Two experiments were conducted to study the antibody response of pigs challenged with the general antigen sheep red blood cells (SRBC). In one experiment SRBC's were injected at one of four sties: intramuscularly into the neck, intramuscularly into the ham, subcutaneously into the fore flank or rear flank. These treatments were repeated four weeks later. The antibody responses to the four treatments were determined by microtiter and analyzed statistically. No significant (P> 0. 10) differences were found among responses to the four treatments during the fourth and eighth weeks after injections, but a significant (P<0.05) difference was found during the fifth week among all four groups. Coefficients of correlation showed highly significant (P<.0.01) relationships between SRBC antibody titer during the fourth week after injections and increase in weight of test animals from the beginning of the study until slaughter. In a second experiment pigs were given intramuscularly either 2 milliliters of a 5% or 4 milliliters of a 10% SRBC suspension to determine the optimum dosage level. The difference between the antibody responses to these two treatments was not significant (P)0.10). Results of this study indicate that when challenging hogs with SRBC, any of the commonly used sites for injection is acceptable. The injection of 2 milliliters of a 5% SRBC suspension is sufficient to obtain antibody titers which differentiate among individuals. Coefficients of correlation indicate a relationship may exist between SRBC antibody titer and some economically important traits.

An investigation into the genetic differences in the humoral immune response of swine following vaccination with a sheep red blood cell solution (SRBC) and a commercially prepared Pasteurella multocida (serotype A) bacterin (PmA) was conducted on a total of 268 pigs from two individual trials. This study was also conducted to evaluate the humoral immune response of pigs to a non-pathogen (SPEC) and a known pathogen to swine (PmA). The pigs used in the first trial were from 22 litters born between January 1991 and July 1991. The pigs consisted of Hampshire x Yorkshire (n=114), purebred Yorkshire (n=70) and Hampshire (n=17). Individual pigs were vaccinated at five and eight weeks of age with 2 ml of a 5% SRBC solution and 1 ml of a killed PmA bacterin. AL 11 weeks of age 8 uE of blood was collected frun each animal and serum prepared to determine antibody titer levels against the two antigens by agglutination methods. Pigs utilized in the second study consisted of purebred Duroc (n=11), Haupshire (n= 10), Landrace (n=12) and Yorkshire (n=11) and crossbred Hampshire X Durcc (n= 12) and Yorkshire X Landxace (n=12). Results of trial 1 indicate that breed of pig affected the immune response against both PmA (P<.01) and SRBC (P<.01), with the Hampshire x Yorkshire crossbred pigs having higher titer levels against the PmA than either Hampshire or Yorkshire purebred pigs. The purebred Hampshire were not statistically different from either the purebred Yorkshire or the Hampshire x Yorkshire crossbred pigs in their antibody response to SRBC; however, the Hampshire x Yorkshire crossbred pigs were statistically higher than the Yorkshire pigs. Results from trial 2 indicate highly significant (P<.01) breed differences in the humoral immune response to PmA. Purebred Landrace pigs were superior to both Duroc and Hampshire purebred pigs in their immune response to PmA. Purebred Yorkshire and crossbred Yorkshire X Landrace pigs were superior to purebred Durtcs in their immune response to PmA. NO other significant differences among breeds of pigs occurred in trial 2. A low positive correlation of .22 was found between the pigs' antibody responses to PmA and SRBC in trial 1. Correlation differences among breeds were found between average daily gain while an test and the humoral immune response to both PmA and SRBC. Results suggest that further studies into breed differences of the immune response in swine are warranted. Results also suggest that further studies are needed to evaluate sheep /Ed blood cells as a suitable antigen When conducting research to analyze the humoral immune response in swine.

