Effect of the winter diet on meat quality traits of steers finished on mountain pasture with a barley supplement
The aim of this study was to evaluate the effect of two winter diets (WD) (100 F, i.e. 100% forage, 8.3 kg DM of lucerne hay + 0.3 kg DM of straw; and 65F:35C, i.e. 65% forage:35% concentrate, 5.4 kg DM lucerne hay + 0.3 kg DM straw + 3.0 kg DM barley), offered during 118 days on meat quality traits of 20-month old steers finished on mountain pasture supplemented with 4.1 kg DM barley d–1. Longissimus thoracis intramuscular fat content and its fatty acid profile were determined (in vivo) after one month on pasture. The intramuscular fat content, fatty acid profile, texture (1, 8 and 15 days of ageing), colour (1, 2, and 8 days of oxygen exposure) and sensorial quality (8 and 15 days ageing) were evaluated post-mortem after 163 days on the finishing diet. Intramuscular fat content and fatty acid profile were affected by the WD in vivo (p < 0.05) but not post-mortem. Meat pH was not affected by the WD but the texture was affected by the interaction between the WD and the ageing time (p < 0.001), maximum stress decreased more rapidly in the 100F diet in the first 8 days of ageing. Meat colour was only affected by the oxygen-exposure time (p < 0.001). Panel test variables were not affected by the WD, but ageing time affected beef flavour intensity (p < 0.05). In conclusion, the winter diet affected intramuscular fat content after one month of grazing but had no major effects on post-mortem meat quality of pasture-finished steers.
SNP included in candidate genes involved in muscle, lipid and energy metabolism behave like neutral markers
Studies of population structure and diversity in cattle have provided insights into the origins of breeds, their history and evolution, and allow the identification of global livestock diversity hotspots, which is important for conservation of diversity. Genetic diversity, genetic relationship, population structure, and the presence of hotspots of genetic diversity among 15 European bovine breeds from five countries were assessed using 435 single nucleotide polymorphisms (SNP) markers identified in candidate genes for muscle, lipid and energy metabolism, thus providing the opportunity to compare the breed relationships obtained using putatively functional markers with previous data using neutral loci. Individuals belonging to 11 breeds tended to be clearly assigned to a single cluster when the number of pre-defined populations reached a maximum in the likelihood of the data at K= 12, whereas Asturiana de los Valles, Danish Red, Simmental, and Avileña-Negra Ibérica displayed a greater degree of admixture, which may be explained by their diverse ancestry. Although overall results were in agreement with those reported by studies based on neutral genetic variations, some additional breed relationship information emerged using markers in candidate functional loci, including the relationship between the Asturiana de los Valles and Piedmontese, and Danish Red and Charolais breeds. This study indicates that the analysed loci have not been main targets for selection or for adaptation processes, but also that SNP within candidate genes related with beef characteristics and performance may provide a slightly new perspective on past breeding and may also help in the development of strategies for the rational conservation of livestock diversity.
Sur le marché espagnol, il existe huit dénominations de vente de la viande bovine. Le consommateur, au moment de l’achat, tient compte de la couleur et de l’apparence de la viande pour choisir ou non un produit. Or, les différences de couleur mesurées objectivement ne correspondent pas toujours à cette segmentation commerciale. Au total, 78 échantillons de différents types de viande bovine commercialisés en Espagne ont été regroupés en quatre classes de couleur : blanche, rose, rouge et très rouge, par des mesures colorimétriques objectives. A partir des valeurs moyennes des paramètres de couleur et de leur dispersion (écart type), un standard a été calculé pour chaque type commercial.
