Effects of the F94L myostatin gene mutation in beef × dairy crossed cattle on strip loin steak dimensionality, shear force, and sensory attributes.

Carcasses (n = 115) from steers resulting from the mating of four Limousin × Angus sires heterozygous for the F94L myostatin mutation to Jersey, Jersey × Holstein, and Holstein dams were utilized to evaluate the effects of one copy of the F94L allele on strip loin dimensionality, Warner-Bratzler shear force and slice shear force, and sensory panel ratings. In phase I of a two-phase study, 57 carcasses from two sires were utilized to obtain samples of longissimus dorsi (LD), psoas major (PM), gluteus medsius (GM), semitendinosus (ST), serratus ventralis, triceps brachii, and biceps femori muscles, which were vacuum packaged, aged until 10 d postmortem, and frozen. Frozen strip loins were cut into 14, 2.5-cm-thick steaks each, and individual strip loin steaks were imaged at a fixed height on a gridded background and processed through image analysis software. In phase II, to obtain a greater power of test for LD palatability attributes, 58 additional carcasses from three sires were utilized to obtain LD samples only for sensory panel and shear force analysis. Cooked steak sensory attributes evaluated by trained panelists were tenderness, juiciness, beef flavor, browned flavor, roasted flavor, umami flavor, metallic flavor, fat-like flavor, buttery flavor, sour flavor, oxidized flavor, and liver-like flavor. In strip loin steaks from carcasses with one F94L allele, LD muscle area was larger in steaks 4, 5, 7, 8, and 9, and steaks 1, 6, 7, and 9 were less angular than those from carcasses with no F94L allele (P < 0.05). Of the seven muscles observed, there were no shear force differences between F94L genotypes (P > 0.20). F94L genotype did not affect sensory panel ratings of LD and GM steaks (P > 0.07). Cooked ST steaks from carcasses with one F94L rated lower in fat-like flavor compared to those from carcasses with no F94L allele (P = 0.035). Cooked PM steaks from carcasses with one F94L allele rated lower in juiciness, fat-like flavor, buttery flavor, and umami flavor compared to those with no copies of the F94L (P < 0.04). In summary, one copy of the F94L allele utilized in beef × dairy cross steers improved strip loin steak dimensionality, did not affect cooked steak tenderness across seven muscles, and decreased fat-associated flavors in the PM and ST. The use of F94L homozygous terminal beef sires would be an easily implemented strategy for dairy producers to improve steak portion size and shape in carcasses from nonreplacement calves.

In beef × dairy steers, one copy of the F94L allele decreased steak angularity in the strip loin and fat-associated flavor attributes in tenderloin steaks, while tenderness was not impacted. Reduced strip loin steak angularity addresses inherent deficiencies in dairy and dairy-cross carcasses; thus, the F94L allele could improve the consumer and chef acceptability of beef × dairy strip loin steaks. Using a beef sire homozygous for F94L myostatin in a beef-on-dairy system would ensure that all resulting progenies have exactly one copy of the F94L allele, meaning that this genetic strategy could be rapidly implemented in the beef-on-dairy industry segment.

Effects of the F94L myostatin gene mutation in beef × dairy crossed cattle on muscle fiber type, live performance, carcass characteristics, and boxed beef and retail cut yields.