The antioxidant activity of carnosine and phytic acid was investigated using several model systems. Carnosine and phytic acid alone inhibited metal ion-catalyzed deoxyribose degradation. Carnosine strongly inhibited metal ion-catalyzed lipid peroxidation in liposomes and in ground beef homogenates. Phytic acid facilitated oxidation of Fe (II) to Fe (III), and it inhibited hemeprotein + H202-catalyzed lipid peroxidation in linoleic acid micelles. Antioxidant and color stabilizing effects of carnosine and phytate were investigated in a beef model system. Both compounds increased the rate of pH decline in pre-rigor beef muscle and stabilized fresh meat color by inhibiting metmyoglobin formation and lipid peroxidation in raw samples during storage at 4°C. Both compounds inhibited heme degradation and lipid peroxidation in cooked beef during storage at 4°C. Iron released from heme was strongly related to lipid peroxidation in cooked beef. Ascorbic acid inhibited metmyoglobin formation on the surface of ground beef patties but not in the bulk of the product. In contrast, camosine inhibited metmyoglobin formation and brown color development throughout the product. Carnosine increased cook yield and salt-soluble protein, but ascorbic acid had no effect on cook yield and decreased salt-soluble protein. Carnosine was more effective on inhibition of lipid peroxidation than was ascorbic acid. Phytate greatly enhanced water-holding capacity of raw and cooked meat in a dilute beef model system. Effects of 0.5% sodium phytate, sodium pyrophosphate, and sodium tripolyphosphate, along with 1% NaCl, on physicochemical properties of restructured raw and cooked beef were compared. In raw beef, the treatments with sodium phytate, sodium pyrophosphate, and sodium tripolyphosphate increased meat pH and salt-soluble protein level, and inhibited metmyoglobin formation and lipid peroxidation, compared to the control. In cooked beef, the treatments with sodium phytate, sodium pyrophosphate, and sodium tripolyphosphate increased bind strength, cooked yield, moisture level, and meat pH, and inhibited lipid peroxidation. The treatments with sodium pyrophosphate and sodium tripolyphosphate increased inorganic orthophosphate level in both raw and cooked beef, compared to sodium phytate and the control. These results indicate that carnosine and phytate can be used as meat preservatives for extending shelf-life and enhancing water-holding capacity of meat and meat products.

In the poultry industry, further processed meat products have the highest share in the market, and because there is a growing demand of food products with enriched amounts of unsaturated fatty acids, the objectives of this research were to assess lipid oxidation development and quality characteristics of chicken meat as affected by dietary fat and vitamin E levels. Broilers were fed during six weeks with diets containing animal/vegetable, lard, palm kernel, soybean, conjugated linoleic acid, flaxseed, or menhaden oil. Each lipid diet was supplemented with either a control (33 or 42 mg/kg) or a supranutritional level (200-400 or 200 mg/kg) of vitamin E. Breast and thigh meat, or skin, were processed, packaged, and refrigerated as raw meat, cooked patties, or cooked sous vide meat. The results showed that the chicken meat fatty acid composition reflected those from the dietary fats. In the meat or skin there was a higher lipid oxidation susceptibility as the proportion of unsaturated fatty acids increased, shown as malonaldehyde values, particularly in the treatments with low supplemented level of vitamin E (P<0.05). The relative lipid oxidative stability of the meat decreased in consecutive order from raw, cooked sous vide, and cooked meat patties. Sous vide cooked meat developed lipid oxidation at a slow rate and showed not to be affected by nonheme iron values. Dietary fat and vitamin E level affected breast meat lightness (L* color space) values (P<0.05), but not muscle pH, Allo-Kramer shear force, or water holding capacity. In conclusion, the increment in the proportion of unsaturated fatty acids increases the susceptibility to lipid oxidation in the meat. Supranutritional supplementation levels of vitamin E are more effective at inhibiting the lipid oxidation development in chicken meat than some current levels used by the poultry industry. Neither dietary fat nor vitamin E level seems to affect the development of pale, soft, and exudative meat condition in chicken meat.

Background: Recently, some US cohorts have shown a moderate association between red and processed meat consumption and mortality supporting the results of previous studies among vegetarians. The aim of this study was to examine the association of red meat, processed meat, and poultry consumption with the risk of early death in the European Prospective Investigation into Cancer and Nutrition (EPIC). Methods: Included in the analysis were 448,568 men and women without prevalent cancer, stroke, or myocardial infarction, and with complete information on diet, smoking, physical activity and body mass index, who were between 35 and 69 years old at baseline. Cox proportional hazards regression was used to examine the association of meat consumption with all-cause and cause-specific mortality. Results: As of June 2009, 26,344 deaths were observed. After multivariate adjustment, a high consumption of red meat was related to higher all-cause mortality (hazard ratio (HR) = 1.14, 95% confidence interval (CI) 1.01 to 1.28, 160+ versus 10 to 19.9 g/day), and the association was stronger for processed meat (HR = 1.44, 95% CI 1.24 to 1.66, 160+ versus 10 to 19.9 g/day). After correction for measurement error, higher all-cause mortality remained significant only for processed meat (HR = 1.18, 95% CI 1.11 to 1.25, per 50 g/d). We estimated that 3.3% (95% CI 1.5% to 5.0%) of deaths could be prevented if all participants had a processed meat consumption of less than 20 g/day. Significant associations with processed meat intake were observed for cardiovascular diseases, cancer, and 'other causes of death'. The consumption of poultry was not related to all-cause mortality. Conclusions: The results of our analysis support a moderate positive association between processed meat consumption and mortality, in particular due to cardiovascular diseases, but also to cancer.