Polymorphisms in twelve candidate genes are associated with growth, muscle lipid profile and meat quality traits in eleven European cattle breeds
Current customers’ demands focus on the nutritional and sensory quality of cattle meat. Candidate gene approach allows identification of genetic polymorphisms that have a measurable effect on traits of interest. The aim of this work is to identify new molecular markers for beef production through an association study using 27 candidate genes and 314 purebred bulls from 11 European cattle breeds. Twelve genes were found associated with different lipid and meat quality traits, and among these stand out the considerable effect of CAST on fatness score, CGGBP1 on growth traits, HSPB1 on the percentage of lauric acid (12:0) and phospholipid docosahexaenoic acid (DHA 22:6 n -3), RORA on the ratio of light absorption (K) to light scattering (S) (K/S), and TNFA on lightness (L*). Most of these traits are related to post-mortem muscle biochemical changes, which are key factors controlling meat quality and consumers’ acceptance. Also, the variations produced on muscle fatty acid profiles, such as those of AANAT, CRH, CSN3, HSPB1, and TNFA, give insights into the genetic networks controlling these complex traits and the possibility of future improvement of meat nutritional quality.
Phenotypic and genotypic background underlying variations in fatty acid composition and sensory parameters in European bovine breeds
Background: Consuming moderate amounts of lean red meat as part of a balanced diet valuably contributes to intakes of essential nutrients. In this study, we merged phenotypic and genotypic information to characterize the variation in lipid profile and sensory parameters and to represent the diversity among 15 cattle populations. Correlations between fat content, organoleptic characteristics and lipid profiles were also investigated.
Methods: A sample of 436 largely unrelated purebred bulls belonging to 15 breeds and reared under comparable management conditions was analyzed. Phenotypic data -including fatness score, fat percentage, individual fatty acids (FA) profiles and sensory panel tests- and genotypic information from 11 polymorphisms was used.
Results: The correlation coefficients between muscle total lipid measurements and absolute vs. relative amounts of polyunsaturated FA (PUFA) were in opposite directions. Increasing carcass fat leads to an increasing amount of FAs in triglycerides, but at the same time the relative amount of PUFAs is decreasing, which is in concordance with the negative correlation obtained here between the percentage of PUFA and fat measurements, as well as the weaker correlation between total phospholipids and total lipid muscle content compared with neutral lipids. Concerning organoleptic characteristics, a negative correlation between flavour scores and the percentage of total PUFA, particularly to n-6 fraction, was found. The correlation between juiciness and texture is higher than with flavour scores. The distribution of SNPs plotted by principal components analysis (PCA) mainly reflects their known trait associations, although influenced by their specific breed allele frequencies.
Conclusions: The results presented here help to understand the phenotypic and genotypic background underlying variations in FA composition and sensory parameters between breeds. The wide range of traits and breeds studied, along with the genotypic information on polymorphisms previously associated with different lipid traits, provide a broad characterization of beef meat, which allows giving a better response to the variety of consumers’ preferences. Also, the development and implementation of low-density SNP panels with predictive value for economically important traits, such as those summarized here, may be used to improve production efficiency and meat quality in the beef industry.
Understanding which are the genetic variants underlying the nutritional and sensory properties of beef, enables improvement in meat quality. The aim of this study is to identify new molecular markers for meat quality through an association study using candidate genes included in the PPARG and PPARGC1A networks given their master role in coordinating metabolic adaptation in fat tissue, muscle and liver. Amongst the novel associations found in this study, selection of the positivemarker variants of genes such as BCL3, LPL, PPARG, SCAP, andSCD will improvemeat organoleptic characteristics and health by balancing the n−6 ton−3 fatty acid ratio inmeat. Also previous results on GDF8 and DGAT1 were validated, and the novel ATF4, HNF4A and PPARGC1A associations, although slightly under the significance threshold, are consistent with their physiological roles. These data contribute insights into the complex gene-networks underlying economically important traits.
