Review: Factors affecting sheep carcass and meat quality attributes

N Schreurs,S Prache,L Guillier

doi:10.1016/j.animal.2021.100330

Abstract

Sheep meat comes from a wide variety of farming systems utilising outdoor extensive to indoor intensive with animals of various ages at slaughter. In Europe, slaughter may occur from 4 weeks of age in suckling light lambs to adult ages. More than any other animal species used for meat production, there are strong country-specific preferences for sheep meat quality linked to production system characteristics such as dairy or grassland-based systems. This article critically reviews the current state of knowledge on factors affecting sheep carcass and meat quality. Quality has been broken down into six core attributes: commercial, organoleptic, nutritional, technological, safety and image, the latter covering aspects of ethics, culture and environment associated with the way the meat is produced and its origin, which are particularly valued in the many quality labels in Europe. The quality of meat is built but can also deteriorate along the continuum from the conception of the animal to the consumer. Our review pinpoints critical periods, such as the gestation and the preslaughter and slaughter periods, and key factors, such as the animal diet, via its direct effect on the fatty acid profile, the antioxidant and volatile content, and indirect effects mediated via the age of the animal. It also pinpoints methodological difficulties in predicting organoleptic attributes, particularly odour and flavour. Potential antagonisms between different dimensions of quality are highlighted. For example, pasture-feeding has positive effects on the image and nutritional attributes (through its effect on the fatty acid profile of meat lipids), but it increases the risk of off-odours and off-flavours for sensitive consumersand the variability in meat quality linked to variability of animal age at slaughter. The orientation towards more agro-ecological, low-input farming systems may therefore present benefits for the image and nutritional properties of the meat, but also risks for the commercial (insufficient carcass fatness, feed deficiencies at key periods of the production cycle, irregularity in supply), organoleptic (stronger flavour and darker colour of the meat) and variability of sheep carcass and meat quality. Furthermore, the genetic selection for lean meat yield has been effective in producing carcasses that yield more meat, but at a penalty to the intramuscular fat content and eating quality of the meat, and making it more difficult to finish lambs on grass. Various tools to assess and predict quality are in development to better consider the various dimensions of quality in consumer information, payment to farmers and genetic selection.

Highlights

Sheepmeat in Europe is farmed through a diverse array of systems, largely driven by the main output and pedo-climatic conditions, and spanning a gradient from extensive to intensive (Sañudo et al, 1998; Berge et al, 2003)
Australian studies recommend an IMF of 5% or greater in the Longissimus lumborum to achieve a ‘better than every day’ score for liking (Pannier et al, 2018), while an IMF level less than 3% is thought to negatively impact eating quality ratings (Watkins et al, 2013) but is recommended for a ‘low fat’ claim (Pannier et al, 2018)
Sheep meat produced in Europe comes from a wide variety of farming systems and types of animals

Summary

Introduction

Sheepmeat in Europe is farmed through a diverse array of systems, largely driven by the main output (meat or milk) and pedo-climatic conditions, and spanning a gradient from extensive to intensive (Sañudo et al, 1998; Berge et al, 2003). Pasture-fed animals have a propensity to produce meat with a high ultimate pH, which further darkens the meat (Calnan et al, 2016), this being due to lower glycogen stores at slaughter and/or greater sensitivity to preslaughter handling-related stresses (Sheath et al, 2001) These differences between pasture-fed and stall-fed animals can be compounded by differences in age at slaughter and IMF content: pasture-fed lambs tend to be slaughtered at an older age (Berge et al, 2003), which decreases lightness and increases redness of the meat. Gkarane et al (2019) observed that finishing pasture-fed lambs on a concentrate-based diet reduced the in-meat concentrations of skatole and indole but did not translate into any effect on the intensity of flavour parameters, possibly as the reduction in volatile compounds were not enough. Research is investigating farming practices that could reduce the incidence of defective quality attributes while exploiting the potential benefit of white clover at pasture (for example, using condensed tannin-rich plants, Rivaroli et al (2019))

Conclusions

Findings

Ethics approval