Retail Yield Research Articles

Adult steers for beef production: breed effect on animal performance, retail yield and carcass quality

The production of adult steers for beef could be a profitable use of the territory in some mountain areas in the south of Europe, where this production is nearly inexistent, owing to an increase in the demand for meat from adult animals in specialized markets. The objective of this study was to evaluate the profitability of beef production in three breeds adapted to these areas but varying greatly in their mature size. The studied breeds were a specialized meat breed Limousin, a dual-purpose breed – Brown Swiss breed and – a Spanish local breed Asturiana de los Valles. Higher growth rates (P < 0.05) and higher carcass weights (P < 0.05) were achieved by Brown Swiss and Limousin. In relation to carcass value, better results of dressing percentage (P < 0.001), conformation (P < 0.001) and saleable meat percentages (P < 0.001) were obtained byLimousin. Due to preferences of the adult steers market for carcass with high fatness, Brown Swiss and Limousin could be more suitable to make this production profitable than Asturiana de los Valles (4.7 and 4.2 vs. 2.7, respectively, on the EUROP scale).  

Retail cutting characteristics for US Choice and US Select beef subprimals

US Choice (Ch) and US Select (Se) beef subprimals from the rib, chuck, plate, loin, and round were obtained to conduct retail cutting tests. Subprimals were merchandised into bone-in or boneless retail cuts and associated components by experienced retail meat merchandisers. These Se subprimals had less ( P < 0.05) trimmable fat than their Ch counterparts: ball tip, top sirloin, outside round, inside round, and ribeye. Se inside rounds, outside rounds, eye of rounds, boneless striploins, and ball tips had greater ( P < 0.05) purge losses than the same cuts from Ch. The only subprimals where grade impacted total saleable yield were the top (inside) rounds (Ch = 80.13%, Se = 87.34%; P = 0.004) and outside rounds cut into roasts, steaks, and cubed steaks (Ch = 87.61%, Se = 90.28%; P = 0.05). Methods to increase retail yields from beef subprimals should consider minimizing purge and increasing cutting efficiencies in addition to reducing fat trim.

Efectos raciales y heterosis materna Criollo-Guzerat para crecimiento posdestete y características de la canal

Records from 52 calves born in Nayarit, Mexico, were used to evaluate breed effects and Criollo-Guzerat maternal heterosis (MH) on feedlot performance and carcass traits. Progeny was born from Angus sires and Criollo (C, n=8), Guzerat (G, n=20), Criollo- Guzerat (CG, n=18), and Guzerat-Criollo (GC, n=6) cows. Response variables were initial weight (PIP), yearling weight (PAE), final weight (PEFIP), average daily gain (GADIP), feed efficiency (EFALI), rib eye (AOC), rib fat thickness (GRC), hot carcass weight (PCC), dressing percentage (PRC), kidney and pelvic fat (RP), yield grade (GR), cutability (RC), and retail yield (PTC). Analyses were carried out with the GLM procedure of SAS. Statistical Models for PIP, PAE, PEFIP, GADIP and EFALI included the fixed effects of sex of calf (S), year of trial, breed of sire of the cow (R1) and breed of dam of the cow (R2). Fixed effects fitted to models for AOC, GRC, PCC, PRC, RP, GR, RC y PTC were S, R1 and R2. Grandpaternal differences for breed effects were favorable (P<0.10) to Guzerat for PIP (29.6+8.6 kg), PAE (44.6+11.9 kg), PEFIP (41.0+13.7 kg), AOC 2.25+.47 inches2), PCC (46.58+11.0) and PRC (3.15+.83 %). Grandmaternal differences for breed effects were favorable (P<0.10) to Criollo for EFALI (0.01+.004 kg), AOC (2.20+.61 inches2) and PCC (39.02+14.4 kg). HM was important (P<0.10) for AOC (1.18+.47 inches2) and RP (-3.88+0.99 kg). Grandpaternal and grandmaternal differences for breed effects suggest that GC cows are better than CG cows to produce calves for feedlot in Nayarit.

