The objective of this study was to verify the influence of the rearing system of the kid goats (different feeding systems of the mothers and milk replacer) on the quality of meat and the correlation between the retinol content of the fat and these quality parameters of meat. Fifty-five Payoya breed male kids were used, divided into four groups: one group fed milk replacer (LA) and three groups fed natural lactation with different feeding managements of the goats: mountain grazing (PM), cultivated pasture grazing (PC) and stabled goats with total mixed ration (RMT). The kids were slaughtered when they reached 8 kg of live weight, around one month old. Retinol concentration in intermuscular fat, pH, proximal composition (CP), color and texture (TPA) were measured in longissimus thoracis and lumborum. The PC kids provided meat with a lower pH, higher luminosity (L*), lower red index (a*) and higher yellow index (b*) and hue (h degrees) than the rest. PC and RMT animals reached slaughter weight earlier and their meat differed from that of PM and LA kids due to retinol content, proximal composition and texture. It was found that it is not the type of lactation (natural or milk replacer) that determines the differences between groups but rather the feeding management of the goats.

The Spanish Merino is the most important worldwide breed due to be the origin of all the Merino and Merino-derived breeds. Its genetic improvement began with the Roman people in the Iberian Peninsula with a clear selection objective: the fineness of the wool. However, in the last six decades, it has been common practice in Spain to cross animals from this breed with other breeds with greater meat aptitude in a clear change of the selection criteria resulting in the existence of a large ovine population (Merine-type) which remains out of the official flock -book. Nevertheless, there are still herds considered as historical strains that maintain the ancestral genetics and are therefore registered as pure. In the present work, 13,484 animals belonging to the Donoso, Granda and Hidalgo historical genetic lines, together with animals registered as pure in the flock -book and animals from the Merino Negro lineage were genotyped with 19 microsatellite markers for their genetic characterization. The Correspondence Factor Analysis (CFA) and the analysis of inferring the population structure showed a clear genetic differentiation between each of the strains that, except for the Granda line, most of the animals were correctly classified to their group. On the other hand, the variability values showed that the populations do not present risk of genetic drift despite many centuries of closed -matted flocks. The results obtained showed that the historical Merino strains, due to their purity and genetic "healthy", are the optimal basis for the "remerinization" of the national sheep population, which for decades has been losing the identity that made the Spanish Merino the most valuable livestock breed in the world.

ResumenEl Merino español es la raza más importante a nivel mundial por ser el origen de todas las razas de merino o derivadas del merino.Se seleccionó en la península ibérica desde la época romana con el objetivo de mejorar la finura de la lana.Sin embargo,

In Spain, lamb consumption has decreased over the last few years. To increase farmers’ income, we studied the nutritional quality of the barren ewes’ meat in comparison to traditional lambs’ meat with 10 barren ewes, 10 male lambs, and 10 female lambs from the Merino breed. We measured the subcutaneous fat, muscle color, and carcass tissue composition, as well as proximal composition, mineral, tocopherol, retinol, lutein, and cholesterol contents, and the TPA texture profile, fatty acid profile, and lipid oxidation of the meat. There was no effect of the animal type (males, females, and ewes) on the pH, and the differences in the subcutaneous fat color, lipid oxidation, and texture were irrelevant from a practical point of view. The tissue composition in the three groups of animals reflected a high percentage of saleable meat, with no penalty incurred for intensive fattening in any of the groups. The ewes’ meat presented a higher percentage of moisture, collagen, ash, calcium, iron, α-tocopherol, and retinol than the lambs’ meat. In addition, it had higher content of DHA and CLA and lower values for the ratio n6/n3, which is beneficial for health, although it also contained more fat, saturated fatty acids, and cholesterol than the lambs’ meat.