Effects of whole linseed and rumen-protected conjugated linoleic acid enriched diets on beef quality
Instrumental assessments and sensory tests were performed to evaluate the effects of diet and postmortem ageing time (1, 7 and 21 days) on beef quality. A total of 48 Friesian calves were randomly allocated to four dietary treatments: control, whole linseed (10% linseed), conjugated linoleic acid (CLA) (2% protected CLA), and whole linseed +CLA (10% linseed and 2% protected CLA). Animals were slaughtered at 458 ± 16.6 kg live weight and 11 months of age. Ageing was more significant than diet on most instrumental parameters. Meat from linseed enriched diets had greater drip loss ( P⩽ 0.001) and intramuscular fat ( P⩽ 0.01) than meat from animals fed CLA. Beef aged for 7 and 21 days had lower cooking losses ( P⩽ 0.01) and shear force ( P⩽ 0.001) than beef aged for 1 day. Lightness was affected only by display time. The addition of CLA in the diet increased hue and yellowness, whereas the inclusion of linseed decreased these values, as well as increased redness. Linseed in the diet decreased fat odour ( P⩽ 0.05), but increased beef ( P⩽ 0.01) and liver ( P⩽ 0.05) flavours. Meat aged for 21 days was significantly more rancid ( P⩽ 0.001), even under vacuum storage. Several organoleptic properties were improved with the inclusion of linseed in the diet, whereas they remained unaffected by the inclusion of CLA.
Puede consultar el documento completo aquí: Animal, 10, 709-717
En España, de modo general, el consumidor de carne de vacuno le da poca importancia a la raza en comparación con otros países Europeos, a pesar de que la misma influye en otras características que sí considera relevantes como el aspecto (color, grasa intramuscular) o la terneza. Las razas bovinas rústicas y locales españolas están ligadas a una región geográfica particular y a un sistema de erra tradicional, donde varios factores como la edad y peso al sacrificio, el sexo, el grado de engrasamiento, el manejo, la alimentación y el tratamiento post-sacrificio intervienen conjuntamente en la definición de cada producto. Estos productos suelen promocionarse a través de denominaciones de origen o marcas de calidad que, por otro lado, permiten al consumidor reducir la incertidumbre cuando compran alimentos, ya que están asociadas a ciertas características sensoriales y/o procesos productivos distintivos.
Algunos autores han descrito la calidad de canal (Piedraflta et al., 2003) y las características bioquímicas (Gil et al., 2001) y sensoriales (Serra et al., 2008) de varias razas españolas vinculadas al sistema de producción, de modo que este trabajo se centra en la textura de la carne evaluada instrumentalmente y en algunas de sus características químicas.
Puede consultar el trabajo completo aquí
Efecto de la dieta invernal sobre la calidad de la carne de cebones finalizados en pastos de montaña suplementados con cebada
El objetivo del estudio fue evaluar el efecto de dos dietas invernales (WD) (100F, es decir, 100% forraje, 8,3 kg MS heno de alfalfa + 0,3 kg MS paja; y 65F:35C, es decir, 65% forraje:35% concentrado, 5,4 kg MS heno de alfalfa + 0,3 kg MS paja + 3,0 kg MS cebada), ofrecidos durante 118 días sobre algunas variables de calidad de la carne de cebones sacrificados a los 20 meses de edad, finalizados en pastos de montaña y suplementados con cebada (4,1 kg MS d–1). Se determinó el contenido en grasa intramuscular y el perfil de ácidos grasos del músculo Longissimus dorsi al mes de iniciarse el pastoreo (in vivo). Tras el sacrificio, se determinó el contenido en grasa intramuscular, el perfil de ácidos grasos, el pH, la textura instrumental (1, 8 y 15 días de maduración), el color (1, 2 y 8 días de exposición al oxígeno) y la calidad sensorial (8 y 15 días de maduración). La dieta invernal afectó al contenido en grasa intramuscular y a su composición después de un mes de pastoreo (p < 0,05) pero no al sacrificio. La dieta invernal no afectó al pH pero la textura se vio afectada por la interacción entre la dieta invernal y tiempo de maduración (p < 0,001). El color se vio afectado sólo por el tiempo de exposición al oxígeno (p < 0,001). La dieta invernal no afectó a las variables sensoriales (p > 0,05), pero la maduración afectó a la intensidad de flavor a vacuno (p < 0,05). En conclusión, la dieta invernal afectó a la cantidad de grasa intramuscular tras un mes de pastoreo pero no tuvo efectos importantes sobre la calidad post-mortem de la carne de los animales acabados en pastoreo.