Assessment of single nucleotide polymorphisms in genes residing on chromosomes 14 and 29 for association with carcass composition traits in Bos indicus cattle1,2

Objective of this study was to assess the association of SNP in the diacylglycerol O-acyltransferase 1 (DGAT1), thyroglobulin (TG), and micromolar calcium-activated neutral protease (CAPN1) genes with carcass composition and meat quality traits in Bos indicus cattle. A population of Brahman calves (n = 479) was developed in central Florida from 1996 to 2000. Traits analyzed were ADG, hip height, slaughter weight, fat thickness, HCW, marbling score, LM area, estimated KPH fat, yield grade, retail yield, sensory panel tenderness score, carcass hump height, and cooked meat tenderness measured as Warner-Bratzler shear force at 7, 14, and 21 d postmortem. Single nucleotide polymorphisms previously reported in the TG and DGAT1 genes were used as markers on chromosome 14. Two previously reported and two new SNP in the CAPN1 gene were used as markers on chromosome 29. One SNP in CAPN1 was uninformative, and another one was associated with tenderness score (P < 0.05), suggesting the presence of variation affecting meat tenderness. All three informative SNP at the CAPN1 gene were associated with hump height (P < 0.02). The TG marker was associated with fat thickness and LMA (P < 0.05), but not with marbling score. No significant associations of the SNP in the DGAT1 gene were observed for any trait. Allele frequencies of the SNP in TG and CAPN1 were different in this Brahman population than in reported allele frequencies in Bos taurus populations. The results suggest that the use of molecular marker information developed in Bos taurus populations to Bos indicus populations may require development of appropriate additional markers.

Explaining standard retail yields in UK locations

The empirical investigation of yields across retail centres is an exercise most useful to property investors as it identifies the systematic determinants of retail yield differentials and markets that are over- or under-priced. Yield differentials reflect diverse performance potential and risk factors in individual retail centres. This study estimates a cross-sectional model of UK retail yields in which yield differentials are examined with respect to rent variation and an extensive database containing economic, social and location-specific information. The study finds that two variables, retail footprint scores and occupational classification coding AB most effectively capture the dynamism of local consumer spending power and best explain yield differentials. The analysis also finds that locations at the high or low end of the yield spectrum are not as well explained as those in the middle range. Although there may be factors specific to highand low-yield retail centres, it is suggested that cluster analysis should be explored in over- and under-pricing examinations.

Prediction of retail product weight and percentage using ultrasound and carcass measurements in beef cattle.

Data from 534 steers representing six sire breed groups were used to develop live animal ultrasound prediction equations for weight and percentage of retail product. Steers were ultrasonically measured for 12th-rib fat thickness (UFAT), rump fat thickness (URPFAT), longissimus muscle area (ULMA), and body wall thickness (UBDWALL) within 5 d before slaughter. Carcass measurements included in USDA yield grade (YG) and quality grade calculations were obtained. Carcasses were fabricated into boneless, totally trimmed retail products. Regression equations to predict weight and percentage of retail product were developed using either live animal or carcass traits as independent variables. Most of the variation in weight of retail product was accounted for by live weight (FWT) and carcass weight with R2 values of 0.66 and 0.69, respectively. Fat measurements accounted for the largest portion of the variation in percentage of retail product when used as single predictors (R2 = 0.54, 0.44, 0.23, and 0.54 for UFAT, URPFAT, UBDWALL, and carcass fat, respectively). Final models (P < 0.10) using live animal variables included FWT, UFAT, ULMA, and URPFAT for retail product weight (R2 = 0.84) and UFAT, URPFAT, ULMA, UBDWALL, and FWT for retail product percentage (R2 = 0.61). Comparatively, equations using YG variables resulted in R2 values of 0.86 and 0.65 for weight and percentage of retail product, respectively. Results indicate that live animal equations using ultrasound measurements are similar in accuracy to carcass measurements for predicting beef carcass composition, and alternative ultrasound measurements of rump fat and body wall thickness enhance the predictive capability of live animal-based equations for retail yield.

Carcass characteristics and meat quality of Suffolk Down suckling lambs

The object of this project was to study the carcass characteristics and meat quality of Suffolk Down suckling lambs as well as the effects of slaughter weight and sex on these characteristics. Thirty lambs were divided into groups by live weight at slaughter (light or heavy averaging 10.6 or 14.9 kg, respectively) and by sex. Live weight varied from 8.73 to 14.90 kg, hot carcass weight from 4.57 to 8.05 kg, commercial dressing percentage from 51.12 to 54.1%, empty body weight from 53.23 to 57.45%, ribeye muscle area from 8.69 to 12.70 cm 2, and back fat depth from 0.97 to 2.19 mm. The highest retail yields were for shoulder and leg cuts. The anatomical composition of the shoulder was 54.68, 22.98, 17.49, 2.31 and 2.53% for muscle, bone, fat, residue, and shrink losses, respectively, while the percentages for the leg were 55.97, 23.78, 16.62, 1.93 and 1.70%, respectively. The average chemical composition (%) of the fresh meat was: moisture 62.19, protein 18.30, ether extract 17.96, and ash 1.11. The moisture, protein, and ether extract contents varied according to live weight ( p<0.05). A sensory evaluation performed on fillet samples ( Psoas major, Psoas minor, Iliacus, and Quadratus lumborum) revealed only one significant difference among groups, a difference in aroma according to live weight ( p≤0.05). However, a physical analysis of loin samples ( Longissimus dorsi) showed that water holding capacity and tenderness tended to increase with weight as well. Also, as weight increased, emulsification capacity increased in males while tenderness increased in females. The fatty acid profile from samples of the pelvic and perirenal fat showed a high percentage of saturated fatty acids. The results of the evaluations of both carcass composition and meat quality indicate that suckling lambs are a viable option as a marketable meat.

