Inbreeding effects on production traits in pigeons

The effects of inbreeding were measured on hatchability and related traits, on viability and growth of squabs until weaning, in two genetically differ ent pigeon populations. In both experiments the performance of randombred a nd that of inbred (F=25%) populations descending from full-sib matings were compared. In one experiment 105 to 105 auto-sexing utility breeding pairs, in the other trial 60 to 60 racing homer pairs produced the inbred and ran dombred breeding populations. All pigeons were kept in the same environment ally controlled house, and were managed and fed identically. All breeding p airs were maintained in special cages, housing one breeding pair each. All production data were collected for a 12 month production period. Inbreeding reduced all traits measured, most of them significantly (P < 0.05 to P < 0 .001). The mean inbreeding depression expressed as a percentage in proporti on related to the performance of the outbred population for the traits stud ied for the auto-sexing utility and the racing homer populations respective ly were: hatchability 72.5% and 65.7%, survival rate of squabs till weaning 81.0% and 93.7%, body weight of squabs till weaning: 86.6% and 98.0%. The difference between inbred and outbred populations in traits influencing hat chability for auto-sexing utility and racing homer populations respectively were: infertile eggs %: 3.57 and 3.82, early embryonic mortality %: 7.55 a nd 4.21, embryo mortality between the 7-14th day of incubation%: 2.42 and 3 .36, late embryonic mortality %: 2.79 and 6.02. The magnitude of in breedin g depression showed similarities in both genetically different pigeon popul ations regarding hatchability. The racing homer population showed less inbr eeding depression in survival rate of squabs, and growth of squabs till wea ning age compared to the auto-sexing utility meat type population.