Effect of sperm diluent and dose on the pregnancy rate in dromedary camels after artificial insemination with fresh and liquid-stored semen

Considerable scope exists for the use of AI in camel breeding programmes but the technology is not fully developed. The fertility of both fresh and liquid-stored (24 h; 4°C) dromedary camel semen diluted in either Green Buffer (GB) or INRA-96 (INRA) was assessed. Different insemination doses were investigated: 150 and 300 x 10 motile sperm for fresh sperm, and 150, 300 and 600 x 10 motile sperm for liquid-stored semen. Semen was diluted 1:1 with GB or INRA and asssessed for sperm quality parameters. Diluted semen was inseminated fresh (<2 h of collection) or after liquid-storage (further diluted 1:2; 24 h at 4°C). Dilution of fresh semen in GB resulted in higher motility (67.4±1.7%; mean±sem) than INRA (59.4±2.1%; P<0.05), but sperm membrane integrity was higher for INRA (64.9±2.5%) than GB diluted semen (55.9±5.0%; P<0.05). Sperm viability (GB: 66.7±2.1%; INRA: 66.7±1.9%) and acrosome integrity (GB: 84.9±1.7%; INRA: 88.5±1.4%) were similar (P>0.05). After liquid-storage, sperm motility (GB: 47.6±2.9%; INRA: 48.3±2.5%), membrane integrity (GB: 54.9±3.5%; INRA: 56.7±2.5%) and acrosome integrity (GB: 84.8±1.9%; INRA:84.6±2.1%) were similar between diluents but sperm viability was higher for INRA (62.2±1.5%) than GB (58.9±1.0%; P<0.05). The pregnancy rate following insemination of fresh semen was similar for GB (34%) and INRA (34%) but increased for insemination doses consisting of 300 (41.6%) compared with 150 x 10 motile sperm (27.2%; P< 0.05). For liquid-stored semen, the pregnancy rate was higher with INRA (23.5%) than GB (0.0%; P<0.05), and was reduced for 150 (0.0%; P<0.05) compared with 300 (10.5%) and 600 x 10 motile sperm (25.0%). INRA is a suitable diluent for the liquid-storage of dromedary semen and insemination doses of 300 and 600 x 10 motile sperm are recommended for AI with fresh and liquid-stored sperm respectively.