The National Beef Quality Audit – 2011 assessed the current status of quality and consistency of fed steers and heifers. Beef carcasses (n = 9,802), representing approximately 10 percent of each production lot in 28 beef processing facilities, were selected randomly for the survey. Carcass evaluation for the cooler assessment of this study revealed these traits and frequencies: steer (63.5%), heifer (36.4%), cow (0.1%), and bullock (0.03%) sex classes; dark-cutters (3.2%); blood splash (0.3%); yellow fat (0.1%); calloused ribeye (0.05%); A (92.8%), B (6.0%), and C or greater (1.2%) overall maturities; native (88.3%), dairy-type (9.9%), and Bos indicus (1.8%) estimated breed types; and United States (97.7%), Mexico (1.8%), and Canada (0.5%) country of origin. Certified or marketing program frequencies were age and source verified (10.7%), ≤ A40 (10.0%), Certified Angus Beef (9.3%), top Choice (4.1%), natural (0.6%), and Non-Hormone Treated Cattle (0.5%), and there were no organic programs observed. Mean USDA YG traits were USDA YG (2.9), HCW (374.0 kg), AFT (1.3 cm), LM area (88.8 cm2), and KPH (2.3%); Frequencies of USDA YG distributions were YG 1 (12.4%), YG 2 (41.0%), YG 3 (36.3%), YG 4 (8.6%), and YG 5 (1.6%). Mean USDA QG traits were USDA QG (Select93), marbling score (Small40), overall maturity (A59), lean maturity (A54), skeletal maturity (A62). Frequencies of USDA QG distributions were Prime (2.1%), Choice (58.9%), Select (32.6%), and Standard or less (6.3%). Marbling score distribution was Slightly Abundant or greater (2.3%), Moderate (5.0%), Modest (17.3%), Small (39.7%), Slight (34.6%), and Traces or less (1.1%). Carcasses with QG of Select or greater and YG of 3 or numerically less represented 85.1% of the sample. This is the fifth benchmark study measuring targeted carcass characteristics, and information from this survey will continue to help drive progress in the beef industry. Results will be used in extension and educational programs as teaching tools to inform beef producers and industry professionals of the current state of the U.S. beef industry.