Farmers in dry mountain areas are changing their management strategies to improve livestock farming efficiency, by using different forages or different breeds. The effect of breed (Parda de Montañana vs. Pirenaica) and finishing diet
(grazing on meadows vs. a total mixed ration (50% alfalfa, 40% maize grain, 10% straw)) on carcass characteristics and meat quality of steers was studied.
Parda de Montaña had a greater (P < 0.01) amount of intramuscular fat than Pirenaica. The finishing diet did not
influence carcass fat color, but fatty acid composition was slightly affected. Finishing steers on a total mixed ration increased the percentage of fat of the 10th rib (P < 0.001). Supplementation with concentrates increased the diet energy concentration and also increased the dressing percentage. Both breeds had similar carcass characteristics. Consumers preferred beef from the Pirenaica breed because of its greater tenderness. Consumers did not differentiate between beef from animals fed different finishing diets. However, consumers who like meat very much preferredmeat aged in a cooler at 4 ◦C for 15 days rather than 8 days.
Effect of including linseed in a concentrate fed to young bulls on intramuscular fatty acids and beef color
The effect of varying concentrate composition to include 5% linseed and 200 IU of vitamin E on the growth performance, fatty acid composition, and muscle color during shelf life was assessed in 46 young Pirenaica bulls finished to two fatness levels. Adding 5% linseed lowered the dressing rate without altering daily gain or carcass classification. It likewise did not alter the total saturated, monounsaturated, or polyunsaturated fatty acids in the intramuscular fat, though the percentage of α-linolenic acid and n−3 fatty acids increased significantly while the n−6 fatty acid to n−3 fatty acid ratio decreased. Higher subcutaneous fat cover depth at slaughter increased the total percentage of oleic acid and monounsaturated fatty acids without affecting the percentage of saturated or polyunsaturated fatty acids. Adding 200 IU of vitamin E in addition to linseed did not alter the color of film-wrapped fresh meat during storage in darkness.
Cattle meat provides essential nutrients necessary for a balanced diet and health preservation. Besides nutritional quality, consumers’ preferences are related to specific attributes such as tenderness, taste and flavour. The present study characterizes the fatty acid composition of beef, which is an important factor in both nutritional and quality values, in 15 European cattle breeds fed a similar diet and reared in five countries (United Kingdom, Denmark, France, Italy and Spain). The effect of possible slight differences on diet composition which might have occurred between countries were included in the breed effect which confounds country, diet, slaughter house and slaughter day as all individuals of a same breed were managed simultaneously. The wide range of breeds studied and the significant differences on lipid profile described here provide a broad characterization of beef meat, which allows giving a better response to the variety of consumers’ preferences. Regarding meat health benefits, the groups that stand out are: the double-muscled animals, which displayed lower total fat, lower proportion of saturated (SFA) and monounsaturated (MUFA) fatty acids, and a higher proportion of polyunsaturated (PUFA) fatty acids; and Limousin and Charolais breeds with a significantly higher conversion of 18:3n-3 PUFA to the long chain 22:6n-3 PUFA.
