Preslaughter stress and beef quality in relation to slaughter transport of cattle

Abstract

Preslaughter handling inevitably exposes cattle to stress, which affects beef quality and yields. Short transports to the slaughterhouse or a short walk across the yard to a mobile abattoir parked on the farm may reduce stress, with potential beneficial effects on meat quality. To compare different road transport distances to a stationary (fixed) slaughterhouse, and the stationary plant with a mobile abattoir, we studied commercial slaughter of 298 cattle in each facility over a period of 13 months. For the stationary slaughterhouse, the estimated transport distance from farm to plant was 7–250 km (mean 99 km) and 96 animals spent one night in lairage there. All animals at both slaughterhouses were stunned with a captive bolt gun. Blood levels of cortisol, glucose and lactate at exsanguination and meat quality indicators were recorded. According to two-sample t-tests, thawing loss was 1 percent unit lower (p<0.0001), Warner-Bratzler shear force was 6.9 N lower (p<0.0001) and compressive load was 3.9 MPa lower (p<0.0001), but mean lactate level was 1.02 mmol/l higher (p<0.0001) and ultimate pH was 0.05 units higher (p=0.0001) in the mobile facility compared with the stationary. Effects of slaughter facility and estimated road transport distance to the stationary plant on blood lactate, ultimate meat pH, shear force and compressive load were analysed by generalized linear mixed models, with delivering farm as random effect. According to the models, predicted shear force was 23% higher at the 95th percentile of the transport distance compared with the 5th percentile (p=0.012), and there was some evidence of a similar difference in compressive load for heifers, albeit only marginally significant (39% higher at the 95th percentile; p=0.056). Predicted blood lactate was 19% higher in the mobile abattoir than the stationary slaughterhouse (p=0.046). Ultimate meat pH was higher in the mobile unit for cows and steers (p≤0.0020), and for carcasses weighing 311–380 kg (p≤0.0020). Compressive load was 27% lower in the mobile abattoir, compared to the stationary (p<0.0001), but shear force did not differ significantly between the two facilities. This study shows a negative effect of long transport distances on beef tenderness. It also provides evidence of differences in beef quality between a mobile abattoir and a stationary slaughterhouse, although these differences may be attributable to specific routines for carcass handling and ageing at the studied facilities, and not the transport and slaughter strategy itself.