Associations among gait score, production data, abattoir registrations, and postmortem tibia measurements in broiler chickens

Abstract

Lameness and impaired walking ability in rapidly growing meat-type broiler chickens are major welfare issues that cause economic losses. This study analyzed the prevalence of impaired walking and its associations with production data, abattoir registrations, and postmortem tibia measurements in Norwegian broiler chickens. Gait score (GS) was used to assess walking ability in 59 different commercial broiler flocks (Ross 308) close to the slaughter d, 5,900 broilers in total, in 3 different geographical regions. In each flock, 100 arbitrary broilers were gait scored and 10 random broilers were culled to harvest tibias. Abattoir registrations on flock level were collected after slaughter. A total of 24.6% of the broilers had moderate to severe gait impairment. The broilers were sampled in 2 stages, first slaughterhouse/region, and then owner/flock. The final models showed that impaired gait is associated with first-week mortality (P < 0.05), region (P < 0.001), height of tibias mid-shaft (P < 0.05), and calcium content in the tibia ash (P < 0.05), and negatively associated with DOA (P < 0.05). The prevalence of impaired gait indicates that this is a common problem in the broiler industry in Norway, although the mean slaughter age is only 31 d and the maximum allowed animal density is relatively low. Impaired walking ability could not be predicted by the welfare indicators footpad lesion score, total on-farm mortality, and decreasing DOA prevalence. Further studies are needed to explore the relationship between first-week mortality and gait score.

Associations between qualitative behaviour assessments and measures of leg health, fear and mortality in Norwegian broiler chicken flocks

“…gait score 3, 4 or 5) (e.g. Bassler et al, 2013;Kittelsen et al, 2017;Louton et al, 2018). In the 50 farms visited in this study, 19 % of the birds had a gait score ≥3, including 2.4 % with score 4 and 0.5 % with score 5 (presented in Vasdal et al, 2018).…”

“…Moreover, lame birds may have difficulties in reaching food and water (Butterworth et al, 2002;Sanotra et al, 2002), resulting in impaired growth and poor production results. Therefore, gait scoring is used to investigate severity of lameness in live birds (Kittelsen et al, 2017), and scoring of the macroscopic appearance of footpad lesions on farm or at the slaughterhouse is used to monitor welfare ante-or post mortem, respectively (Shepherd and Fairchild, 2010).…”

Effects of eggshell temperature pattern during incubation on tibia characteristics of broiler chickens at slaughter age

“…With respect to leg disorders and gait score, fast-growing broiler chickens in general show low locomotion activities and high (worse) gait scores ( Corr et al., 2003 , Bessei, 2006 , Kittelsen et al., 2017 ). Chickens reared at higher stocking densities may have poorer gait scores and higher prevalence of leg disorders ( Bradshaw et al., 2002 ) because of less opportunities of locomotion.…”

Genetic selection of broilers and welfare consequences: a review

“…The mean prevalence of broilers displaying a gait score of 3 or above has previously been reported to be between 15 and 55% (Kestin et al 1992;Sanotra et al 2001;Knowles et al 2008). More recently, studies conducted across multiple flocks, farms and countries have reported the prevalence of birds with a moderate to severe gait impairment (gait score 3 or above) to be between 5.5 and 48.8% (Bassler et al 2013;Tahamtani, Hinrichsen and Riber 2018;Kittelsen et al 2017;Granquist et al 2019).…”