Effect of Frequency of Semen Collection,

This study was carried out to determine the optimum frequency of semen collections, dilution rate , and artificial insemination dose of Domyati duck semen in order to set up the commercial semen quality which could be applied to the conservation of genetic resources, breeding, and commercial production in Domyati ducks. In experiment 1, the three levels of the frequency of semen collections (once, twice and three times weekly) and dilution rates (raw, 1:1 and 1:2) were studied to determine efficacy of these variables on semen quality, fertility percentage and relative weights of thyroid gland, testis and liver as well as some blood plasma hormones were determined at the end of semen collection period. Experiment 2, was conducted to determine the effects of using different artificial insemination dose (10, 20, and 50 million spermatozoa) on fertility percentage as well as economic efficiency. Results showed that the ejaculate volume and sperm concentration were significantly decreased in the thrice semen collections weekly as compared to the once and twice collection. Coiled , clumping and dead sperm percentages were significantly decreased in the twice semen collections weekly and dilution rate 1 : 1 as compared with other treatments, whereas, sperm advanced motility values were significantly increased. Fertility percentage was significantly improved due to interaction between frequency of semen collection twice weekly and dilution rate 1:1, also, it was significantly improved for the groups inseminated by dose containing 20 and 50 million spermatozoa as compared to that contained 10 million sperm. In addition it was significantly improved for the group inseminated A.I.A 1 . Ghonim. et al 1024 by dose containing 20 million spermatozoa at 6 and 10 days from last insemination as compared to the groups inseminated by dose containing 10 and 50 million spermatozoa. Thyroid hormones (T4 and T3) ,testosterone and insulin –like growth factor hormone were insignificantly increased due to increasing the frequency of semen collections per week . These results indicated that the frequency of semen collections twice weekly with dilution rate 1:1 and an artificial insemination dose being 20 million spermatozoa per duck two times a week , could be used in laying duck insemination to maximize the fertility percentage , in addition to the higher economical efficiency of Domyati ducks.