Variations in meat quality traits are under complex genetic control and improvement has
been hampered by the difficulty in their measurement. Several QTL have been reported for
different meat quality related traits, but few genes have been described which explain large
amounts of the phenotypic variation. The use of single nucleotide polymorphism (SNP) marker panels with predictive value for carcass traits have been evaluated for cattle and SNP are commercially available even though their predictive accuracy may below in different breeds.To identify new molecular markers for meat quality, an association study was performed in 15 breeds of cattle using 389 SNP belonging to 206 candidate genes known to be involved in muscle development, metabolism and structure. Fifty-four SNP belonging to 20 different genes were found associated with different growth, carcass and meat quality traits. Some of them were novel associations and other were replications of known associations. Among the former,the gene-network associated with the calpain/calpastatin system was shown to be associated with meat texture, although small effect sare found for the examined polymorphisms. Novel associations also included SNP in AANAT which was associated with collagen(P¼0.006), CAST with fatty acid muscle composition (P¼0.00003), CYP1A1 with juiciness (P¼0.0005), DGAT2 with physical traits (P¼0.0009) and lipid content(P¼0.01) in muscle, MADH3 with the myofibrilar fragmentation index (MFI)(P¼0.01), NEB with weight (P¼0.00009), PCSK1 with juiciness (P¼0.002), PLOD3 with carcass performance(P¼0.0009)
and fattyacids(P¼0.04), and PGAM2 and VIM with post-mortemmaturation(P¼0.00008 and
0.000005, respectively).These dataprovide a starting point to investigate the complex gene-networks underlying economically important traits which are of importance to the beef industry for the improvement of production efficiency and meat quality.
Consumers demand healthy and palatable meat, both factors being affected by fat
composition. However, red meat has relatively high concentration of saturated fatty acids
and low concentration of the beneficial polyunsaturated fatty acids. To select animals prone
to produce particular fat types, it is necessary to identify the genes influencing muscle lipid
composition. This paper describes an association study in which a large panel of candidate
genes involved in adipogenesis, lipid metabolism and energy homoeostasis was tested for
effects on fat composition in 15 European cattle breeds. Sixteen genes were found to have significant effects on different lipid traits, and among these, CFL1 and MYOZ1 were found to have large effects on the ratio of 18:2/18:3, CRI1 on the amount of neutral adrenic acid (22:4 n-6), MMP1 on docosahexaenoic acid (22:6 n-3) and conjugated linoleic acid, PLTP on the ratio of n-6:n-3 and IGF2R on flavour. Several genes – ALDH2, CHRNE, CRHR2,
DGAT1, IGFBP3, NEB, SOCS2, SUSP1, TCF12 and FOXO1 – also were found to be associated with both lipid and organoleptic traits although with smaller effect. The results presented here help in understanding the genetic and biochemical background underlying variations in fatty acid composition and flavour in beef.
Para este estudio, se utilizaron 20 terneros de raza Gascona. La mitas de los animales se criaron en un sistema intensivo (INT), con un destete temprano a los 3-4 meses; la otra mitad de los animes se criaron en un sistema extensivo tradicional (EXT), con destete a los 7 meses. Todos los animales se sometieron al las mismas condiciones durante el periodo de finalización, que duró 145 días. El sistema de producción empleado con anterioridad a la fase de acabado no afect´ni a la conformación no al rendimiento ni a la morfología de la canal, pero se encontraron diferencias en la composición tisular entre ambos grupos. La exposición al oxígeno tuvo mayor efeccto sobre el color de la carne que el sistema de porducción. El porcentaje de mioglobina fue mayor en INT, pero ni la textura ni la calidad sensorial se vieron afectadas por el sistema de porducción. Los animales del lote EXT presentaron una grasa más amarilla y oscura, un mayor porcentaje de ácidos grasos n-3, un porcentaje menor de ácidos grasos saturados y un menor índice n-6/n-3.
Relationship between collagen characteristics, lipid content and raw and cooked texture of meat from young bulls of fifteen European breeds
Variations in texture were determined for 10 day aged raw and cooked Longissimus thoracis (LT) muscle from 436 bulls of 15 European cattle breeds slaughtered at an age of 13–16 months. Variations in texture were related to differences in pH 24 h post-mortem, sarcomere length, collagen characteristics and lipid content. The shear force of cooked meat samples varied from 43.8 to 67.4 N/cm2. Simmental, Highland and Marchigiana cattle had the highest shear force values and Avileña-Negra Ibérica, Charolais, Casina and Pirenaica cattle had the lowest values. Cooked meat toughness showed a weak negative correlation to lipid content (Pb0.001) but no correlation to collagen characteristics. Raw meat texture measured by compression correlated positively (Pb0.001) with total and insoluble collagen. In conclusion, collagen characteristics
showed correlation to raw meat texture but not to cooked meat toughness of LT muscle in European young bulls.
