• Enhancement of pigmeat quality by altering pre-slaughter management

      Lawlor, Peadar G; Lynch, P Brendan; Mullane, J.; Kerry, Joseph P.; Hogan, Sean; Allen, Paul (Teagasc, 25/10/2005)
      The studies presented in this report were conducted to investigate the effect of breed, slaughter weight, castration of male pigs and strategic feeding strategies on the performance of pigs to slaughter and on their carcass quality. The effect of breed, gender and feeding regimen on the performance of pigs and their carcass quality was examined in the first study (Section 3). From weaning to slaughter Landrace-sired pigs grew at a similar rate but had a better feed conversion efficiency compared with Duroc-sired pigs. Landrace-sired pigs also had a higher carcass lean and greater muscle depth than Duroc-sired pigs. Entire male pigs grew more efficiently, had lower lean content in their carcasses and had a reduced kill out yield when compared with gilts. The eye muscle depth was greater for gilts than entire males. Diluting the diet with grass-meal (GM) reduced growth rate, caused a deterioration in feed conversion efficiency, reduced back fat thickness, reduced eye muscle thickness and reduced kill out yield compared to the control feeding regimen of a cereal based diet. Compensatory growth was observed during a re-alimentation period following a period of diet dilution with grass-meal. However, where it did occur, in most cases it was only partial. Adding 5% rapeseed oil instead of lard to the finisher diet increased nitrogen utilization efficiency and phosphorous utilization efficiency. The effect of gender (boar, castrate, gilt) and slaughter weight (80 to 120kg) on pig performance, carcass quality, meat quality, and nitrogen excretion was investigated in the second study (Section 4). Boars grew faster than gilts and more efficiently than castrates or gilts. Castrates had a higher kill out yield than boars. Nitrogen excretion from castrates was similar to gilts which were both higher than that from boars. The processing value of carcasses from castrates may be higher than that of boars and gilts. In particular castrates had heavier loins and bellies than either boars or gilts. Carcasses from castrates and gilts had a higher temperature (recorded 24 hours post slaughter) than boars. However, pH24 was not affected by gender. The intramuscular fat content of the l. dorsi in castrates was higher than that of boars or gilts, however at 1.65% this was well below the level (2.0%) above which any noticeable sensory attributes might be detected. Feed intake increased with increasing slaughter weight and feed conversion efficiency deteriorated. N excretion also increased with each increment in weight. Carcass lean content increased up to 90kg live EOP 4939.doc 4 25/10/2005 weight then reached a plateau and declined after 110kg live weight. Heavier carcasses yielded more product for approximately the same slaughtering cost and the associated larger muscles could make it easier to use seam butchery techniques that result in lean, well-trimmed, attractive cuts and joints. The pH45 and pH24 were reduced with increasing slaughter weight and drip loss increased. Heavier pigs may be more prone to the development of PSE than lighter pigs as their carcass temperature remains higher for longer than that of lighter pigs.
    • Enhancing the healthiness, shelf-life and flavour of Irish fresh packaged beef

      Moloney, Aidan P; Murray, Brendan; Troy, Declan J.; O'Grady, Michael; Kerry, Joseph P.; Downey, Gerard (Teagasc, 2007-02)
      Consumer concern about the nutritional aspects of health has heightened interest in developing methods for manipulation of the fatty acid composition of ruminant products. Ruminant meats such as beef and lamb are often criticised by nutritionists for having high amounts of saturated (S) fatty acids and low levels of polyunsaturated (P) fatty acids. The P:S ratio in beef is approximately 0.1, the ideal being about 0.4. However, an excessive increase in P concentration could predispose beef lipids to rancidity and loss of shelflife. Moreover, the colour of meat is an important influence on the purchase decision of the consumer. This report summarises the Teagasc contribution to a larger project supported under the Food Institutional Research Measure programme administrated by the Department of Agriculture and Food. The Teagasc contribution focused on enhancing the fatty acid composition of beef by nutritional manipulation of cattle using grazing and plant oils, the use of healthy - fatty acid enriched bovine tissue to make a processed beef product and the efficacy of dietary inclusion of tea catechins and rosemary to enhance the shelf-life of beef.
    • Influence of feeding systems on the eating quality of beef

      Troy, Declan J.; Murray, Brendan; O'Sullivan, Aileen; Mooney, Teresa; Moloney, Aidan P; Kerry, Joseph P. (Teagasc, 2002-10)
      The objective was to determine pre-slaughter factors which may enhance the eating quality of beef and to assist the Irish beef production chain to exploit these factors to produce beef of higher quality and increased consumer acceptability. The effects of pre-slaughter growth rate, high energy diets, feed type and age at slaughter on beef quality were examined.
    • Variation in the quality of meat from Irish steers at the time of slaughter.

      Moloney, Aidan P; Mullen, Anne Maria; Maher, S.C.; Buckley, D.J.; Kerry, Joseph P. (Teagasc, 01/01/2004)
      There is no information on the variation in quality, in particular tenderness, that exists in Irish Beef nor is there information on the variation that would remain if optimum practices were imposed at all stages of the beef production chain. Evaluation of the success of measures to improve beef consistency requires information on existing variation and the minimum variation achievable.The objectives of this project were (i) to establish the variation that exists in the quality of meat from Irish cattle, (ii) to quantify the minimum variation in meat quality that can be achieved in a practical beef production system, (iii) to determine the effects and mechanisms of additional sources of variation. The conclusions from this project are: • The M. longissimus dorsi (loin) was found to be more variable than the M. semimembranosus (topside) for most quality attributes examined (tenderness, sarcomere length and pH). The scale of variation within the loin was similar to that reported by the other research groups within the EU and US. Heifers were more variable than steers for most attributes, while there was no consistent classification effect on the variability of meat quality attributes. • Tenderness was equally variable in meat from genetically similar steers, managed similarly, compared to commercial steers randomly selected from a factory lairage but matched for weight and grade.This was likely a result of both groups being crossbred beef cattle of similar age, fat score, carcass weight and managed identically post-mortem. However, variation in tenderness of both groups was less than that observed in a survey of commercial throughput (experiment 1). This decrease is attributed to better pre-and-post-slaughter handling practices. • The data suggest that selection of sires (within a breed) with better than average conformation has no deleterious effect on the eating quality of beef of their progeny.A more comprehensive comparison of sires within a breed and between breeds is required to confirm the generality of this conclusion. • In a comparison of genotypes, gender and slaughter weights, there was no evidence that variation around the mean value for tenderness differed between breeds or liveweights after 14 days ageing. Bulls were more variable than steers for some quality traits but the variation in tenderness was similar for bulls and steers after 14 days ageing. • While optimising the management of animals during the pre and post-slaughter period reduced variation in tenderness, some residual variation remained. A large percentage of the residual variation in tenderness (Warner Bratzler shear force) after 2 and 7 days post-mortem was explained by proteolysis (breakdown of myofibrillar proteins).Variation in tenderness (Warner Bratzler shear force) after 2 days post-mortem was largely explained by phosphates (energy) and proteolysis, while sensory tenderness was largely explained by phosphates and glycolytic potential. • Further work is required to reduce residual variation in Irish beef and to determine the causes of this variation.