Estimated genetic parameters for carcass traits of Brahman cattle

Heritabilities and genetic and phenotypic correlations were estimated from feedlot and carcass data collected from Brahman calves (n = 504) in central Florida from 1996 to 2000. Data were analyzed using animal models in MTDFREML. Models included contemporary group (n = 44; groups of calves of the same sex, fed in the same pen, slaughtered on the same day) as a fixed effect and calf age in days at slaughter as a continuous variable. Estimated feedlot trait heritabilities were 0.64, 0.67, 0.47, and 0.26 for ADG, hip height at slaughter, slaughter weight, and shrink. The USDA yield grade estimated heritability was 0.71; heritabilities for component traits of yield grade, including hot carcass weight, adjusted 12th rib backfat thickness, loin muscle area, and percentage kidney, pelvic, and heart fat were 0.55, 0.63, 0.44, and 0.46, respectively. Heritability estimates for dressing percentage, marbling score, USDA quality grade, cutability, retail yield, and carcass hump height were 0.77, 0.44, 0.47, 0.71, 0.5, and 0.54, respectively. Estimated genetic correlations of adjusted 12th rib backfat thickness with ADG, slaughter weight, marbling score, percentage kidney, pelvic, and heart fat, and yield grade (0.49, 0.46, 0.56, 0.63, and 0.93, respectively) were generally larger than most literature estimates. Estimated genetic correlations of marbling score with ADG, percentage shrink, loin muscle area, percentage kidney, pelvic, and heart fat, USDA yield grade, cutability, retail yield, and carcass hump height were 0.28, 0.49, 0.44, 0.27, 0.45, -0.43, 0.27, and 0.43, respectively. Results indicate that sufficient genetic variation exists within the Brahman breed for design and implementation of effective selection programs for important carcass quality and yield traits.

Interaction of dietary magnesium level on the feeding value of supplemental fat in finishing diets for feedlot steers.

A feeding trial involving 160 crossbred steers (357 kg) and a metabolism trial involving eight Holstein steers (189 kg) cannulated in the rumen and proximal duodenum were conducted to evaluate the interaction of dietary Mg level (.18 vs .32%, DM basis) and supplemental fat (0% supplemental fat vs 4% tallow [T], yellow grease [YG], or griddle grease [GG]) on growth performance and NE value of the diet. Dietary Mg level did not influence (P > .10) growth performance. Daily weight gain was lower (11%, P < .05) for steers fed GG than for those fed YG. Supplemental fat decreased (5%, P < .10) DMI and increased (P < .05) gain efficiency (7%). There was a fat x Mg level interaction (P < .01) for dietary NE. The increase in dietary NEg with T and YG supplementation was similar (8.6 vs 8.0%) for diets containing .18 and .32% Mg. In contrast, the increase in dietary NEg with GG supplementation was 8.9% with .18% dietary Mg, but the NEg value of the diet did not increase when GG was added to diets with .32% dietary Mg. Dressing percentage was lower (1.5%, P < .1) and retail yield was greater (2.2%, P < .05) for steers fed GG- than for steers fed YG-supplemented diets. Increasing dietary Mg level increased kidney, pelvic, and heart fat (5.5%, P < .05). There was a fat x Mg level interaction (P < .1) for marbling score. With diets containing no supplemental fat, increasing dietary Mg decreased (15.2%) the marbling score, and with diets containing supplemental fat, increasing dietary Mg increased (7.2%) the marbling score. Fat supplementation decreased (P < .01) ruminal and total tract digestion of OM (10 and 3.5%, respectively) and NDF (37 and 17%, respectively). Supplemental fat did not affect (P > .10) Ca digestion but decreased (41.7%, P < .01) apparent Mg digestion. Increasing dietary Mg level increased (77.7%, P < .05) apparent Mg digestion. There were no treatment effects (P > .10) on postruminal fatty acid digestion. Fat supplementation decreased (17.3%, P < .01) the acetate:propionate molar ratio. Total ruminal protozoal counts were increased (12.7%, P < .05) by increasing dietary Mg level and decreased (12.9%, P < .05) by fat supplementation. We conclude that supplemental fats may depress Mg absorption. Increasing dietary magnesium levels beyond current recommendations may increase marbling scores in cattle fed fat-supplemented diets but may not affect growth performance or dietary NE. The NE value of fat is a predictable function of level of fat intake.