Lucerne grazing compared with concentrate-feeding slightly modifies carcase and meat quality of young bulls
Carcase and meat quality of young bulls raised on one of three fattening strategies from 224 to 450 kg were compared. One group was fed concentrates (CON), another group grazed on lucerne plus 1.8 kg DM barley/day (LUC) and the last group had the same management as LUC young bulls for 3 months and was then finished on concentrates for 2 months. Among carcase traits, only tissue composition differed, with LUC young bulls having more muscle and less subcutaneous and intermuscular fat than their counterparts. Concerning meat quality, most attributes did not differ among fattening strategies but LUC young bulls had the lowest intramuscular fat, which presented greatest n3 PUFA content. It can be concluded that lucerne grazing can be a good alternative to concentrates for young bulls, with similar carcase and meat quality but with lower fat content and healthier fatty acid composition than young bulls fed concentrates during the finishing period.
Near-infrared reflectance spectroscopy for predicting chemical, instrumental and sensory quality of beef
Near-infrared spectroscopy has been successfully used by the industry for chemical analysis due to its recognised advantages as a rapid and accurate tool (Bartholomew & Osuala, 1988; Mitsumoto, Maeda, Mitsuhashi, & Ozawa, 1991; Tøgersen, Isaksoon, Nielsen, Bakker, & Hildrum, 1999). The dairy industry uses infrared technology effectively to determine lactose, protein and fat contents in milk. Furthermore, this technology is widely used in the grain and livestock feed industry (Bjarno, 1982; Rotolo, 1979; Shenk, Westerhouse, & Hoover, 1979). Near-infrared reflectance (NIR) spectroscopy has also been used previously in meat analyses (Ben-Gera & Norris, 1968) and, recently, numerous studies and applications have been developed for the prediction of meat properties, particularly chemical composition (Denoyelle & Cartier, 1996; Hildrum, Nilsen, Tøgersen, Rødbotten, & Isaksoon, 1999; Lanza, 1983; Mitsumoto et al., 1991; Oh & Großklaus, 1995; Oliván, 1999; Oliván, de La Roza, Mocha, & Martínez, 2001; Tøgersen et al., 1999). Other characteristics of meat, such as tenderness, are studied by means of slow and destructive methods such as texturemeters equipped with Warner–Bratzler, Kramer or compression devices. Similarly, sensory analyses with trained panellists require a great amount of meat samples and this is a complex, expensive and time-consuming technique. Applications of NIR spectroscopy in the prediction of sensory meat quality are less developed than in other fields. Taking into account that covalent bonds that involve hydrogen are dominant in the near-infrared region (Davies & Grant, 1987), changes in meat that involve bond absorption energy could be measured by NIR spectroscopy. Such changes evidently also occur in meat during ageing (Hildrum et al., 1995) by oxidation or enzyme activity and are reflected in many characteristics such as tenderness, flavour and juiciness. Thus, both instrumental and sensory tenderness, and related variables such as sensory overall appraisal and juiciness could be predicted by NIR spectroscopy, although until now tenderness predictions have usually been inconsistent (Liu et al., 2003). The aim of this work is to evaluate NIR spectroscopy as a tool for determining instrumental texture variables and sensory properties, as well as chemical characteristics of beef.
