The Science of Meat Quality

Posted in: Production by admin on January 1, 2002 | No Comments

Raising pigs in optimal conditions is important to produce the best meat quality. However, producers have to be aware that their efforts will get better results if they are conscious that good care of piglets starts at the foetal level. During foetal growth muscle fibres develop and the total number of fibres is determined. Fibres can be divided into three general categories: red, white and intermediate. A darker muscle has a larger amount of red fibres, while a lighter coloured muscle has more white fibres. It is the number of muscular fibres, rather than their size, that is the primary influence on the growth of the animal. The role of red fibres is more important at birth, but during development and at slaughter weight, white fibres become more important. After slaughter, the pH level of muscle decreases as a result of anaerobic degradation of glycogen in lactic acid. This metabolic activity is more important in white muscles and has a major impact on meat quality. Other factors influencing the level of acidification of the post-mortem muscle are exercise and stresses from pre-slaughter handling and transportation. The rate and extent of the drop in pH levels (becoming more acidic) has an impact on the quality of fresh meat, its shelf life and ability for further processing. A higher proportion of white fibres will reduce the pH. Good proteins make good processed meat – white fibre myosin (myosins are molecular motor proteins) offers superior functional properties to that of red fibre myosin subject to post-mortem metabolic activities that don’t interfere with protein integrity. In order to maintain the quality of protein, pre-slaughter management is essential but other factors are also important, including genetic selection, environment, and perhaps feeding of the gestating sow. Molecular biology also provides some interesting possibilities. There are studies currently being conducted to identify new genetic markers that influence growth and meat yield. In the near future, other research projects will likely concentrate on production of meat with qualities that meet specific requirements such as functional or nutraceutical foods. Scientists have also been able to extend the shelf life of fresh meat by better controlling bacteria. Their new objective is to improve the meat’s resistance to its own degradation by oxidation.

Growth performance and carcass traits in pigs fed sweet potato (Ipomoea batatas [Lam.] L) root meal

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Asdditivity of Apparent ileal and Fecal Phosphorus Digestibility Values Measured in a Single Feed Ingredients for Growing-Finishing Pigs

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Two experiments were conducted to determine apparent ileal and fecal P digestibility values in barley, wheat, peas and canola meal and to examine whether the apparent P digestibility values measured in single feed ingredients are additive when used in diet formulation for growing-finishing pigs. In both experiments, five barrows, with average initial body weights of 40 and 35 kg, were fitted with a simple T-cannula at the distal ileum and fed five diets according to a 5 x 5 Latin square design. In exp. 1, the barrows were fed five diets (diets 1, 2, 3, 4, and 5) formulated to contain five graded levels of barley (0, 22.5, 45.0, 67.5 and 90%, respectively) and canola meal (42.7, 36.6, 30.5, 24.4 and 0%, respectively). In exp. 2, the barrows were fed five diets (diets 1, 2, 3, 4, and 5) formulated to contain five graded levels of wheat (88.5, 66.4, 44.3, 22.1 and 0%, respectively) and peas (0, 16.8, 33.6, 50.4 and 67.1%, respectively). Chromic oxide (0.4%) was used as a digestibility marker in both experiments. The pigs were fed twice daily, at 0800 and 2000. The dietary allowance was 1800 g d(-1). Each experimental period lasted 8 d. Representative fecal samples were collected during days 5 and 6. Ileal digesta were collected for a total of 24 h, at 2-h intervals, during days 7 and 8. The ileal and fecal P digestibility values in barley, wheat, peas and canola meal were associated with large standard errors, suggesting a large variability within each feed ingredient. There were no differences (P > 0.05) between the directly determined and predicted apparent fecal P digestibility values in diets 2, 3 and 4 of exp. 1. However, there were differences (P < 0.05) between the directly. determined and the predicted apparent fecal P digestibility values in diets 3 (46.5 +/- 1.0 vs. 38.7 +/- 0.6) and 4 (48.2 +/- 1.2 vs. 41.6 +/- 1.2) in exp. 2, indicating that apparent fecal P digestibility values are not always additive in diet formulation. It is concluded that apparent P digestibility values are variable and not very reliable in diet formulation for swine.

AMMONIA VOLATILIZATION FROM CONSTRUCTED WETLANDS THAT TREAT SWINE WASTEWATER

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Slurry Application Techniques to reduce Ammonia Emissions: Results of some UK Field-scale Experiments

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Shallow injection, trailing shoe and band spreading machines were evaluated, in terms of their potential for reducing ammonia (NH3) emission, by making measurements after application and in direct comparison with surface broadcast applied cattle slurry (pig slurry on one occasion). Several sets of comparative measurements were made with each type of machine on both grassland and arable land (mostly cereal stubbles), covering a range of soil, crop and weather conditions. Measurements of NH3 emissions were made for 5a

Exposure and respiratory health in farming in temperate zonesa

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EFFECTS OF MANURE REMOVAL STRATEGIES ON ODOR AND GAS EMISSION FROM SWINE FINISHING

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Odor, ammonia (NH3) and hydrogen sulfide (H2S) concentrations and emission rates were measured in two small rooms of finishing pigs with different manure removal strategies. The strategies included daily flush, and static pits with 7-, 14-, and 42-d storage times with and without pit recharge. Tests were conducted with three successive groups of 25 pigs per room. Pigs were fed standard corn-soybean diets. Ammonia and H2S concentrations were automatically measured 15 to 24 times per day. Odor samples were collected and evaluated for odor concentration, intensity and hedonic tone by an odor panel, whose performance was verified with a reference odorant. Geometric mean odor emission rates were 19, 33, and 29 OUE s-1 AU-1 (OUE = European odor unit equivalent to 123 A

Methane emissions from swine lagoons in Southeastern US

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Use of liquid hog manure for sustainable forage production

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Manitoba Agriculture and Food and Turtle Mountain Conservation District, with financial assistance from Covering New Ground, established two demonstration sites in the Killarney area. The focus of the project was to measure the effects of hog manure on the yield and quality of tame and native pastures, and to look at these pastures ability to support grazing livestock. Complementary focus was placed on evaluating crop nutrient uptake by conducting soil tests before fertilization and following the growing season. The tame pasture consisted of a tall fescue- alfalfa mixture. The native pasture had been sod-seeded with alfalfa in 1999, but was dominated by native grass species. Forage clippings were taken on August 20-21. Forage quality was consistently better when fertilized. Energy content (measured in Total Digestible Nutrient) was also greater when pastures were fertilized. Soil tests taken following the growing season showed that soil N and P were, in most cases; lower than pre-fertilization soil N and P. This indicates that the actively growing vegetation had taken up the applied nutrients. Manure also had a positive effect on forage yield and forage quality. The yield increases in particular had an effect on the carrying capacity of fertilized pastures vs. unfertilized pastures. Actively growing forages use manure nutrients well, as indicated by the post-growing season deficiencies in both soil N and P. Other benefits of using liquid hog manure on forage crops are the expansion of the practical spreading season from traditional spring and fall demand peaks. As forages have much higher N and P requirements than most annual crops they also allow a reduction in spread acres required.

Effect of extender, cooling method and incubation time on storage of extended boar semen at 5A?A?C

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A study was carried out to determine if cooling method, incubation time and extender affected the success of storing boar semen at 5A?A?C. Extended boar semen can be stored at 5A?A?C with acceptable values of sperm progressive motility, total motility and viability over time. This success depends upon incubating the sperm at 17A?A?C for at least 24 hours prior to 5A?A?C storage.