The Merino breed, which originates from Spain, is the most emblematic livestock breed in the world, since it is the first with a worldwide extension and has had an important impact on the genetic origin of several of the main current sheep populations. For this reason, it is of vital importance to typify the historical genetic lines of the original Spanish Merino breed and thereby ensure the conservation of its variability. In the present study, we used 337 purebred animals (males and females) registered in the Genealogical Book of the Native Merino Breed. All the animals were descendants of herds from six ancestral genetic lines (Maesso, Egea, Granda, López-Montenegro, Hidalgo, and Donoso). Significant differences were found in all the morphometric traits and indexes between the different genetic lines. Using discriminant analysis, 84% of the animals were classified correctly into their historical genetic lines. Furthermore, the distances between the lines, calculated by a cluster test, showed that Hidalgo, Maesso, and Donoso had the most clearly defined lines, while the Granda, López-Montenegro, and Egea lines were more similar to each other. All this demonstrates the rich genetic variability existing in the genuine gene pool of the Merino sheep breed.

The goat meat preferred by consumers in Spain comes from suckling goat kids, slaughtered at a live weight of 8-10 kg. However, consumption of this meat is very uncommon, so it is necessary to show its value. To achieve this, we planned to investigate consumers' perceptions about goat kid meat and to study whether their perceptions are related to their sensory appraisal of the meat, measured by the mean of the consumers' home tests. The experiment was conducted with 30 volunteer families (from two cities with different consumption patterns), who were surveyed regarding their sociodemographic parameters, purchasing and eating habits, and the importance of the meat's attributes. As a result, four clusters were obtained, which were labeled "negative," "idealistic," "positive," and "concerned about fat content". The parameters of the animal production system were valued differently by the clusters. Meat tenderness, taste, and amount of fat were considered very decisive factors by most respondents. When the goat kid meat was valued, tenderness was considered more important than taste among older people ("negative" cluster), whereas there was not so much difference between the appraisal of all parameters for the other three clusters. We conclude that it is necessary to improve the information received by consumers about goat production systems and meat quality parameters. There is certainly potential for creating new markets, especially targeted toward young consumers and considering specific strategies for the different groups of consumers, depending on the region and habits of consumption.

According to historiographical documentation, the Romans first began to select Merino sheep in the Iberian Peninsula during the first century, with the aim of obtaining a breed appreciated for the quality of its wool. This process continued locally during the Middle Ages, when Spanish sheep were protected, and their export to foreign countries was banned. It was during the 16th century when individual Merino sheep were allowed to spread around the world to be used to improve the wool quality of local breeds. However, the wool crisis of the 1960s shifted the selection criteria of the Merino breed towards meat production at the expenses of wool. Consequently, individuals that display the genetic and phenotypic characteristics of those sheep originally bred in the kingdom of Spain in the Middle Ages are extremely difficult to find in commercial herds. In this study, we characterized the genetic basis of 403 individuals from the main historical Spanish Merino genetic lines (Granda, Hidalgo, Lopez-Montenegro, Maeso, Donoso and Egea), which were bred in isolation over the last 200 years, using a genomic approach based on genotyping data from the Axiom™ Ovine 50K SNP Genotyping Array. Our analysis included measuring population structure, genomic differentiation indexes, runs of homozygosity (ROH) patterns, and an analysis of molecular variance (AMOVA). The results showed large genetic differences between the historical lines, even though they belong to the same breed. In addition, ROH analysis showed differences due to increased inbreeding among the ancient generations compared with the modern Merino lines, confirming the breed’s ancestral and closed origin. However, our results also showed a high variability and richness within the Spanish historical Merino lines from a genetic viewpoint. This fact, together with their great ability to produce high-quality wool, suggests that ancestral Merino lines from Spain should be considered a valuable genetic population to be maintained as a resource for the improvement of wool-producing sheep breeds all around the world.

