Oxidative Stress and Impact on Meat Quality

What is oxidative stress? 

Essentially, antioxidants act to neutralise free radicals produced in normal cell function. In periods of physiological stress (stress of handling, management or disease), free radicals are produced, which are, in turn, neutralised by antioxidant enzymes. This cycle is happening continuously in the body; however, in periods of sustained stress, an imbalance will occur, leading to an inability of the antioxidant network to keep up with free radical formation. This process leads to oxidative stress, which can, in turn, lead to oxidative damage. This damage may take many forms, including uncontrolled cell death, tissue damage or even malignant cell development leading to disease. 

What is the impact on cattle? 

Choosing cattle as an example for this piece, the effect of oxidative stress on cattle can take many forms and has been linked to increased risk of disease development. The most obvious example for this is the stress experienced by weaned calves heading for the mart and their subsequent propensity to develop respiratory disease. This has been confirmed with studies showing increased oxidative stress biomarkers following transport and subsequent disease outbreaks (Chirase et al., 2004). 

What are the forms of consistent stress we might put our cattle under? 

Essentially, any time we are handling animals. Consider weaning, tagging, weighing, clipping backs out, vaccination, movement, sale, breeding, mating, vet work – all of these will lead to stress responses. Now, if we add the potential challenge of disease on farm, poor hygiene, sheds with poor ventilation and high stress handling, which may wind up cattle. All of these factors can contribute to cattle entering a period of heightened and prolonged stress. 

As for humans, chronic stress is not good. With welfare at the heart of farming, no farmer wants their animals to be stressed, nor do they want this to impact the health of the stock. 

Oxidative stress and the impact on meat quality 

The concern for stress on cattle and resultant impact on their health and welfare has evolved with our understanding of nutrition to now also include the resultant quality of meat products. 

The impact of slaughterhouse and transport to stress and meat quality are well-known, with adjustments to prevent negative impacts now common and widespread. However, published data comparing intensive farming systems vs conventional grazing-based systems has now contributed to our knowledge of longer-term stress and meat quality (Tatar, 2024). This study has shown results that strongly support the observation that intensive agricultural practices influence pre-slaughter conditions, producing meat that may have shorter shelf lives and molecular quality changes. An undeniable connection between rearing practices, the impact of stress and meat quality exists. 

This intersection between animal management on farm and subsequent product quality is extremely important. We know there are many benefits to operating a low-stress system – most importantly, animal welfare however, we must remember there may be a significant impact on the end-product, too.