J. Piedrafita

Carcass quality of 10 beef cattle breeds of the Southwest of Europe in their typical production systems

A sample of about 70 young bulls of each of 10 beef cattle breeds from France and Spain, reared in their typical production systems, was studied regarding growth and carcass quality traits. There were large differences between and within breed-systems. The animals slaughtered in Spain weighed between 444 and 551 kg, whereas the range in France was from 610 to 750 kg. Growth showed a linear tendency; the daily weight gain ranging from 1.03 to 1.65 kg/day. Asturiana de los Valles and Pirenaica were, among the Spanish populations, the breed-systems with more muscle (around 75%) and less fat (8-10%) in the carcass, whereas Avilena-Negra Iberica, Morucha and Retinta showed opposite characteristics (60-65% muscle and 17-19% total fat at the 6th rib). Bruna dels Pirineus and Asturiana de la Montana occupied an intermediate position. All of the French breed-systems, Aubrac, Gasconne and Salers surpassed 73% muscle, while the percentage of total fat ranged from 7.6 to 10%. Salers breed-system also showed the longest and thinnest hind-limb. In the wide range of carcass weights studied in this paper, the general relationships among carcass traits were confirmed. Animals with the better conformation were also leaner. Longer carcasses tended to be associated with poor conformation and fatness. Bone content was clearly opposed to carcass conformation and muscle content.

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), Avileña-Negra Ibérica (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).

The effect of breed-production systems on the myosin heavy chain 1, the biochemical characteristics and the colour variables of Longissimus thoracis from seven Spanish beef cattle breeds

The effect of breed-production system on the myosin heavy chain 1 (MHC-I), the biochemical characteristics and the colour variables of longissimus thoracis (LT) from seven beef breeds was studied: Asturiana de la Montaña (AM), Asturiana de los Valles (AV), Avileña-Negra Ibérica (A-NI), Bruna dels Pirineus (BP), Morucha (MO), Pirenaica (PI) and Retinta (RE) (Age at slaughter between 368 and 541 days; carcass weight between 249 and 334 kg). Significant differences between breed-production systems were found for all traits evaluated. LT from the MO, a rustic type breed, was the most oxidative (MHC-I, 39.3%; isocitrate dehydrogenase activity, 52 nmol min(-1) mg(-1); pigment content, 188.4 μg acid haematin g(-1)) and showed a low L* value (32.6) and high a* and C* values (24 and 27.2, respectively). In terms of meat colour (L* and a*) the canonical discriminant analysis separated the breeds into two groups, the AV, the PI and the A-NI (the lightest ones) from the AM and the MO breeds (the reddest and darkest) whereas the BP showed an intermediate position. The RE and the A-NI were distinguished from the others by their high intramuscular fat content. Meat colour was affected by the muscle biochemical traits in the breed-production systems studied.

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).

Analysis of founder-specific inbreeding depression on birth weight in Ripollesa lambs.

Although inbreeding (F) is a topic of major concern in animal breeding, estimates of inbreeding depression are usually obtained by modeling the overall F coefficient of each individual, without considering that the recessive (deleterious) genetic load of a given population may be unevenly distributed among the founder genomes. The founder-specific partial F coefficient is calculated as the identity-by-descent probability at any given autosomal locus related to a particular founder and allows a more detailed analysis of inbreeding depression on productive traits. Within this context, birth BW data from 2,459 Ripollesa lambs were analyzed under a hierarchical animal model without F-related covariates (model 0), with inbreeding depression modeled by the overall F coefficient (model F1), or by the partial F coefficient of 9 founders that made a relevant contribution to the population inbreeding (model F2). A straightforward empirical Bayes factor (BF) was developed for testing statistical relevance of each F-related covariate, in which greater-than-1 values favored the model including the covariate. The deviance information criterion (DIC) clearly supported model F1 (5,767.8) rather than model 0 (5,771.2), suggesting that inbreeding depression had a relevant influence on birth BW data. The linear effect of inbreeding depression was statistically relevant in model F1 (BF = 2.52 x 10(35)), with lamb birth BW declining by -13.6 g with each 1% F increase. The quadratic effect of inbreeding depression was almost null in model F1 (BF = 0.02), as suggested by the reduction in DIC (5,766.9) when this effect was removed from model F1. On the other hand, model F2 provided a similar DIC (5,767.9) value, with this parameter decreasing to 5,764.7 when nonrelevant founder-specific inbreeding depression effects were removed. Substantial heterogeneity in founder-specific inbreeding depression was reported by model F2, in which estimates for 4 of the 9 founders did not differ from zero (BF between 0.05 and 0.42), whereas 5 founders originated moderate (-8.2 g for each 1% F increase; BF = 1.42) to large inbreeding depression (-96.2 g for each 1% F increase; BF = 8.80 x 10(19)). The substantial variability between founder estimates suggested that inbreeding depression effects may mainly be due to a few alleles with major deleterious effects. These results contribute valuable information that should help to achieve more accurate management of inbreeding in the Ripollesa breed.