Producer live performance data and carcasses from steers (n = 116) resulting from the mating of four Limousin/Angus sires heterozygous for the F94L myostatin mutation to Jersey/Holstein dams were utilized to evaluate the effects of one copy of the F94L allele on live performance, carcass traits and USDA grades, and boxed beef and retail yields. Slaughter data were collected at time of harvest and carcass data were collected 48 hours postmortem. One side from each of the 58 carcasses was fabricated into boxed beef and retail cuts by experienced lab personnel 5-8 d postmortem. One copy of the F94L allele did not affect gestation length, birth weight, percentage of unassisted births, feedlot average daily gain, live weight at harvest, hot carcass weight, or dressing percentage (P > 0.05). Muscle fiber analysis indicated that the increase in muscularity by the F94L allele in the semitendinosus and longissimus was likely due to hyperplasia as there was a 19% increase in the quantity of myosin heavy chain type IIA and IIX fibers in the semitendinosus (P < 0.05) with no effect on muscle fiber size (P > 0.05). Carcasses from steers with one F94L allele had larger ribeye areas (99.2 vs. 92.3 sq.cm.), greater ribeye width:length ratios (0.498 vs. 0.479), lower USDA yield grades (2.21 vs. 2.66), and lower marbling scores (438 vs. 480) (P < 0.05). Additionally, for boxed beef yields, one F94L allele, vs. zero F94L alleles, increased (P < 0.05) 85/15 trimmings (+0.59%), top round (+0.28%), strip loin (+0.12%), eye round (+0.11%), tenderloin (+0.07%), boneless foreshank (+0.07%), cap/wedge (+0.06%), and tri-tip (+0.04%). Overall, carcasses from steers with one F94L allele had a greater boxed beef yield (+1.06%), boxed beef plus 85/15 trimmings yield (+1.65%), and total retail cuts plus ground beef 85/15 yield (+1.78%) than carcasses from steers with zero F94L alleles (P < 0.05). One copy of the F94L allele utilized in beef-on-dairy breeding system had no significant impact on live performance traits but resulted in lower marbling scores and increased muscularity as evidenced through larger, more beef-shaped ribeyes, lower USDA yield grades, and greater carcass cutout yields (both boxed beef and retail yields).

In a beef-on-dairy system, one copy of the F94L myostatin allele caused increased muscling, resulting in larger, more beef-shaped ribeyes, more desirable yield grades, and greater boxed beef and retail yields, all of which address inherent deficiencies in dairy and dairy-cross carcasses. These improvements were realized with no negative effects on calving ease or live performance. The F94L did cause a significant and meaningful reduction in marbling score; therefore, marbling ability should be paramount in sire selection if F94L sires are utilized. Using a beef sire homozygous for F94L myostatin in a beef-on-dairy system would ensure that all resulting progenies have exactly one copy of the F94L allele, meaning that this genetic tool could be rapidly implemented in the beef-on-dairy industry segment. When selecting sires for beef-on-dairy programs, accurate EPDs should remain the primary evaluation tool as the F94L effects are reflected in accurate EPDs; however, using a sire homozygous for F94L (2 or 0 copies) should result in more consistent progeny.

Evaluation of the prevalence and onset of lung lesions and their impact on growth of lambs.

OBJECTIVE: To determine the prevalence and temporal onset of lung lesions in lambs and the impact of lung lesions on growth of affected lambs. ANIMALS: 259 crossbred wether lambs from a single flock in the upper Midwestern United States. PROCEDURE: An observational study was conducted. Lambs born in the spring and fall were slaughtered at finished weight or at a predetermined time point. Lungs of each lamb were examined and classified as normal, moderate lesions (consolidation > 5% but < or = 50% of any lobe), or severe lesions (consolidation > 50% of any lobe). Data were examined to detect effects of prevalence or severity of lung lesions on growth and carcass traits. RESULTS: 57 of 89 (64%) spring-born lambs had lung lesions characterized by consolidation of lung tissue. A small number of lambs had pulmonary adhesions or active abscesses. In contrast, only 31 of 108 (29%) fall-born lambs had lung lesions. Severe lung lesions were associated with a significant reduction in average daily gain. Severe lung lesions were not detected until the middle of the finishing period and were associated with culture of Mannheimia haemolytica or Pasteurella multocida. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of results indicates that the prevalence of severe lung lesions can be quite high in lambs. Severe lung lesions can lead to greatly decreased growth performance of lambs.

