الفهرس 
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Abstract
Two experiments were carried out. The first experiment aimed to investigate the effects of breeding (December till April) and non-breeding (May till November) seasons either hot-humid (May till July) or hot-dry (August till November) months of the male dromedary camels on body thermoregulation, testicular measurements, epididymal semen characteristics, blood haematology and blood serum components. The histological changes in the right and left testes were also observed. The second experiment, aimed to define the effects of breeding and non-breeding seasons on epididymal semen quality and enzymatic activities, during storage at 5 °C for up to 3 days.
The obtained results showed that, rectal temperature (RT), respiration rate (RR) and pulse rate (PR) were significantly (P<0.05) lower, while testis weight, testicular volume, scrotal circumference and testis tone firmer score of the dromedary camels were significantly (P<0.05) higher during breeding season as compared to non-breeding season either hot-dry or hot-humid months. Semen colour of the dromedary camels were creamish white, milky white and watery white during breeding season, hot-dry and hot-humid months, respectively. Semen consistency of the dromedary camels was viscous during breeding season and hot-dry months, semi-viscous during hot-humid months. The percentage of sperm motility and the sperm-cell concentration were significantly (P<0.05) higher during breeding season as compared to both hot-dry and hot-humid months.
Seminal pH was significantly (P<0.05) higher during hot-humid months as compared to breeding season and hot-dry months. The percentages of dead spermatozoa, sperm abnormalities and acrosomal damage of spermatozoa increased significantly (P<0.05) in hot-humid months as compared to both hot-dry months and breeding season. Haemoglobin (Hb) and haematocrit (Ht) were significantly (P<0.05) higher during non-breeding season either hot-humid or hot-dry months than breeding season. Red blood cells (RBC’s) count was significantly (P<0.05) higher, while white blood cells (WBC’s) count was significantly (P<0.05) lower during non-breeding season at hot-humid months than hot-dry months and breeding season. Total proteins, sodium concentrations, alkaline phosphatase (ALP), alanine-aminotrasferase (ALT) and aspartate-aminotransferase (AST) enzymes were significantly (P<0.05) higher, while albumin and globulin concentrations were insignificantly increased in the non-breeding season at hot-humid months as compared with hot-dry months and breeding season. Cholesterol, urea-nitrogen, potassium, calcium, total phosphorus concentrations and testosterone hormone increased significantly (P<0.05), while creatinine concentration in blood serum decreased significantly (P<0.05) during breeding season as compared with non-breeding season in hot-dry and hot-humid months. The testes examination revealed that more active during breeding season especially in the left testes than the non-breeding season either hot-dry and hot-humid months (Experiment 1).
The percentage of sperm motility and storagability of spermatozoa were significantly (P<0.05) higher, while the percentages of dead spermatozoa, sperm abnormalities, acrosomal damage of spermatozoa and the amount of ALT and AST enzymes were significantly (P<0.05) lower during breeding season than non-breeding season either hot-dry or hot-humid months. The percentages of dead spermatozoa, sperm abnormalities and acrosomal damage of spermatozoa were significantly (P<0.05) higher during hot-humid months than hot-dry months and breeding season. The activities of ALT and AST enzymes of the dromedary camels semen were insignificantly higher during non-breeding season in hot-humid months than hot-dry season. The percentage of sperm motility was significantly (P<0.05) higher, while the percentages of dead spermatozoa, sperm abnormalities, acrosomal damage of spermatozoa and the amount of ALT and AST enzymes were significantly (P<0.05) lower during storage at 5°C for 3 days. There was no significant difference on the percentage of acrosomal damage of spermatozoa, ALT and AST activities between hot-humid and hot-dry seasons at storage at 5°C for up to 1 day. The prolongation of storage at 5°C for up to 3 days significantly (P<0.05) decreased the percentage of sperm motility, while significantly (P<0.05) increased the percentages of dead spermatozoa, sperm abnormalities, acrosomal damage of spermatozoa and the amount of ALT and AST activities of the dromedary camels during breeding and non-breeding seasons. The penetrating ability of spermatozoa into she-camel cervical mucus was significantly (P<0.05) better during breeding season than non-breeding season in hot-humid months and insignificantly (P<0.05) better during hot-dry months. While, the penetrating score was significantly (P<0.05) decreased during breeding and non-breeding seasons either hot-humid or hot-dry months with the advancement time of incubation at 37°C for 4 hours (Experiment 2).