G.A. María

Fatty acid composition and sensory characteristics of lamb carcasses from Britain and Spain

Fatty acid composition of intramuscular fat in M. Longissimus was measured in four groups of lambs representing two Spanish breeds: Rasa Aragonesa (RA) and Merino (ME) and two British lamb types: the Welsh Mountain breed (WM), whose carcasses were purchased in Spain and typical early lambs (EL) purchased in Britain. The lambs grown in Spain were concentrate fed and slaughtered at a lighter weight and lower age than those grown in Britain. The British lamb carcasses purchased in Spain were of a similar weight to the Spanish lambs but were lighter than the lamb carcasses purchased in Britain. The British lambs were grass fed. Relationships between fatty acid (FA) composition and sensory attributes were examined following sensory testing of all lambs by both British and Spanish taste panels. The production system was shown to be more important than breed in determining FA composition. British lambs had higher percentages, within total fatty acids, of 18:0, 18:3 (n-3) and long chain polyunsaturated n-3 FA and lower percentages of 18:2 (n-6) and long chain polyunsaturated n-6 FA than Spanish lambs. These differences were due to the different feeding systems used. The amounts of these FA in muscle (mg/100 g) were also different between the British and Spanish groups, not only because the British lambs had more total fat. For both taste panels, odour and flavour intensity were positively correlated with the amounts and percentages of 18:0 and 18:3 and negatively correlated with those of 18:2. This was explained by the fact that both panels gave higher odour and flavour intensity scores to the grass-fed British lamb with high 18:3 levels and lower scores to the concentrate-fed Spanish lamb with high 18:2 levels. However, 18:0 and 18:3 were positively correlated with flavour quality and overall appraisal for the British panel and negatively for the Spanish panel. Conversely, 18:2 was a positive contributor to flavour and overall preference for the Spanish panel and was negative for the British panel. The results show that the production system affects muscle fatty acid composition and the flavour of lamb. However, peoples preference is determined to a large extent by their past experience.

Influence of carcass weight on instrumental and sensory lamb meat quality in intensive production systems

The influence of carcass weight (CW) on instrumental and sensory meat quality traits was studied in Rasa Aragonesa lamb carcasses. Forty-six intact male lamb carcasses were divided into three groups: 8.07 (S.D. 0.36) kg (A); 10.22 (S.D. 0.79) kg (B) and 13.42 (S.D. 1.36) kg (C). Results indicate that CW significantly influenced instrumental measurements in all the traits considered, except for waterholding capacity. The weight increase produced higher pH, haem pigment and redness (a (∗)) and lower lightness. Shear values were higher (p ≤ 0.01) in group B. Sensory traits were not influenced by CW with the exception of juiciness. This parameter increased in the order A-B-C, and the subjective colour estimation was darker in groups B and C. The results show that it is possible to produce heavier or lighter lamb carcasses than traditional lamb (Ternasco de Aragón, group B), without significant losses in meat quality. This fact could give flexibility to a system permitting the slaughter weight to be adjusted to variations in seasonal prices.

Assessment of commercial lamb meat quality by British and Spanish taste panels

Trained sensory panels in Britain and Spain assessed loin meat from commercial lambs purchased in Spain, which included Welsh lamb (imported from Britain) and two Spanish breeds (Merino and Rasa Aragonesa). The British panel also assessed British lamb purchased in local butcher shops and supermarkets. Sensory panels, in each country, received meat from the same lambs and used their local methods of cooking and assessment. Spanish panels used unstructured line scales to measure lamb odour intensity, tenderness, juiciness, lamb flavour intensity and two hedonic scales of flavour liking and overall liking. The British panel used 8 point category scales with the same attributes. Results from both panels in objective parameters were in agreement, hence showing that different trained sensory panels may arrive at the same conclusion. However, when panellists were allowed to make hedonic judgements (preference), the British panel preferred British lamb and the Spanish panel preferred Spanish lamb. This finding has important consequences for lamb producers who export their lambs and demonstrates that the underlying reasons for different preferences should be investigated. Production variables are discussed in relation to their influence on lamb eating quality and as a way to tailor lamb eating quality attributes familiar to consumers in the importing country.

Breed effect on carcase and meat quality of suckling lambs

The influence of breed on carcase and meat quality traits was studied in 48 suckling lambs (approximately 1 month old) from the Churra, Castellana and Manchega Spanish breeds and Awassi crosses. Carcase quality traits were determined by visual assessment and objective measurements. Meat quality was assessed by instrumental and sensory analysis. Breed effect was significant for fatness, carcase conformation and fat colour (visual indicators); dressing %, carcase weight, carcase length, buttock and chest measurements, and lean and fat proportions in the left half of the carcase. A significant breed effect was observed for some instrumental measurements of meat quality (meat colour and cooking losses), and for some sensorial attributes (tenderness and juiciness). These results suggest that there is a measurable effect of breed on both carcase and meat quality traits in this type of young suckling lamb, owing to differences in precocity and inherent productive capabilities.

