الفهرس 
Sire evaluation through genetic characterization of some important genes in buffalo
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Abstract
This study aimed to evaluate semen characteristics in buffalo bulls and to detect the genetic polymorphisms in pituitary-specific transcription factor (PIT-1) and prolactin (PRL) genes as bases for selection of bulls with good breeding value. A total number of 60 buffalo bulls aged 2-8 years was used in the study. The animals were divided into three groups according to the age. The first group aged between 2 to <3 years (n=35). The second group aged between 3 to <5 years (n=14). The third group aged between 5 to <8 years (n=11). Also, the animals were divided according to body condition score into two groups. The first group scores were between 2 to <3 (n=33). The second group scores were between 3 to <4 (n=27). Three collections were obtained from each animal and evaluated for volume, individual motility, live sperm percentage and chromatin integrity. DNA was extracted from semen and blood samples for genotyping of PIT-1 gene using HinfI-RFLP and PRL gene using XbaI RFLP. Ejaculate volume, individual motility and live sperm percentage were significantly lower in old than adult and young buffalo bulls. While chromatin damage percentage had no significant differences among age groups. Body condition score had no significant effect on semen characteristics except live sperm percentage that was significantly higher (p>0.05) in animals having body condition score between 2 to <3 than in animals having body condition score between 3 to <4. All buffalo bulls were genotyped as BB with the predominance of B allele for PIT-1 gene without genetic variation where PCR 451 bp fragment were digested into two fragments 244 and 207 bp. XbaI RFLP of PRL gene recorded genetic polymorphism in 678 bp PCR fragment with presence of AA genotype of undigested fragment in high frequencies (91.67%) while BB genotype of digested fragments into 231 and 447 bp in low frequencies (8.33%). It could be concluded that, age had adverse effect on semen quality. Monomorphic pattern of the amplicon 451 bp in PIT-1 HinfI locus in exon 6 in Egyptian buffalo (Bubalus bubalis) while presence of genetic polymorphism in PRL XbaI locus in regulatory region which acts as a genetic marker in buffalo bulls