This study utilized 12 mature fertile Barki rams located in the Maryout
Research Station. Semen was collected during June - August (summer season.
1999) and during December - March (winter season, 1998). Semen was collected
using an artificial vagina with 0.5 ml Tris buffer in the collection tubes (1: 1 dilution).
Semen samples were diluted and packed in straws (O.25ml) and frozen in liquid
nitrogen (·196°C). Data on physicat characteristics of semen were recorded (volume.
motility, % acrosome integrity. % dead and live sperm. pH. concentration and %
abnormality). In addition. seminal plasma of both seasons were harvested and Na'.
K+. free amino acids and total protein were determined. Also, 50S-PAGE was
conducted to characterize the peptide fraclions of seminal plasma of both seasons.
Results indicated higher (p < 0.05) post-thaw (Oh) motility in winter (44.1%) Ihan in
summer (17.2%) ejaculates, whereas at 4 hrs. post-thaw the percent intact acrosome
approached 72.3% and 65.9% for summer and winter ejaculates, respectively.
Moreover, percent of dead and abnormal spermatozoa were higher (p < O.05) in post-
thaw spermatozoa of summer than winter ejaculates. Sodium concentration was nol
different between summer and winter ejaculates. however K' concentration was
higher (p < O.05) in winter (71.7 ppm) Ihan in summer (47.3 ppm) ejaculates. This
resulted in different K'/Na + ratio between the two seasons. Approximately, total
protein was found to be as much twice (14.0g/dL) in summer as in winter (7.7g/dL).
The glutamic acid and glycJne were higher in winter than summer season. The SOS·
PAGE exhibited two more peptide fractions (330 and 24 kOa) in winter than summer
seminal plasma. The total number of peptide fractions was 14 in winter and 12 in
summer.