Influence of free fatty acid content on the feeding value of yellow grease in finishing diets for feedlot cattle.

Holstein steers (n = 96; 375 kg) were used in a 144-d growth-performance trial to evaluate influence of level (42, 28.5, and 15%) of FFA content on feeding value of yellow grease. Two sources of yellow grease were compared: conventional yellow grease (CYG), containing 15% FFA, and griddle grease (GG), containing 42% FFA. Dietary treatments consisted of an 88% concentrate finishing diet supplemented with either 1) 0% fat, 2) 5% GG, 3) 2.5% GG and 2.5% CYG, or 4) 5% CYG. Fat supplementation increased ADG (11%; P<.05), feed efficiency (9%; P<.05), diet NE (6.4%; P<.05), carcass weight (4%; P<.10), dressing percentage (1%; P<.10), and kidney, pelvic, and heart fat (20%, P<.05). Increasing the FFA in supplemental fat increased (linear effect, P<.10) DM intake, ADG, and feed efficiency and decreased (linear effect, P<.10) retail yield. These improvements in performance were primarily due to increased DM intake. The NEm and NEg values of supplemental fats were not affected by FFA content, averaging 4.98 and 3.85 Mcal/kg, respectively. Treatment effects on characteristics of ruminal and total tract digestion were evaluated using four Holstein steers (180 kg) with cannulas in the rumen and proximal duodenum. Supplemental fat did not influence (P>.10) ruminal or total tract digestion of OM, ADF, starch or N. Postruminal fatty acid digestion was less (P<.10) for fat-supplemented diets than for unsupplemented diets (73.0 vs. 78.6%). The decrease in postruminal fatty acid digestibility with fat supplementation was mainly due to a decreased (16.7%; P<.05) digestibility of C18:0. Postruminal digestibility of the supplemental fat was 68%. There were no treatment effects (P>.10) on ruminal pH. Ruminal biohydrogenation of fatty acids was directly proportional to estimates of methane production. We conclude that the feeding value of conventional yellow grease and griddle grease is similar and that differences in the FFA content of yellow grease will not negatively affect diet acceptability and growth performance of feedlot cattle.

Retail yield and fabrication times for veal as influenced by purchasing options and merchandising styles.

Twenty-nine selected styles of subprimals or sections of veal were obtained from a commercial facility to assist in the development of a support program for retailers. They were fabricated into bone-in or boneless retail cuts and associated components by trained meat cutters. Each style selected (n = 6) was used to generate mean retail yields and labor requirements, which were calculated from wholesale and retail weights and processing times. Means and standard errors for veal ribs consisting of five different styles (n = 30) concluded that style #2, 7-rib 4 (10 cm) x 4 (10 cm), had the lowest percentage of total retail yield (P < .05) owing to the greatest percentage of bone. Furthermore, rib style #2 required the longest total processing time (P < .05). Rib styles #3, 7-rib chop-ready, and #5, 6-rib chop ready, yielded the greatest percentage of total retail yield and also had the shortest total processing time (P < .05). Within veal loins, style #2, 4 (10 cm) x 4 (10 cm) loin kidney fat in, had the greatest percentage fat (P < .05). Loin styles #2 and #3, 4 (10 cm) x 4 (10 cm) loin special trimmed, generated more lean and fat trimmings and bone, resulting in lower percentage of total retail yields than loin style #1, 0 (0 cm) x 1 (2.5 cm) loin special trimmed (P < .05). Results indicated that bone-in subprimals and sections required more processing time if fabricated into a boneless end point. In addition, as the number of different retail cuts increased, processing times also increased.

Phenotypic characterization of Rambouillet sheep expressing the callipyge gene: II. Carcass characteristics and retail yield.