Validation of an approximate approach to compute genetic correlations between longevity and linear traits

The estimation of genetic correlations between a nonlinear trait such as longevity and linear traits is computationally difficult on large datasets. A two-step approach was proposed and was checked via simulation. First, univariate analyses were performed to get genetic variance estimates and to compute pseudo-records and their associated weights. These pseudo-records were virtual performances free of all environmental effects that can be used in a BLUP animal model, leading to the same breeding values as in the (possibly nonlinear) initial analyses. By combining these pseudo-records in a multiple trait model and fixing the genetic and residual variances to their values computed during the first step, we obtained correlation estimates by AI-REML and approximate MT-BLUP predicted breeding values that blend direct and indirect information on longevity. Mean genetic correlations and reliabilities obtained on simulated data confirmed the suitability of this approach in a wide range of situations. When nonzero residual correlations exist between traits, a sire model gave nearly unbiased estimates of genetic correlations, while the animal model estimates were biased upwards. Finally, when an incorrect genetic trend was simulated to lead to biased pseudo-records, a joint analysis including a time effect could adequately correct for this bias.

The rate of L-lactate production: a feasible parameter for the fresh diluted boar semen quality analysis

Abstract The rate of L-lactate production was defined as the ability of a boar semen sample to produce L-lactate in a medium containing known levels of fructose. When this parameter was studied jointly with others used in boar semen analysis, good correlations between L-lactate production and the percentages of viability, altered acrosomes, total motility and osmotic resistance test were observed. The rate of L-lactate production was the strongest parameter when a principal component analysis was performed in a semen analysis which also included the percentages of viability, altered acrosomes, morphological abnormalities, total and progressive motilities and osmotic resistance test. Additionally, L-lactate production showed a poor repeatability coefficient, similarly to other parameters. These results indicated that some poorly defined external factors seriously affect the ability of these parameters to predict the future semen quality for a boar when an analysis from a single sample had been performed. A relatively high correlation was observed between the rate of L-lactate production and the quotient between the number of farrowings and the number of inseminations when the analyzed semen samples were used in artificial insemination, although the data in vivo were too scarce to show stronger evidence. These results indicated that the rate of L-lactate production was a feasible and potent parameter to evaluate the fresh boar semen quality.

Resistance to hyperosmotic stress in boar spermatozoa: the role of the ionic pumps and the relationship with cryosurvival

