Effect varying doses of fresh semen on fertility, duration of fertility and hatchability
M. NIRANJAN, D.C. JOHARI AND D. CHAUDHURY
Central Avian Research Institute
Izatnagar - 243122 U.P.
Males belonging to two White Leghorn lines i.e. IWG and IWJ were utilized in the present study. All the males available in each line were categorized into good and medium groups based on the fertilizing ability. The fertilizing ability of spermatozoa was estimated based on a dye (Iodonitrotetrazolium) reduction test. Any semen sample producing 20 or more moles of formazan/monute/10 9 spermatozoa was categorized as good where as any sample producing less than 20 as medium. The semen was collected fresh and density of spermatozoa was estimated by a spectrophotometric method. A calculated dose of suitably diluted semen was inseminated to get desired insemination dose. The insemination doses tested were 5, 10, 15, 20, 30, 50 and 75 millions of spermatozoa per insemination dose and the trial was conducted during peak summer season. Twelve females were inseminated for each dose in both the lines.
The fertility obtained during the first five days was 90% and above when insemination doses were 10x10 6 and 50x10 6 in IWG line and 15x10 6 and 30x10 6 in IWJ line for good and medium fertilizing ability groups. The desired level of fertility (90% and above) during first 7 days was obtained by insemination of freshly diluted semen containing 30x10 6 and 50x10 6 in IWG line and 15x10 6 and 30x10 6 in IWJ line for good and medium fertilizing ability groups, respectively. The average duration of fertility for above mentioned insemination doses which gave 90% and above fertility in good and medium fertilizing ability were 10.36and 9.82 days in IWG line and 10.58 and 9.33 days for IWJ line, respectively. In both lines, irrespective of good and medium categories, insemination dose had no effect on hatchability or livability of progeny. From the results, it is evident that there is a significant influence of season on fertility with highest in spring followed by monsoon and least in summer. How ever, there is hardly any effect of behavior of the breeder cocks on fertility. The percentage of fertility ranged from 77.1 to 93.2, 26.2 to 42.6 and 56.2 to 69.8 during first second and up to 2 nd week end respectively over three seasons.