Evaluation of growth production factors as predictors of the incidence and severity of white striping and woody breast in broiler chickens

Abstract

White striping (WS) and woody breast (WB) have been previously associated with older and heavier birds. However, there is limited information supporting the association between these 2 muscle conditions and growth parameters. The objectives of this study were 1) to investigate the relationship between WS and WB using different growth production factors and 2) to propose a predictive model that uses growth production factors to investigate the incidence and severity of WS and WB. A combined database of 4,332 broilers pooled from 7 research experiments conducted from 2016 to 2017 at Texas A&M University was used in this study. Parameters such as sex, age (4 wk, 6 wk, and 8 wk), strain (standard A vs. high-breast-yield [B and C]), live weight categories (500 g increments), and breast weight categories (250 g increments) were included in the model. Results showed that WS was 12% more likely to be present in non-WB fillets. The association between WS and WB suggests a moderate relationship between the ranks of both outcome variables (ρ = 0.57, P < 0.0001). Variables such as age, live weight, and sex were not as important as breast weight and strain in the severity prediction of WS and WB. Butterfly fillets above 750 g and with high-breast-yielding strains were more likely associated with higher severity of WS and WB scores. No post hoc variable selection was performed. Both models show good discrimination. The WS model produced an uncorrected area under the curve (AUC) of 0.739, with a bootstrap corrected estimate of 0.736. The WB model produced an uncorrected AUC of 0.753 and a bootstrap corrected estimate of 0.752. Therefore, the growth production factors analyzed in this study indicated that there is a moderate relationship between WS and WB myopathies and were jointly predictive of the severity of WS and WB. Potentially other factors not included in this study may play a major role in the relationship of these 2 myopathies. More research should be done to investigate this possibility.

Keywords: association; broilers; prediction model; white striping; woody breast.

Figure 1

Frequency of breast fillets with different white striping scores and percentage of woody breast scores within each white striping score category.

Figure 2

Frequency of breast fillets with different woody breast scores and percentage of white striping scores within each woody breast score category.

Figure 3

Variable importance plots on the incidence of white striping (WS) and woody breast (WB) measured by Wald chi-square. ∗P = P–value, X² = chi-square.

Figure 4

Model validation plots using bootstrap calibration for the predictive probability of white striping (A) ≥1, (B) ≥1.5, (C) ≥2, and (D) ≥2.5.

Figure 5

Model validation plots using bootstrap calibration for the predictive probability of woody breast (A) ≥1, (B) ≥2, and (C) ≥3.