The resistance to changes in the osmolarity of boar sperm was used to measure the resistance of boar sperm cells against freezing/thawing. Semen was incubated for 5 min in different solutions ranging from about 600 mOsm to about mOsm, and at 4 degrees C, 16 degrees C or 37 degrees C (undisturbed media). This undisturbed media was constituted by NaCl, glycerol or glucose. This semen was then placed in an isoosmotic solution (disrupted solutions). Incubation in undisturbed media did not alter the percentages of viability or altered acrosomes, except when the initial incubation has been at 37 degrees C and with osmolarities above 1000 mOsm. Viability and altered acrosome statistics were strongly modified in disrupted media. These effects are dependent upon the initial osmolarity of the media, but not upon the temperature. Pre-incubation with ouabain or amiloride did not affect spermatozoa incubated at 16 degrees C in a 2211 mOsm, NaCl medium. However, in sperm incubated in this 2211 mOsm medium and then rapidly placed in an isoosmotic solution, ouabain induced a decrease in viability and an increase in altered acrosomes. Amiloride did not affect the response of cells to the disrupted medium. Some significant correlations were observed among the percentages of altered acrosomes after hyperosmotic stress and some quality parameters of the fresh boar semen, especially the motion parameters. Although the resistance to hyperosmotic stress could be a valuable parameter in assessing fresh quality analysis, its usefulness in frozen-thawed semen is compromised, since other factors beside osmotic changes are involved in the resistance of boar semen to freezing-thawing. The NA+/K+, ouabain-dependent ATP-ase activity seems to be related to the mechanisms of resistance to hyperosmotic stress in boar sperm.

Proteomic analysis reveals oxidative stress response as the main adaptative physiological mechanism in cows under different production systems.

Three groups of cows representing three ranges of welfare in the production system were included in the study: two groups of Bruna dels Pirineus beef cattle maintained under different management systems (good and semiferal conditions) and a group of Alberes cows, a breed that lives in the mountains (hardest conditions). In order to identify new stress/welfare biomarkers, serum from Bruna cows living in both environments was subjected to DIGE labelling, two-dimensional electrophoresis and MALDI-MS or ion trap MS. Identification was achieved for 15 proteins, which mainly belonged to three biological functions, the oxidative stress pathway (glutathione peroxidase (GPx) and paraoxonase (PON-1)), the acute phase protein family (Heremans Schmid glycoprotein alpha2 (α2-HSG)) and the complement system. Biological validation included the Alberes breed. GPx and PON-1 were validated by an enzymatic assay and found to be higher and lower, respectively, in cows living in hard conditions. α2-HSG was validated by ELISA and found to be reduced in hard conditions. Other biomarkers of the redox status were also altered by living conditions: protein carbonyl content, superoxide dismutase (SOD) and glutathione reductase (GR). Our results show that changes in the redox system are the main adaptation of cows living in challenging environmental conditions.

Effect of column filtration upon the quality parameters of fresh dog semen.

We filtered dog semen through various resin columns to obtain a quick, simple system for improving semen quality. Fresh ejaculates were filtered through columns with either glasswool or a chemically-inert polypropylene network disc. The columns were filled with Sephadex G-15 (nonionic resin), Sephadex A-50 (anionic-exchange resin), Sephadex C-50 (cationic-exchange resin) or a combination of Sephadex A-50 and C-50. Filtration through glasswool improved semen quality, with a significant (P < 0.001) increase in the percentage of viability and decrease in the percentage of altered acrosomes (P < 0.001) and total abnormalities (P < 0.001). Total motility was not modified, but curvilinear velocity or linearity of the movement were improved using the glasswool bed. The effect of the glasswool was so intense that it masked the effects of the filtration resins. Substitution of glasswool by polypropylene discs resulted in an unmasking of the effects of the resins, although the polypropylene exerted slight effects on semen. Elution of the spermatozoa through Sephadex G-15 or Sephadex C-50 resulted in a decrease of altered acrosomes. However, filtration through Sephadex A-50 increased viability and decreased the percentage of altered acrosomes and total abnormalities. Combined filtration through Sephadex A-50 and C-50 yielded the combined results observed with the resins individually. Ultrastructural imaging of the interaction between spermatozoa and the beds and resins showed that the cells were loosely deposited upon the glasswool fibers and the Sephadex G-15 particles, whereas close interaction was observed between spermatozoa and Sephadex A-50 and C-50 particles. The whole of the sperm cell bound to C-50 particles, whereas spermatozoa were specifically bonded to A-50 particles in the apical region of the head and in segments of the tail, which were periodically distributed. The data suggest that filtration through glasswool or an anionic resin-exchange can significantly improve dog semen quality.