The Impact of Handling Conditions and New Environments on the Stress of Cattle

Summary

​Cattle welfare is important from the perspective of the cattle themselves, marketing of beef product and improved production characteristics. This project aimed to assess time points in the supply chain from the time of induction to a feedlot through to slaughter to assess the relative levels of stress at these time points and the impact of cattle temperament on stress.

Qualitative behavioural assessment was also investigated as an adjunctive or alternative method of assessing welfare. The impact of stress and temperament on cattle production and the potential for prediction of cattle performance was assessed and quantified. Data was collected from 240 cattle that originated from a single property from induction to slaughter.

Although some measures of acute stress were greatest at slaughter, many measures of longer-term stress indicated that compared to induction this time point was less stressful for cattle. Cattle were shown to habituate to their environment in this study which may be a factor in their low expression of stress at slaughter. Temperament had an impact on production and carcase characteristics, however measurements taken in the feedlot and preslaughter periods are poor predictors of these traits. Results from this experiment can be used to develop indices for welfare assessment throughout the cattle supply chain.

Key findings

Cattle under the handling and management strategies utilised at this feedlot showed significant improvement in their temperament over their 100-day feedlot stay, which is likely related to the excellent low-stress stock handling of cattle at the feedlot and in the preslaughter period. 

The level of stress as measured by a range of blood indicators was considered low to moderate at all time points throughout the 100-day feedlot program and slaughter process. Compared to slaughter, cattle having been transported and inducted to the feedlot had a greater magnitude in chronic stress responses as indicated by markers of immune function, muscle damage, dehydration and feed deprivation. In comparison, the acute measures of stress (cortisol, lactate and glucose) were higher at the time of slaughter compared to induction, likely reflecting the increasing anticipation (short-term psychological stress) of the blood sampling regimen by the cattle over time.

There were few accurate indicators of cattle growth and carcase characteristics linked to the blood samples and temperament measures collected during the feedlot and pre-slaughter periods. However, one of the most useful indicators of future cattle performance was temperament as measured by flight speed at the time of induction. Cattle with poor temperament at the time of induction were shown to exhibit lower average daily gains, hot carcase weights, and increased shear force, despite habituation to the feedlot environment. These cattle were also more likely to show signs of acute stress at slaughter. 

Qualitative behavioural assessment (QBA) was able to differentiate between the stress levels of cattle at induction and slaughter and these results aligned well with the results of the blood and temperament indicators. The use of novel methods for prediction of post-slaughter muscle glycogen such as eye thermography showed some promising results.