Abstract: In the Northern hemisphere, sheep reproduction is
seasonal (September-November). Among several natural factors
influencing the reproduction status of rams, we studied the daylight
length and temperature. Rams from different breeds were studied:
Merinos de Palas (half-precocious), Karakul de Botosani (halfbelated)
and Turcana (belated breed, low reproductive plasticity). In
Merinos de Palas, ejaculate volume during sexual repose is 51.3%
from normal quantity. When autumn climate was experimentally
induced, ejaculate volume reached 98.45% (Merinos), 94.97%
(Karakul) and 97.59% (Turcana). Semen density increased from
1.031-1.033 till 1.035 after exposition to artificial light and
temperature conditions. Spermatozoids mobility and sperm pH
improved, passing over 82% and 6.75, values identical to those in the
natural reproduction season. Behaviour analysis after
photoperiodicity indicated that over 83.3% Merinos and Karakul
males and all Turcana rams exteriorised normal and intense sexual
reflexes. Certain effort and reduced expenses brought rams in good
condition, producing higher quantity and quality sperm.