Variations in the sexual behaviour and seminal characteristics of saanen and nubian bucks kept under the tropical climate of sudan

الملخص EN

Twelve bucks (6 Saanen and 6 Nubian) were used to compare the effects of the climatic seasons on the sexual behavior and semen characteristic of the Nubian and Saanen bucks.

Libido was assessed by recording the time elapsed from introduction of the buck to a goat in oestrus until ejaculation into an Artificial Vagina (AV).

The scrotal circumference was measured by tightening the measuring tape around the greatest width of the two testicles.

Semen was collected once per week.

Seminal characteristic quantified were volume of the ejaculate, spermatozoa motility, concentration of sperm cells, percentages of dead and percentage of abnormal spermatozoa.

The sexual behavior and seminal characteristic of Saanen bucks showed clear seasonal variations as attested by the significant differences when the winter and summer means were compared no seasonal variations were observed for the Nubian breed.

The testicular sizes of the Nubian bucks were observed to have earlier and faster development compared no the Saanen bucks.

Earlier testicular development has a close correlation with potential sperm production and can be further improved in the Nubian bucks by selection and breeding programmers.