En la present tesis s'han estudiat estratègies per incrementar l'eficiència de la producció intensiva de vedells mitjançant pràctiques de maneig i d'alimentació. La primera estratègia plantejada per augmentar l'eficiència de la producció intensiva de vedells ha estat la millora de la qualitat de la canal i la carn. Per aquesta raó, es va desenvolupar un estudi per avaluar els efectes de diferents factors pre-sacrifici sobre la incidència de carns amb pH alt o canals amb danys tissulars extrems, i per aconseguir propostes i decisions tècniques de maneig per disminuir la incidència de carns amb pH alt o canals amb danys tissulars extrems. Desafortunadament, l'objectiu per se no es va assolir perquè la variablititat del pH últim de la carn i la incidència de canals amb dany tissular extrem explicada per aquests factors va ser molt baixa. Conseqüentment, la indústria càrnia ha d'acceptar com a "normal" un percentatge de canals amb pH elevat (per sobre 13%) i/o presència de dany tissular extrem (per sobre 2%). La castració pre-pubertal-l de vedells Holstein (8 mesos d'edat) mitjançant Burdizzo també s'ha estudiat com a pràctica de maneig per millorar la qualitat de la canal i la carn. De fet, els resultats d'aquest estudi demostren que la castració millora la classificació d'engreixament de la canal, el contingut de greix intramuscular, el valor dels paràmetres colorimètrics, i la tendresa. A més a més, l'assoliment d'una tendresa òptima en els animals castrats sense pràcticament temps de maduració, representa una avantatge competitiva en la indústria espanyola de la carn. No obstant, la castració mitjançant el mètode Burdizzo pot fallar en un 23% dels casos, i reduir el guany de pes total durant la fase d'acabat. A més a més, la castració il·lustra la delicada situació relacionada amb temes de benestar animal i pràctiques de maneig a la granja, per tant, més investigació relacionada amb els efectes de la castració sobre el dolor crònic i agut i l'estrès és necessària per assegurar que és una bona estratègia per augmentar la qualitat de la carn i la canal de vedells Holstein. Finalment, la suplementació en les dietes dels vedells amb ingredients rics en omega-3 també s'ha proposat com a estratègia per augmentar la qualitat de la canal i la carn. Efectivament, la suplementació a les dietes amb llavor de lli per sobre el 12% en el total de matèria seca ingerida, augmenta la qualitat de la carn, i a més converteix la carn en un producte funcional (carn enriquida amb omega-3), sense afectar la producció animal i la fermentació ruminal. La oportunitat d'expansió en el mercat sembla favorable i l'interès dels consumidors és elevat, però la difusió d'aquest productes necessita de la superació de la legislació per a la certificació, així com el preu elevat de les llavors de lli i la seva disponibilitat. La segona alternativa plantejada per augmentar l'eficiència de la producció intensiva de vedells ha estat la reducció dels costos d'alimentació a través de la utilització de sub-productes de la indústria. Per aquesta raó, s'ha proposat estudiar els efectes de l'inclusió de glicerina per sobre el 12% en el total de matèria seca ingerida, com a ingredient energètic alternatiu als cereals. Amb èxit, la inclusió de glicerina com a ingredient energètic no ha afectat negativament els índexs de producció animal, la fermentació ruminal, el metabolisme, i els paràmetres de qualitat de la canal i la carn. No obstant, avui en dia, la reducció dels costos d'alimentació a través de la inclusió de glicerina pot no ser una bona estratègia degut al seu alt cost en relació als altres ingredients.En resum, la present tesis no només ha proporcionat resultats sobre diferents estratègies de maneig i alimentació que milloren la eficiència de producció intensiva, sinó també informació sobre les seves limitacions i inconvenients. / In the present thesis, strategies to increase efficiency in intensive beef production focused mainly on feeding and management practices have been studied. The first strategy proposed to increase the efficiency of intensive beef production has been the improvement of carcass and meat quality. Indeed, a study was conducted to evaluate the effect of different pre-slaughter factors on the incidence of high ultimate pH and extreme carcass bruises, and to make proposals pertaining to management, technical, or economic decisions, which could lead to improvements on the high incidence of high ultimate meat pH and the extreme carcass bruises observed in intensive beef production systems. Unfortunately the objective per se was not achieved because the variability of ultimate meat pH and carcass bruises explained by these factors was very low. In consequence, the percentage of beef carcasses with high ultimate meat pH (up to 13%) and extreme bruises (up to 2%) needs to be accepted as "normal" by the current beef industry. Burdizzo castration of pre-pubertal (8 months of age) Holstein bulls has also been studied as an animal management practice, in order to improve carcass and meat quality. For instance, results from this study stated that castration improves the grade of backfat classification, the intramuscular fat content, colorimetric parameters, and tenderness. Furthermore, as the optimal tenderness might be achieved in castrated animals without a long ageing period, it represents a good competitive advantage for the Spanish beef industry. However, Burdizzo castration might fail in 23% of the cases, and might reduce the total weight gain during the finishing phase. Additionally, the practice of castration illustrates the delicate balance between animal welfare and some management practices on the farm. Therefore, further research (specially in acute and chronic pain and stress) will be necessary to ensure that castration is a good method of improving the meat quality in Holstein bulls. Finally, the supplementation of specific omega-3 rich-ingredients in the ruminant diets has also been proposed as a strategy to increase the carcass and meat quality. Effectively, the supplementation of whole linseed of up to 12% of total dry matter intake, enhances meat quality, and additionally converts meat into functional food (meat rich in omega-3), without affecting animal performance and rumen fermentation. The opportunities for expansion of the market seem to be quite favourable and the interest of the consumers is quite high, but the diffusion of these products in the community area is slowed down by some obstacles, including certification, the prices of whole linseed, and its availability.The second strategy proposed to increase the efficiency of intensive beef production has been the reduction of feeding cost through the use of industrial by-products. Indeed, the study of the effect of the inclusion of crude glycerin up to 10% of total dry matter intake, as an alternative energy source, to substitute cereals in the diet, has been proposed. Fortunately, the inclusion of crude glycerin of up to 12.1%, does not incur any negative effects in performance, ruminal fermentation, metabolism, animal health, or carcass and meat quality parameters. However, today the reduction of feeding cost through the inclusion of crude glycerin may not be a feasible strategy as a result of the high price of crude glycerin in relation to other concentrate ingredients.In summary, the present thesis not only provides the results of different feeding and management strategies to improve intensive beef production efficiency, but also highlights concerns about their constrains and limitations.