Eating quality of young bulls from three Spanish beef breed-production systems and its relationships with chemical and instrumental meat quality
Sensory characteristics of longissimus thoracis muscle from three local Spanish beef breed-production systems and their relationships with chemical and instrumental meat quality traits were studied. Young bulls of Bruna dels Pirineus (BP; n = 69), Avilen˜a-Negra Ibe´rica (A-NI; n = 70) and Morucha (MO; n = 70) breeds were reared in their own production systems. MO breed showed the highest water holding capacity and also the highest thawing loss and haem pigment content (P < 0.001). No differences in moisture and protein contents were found among breeds. A-NI showed the highest intramuscular fat (IMF, P < 0.05) and total collagen (P < 0.001) contents, whereas BP showed the lowest IMF content (P < 0.05) and the highest collagen solubility (P < 0.001). Beef flavour, tenderness and juiciness accounted for the eating quality differences among the three breed-production systems. Meat from A-NI was rated significantly higher (P < 0.01) for beef flavour and tenderness than that from BP and MO animals. Furthermore, MO showed the lowest juiciness (P < 0.001) which could be due to its higher thawing loss. Within the three breeds, thawing loss was negatively correlated with juiciness
and, likewise cooking loss with juiciness and tenderness (P < 0.05). The canonical discriminant analysis showed that the three breeds were significantly different (P < 0.05) from each other according to sensory attributes, which justifies their involvement in different protected geographical indications (PGI).
In this paper we propose a method to learn the reasons why groups of consumers prefer some beef products to others. We emphasise the role of groups since, from a practical point of view, they may represent market segments that demand different products. Our method starts representing people’s preferences in a metric space; there we are able to define a kernel based similarity function that allows a clustering algorithm to identify significant groups of consumers with homogeneous likes. Finally, in each cluster, we developed, with a support vector machine (SVM), a function that explains the preferences of those consumers grouped in the cluster. The method was applied to a real case of consumers of beef that tasted beef from seven Spanish breeds, slaughtered at two different weights and aged for three different ageing periods. Two different clusters of consumers were identified for acceptability and tenderness, but not for flavour. Those clusters ranked two very different breeds (Asturiana and Retinta) in opposite order. In acceptability, ageing period was appreciated in a
different way. However, in tenderness most consumers preferred long ageing periods and heavier to lighter animals.
Using machine learning procedures to ascertain the influence of beef carcass profiles on carcass conformation scores
In this study, a total of 163 young-bull carcasses belonging to seven Spanish native beef cattle breeds showing substantial carcass variation were photographed in order to obtain digital assessments of carcass dimensions and profiles. This dataset was then analysed using machine learning (ML) methodologies to ascertain the influence of carcass profiles on the grade obtained using the SEUROP system. To achieve this goal, carcasses were obtained using the same standard feeding regime and classified homogeneous conditions in order to avoid non-linear behaviour in grading performance. Carcass weight affects grading to a large extent and the classification error obtained when this attribute was included in the training sets was consistently lower than when it was not. However, carcass profile information was considered non-relevant by the ML algorithm in earlier stages of the analysis. Furthermore, when carcass weight was taken into account, the ML algorithm used only easy-to-measure attributes to clone the classifiers decisions. Here we confirm the possibility of designing a more objective and easy-to-interpret system to classify the most common types of carcass in the territory of the EU using only
a few single attributes that are easily obtained in an industrial environment.
A total of 159 bulls representing seven Spanish beef breeds were fed with concentrates, managed in the same conditions and slaughtered at two commercial weights (veal and young-bull). Carcasses were measured and classified in order to characterise the carcass variation in the Spanish beef market and to assess the relationship among carcass measurements and grading. Principal Component Analysis clearly separated commercial types regardless the inclusion of the carcass weight in the input data. Within commercial weights the studied breeds clustered into three groups according to muscular development and carcass classification score: high meat producer breeds (Asturiana de los Valles and Rubia Gallega); medium meat producers (Parda Alpina and Pirenaica); and low meat producers (Avilen˜a, Retinta and Morucha). The perimeter and width of the leg (muscular development) besides the length and width of the carcass basically defined these three carcass types. Conformation was an important trait in explaining variation between breeds because its values were positively correlated with muscular development and carcass compactness.
