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Quality measures of lamb longissimus dorsi were evaluated in 514 crossbred wether lambs to assess sire breed differences. Wethers were produced over 3 yr from single-sire matings of 22 Columbia, 22 U.S. Meat Animal Research Center (USMARC)-Composite (Composite), 21 Suffolk, and 17 Texel rams to adult Rambouillet ewes. Lambs were reared to weaning in an extensive western rangeland production system and finished in a feedlot on a high-energy finishing diet. One of three harvest groups were randomly assigned to each lamb, and lambs were transported to The Ohio State University abattoir when the mean BW of wethers remaining in the feedlot reached 54.4, 61.2, or 68.0 kg. After harvest, subjective lean quality scores were assigned and LM pH (immediately after and 24 h after harvest), color (quantified as Minolta L*, a*, and b*), intramuscular fat (IMF), cooking loss percentage, and Warner-Bratzler shear force (WBSF) were determined. Statistical models included fixed effects of sire breed, year of birth, and harvest group and random effects of sire (nested within sire breed and year) and maternal grandsire. Year and harvest group were significant (P < 0.04) for all traits, except harvest group was not for WBSF and lean quality (P > 0.28). At comparable numbers of days on feed, Texel-sired wethers had the greatest (more desirable; P < 0.01) subjective lean quality scores while Composite- and Suffolk-sired lambs were intermediate and Columbia-sired lambs had the lowest (less desirable). Minolta L* values were greater (P < 0.02) for Texel- than Columbia-sired lambs, although this difference is not visually discernible by humans. No significant (P > 0.05) sire breed effects were detected for LM pH at or 24 h after harvest, Minolta a* and b*, IMF, percentage of cooking loss, and WBSF at comparable numbers of days on feed. At comparable chilled carcass weight, significant (P < 0.01) sire breed effects were detected for subjective lean quality score. Texel-sired lambs had greater scores than Columbia- and Suffolk-sired lambs, but Composite-sired lambs did not differ from lambs sired by the other sire breeds. Sire breed effects were not detected (P > 0.15) for LM pH at or 24 h after harvest, Minolta L*, a*, and b*, cooking loss percentage, IMF, and WBSF at comparable chilled carcass weight. Therefore, results of the present study indicated that the 4 sire breeds produced crossbred lamb carcasses that had similar and desirable LM quality measurements, meeting consumer expectations.

Pork loins (N=53) were selected from a commercial packing plant to determine the influence of subjective marbling score on sensory attributes and eating quality properties. The pork loins were obtained from commercially raised hybrid barrows (average carcass weight=67.7 kg), originating from nine cooperating herds, and fed similar diets throughout the finishing period. Carcass quality measurements, trained sensory panel analyses, fatty acid composition, thiobarbituric acid-reactive substance (TBARS) index, and cholesterol content were assessed and analyzed on the individual pork loins. With an increase in marbling level, there was a corresponding decrease in drip loss (P=0.049) and observed increases in pH (P=0.001), sensory tenderness (P=0.001), and sensory juiciness scores (P=0.017). The most notable results demonstrated that protein concentrations were reduced as marbling levels amplified (P=0.012). The increase in marbling score was observed to be a significant source of variation in polyunsaturated fatty acid (PUFA) concentrations. Linoleic and arachidonic acids decreased in both raw and cooked samples as marbling score increased. The data demonstrated that visual marbling score does have an influence on sensory properties and pork quality., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Two genetic lines with different lean gains were evaluated for various body measurements and indices of lean tissue in barrows and gilts from 20 to 125 kg of BW. One genetic line was identified as the low-lean line [280 g of fat-free lean (FFL)/d], and the second line was the high-lean line (375 FFL gained/d). The experiment was conducted as a completely randomized