Paternal half-sibling Rambouillet ram lambs (n = 18) representing two muscle phenotypes were slaughtered at 54.5 kg to evaluate carcass characteristics and composition. Lambs were produced from a sire that was heterozygous for the callipyge gene. Carcasses were broken into wholesale and retail cuts to evaluate percentage bone-in retail yield of carcasses at various fat trim levels and percentage of boneless retail cuts. Retail cuts were trimmed to .6 and then to 0 cm fat trim and bones were removed to determine boneless, closely trimmed retail cut yield. Chemical composition was determined using proximate analysis. Lambs expressing the callipyge gene had higher dressing percentages (57.3 vs 53.9), leg (14.4 vs 11.0) and conformation (14.4 vs 11.0) scores, and larger longissimus muscle (LM) areas (17.6 cm2 vs 10.3 cm2). All other carcass measurements were similar between phenotypes except marbling score, which was higher (417.8 vs 325.6) for controls. Lambs expressing the callipyge gene had a higher (40.2 vs 32.9) percentage boneless retail yield than controls. Retail yield of the boneless shoulder did not differ between phenotypes (8.9 vs 8.0). All other percentages of boneless retail cuts were higher (P < .02) for lambs expressing the callipyge gene. Carcasses from lambs with the callipyge gene had higher protein (16.6 vs 15.2), moisture (63.6 vs 58.6) and ash (.85 vs 77) percentages and lower fat (18.9 vs 25.4) percentages than controls. These data suggest that ram lambs expressing the callipyge gene have an advantage in retail yield and carcass conformation when compared to normal-muscled half-siblings.

Feeding value of cottonseed meal for feedlot cattle.

One hundred twenty crossbred steers (294 kg, initially) were used in a 141-d finishing trial. Four concentrations (8, 16, 24, and 32% of diet DM) of cottonseed meal (CSM, prepressed solvent-extracted) replaced steam-flaked corn in a corn-based finishing diet. Increasing level of CSM decreased ADG (linear component, P < .10), feed efficiency (linear component, P < .01), and dietary NE (linear component, P < .01). Observed dietary NE was 99% of expected at 8 and 16% CSM but 95% of expected at higher levels of inclusion (linear component, P < .05). Level of CSM did not influence (P > .10) dressing percentage, longissimus area, fat thickness, or retail yield. Eight Holstein steers (285 kg) were used in a replicated 4 x 4 Latin square design to evaluate treatment effects on characteristics of digestion. Ruminal digestibility of OM decreased (linear component, P < .05) as CSM increased, although ruminal digestibility of starch and feed N were not affected (P > .10). Ruminal escape protein from CSM was 58%. Total tract starch digestion was not altered (P > .10), but total tract digestibility of OM and GE decreased (linear component, P < .05) and digestion of N increased (linear component, P < .01) as CSM replaced steam-flaked corn. The ratio of observed to expected DE value of the diets was similar across CSM levels, averaging .99. Thus, comparative DE value of CSM was not affected by level of inclusion, averaging 3.32 Mcal/kg. We conclude that the NEm and NEg values of CSM are 1.88 and 1.24 Mcal/kg, respectively, and in close agreement with tabular values. However, CSM should not exceed 16% of DMI, because higher levels may depress cattle performance and replacement value of CSM.

Relationships Between Body Measurements Obtained on Yearling Brangus Bulls and Measures of Carcass Merit Obtained from Their Steer Clone-Mates

This study was designed to determine the relationship between ultrasonic and linear body measurements of yearling bulls and percentage retail product (pRP) of slaughter steers using genetically identical bulls and steers as experimental animals. Four groups of Brangus, second-generation nuclear transfer calves (two steers and two to four bulls per clone group) were used in this study. Serial (every 28 d) measurements of hip height (HH), body length (BL), rump length (RL), rump width (RW), shoulder width (SW), round mass (RNMS), metacarpal length and circumference (MCL and MCC), metatarsal length and circumference (MTL and MTC), and ultrasonic measurements of backfat thickness (BFT), Longissimus muscle area (LMA), Longissimus muscle depth (LMD), body wall thickness (BWT), rump fat thickness (RFT), and rump muscle depth (RMD) obtained on each bull from weaning (6 to 7 mo) until 16 to 17 mo of age were regressed on age to obtain 365-d age constant estimates for the traits. Steers were slaughtered between 480 and 520 d of age and percentage of retail cuts (trimmed to 0.64 em) was obtained. Genetic correlations of the adjusted traits of the bulls to age-constant percentage retail yield of the steers were obtained following Yamada (1962). The highest genetic correlations (P<0.05) with PRP were 0.568, −0.532, and −0.523 with RNMS, RMD, and BIT, respectively. The best three-variable equation for predicting PRP developed from these data included RNMS, RL, and BFT (R2=0.80, P=0.0001).