Effects of dietary barley on growth performance, carcass traits and pork quality of finishing pigs / Efecto de la inclusión dietaria de cebada sobre el crecimiento, calidad de la canal y de la carne de cerdos en engorde / Efeito da inclusão de cevada no crescimento, qualidade da carcaça e da carne de suínos em engorda

Background: the relatively high concentration of polyunsaturated fatty acid in yellow corn may reduce the quality of pork fat, but feeding barley instead of yellow corn may increase pork quality. Objective: to determine the effects of feeding graded levels of barley on performance, carcass composition, and pork quality of finishing pigs. Methods: in experiment 1, diets containing 0, 20, 40, 60, or 80% barley were fed to pigs (initial BW: 67.9 kg) for 8 weeks. In experiment 2, a diet containing 60% barley was fed to pigs for 0, 2, 4, 6, or 8 weeks prior to slaughter. Results: feeding diets with increasing levels of barley resulted in a linear decrease in daily gain (p<0.01) and backfat thickness (p<0.01). Dressing percentage linearly decreased with length of barley feeding (p<0.05), but the concentration of saturated fatty acids in backfat increased (linear, p<0.05) the longer the barley diet was fed. Conclusion: there was no effect of barley on loin muscle quality and barley did not consistently change fat color or belly and bacon quality.

Antecedentes: la relativamente alta concentración de ácidos grasos poliinsaturados presente en el maíz amarillo puede reducir la calidad de la grasa del cerdo. Alimentar con cebada en lugar de maíz amarillo podría mejorar la calidad de dicha carne. Objetivo: determinar los efectos del suministro de niveles incrementales de cebada sobre el rendimiento, composición de la canal y calidad de la carne de cerdos en ceba. Métodos: en el experimento 1 se suministraron dietas que contenían 0, 20, 40, 60, o 80% de cebada a cerdos en ceba (PV inicial: 67,9 kg) durante 8 semanas. En el experimento 2 se suministró una dieta con 60% de cebada a cerdos durante 0, 2, 4, 6, u 8 semanas antes del sacrificio. Resultados: el introducir mayores niveles de cebada en la dieta resultó en una disminución lineal de la ganancia diaria (p<0,01) y del espesor de la grasa dorsal (p<0,01). El porcentaje de rendimiento disminuyó linealmente con la duración del suministro de cebada (p<0,05), pero la concentración de ácidos grasos saturados en la grasa dorsal aumentó (lineal, p<0,05) a medida que se incrementó la duración del suministro de cebada. Conclusión: no hubo efecto de la cebada en la calidad del músculo del lomo. La cebada no cambió el color de la grasa ni la calidad del vientre o del tocino.

Antecedentes: a concentração relativamente elevada de ácidos gordurosos poli-insaturados presentes no milho amarelo pode reduzir a qualidade da gordura suína. Fornecendo cevada ao invés de milho amarelo poderia melhorar a qualidade da carne. Objetivo: determinar os efeitos de níveis crescentes de cevada sobre o desempenho, composição e qualidade da carne a da carcaça de suínos de engorda. Métodos: no primeiro experimento os suínos foram alimentados durante o período de engorda com dietas contendo 0, 20, 40, 60, ou 80% de cevada (PV inicial de 67,9 kg) durante oito semanas. No segundo experimento se subministrou uma dieta com 60% de cevada aos suínos durante 0, 2, 4, 6 ou 8 semanas antes do abate. Resultados: a introdução de maiores níveis de cevada na dieta resultou em uma redução linear do ganho de peso diário (p<0,01) e da espessura de toucinho (p<0,01). A porcentagem de rendimento no período de engorda diminuiu linearmente com a duração de fornecimento de cevada (p<0,05), mas a concentração de ácidos gordurosos saturados do bacon aumentou enquanto se incrementou a duração de fornecimento de cevada (linear, p<0,05). Conclusão: não houve efeito de cevada na qualidade do olho de lombo. A cevada não mudou a cor da gordura nem a qualidade da barriga e do bacon.