Estimation of inbreeding rate and its depression on the economic traits of genetically improved native chickens of north of Iran

Inbreeding control in native chicken breeding stations is of great importance due to closed population and increased inbreeding. Therefore, preventing inbreeding depression at the stations is a fundamental strategy to increase productivity. The aim of this study was to estimate the amount of inbreeding coefficient in Mazandaran native fowls and its impact on important economic traits. In this research, data were collected from 1990 to 2018 (26 generations) from the Mazandaran native fowls breeding station. Estimation of inbreeding coefficient was done by CFC program and the genetic parameters were estimated by using WOMBAT software. Results of the pedigree analysis showed that 59075 (73 percent) of all chickens were inbred. The mean individual and maternal inbreeding coefficient was estimated to be 4.3 and 3.6 percent, respectively. Inbreeding depression per 1 percent increase of individual inbreeding for BW1, BW8, BW12, ASM, WSM, EN, EW1 and MEW was 0.02, -1.32, -2.04, 0.31, -0.11, -0.18, 0.03 and -0.03, respectively. The results of this study showed that the inbreeding rate was low in the closed population of Mazandaran native chicken station. This is because of implementing appropriate mating designs. In these populations, the absence of inbred birds is almost impossible, but it is possible to have a suitable mating design for reducing the probable undesirable effects of inbreeding.