design using a 2 x 2 x 5 factorial arrangement of treatments in 6 replicates (n = 120 pigs). The 2 genetic lines and sexes were provided ad libitum access to cornsoybean mixtures that met or exceeded their required amino acid requirements for their respective lean gain potentials. Six pigs of each sex and genetic line were slaughtered initially and at 25-kg of BW intervals to 125 kg of BW. Pigs slaughtered were measured for height, width, and length using metal calipers. Backfat and LM area were measured using real-time ultrasound, with backfat depth also measured using A-mode ultrasound technology. Longissimus muscle area and back-fat thickness at the 10th rib were measured on the chilled carcass. Data was analyzed using the MIXED procedure of SAS, with the animal as the experimental unit. Shoulders (P < 0.05) and lumbars (P < 0.05) were wider in the low-lean genetic line and in barrows. Gilts and the high-lean genetic line had less backfat and greater LM areas than the low-lean genetic line. As BW increased, there was a greater increase in FFL tissue and lower backfat depths in the high-lean vs. the low-lean genetic line. This resulted in a greater divergence of measurement values as BW increased. Femur weight, length, and cortical wall thickness were greater in the high-lean genetic line, but the differences were not significant. The high-lean genetic line had a greater (P < 0.01) organic matrix content in the femur and less ash, resulting in a lower percentage of bone ash (P < 0.01). The results indicate that differences occurred phenotypically between pigs having more muscle (wider hams) or more fat (wider shoulder and lumbar). As BW increased, the high-lean pigs had an increase in lean tissue, particularly after 75 kg of BW, and less backfat and less bone mineralization, whereas the low-lean line pigs had increased backfat and greater bone mineralization. Real-time ultrasound measurements using various formulas to estimate lean tissue produced values close to those determined from carcass measurements at 100 and 125 kg of BW.

A divergent selection experiment for serum IGF-I concentration began at the Eastern Ohio Resource Development Center in 1989 using 100 spring-calving (50 high line and 50 low line) and 100 fall-calving (50 high line and 50 low line) purebred Angus cows. Following weaning, bull and heifer calves were fed in drylot for a 140-d period. Real-time ultrasound measurements of backfat thickness and longissimus muscle area were taken on d 56 and 140 of the postweaning test. Only ultrasound data from calves born from fall 1995 through spring 1999 were included in the analysis. At the time of this study, IGF-I measurements were available for 1,521 bull and heifer calves, and ultrasound data were available for 636 bull and heifer calves. Data were analyzed by multiple-trait, derivative-free, restricted maximum likelihood methods. Estimates of direct heritability for IGF-I concentration at d 28, 42, and 56 of the postweaning period, and for mean IGF-I concentration were 0.26 +/- 0.07, 0.32 +/- 0.08, 0.26 +/- 0.07, and 0.32 +/- 0.08, respectively. Direct heritabilities for ultrasound estimates of backfat thickness ranged from 0.17 +/- 0.11 to 0.28 +/- 0.12, whereas direct heritabilities for longissimus muscle area ranged from 0.20 +/- 0.10 to 0.36 +/- 0.12, depending on the time of measurement and the covariate used for adjustment (age vs. weight). Direct genetic correlations of IGF-I concentrations with backfat thickness at d 56 and 140 and with longissiumus muscle area at d 56 and 140 averaged 0.02, 0.20, -0.08, and 0.23, respectively, when age was used as the covariate for both IGF-I and ultrasound measurements. Corresponding genetic correlations when age was used as the covariate for IGF-I and weight was used as the covariate for ultrasound measurements were 0.05, -0.07, -0.22, and -0.04, respectively. Therefore, the positive associations of serum IGF-I concentration with backfat thickness and longissimus muscle area at d 140 seem to have been partially mediated by weight. Results of this study do not indicate strong associations of serum IGF-I concentration with fat thickness or muscling of bulls and heifers during the postweaning feedlot period.