Effect of muscular hypertrophy on physico-chemical, biochemical and texture traits of meat from yearling bulls
The effect of the presence of the double-muscling gene either homozygous (mh/mh) or heterozygous (mh/+) on the physicochemical, biochemical and texture traits of Longissimus thoracis muscle of yearling bulls of the Asturiana de los Valles (AV) breed was studied. Meat of mh/mh bulls had lower amount of intramuscular fat (p < 0:001) and also lower total (p < 0:01) and insoluble collagen (p < 0:05), although the double-muscling genotype did not affect collagen solubility. Homozygous animals had lower pigment content (p < 0:05) and a lighter meat, showing lower water holding capacity, estimated as expressible juice under pressure (p < 0:001). Genotype affected significantly the metabolic traits of muscle, with mh/mh animals having higher muscle glycolytic metabolism, assessed by a higher (p < 0:001) lactate dehydrogenase (LDH) activity and lower (p < 0:001) oxidative activity of the isocitrate dehydrogenase (ICDH). The percentage of myosin heavy chain I in muscle was lower, although not significantly, for mh/ mh bulls compared to mh/+ bulls. Texture measurements performed on raw material showed that meat of mh/mh bulls had lower resistance to total and 80% compression, which means lower background or collagen toughness. However, there were no differences between genotypes on shear force of cooked meat. Therefore, the physico-chemical, biochemical and texture trait of meat from mh/
mh and mh/+ bull are in general significantly different, which could affect the sensorial quality of meat and hence the consumer acceptance.
The effects of slaughter weight, breed type and ageing time on beef meat quality using two different texture devices
Physical characteristics of meat texture were measured on the M. longissimus dorsi of 103 entire yearling bulls in terms of the effect of slaughter weight (300 or 550 kg), breed type (double muscle, fast growth, dual purpose and unimproved) and ageing time (1, 7 and 21 days). Live weight, breed and ageing effects were statistically significant for all the Warner–Bratzler variables measured on cooked meat. For compression values (raw meat), live weight had a significant effect at higher compression rates, which were higher in the heaviest animals, and ageing had a significant effect at lower compression rates, which were progressively lower as ageing time increased. Breed effect was significantly different for all compression values. At the highest rates of compression, unimproved and dual purpose breed types had the highest values. At 20% compression, double muscled animals had the lowest values, but only at one day of ageing. The differences between breed types tended to decrease or disappear with longer periods of ageing.
Characterisation of young bulls of the Bruna dels Pirineus cattle breed (selected from old Brown Swiss) in relation to carcass, meat quality and biochemical traits
Seventy-four young bulls of the Bruna dels Pirineus beef cattle breed were reared in a typical production system and slaughtered at an average age of 381 days and live weight of 541 kg. The animals were evaluated for productive traits, carcass quality, meat quality, eating quality and biochemical characteristics of m. longissimus thoracis (LT). Biochemical measurements included intramuscular fat (IMF) and collagen proportion, haem pigment concentration, lactate dehydrogenase and isocitrate dehydrogenase activities and type I (MHC I) fibre percentage determined by ELISA. Bruna dels Pirineus bulls achieved high growth rates during the fattening period (1.63 kg/day) and showed good carcass quality, with a high dressing-out proportion (607 g/kg, hot carcass), a good conformation score (U; EUROP) and a moderate fatness score (3;1–5). Carcass composition was estimated from the sixth rib joint dissection (682 g/kg lean proportion, 127 g/kg total dissectable fat and 163 g/kg bone). IMF (24.3 g/kg) and MHC I (27.9%) showed high variabilities (CV>30%). Sensory analysis of LT included beef and livery odour and flavour intensity, and overall tenderness and juiciness assessment of loin samples (14-day ageing). Beef odour and flavour were slightly positively correlated with IMF and carcass fatness score (P<0.05). Fatness, MHC I, insoluble collagen and cooking losses tended to affect the livery flavour intensity positively. This variable was significantly higher in meat from bulls of lower carcass quality (i.e. lower conformation score, lower lean proportion; P<0.05) and higher type I fibre percentage. Loin overall tenderness and juiciness were not affected by the biochemical traits studied, however, they were negatively affected by cooking loss (P<0.05).