Abstract. This paper describes the methodology used for the collection of carcass yield and meat quality data from straightbred and crossbred cattle in the Cooperative Research Centre for Cattle and Beef Quality core program. IntroductionIn order to fulfil the aims of the Cooperative Research Centre for Cattle and Beef Quality (CRC), about 10 000 cattle needed to be slaughtered, processed, sampled and measured for a range of carcass and meat quality traits. Both pre-and post-slaughter treatments were standardised, to minimise confounding of genetic comparisons and management effects by variation in environmental factors. They were also designed to result in minimal animal stress and to avoid adverse post-slaughter processing effects on meat quality. Animals were slaughtered at commercial abattoirs. Due to the geographical spread and time span of CRC activities, several abattoirs were used.In this paper, details of the methodologies used in assessing, or measuring, the carcass and meat quality traits are described. Where specific deviations from these methods occurred, they will be detailed in papers using that data.

Abstract. The potential eating quality of beef is set by the intrinsic structural and compositional characteristics of muscle. However, the extrinsic factors that prevail during the production of the animal, slaughter and processing of its carcass and finally, cooking can produce changes in these structural and compositional characteristics that ultimately manifest as large variations in beef palatability. The conditions that apply in the 24-48 h immediately before and after slaughter are recognised as having the largest influence on beef palatability. This review specifically examines the critical pre-and post-slaughter factors and discusses their putative effects on biochemical and physical changes in muscle and the consequences to beef palatability. Areas for future research within this domain are also discussed.

Abstract. Beef cattle data from temperate (TEMP, n = 3947) and tropically adapted (TROP, n = 4137) breeds were analysed to compute estimates of genetic and phenotypic correlations between animal, abattoir carcass, and meat quality measures. Live animal traits included: liveweight (S2LWT), scanned subcutaneous rump fat depth (S2P8), scanned eye muscle area (S2EMA), flight time (S1FT), and finishing average daily gain (FADG). Carcass traits included: hot carcass weight (CWT), retail beef yield percentage (RBY), intramuscular fat percentage (IMF), subcutaneous rump fat depth (P8), eye muscle length by width (ELW), and meat colour score (MEATC). Meat quality measures taken on 2 muscles [M. longissimus thoracis et lumborum (LTL) and M. semitendinosus (ST)] included: shear force of LTL (LTL_SF) and ST (ST_SF); compression of the ST (ST_C); cooking loss % of the LTL (LTL_CL%) and ST (ST_CL%); Minolta LTL L* (LTL_L*), a* (LTL_a*), ST a* (ST_a*); and consumer-assessed LTL tenderness score (LTL_TEND). Genetic and phenotypic correlations between animal measures and related carcass traits were moderate to very high for TEMP and TROP. Genetic correlations between S2LWT and CWT were 0. 89 and 0.82, between S2P8 and P8 0.80 and 0.88, and between S2EMA and ELW 0.62 and 0.68, for TEMP and TROP, respectively. Genetic correlations between animal measures and other carcass traits varied; moderate genetic correlations were estimated between S2P8 and RBY (-0.57, -0.19 for TEMP, TROP) and S2P8 and IMF (0.39, 0.23 for TEMP, TROP). Genetic correlations between animal and meat quality measures were moderate to low. For TEMP, moderate genetic correlations were estimated between S2P8 and LTL_TEND (0.38), FADG and ST_a* (-0.49), and FADG and LTL_TEND (0.45); and for TROP, S1FT and LTL_SF (-0.54), and S2EMA and LTL_L* (-0.46). Phenotypic correlations between animal and meat quality were generally low and close to zero. Several moderate to high genetic correlations existed between carcass and meat quality traits. In general, fatness measures were genetically correlated with tenderness (e.g. IMF and LTL_TEND 0.61, 0.31 for TEMP, TROP). CWT was genetically correlated with meat colour (CWT and LTL_L* 0.66, 0.60 for TEMP, TROP) and objective tenderness measures (CWT and ST_C -0.52, -0.22 for TEMP, TROP). Once again phenotypic correlations between carcass and meat quality were low, indicating that few phenotypic predictors of meat quality traits were identified. Several of the genetic correlations show that both animal and abattoir carcass traits may be of use as indirect measures for carcass and meat quality traits in multiple trait genetic evaluation systems.A R 0 2 0 8 8 A n i ma l , c a r c a s s , a n d m e a t q u a l i t y t r a i t s i n b e e f A . R e v e r t e r e t a l .

Domestic trade weight steers (149) were assessed visually for subcutaneous fat and then given a live muscle score based on the thickness and convexity of their shape relative to frame size, having adjusted for subcutaneous fat. After slaughter, carcasses were given visually assessed carcass muscle scores based on the same critera. Fat depths at the P8 site and 12-13th eye muscle area were measured. Half of each carcass was boned-out into primal joints with subcutaneous fat trimmed to 6 mm. The weights of these joints plus meat trim (85% visual lean) were added to obtain the weight of saleable meat. The weight of fat trimmed from the carcass, primal joints, and meat trimmings during the bone-out process was added to obtain weight of fat trim. The assessors did not give steers with a greater subcutaneous fat depth better muscle scores when scoring for muscle and intermuscular fat. There was a negative correlation between live muscle score and P8 fat depth (-0.37), and no significant correlation between carcass muscle score and P8 fat depth. The associations between muscle score and yield of saleable meat were investigated using multiple regression techniques, with fat depth and muscle score sequentially added after weight in the model. The coefficient of determination and the residual standard deviation were compared at each stage. For saleable meat yield (kg), liveweight and carcass weight were the main contributors to the variation explained by the models fitted. For saleable meat yield as a percentage of carcass weight, most of the variation accounted for by the models fitted was explained by fat depth, muscle score, and eye muscle area. When added after weight and fat depth in regression models, muscle score significantly increased the coefficient of determination in all cases, with an associated decrease in the residual standard deviation. The effect was strongest for percentage of saleable meat. At the same weight and fat depth, animals or carcasses with better muscle scores produced more saleable meat.

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