The present experiment utilized Berkshire (n = 76), Duroc (n = 81), and high-lean commercial crossbred (n = 75) barrows and gilts with an initial BW of approximately 85.1 kg. Pigs were fed a standard commercial diet (17.6% CP, 1.02% lysine) supplemented with ractopamine hydrochloride at a level of 0 or 10 ppm for 28 d. The experiment was conducted in a randomized complete block design, with animals blocked within genetic line according to litter, gender, and weight, for a total of four blocks per genetic line for each treatment. Pigs were harvested at a commercial abattoir and chilled for 24 h at 1 to 4 degrees C. At 24 h postmortem, wetness and firmness scores and ultimate muscle pH were measured in the center of the longissimus muscle (LM) at the 10th to 11th rib interface. Visual and instrumental color and marbling score were measured at 48 h postmortem on a fresh cut LM surface. Percentage of chemically extracted intramuscular fat (IMF) was measured, and a trained sensory panel evaluated cooked LM chops for juiciness, tenderness, and chewiness. Cooking loss (%) and instrumental measurement of tenderness also were measured on cooked LM chops. Ractopamine treatment increased ADG (P < 0.01) and LM area (P < 0.05), but had no effect (P > 0.05) on LM quality, sensory attributes, or instrumental measures of palatability. Berkshire LM received higher tenderness and juiciness (P < 0.05) scores and had lower cooking losses (P < 0.05) and instrumental tenderness (P < 0.05) than LM from the Duroc and high-lean lines. Loins from barrows were firmer (P < 0.05), had lower drip loss percentages (P < 0.05), and received greater tenderness scores (P < 0.05) than the LM from gilts. Genetic line x treatment and gender x treatment interactions were detected for IMF. The LM of Berkshire pigs fed ractopamine had lower (P < 0.05) IMF than Berkshires fed the control diet, with no interaction in the other lines. Purebred barrows (Berkshire and Duroc) had greater (P < 0.001 and P < 0.05, respectively) IMF than their respective purebred gilts, with no gender difference in IMF in the high-lean line. Results from the present study indicate that feeding ractopamine does not affect most muscle quality and palatability characteristics. However, the genetic line x treatment interaction for loin IMF suggests that feeding ractopamine might reduce IMF within the loin muscle of genetic lines that have a propensity to produce greater levels of IMF.

One hundred beef carcasses were selected at three packing plants and were used to determine the relationship between glycolytic potential (GP) and dark, firm, and dry (DFD) beef and to determine the effects of DFD status and GP on cooked beef palatability. Eight individual muscles were excised from one hindquarter of each carcass at d 7 postmortem: longissimus lumborum, psoas major, gluteus medius, tensor fasciae latae, rectus femoris, semimembranosus, biceps femoris, and semitendinosus. Ultimate pH, colorimeter readings, and Warner-Bratzler shear force were determined for all eight muscles at d 7 postmortem. A nine-member trained sensory panel evaluated cooked longissimus lumborum, gluteus medius, and semimembranosus steaks. Traits determined solely for the longissimus lumborum were GP (2 x [glycogen + glucose + glucose-6-phosphate] + lactate) and ether-extractable fat. A curvilinear relationship existed between GP and ultimate pH within the longissimus muscle. There appeared to be a GP threshold at approximately 100 micromol/g, below which lower GP was associated with higher ultimate pH and above which GP had no effect on ultimate pH. The greatest pH and muscle color differences between normal and DFD carcasses were observed in the longissimus lumborum, gluteus medius, semimembranosus, and semitendinosus muscles. Cooked longissimus from DFD carcasses had higher shear force values (46% greater) and more shear force variation (2.3 times greater variation) than those from normal carcasses. Dark cutting carcasses also had higher shear force values for gluteus medius (33% greater) and semimembranosus (36% greater) than normal carcasses. Sensory panel tenderness of longissimus, gluteus medius, and semimembranosus was lower for DFD carcasses than for normal carcasses. Longissimus and gluteus medius flavor desirability scores were lower for DFD than for normal carcasses. Steaks from DFD carcasses had more off-flavor comments than steaks from normal carcasses, specifically more "peanutty," "sour," and "bitter" flavors. The DFD effect of higher shear force values was approximately five times greater (+3.11 kg vs +0.63 kg) for carcasses with "slight" marbling scores than for carcasses with "small" marbling scores. In general, higher GP was associated with increased tenderness, even among normal carcasses. In conclusion, low GP was associated with DFD beef and resulted in substantially less-palatable cooked steaks.