In the poultry industry, further processed meat products have the highest share in the market, and because there is a growing demand of food products with enriched amounts of unsaturated fatty acids, the objectives of this research were to assess lipid oxidation development and quality characteristics of chicken meat as affected by dietary fat and vitamin E levels. Broilers were fed during six weeks with diets containing animal/vegetable, lard, palm kernel, soybean, conjugated linoleic acid, flaxseed, or menhaden oil. Each lipid diet was supplemented with either a control (33 or 42 mg/kg) or a supranutritional level (200-400 or 200 mg/kg) of vitamin E. Breast and thigh meat, or skin, were processed, packaged, and refrigerated as raw meat, cooked patties, or cooked sous vide meat. The results showed that the chicken meat fatty acid composition reflected those from the dietary fats. In the meat or skin there was a higher lipid oxidation susceptibility as the proportion of unsaturated fatty acids increased, shown as malonaldehyde values, particularly in the treatments with low supplemented level of vitamin E (P<0.05). The relative lipid oxidative stability of the meat decreased in consecutive order from raw, cooked sous vide, and cooked meat patties. Sous vide cooked meat developed lipid oxidation at a slow rate and showed not to be affected by nonheme iron values. Dietary fat and vitamin E level affected breast meat lightness (L* color space) values (P<0.05), but not muscle pH, Allo-Kramer shear force, or water holding capacity. In conclusion, the increment in the proportion of unsaturated fatty acids increases the susceptibility to lipid oxidation in the meat. Supranutritional supplementation levels of vitamin E are more effective at inhibiting the lipid oxidation development in chicken meat than some current levels used by the poultry industry. Neither dietary fat nor vitamin E level seems to affect the development of pale, soft, and exudative meat condition in chicken meat.

Correlations between cattle disposition and meat quality were expected to be found, as well as differences in meat quality traits among contemporary groups, sires, and families nested within sires. Temperament effects on meat quality were evaluated in Nellore × Angus F2 cross cattle (n = 238) over a 3-yr period, with harvests twice a year. Five aspects of temperament -- aggressiveness, nervousness, flightiness, gregariousness, and overall temperament -- were evaluated at weaning and yearling ages, as well as an overall temperament score at slaughter. USDA quality grade, fat thickness, adjusted fat thickness, hot carcass weight, USDA yield grade, and chemical fat were correlated negatively (P < 0.05) with weaning temperament scores, aggressiveness, nervousness, flightiness, gregariousness, and overall temperament. No significant correlation was found between Warner-Bratzler shear and weaning temperament traits. USDA quality grade and live weight were correlated negatively (P < 0.05) with yearling temperament scores, nervousness, flightiness, gregariousness, overall temperament score as well as the temperament score observed at slaughter. Fat thickness and adjusted fat thickness also were correlated negatively (P < 0.05) with yearling gregariousness, yearling overall, and slaughter overall temperament. Yearling gregariousness was correlated positively (P < 0.05) with Warner-Bratzler shear from both ES and NON carcasses. Least squares mean differences were evaluated among contemporary groups, sires, and families nested within sires for overall temperament traits and meat quality traits. Contemporary group differences found were thought to be explained by environmental factors, as seen in contemporary group 5, which had the smallest ribeye possibly caused by the shortest feeding period. Steers sired by 297J had the lowest (calmest) temperament scores, most 12th rib fat, highest numerical yield grade, and the heaviest weights. Sire 437J had steers with the highest (wildest) temperament scores, the least fat and lowest numerical yield grade. This population was designed to identify QTL for economically important traits and appears to be useful for this purpose because of the differences found both between and within families.

An in-home evaluation of beef value cuts from the round was conducted to determine ways to improve palatability attributes for steaks prepared by consumers. The M. vastus lateralis, M. rectus femoris, M. semimembranosus, and M. adductor (n = 266) muscles were either blade tenderized, enhanced with a salt and phosphate solution, or served as a control. Consumers (n = 261) cooked these steaks as they normally would and were asked to document cooking method and degree of doneness, as well as palatability ratings for overall like, tenderness, juiciness, flavor intensity, and flavor desirability for each steak. Enhancing round muscles with a salt and phosphate solution improved most palatability traits compared to those that were blade tenderized or not treated. For M. semimembranosus and M. vastus lateralis, the enhanced steaks received higher (P < 0.05) ratings for all palatability traits. For the most part, cooking method and degree of doneness had little influence on consumer palatability ratings. Where differences occurred, they were muscle specific, which may allow limited recommendations for certain muscles with respect to the most appropriate cooking method and degree of doneness.