Genetic parameters of fear-related behaviors in Nigerian indigenous turkey poults: A pilot study

Abstract

Accurate estimates of genetic parameters will enable turkey breeders to determine the effect of selection on fear-related behaviors in breeding programs. Currently, no published reports exist on genetic parameters of fear-related behaviors in Nigerian indigenous turkey (NIT). The objective of this pilot study was to estimate genetic parameters of fear-related behaviors in NIT poults to know the relative contribution of genes and environment to these traits. Three behavioral tests were used as measures of fear response in randomly selected 200 NIT poults generated from mating of 10 sires and 20 dams. Emergence, inversion and open field tests were conducted at 9, 12, and 14 days of age, respectively. Fear tests were conducted in early life to measure innate fear and not learned fear. Heritability, genetic and phenotypic correlations were estimated for latency to emerge from a dark box (EMG), duration of wing flapping during inversion (INV), and behavioral activities performed during open field test such as preening frequency (PN), preening duration (PD), wall pecking duration (DPW), number of times a bird rested on its chest (NRC), duration of movement (DM), total number of floor squares explored (BE) and percentage of floor squares explored (PBC). Variance and covariance parameters of the fear-related behaviors were estimated using restricted maximum likelihood method. Heritability estimates ranged from very low to moderate. The lowest heritability (0.004) was estimated for NRC performed during the open field test while the highest heritability (0.364) was estimated for EMG. All genetic correlations between all pairs of fear-related behaviors were low except between INV and NRC (0.8132); INV and DM (0.7326), and between INV and PN (0.7115). Positive phenotypic correlations were found between INV and other fear-related behaviors while negative phenotypic correlations were found between NRC and the other fear-related behaviors. The highest phenotypic correlation was found between INV and BE (0.9985) while the lowest was between EMG and NRC (-0.0001). The very low to moderate heritability estimated for most of the fear-related behaviors indicates little genetic contribution to fear-related behaviors in NIT, suggesting that fearfulness can be best reduced in these birds by improving the rearing environment. The high genetic correlation between INV and NRC; DPW and PN; INV and DM as well as between INV and PN may indicate that the genes that contribute to these pairs of fear-related behaviors are co-inherited.