Research on pre-slaughter stress and meat quality: A review of challenges faced under practical conditions

Transportation and handling of animals are important components in meat production systems. Animals destined for slaughter are stressed by factors such as loading, transportation, restraint, handling, and novelty of the slaughter environment, adverse weather conditions, hunger, thirst and fatigue. When an animal is stressed in the pre-slaughter environment, there is a rapid release of enzymes, cortisols and catecholamines which may lead to depletion of glycogen, high meat ultimate pH (pHu) and dark cuts. Pre-slaughter stress also affects the physiology of the animal resulting in an increase in creatine kinase (CK) activity, glucose, lactate and other blood metabolites. Pre-slaughter stress and meat quality is a wide topic and some research have been done albeit was conducted under experimental and controlled conditions. In real life situations many variables are not controlled. Data collection in practical conditions is complex because it is difficult to accurately take some of the measurements; for example the onset of the release of the enzymes and hormones. Moreover, there are difficulties in taking measurements from slaughterhouses and butcheries. Challenges that researchers, marketers and consumers face under practical conditions either on-farm, research stations, transfer centres, slaughter plants, abattoirs or butcheries; with regard to pre-slaughter stress and meat quality may affect the quality of the final products developed under such conditions. This review therefore aims to give a detailed outline on pre-slaughter stress, meat science research and challenges under practical conditions