Benjamin Wood

Fault bars are visible deformities in the feather structure potentially related to the stress response and may be an interesting trait that can reflect robustness. This study’s objective was to describe fault bars along the length of domestic turkey feathers and investigate whether fault bars are associated with feather corticosterone (FCORT). The same primary wing feather was evaluated from 75 male turkeys from three genetic lines. Feathers were cut into three (proximal, middle, and distal) sections to score fault bar presence, incidence, and severity. FCORT was measured for each feather section using ELISA. Linear mixed models were used to investigate differences in the fault bar presence, incidence, and severity between feather sections and genetic line, as well as investigate associations between the fault bar measures and FCORT. There was a significant increase in FCORT and fault bar incidence from proximal to distal feather sections ( P < 0.0001). In the distal section only, sections with fault bars had significantly higher FCORT compared to sections without fault bars ( P = 0.0088). No associations were found between fault bars and FCORT in the other sections. Consequently, associating FCORT and fault bars using whole primary wing feathers may be challenging. Future work should reevaluate this relationship longitudinally to better understand fault bar development.

The aim of this study was to investigate the potential non-linear relationship between growth and walking ability (WA). The phenotypic data included body weights at 12 and 20 weeks and WA at 20 weeks of age measured on 276,059 male turkeys. The growth rate at three age periods (0 to 12, 12 to 20 and 0 to 20 weeks) was calculated. Each bird was assigned to one of the quartiles of the growth rate distribution for each age period. Between the first and fourth quartiles, the incidence of score 1 (bad WA) increased by 31, 18, and 33% for the first, second, and third age periods, respectively. For good WA (scores 4, 5, and 6), the incidence decreased by 55, 66, and 72% between the first and fourth quartiles for the first, second, and third age periods, respectively. Estimates of heritability of WA ranged between 0.18 and 0.26. The genetic correlations between adjacent growth rate quartiles were high and decayed as the interval between quartiles increased. The magnitude of the variation in the incidence of walking scores and genetic correlations across the growth rate quartiles point towards a non-linear relationship between growth and mobility suggesting other factors may affect walking ability.