Scoring system for evaluating the stress to cattle of commercial loading and unloading.

The loading and unloading of cattle for road transport is stressful but the stress is difficult to evaluate in terms of the welfare of the cattle. Over one year, 40 normal commercial journeys in northern Spain were analysed in terms of time limits and behavioural events in order to design an objective method for assessing the stresses imposed on the animals, and a scoring method was developed for assessing the welfare of the animals during loading and unloading. Several definitions of time intervals were assessed to calculate a time score per animal, and easily observable behavioural events were scored and combined with the time score to obtain a total loading/unloading score. More than half of the loadings and unloadings involved turns, slips and vocalisations. Mounts and bouts of fighting were infrequent and balks and falls were significantly more frequent during loading than unloading. The plasma concentrations of cortisol, glucose and lactate, the activity of creatine kinase and the pH of the meat 24 hours after the animals were slaughtered were also measured. The results indicated that loading was more stressful than unloading and that higher scores implied significantly higher levels of stress.

Effect of transport time and ageing on aspects of beef quality

Forty-eight bulls were transported by road in groups of eight for approximately 30 min, 3 or 6 h in two replicates. After slaughter, steaks from the longissimus dorsi thoracis of all transported animals were analysed in terms of pH, water-holding capacity, myoglobin concentration, texture at 7 and 14 days of ageing (compression and Warner-Bratzler analyses) and colour of the same surface of meat cut at 24 h post-mortem and allowed to bloom for 24 h and 7 d (L(∗)a(∗)b(∗), chroma and hue). The myofibrillar resistance of the meat from animals transported 30 min was significantly greater at 20% compression (P<0.05). The maximum load and a(∗)b(∗) and chroma were all lower for meat aged 14 days.

Effect of the pre-slaughter logistic chain on meat quality of lambs.

A total of 144 lambs were sampled in a 3×2×2 factorial design, testing three residence (stay) times at a pre-slaughter classification centre (0, 7, and 28days) and two seasons (summer and winter), with two replicates in each season. Meat from the longissimus dorsi was analysed in terms of pH, WHC, texture, colour (L∗a∗b∗, chroma and hue) and carcass bruising. Stay time had a significant effect (p<0.001) on meat texture, while season had a significant effect (p<0.001) on all variables analysed. Overall, stay time had less effect on meat quality than season and the interaction between treatments was not significant. Meat from lambs slaughtered in winter had some dark-cutting characteristics, with darker colour, higher ultimate pH, tougher meat and lower press juice. In conclusion, pre-slaughter classification and season are sources of stress for lambs and affect meat quality traits.

Effect of transport time on sensorial aspects of beef meat quality

Forty-eight slaughter bulls were transported by road in groups of eight for approximately 30 min, 3 h and 6 h in two replicates. After slaughter and an ageing time of 7 days, steaks from the longissimus dorsi thoracis were tasted by a trained sensory panel in terms of odour, tenderness, residue, juiciness, flavour intensity, flavour quality, and overall liking. Transport time had a significant effect (P<0.05) on meat tenderness and overall liking. The panel preferred meat from animals given the 3-h journey as opposed to the 30 min or 6-h journey and found it was more tender and had a better overall liking.

Livestock transport from the perspective of the pre-slaughter logistic chain: a review

New developments in livestock transport within the pre-slaughter chain are discussed in terms of three logistic nodes: origin, stopovers and slaughterhouse. Factors as transport cost, haulier, truck specifications, micro-environment conditions, loading density, route planning, vehicle accidents and journey length are discussed as well as causes of morbidity, mortality, live weight and carcass damage. Taking into account current trends towards increased transport times, logistics stopovers and mixed transport, there is a need to develop systems of evaluation and decision-making that provide tools and protocols that can minimize the biological cost to animals, which may have been underestimated in the past.

Assessment of cattle welfare at a commercial slaughter plant in the northwest of Mexico

Slaughter plants have been undergoing radical transformations in recent years due to the need to increase efficiency and incorporate new technologies for the improvement of the infrastructure, animal welfare, and product quality. The aim of this study was to assess the cattle welfare status during the unloading, lairage, stunning, bleeding and quantify bruising incidence at a commercial slaughter plant in the northwest of Mexico. We monitored 8,118 cattle during the unloading, lairage, stunning, bleeding, and carcass bruise incidence. Our results showed that in the unloading stage, 2% of the cattle vocalized, 5% were prodded with an electric goad, and 4% either slipped or fell. In the lairage stage, 12% of the animals vocalized, 80% prodded with an electric goad, and 8% of the animals slipped or fell. In the stunning stage, 10% of the animals vocalized, 67% prodded with an electric goad, and 15% of the animals slipped or fell. Ninety-five percent of the animals were stunned with a single shot, and 51% of the animals were effectively desensitized. Ninety-two percent of the carcasses had some type of bruise. Although the slaughter plant had adequate infrastructure and stringent operational standards, in all of the stages except unloading handling had an impact on the welfare of the animals being slaughtered.