SIMPLE SUMMARYMuscle fibres have an important impact on meat quality. There are different types of skeletal muscle fibres, mainly oxidative and glycolytic. The present study showed that dairy breeds and goat kids raised with milk replacer had less oxidative fibres than meat breeds and goat kids raised with their dams. In addition, the muscle fibres measured in this study were smaller in dairy breeds and kids raised with milk replacer than in meat breeds and goat kids raised with the dams.

The effects of Payoya kid feeding systems on the fat-soluble vitamin (retinol/α-tocopherol) contents, fat content, fat color, and the oxidation index were evaluated to determine their potential for use as feeding system traceability tools. Four groups of Payoya kids (55 animals in total) fed milk exclusively were studied: a group fed a milk replacer (MR) and three groups fed natural milk from dams reared with different management systems (mountain grazing (MG), cultivated meadow (CM) and total mixed ration (TMR)). Kids were slaughtered around one month of age and 8 kg of live weight. Kids from the MG and CM groups presented lower retinol (5.56 and 3.72 µg/mL) and higher α-tocopherol plasma (11.43 and 8.85 µg/mL) concentrations than those from the TMR and MR groups (14.98 and 22.47 µg/mL of retinol; 2.49 and 0.52 µg/mL of α-tocopherol, respectively) (p < 0.001). With respect to fat, kids with a higher intramuscular fat percentage (CM and TMR groups) had lower retinol contents (16.52 and 15.99 µg/mL, respectively) than kids from the MG and MR groups (26.81 and 22.63 µg/mL, respectively) (p < 0.001). A dilution effect of vitamins on fat was shown: the higher the amount of fat, the lower the vitamin concentrations, the higher the lipid oxidation index (MDA), and the lower the SUM (absolute value of the integral of the translated spectra between 450 and 510 nm). A discriminant analysis that included all studied variables showed that 94.4% of the kids were classified correctly according to their feeding system and could allow traceability to the consumer.

The retinol and α-tocopherol concentrations were quantified (μg/mL) using high-performance liquid chromatography (HPLC) in both plasma and milk of goats from three management systems. The aim was to investigate if the compounds pass from feed to animals’ fluids and to evaluate their potential use as feeding regime biomarkers. A total of 45 Payoya dams were distributed in three groups according to management system during the first month of lactation: mountain grazing (MG), cultivated meadow (CM) and total mixed ration (TMR). TMR group had higher concentrations of retinol in both plasma (25.92 ± 3.61 at 30 days postpartum) and milk (8.26 ± 0.79 at 10 days postpartum), and they were also the unique animals whose milk contained detectable concentrations of α-tocopherol (3.15 ± 0.19 at parturition). However, MG and CM goats showed higher plasma concentrations of α-tocopherol (64.26 ± 14.56 and 44.65 ± 5.75 at 30 days postpartum, respectively). These results could imply differences in the bioavailability of supplemented vitamin A and natural β-carotene and between the natural/synthetic forms of α-tocopherol. An inverse relationship between the fluids (plasma/milk) in the contents of α-tocopherol and retinol was observed as lactation progressed. Since 80% of the animals were correctly classified using a discriminant analysis based on these vitamins, these compounds could be used as traceability biomarkers of feeding system, but further studies are necessary to know the possible passage to kid meat.

Goat production is quite important in Spain having high census and economic impact. This review has been performed systematically with studies about suckling kids with slaughter weight lower than 13 kg and fed exclusively milk. The carcass weight of kids were distributed into two groups, above and below of 5 kg. Kid meat appears as a useful protein source with low fat content. It was found any linear relationship between rearing system or carcass weight with pH. Meat of kids fed maternal milk had greater yellowness index than those fed milk replacers. Toughness was not affected by carcass weight or rearing system and the average value was 35 N. In general, meat of carcasses heavier than 5 kg had less saturated and more unsaturated fatty acids, as well a higher n-6/n-3 ratio than meat of carcasses with less than 5 kg. There is few scientific information on the instrumental quality of suckling kid meat. Therefore, there is a wide field of research to cover the absence of knowledge in this topic.

