线度和线性度均无差异。精液 pH 值在整个季节没有差异；精子形态也在一年中没有显著差异。本研究表明，在我们的气候和管理条件下，Martina Franca 公驴在一年中的睾丸形态计量学特征没有显著差异，尽管反应时间和一些精液参数存在一定的季节性影响。考虑到在进行研究的四个季节中温度和光照时间的变化，这种实质性差异的缺乏可能与 Martina Franca 品种的特性有关。