Real-time ultrasonic measurements of 10th-rib backfat (BF10) and loin muscle area (LMA) were made by a single technician at four mean BW (67.4, 80.3, 93.4, and 104.9 kg) on live hogs to assess the accuracy of predicting carcass measurements before and at slaughter weight. Records were evaluated on 655 purebred barrows and 472 purebred gilts in two tests. Residual correlations-accounting for test, sex, and breed effects, among and between scans and carcass measurements--were moderate to high for BF10 (r=.69 to .82) and LMA (r=.57 to .68), with the largest correlations at 104.9 kg of live weight. Ultrasonic BF10 and LMA were within +/-4 mm and +/-6.45 cm2, respectively, of the corresponding carcass measurement 75.9 and 89.8% of the time. Sex differences for LMA bias were significant (P < .001); ultrasonic LMA was overestimated in barrows by .75 cm2 and underestimated in gilts by .91 cm2. Breed differences were significant (P < .001) for BF10 and LMA bias. Standard errors of prediction (SEP) for BF10 and LMA across the two tests were 3.46 mm and 4.04 cm2, respectively. The SEP for BF10 were 3.60 mm for barrows and 3.19 mm for gilts. The SEP for LMA were 3.77 cm2 for barrows and 4.22 cm2 for gilts. The SEP for BF10 within breeds ranged from 3.25 to 3.72 mm, and for LMA, ranged from 2.98 cm2 to 4.90 cm2. Ultrasound measurements overestimated the carcass measurement by .57 mm for carcasses measuring < 24.1 mm and underestimated by 2.81 mm carcasses with BF10 > 30.3 mm. Ultrasonic LMA overestimated the carcass by 2.35 cm2 in carcasses measuring < 32.5 cm2 and underestimated by 2.29 cm2 in carcasses measuring greater than 37.9 cm2. Results indicate that the magnitude of the carcass measurement affects bias and accuracy of prediction for real-time ultrasonic measurements of BF10 and LMA. The SEP statistic is more consistent in evaluating accuracy of ultrasonic measurement than bias, absolute deviations, and percentage of absolute deviation.

We recorded serial real-time ultrasonic measurements of backfat and loin muscle area to assess the rate of change per unit of live weight and growth rate measured as the change in weight per day of age during the finishing stage of production. Barrows (648) and gilts (459) representing eight major U.S. pure breeds of swine were evaluated in the study. Real-time ultrasonic measurements of backfat and loin muscle area were collected at average live weights (LW) of 67.4, 80.3, 93.4, and 104.9 kg. Backfat was measured at the midline over the last rib (LR) and last lumbar vertebra (LL) and off the midline at the 3/4 point (BF10) over the 10th rib. Loin muscle area (LMA) images were collected from the right-hand side of each pig at the 10th rib. Deposition rates were calculated on an intrapig basis for the dependent scan variables BF10, LMA, LR, and LL in models that included the independent variables LW and LW2. For growth rate (WDA), LW was regressed on age and age. Intrapig linear regression coefficients and y-intercepts were further analyzed as dependent variables in a mixed model that included the fixed effects test group, sex, and breed and random effects of sire and dam nested within breed. Significant breed effects were present for deposition rates of BF10, LMA, LR, LL, and WDA. Across the eight breeds, BF10 was deposited at a mean of .271 +/- .008 mm/kg, a rate faster than the average for LR (.201 mm/kg) and LL (.206 mm/kg). The LMA deposition rate across breeds averaged .304 cm2/kg. Average WDA across the breeds was .774 kg. Barrows deposited fat faster at all locations, deposited muscle slower, and grew faster than gilts in this study (P < .001). The results of this study indicate a need for breed- and sex-specific adjustment factors for rates of backfat and loin muscle deposition and for weight per day of age in swine.