Since goat milk has a higher value than kid meat in Europe, some farmers rear kids with milk replacers, although some studies have stated that kids raised on natural milk yield higher-quality carcasses. Our previous studies showed some interactions between breed and rearing system on carcass and meat quality. This study evaluated the influence of the use of milk replacers on several carcass characteristics of suckling kids from eight Spanish goat breeds (Florida, Cabra del Guadarrama, Majorera, Palmera, Payoya, Retinta, Tinerfeña, and Verata). A total of 246 kids fed milk replacer (MR) or natural milk (NM) were evaluated. Carcass, head, viscera, and kidney fat weights, as well as several carcass measurements (round perimeter, forelimb width, carcass length, forelimb length, and carcass compactness index), were registered. Forelimbs were dissected to study tissue composition. For all studied variables, interactions were found between rearing system and breed. In general, the MR rearing system increased the head and visceral weights, as well as the length measurements and muscle percentages. Conversely, the NM rearing system increased carcass compactness and resulted in higher fat contents, independent of the deposit. The choice of one or another rearing system should be made according to the needs of the target market.

In this work we follow a multiscale methodology to characterize the structural performance of post-tensioned steel fiber-reinforced concrete dry joints. At the material level, we use an experimentally validated lattice-particle model whose input parameters are the properties of the different phases themselves (i.e., mortar, aggregates, fibers) and mixing information. This model is used to obtain the mechanical properties used in the structural-level simulations of the joints in terms of constitutive laws. The structural analyses are performed using the concrete damage plasticity model, which allows us to quantify the effect of fiber addition on the shear strength of the dry joints and their ductility. Our simulations agree well with other macroscopic models in the case of plain concrete and show, once again, that the American Association of State Highway Transportation Officials (AASHTO) code overestimates the nominal shear capacity of multiple-keyed joints. Regarding the fiber addition, we observe that it promotes an important increase in the shear capacity, but the prestress level is still more relevant in this sense. Based on our simulations, we propose an updated shear capacity estimate accounting for the fiber volume fraction. Finally, a clear increase in the ductility of the joint is observed when the fiber volume content is increased.

The combined effect of farm management practices, transport time, and ageing time on the electrophoretic changes of sarcoplasmic (SPP) and myofibrillar (MFP) protein fractions of goat kids was studied. A total of 64 suckling goat kids were withdrawn from two farms with “high” (GW) and “low” (DW) welfare-friendly management practices, and they were transported for 2 or 6 h immediately before slaughtering. Longissimus lumborum samples were obtained at 3, 8, and 21 days post-mortem, and muscle proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis SDS-PAGE. Both protein extracts displayed significant changes attributable to meat maturation. Managing conditions of kids in DW farms increased the post-mortem susceptibility of muscle proteins. Some MFP of Longissimus lumborum muscle, such as troponin T, as well as 26–30 and 35–37 kDa fractions were influenced significantly by deficient on-farm management, and therefore, these protein fragments might be considered as indicators of low-welfare on-farm management in goat kids.

Este artículo es un resumen de la tesis doctoral ‘Valoración sensorial e instrumental de la carne de cabrito lechal’ defendida en la Universidad de Sevilla por Guillermo Ripoll. En esta tesis se ha estudiado la calidad instrumental y sensorial de la carne de cabrito lechal de ocho razas españolas (Cabra del Guadarrama, Florida, Palmera, Payoya, Majorera, Tinerfeña, Retinta y Verata) alimentados con lactoreemplazantes o con leche materna. Se realizó una cata de la carne y valoración visual de consumidores. La carne de cabrito alimentado con leche materna fue más apreciada en la cata por parte de los consumidores mayores de 55 años, los que consumen carne entre 3 y 6 veces a la semana y los que no habían probado anteriormente la carne de cabrito. Sin embargo, visualmente fue mejor valorada la carne de cabrito de lactancia artificial, teniendo además una mayor vida útil.