The research aim was to establish the role and influence of reproduction season, photoperiodicity and temperature on reproductive activity, sexual behaviour and on quantity and quality of seminal liquid. The biologic material comprised rams belonging to the main sheep breeds of Romania: Merinos de Palas, Karakul de Botoşani and Ţurcană. The working methods during research were based on observations, sampling, objective assessments of the main quantitative and qualitative features of the seminal liquid. The research results confirmed that sexual activity was also increased at rams, due to the influence of inverse evolution of day time, generating increased libido and maximum sperm secretion. If in the repose period the collection of sperm reached an average level of 1.3 ml, in the period of natural or induced sexual activity by the applied programme of light and temperature, ejaculation increased to an average volume of 2.1 ml. Qualitative speaking, it was observed that sperm had more valuable features in early autumn, very close to the natural season, being kept till mid winter. Photoperiodicity influence was tracked in two years (2010 and 2012) from March to May. The main studied aspects were the sexual behaviour and the spermatic liquid production (ejaculation volume, sampling frequency). The results showed that the seminal liquid volume increased with 25% under the influence of the above mentioned factors. It was also found that under the straight influence of photoperiodicity, 68% of males became sexually active (erection, appropriate jump and ejaculation).