Real-time ultrasonic measurement of fat thickness and longissimus muscle area: II. Relationship between real-time ultrasound measures and carcass retail yield.

Feedlot steers (n = 180) representing 11 sire-breed groups were ultrasonically measured for fat thickness (FTU) and longissimus muscle area (LMU) at two 60-d intervals during the feeding period and four 21-d intervals corresponding to serial slaughter dates to predict carcass retail yield parameters. Two fat trim levels, 8 and 0 mm, were used to calculate percentage of trimmable fat (FAT8P and FAT0P) and retail product percentage (RPD8P and RPD0P) for each carcass. Regression techniques were used to evaluate best-fit equations that explained variation in retail product components. When FAT8P, FAT0P, RPD8P, and RPD0P were regressed on USDA yield grade (YG), R2 values ranged from 75 to 76% (P < .001). Comparatively, when live animal predictors of YG components (FTU, LMU, and final live weight) were used as the independent variables, equations predicting retail yield had R2 values of 61 to 65% (P < .01). Equations using final FTU as the independent variable explained 58 to 64% (P < .001) of the variation in FAT8P, FAT0P, RPD8P, and RPD0P. Equations with FTU, LMU, and either WT, AGE, marbling, or quality grade resulted in R2 values similar to those with only FTU, indicating the strong influence of fat on retail yields. These results indicate that ultrasonic predictors explained about 10% less variation in retail product percentage than did carcass measures.

Evaluation of Angus, Charolais and Hereford as terminal sire breeds on Hereford and first-cross cows. II. Carcase characteristics and retail yield of progeny

The characteristics and retail yield of carcases of 482 Angus, Charolais and Hereford sired progeny out of straightbred Hereford (HxH), and first-cross Brahman x Hereford (BxH), Simmental x Hereford (SxH) and Friesian x Hereford (FxH) dams were evaluated. The cattle had been raised and slaughtered for either the vealer (both sexes), yearling domestic (both sexes) or the heavy export steer market. The data were analysed within market type, and at a constant age at slaughter (281, 478 and 829 days for vealer, yearling domestic and heavy export carcases respectively) and also at a constant hot P8 fat depth (4.6, 7.8 and 14.9 mm for the three markets respectively) and constant hot carcase weight (160, 200 and 343 kg for the three markets respectively). At a constant age, carcases of Charolais sired progeny were significantly (P &lt; 0.05) heavier (8-16%, depending on market type), leaner, had larger eye muscle area and higher dressing percentage than those of Angus and Hereford sired progeny. This resulted in 12 to 17% (P &lt; 0.05) more kg of boneless saleable meat (retail yield) from carcasses of Charolais sired progeny. At a constant hot P8 fat depth, the magnitude of the sire breed differences increased, whereas at a constant hot carcase weight, the differences became non-significant or were reduced in magnitude. At a constant age, progeny of BxH dams had higher ( P &lt; 0.05) dressing percentage than those of the other dam breeds for all market types except the vealer market. Progeny of FxH dams had more (P &lt; 0.05) channel and kidney fat than those of the other dam breeds, even at a constant hot P8 fat depth. Retail yield, as a percentage of the boned side, was highest for carcases of progeny of BxH dams and lowest for those of progeny of FxH dams (70.2% and 70.3% v. 69.1% and 69.2%, for vealer and yearling domestic carcases respectively, at a constant age). Sire and dam breed effects for the individual primal cuts, as percentages of the boned side, were not significant for most of the primal cuts, and where significant, the differences were very small.

Carcass composition of cull sows

Two hundred and four sows were slaughtered in seven weight classes (WCs) from &lt; 99.9-kg to &gt; 225-kg carcass weight in 25-kg increments and 11 fat classes (FCs) from &lt; 9.9-mm to &gt; 55-mm backfat depth in 5-mm increments. Backfat thickness (probe fat) and loin muscle depth (probe lean) were measured on the left side of the carcass between 3rd and 4th last rib 7 cm from midline by electronic probe. The left side was cut into four primals: shoulder, ham, loin and belly. Shoulder, ham and loin were then separated into trimmed commercial cuts to determine commercial yield and then defatted and deboned to determine retail yield, lean yield, fat yield and bone yield. Dressing percentage was lowest for those sows in fat class 1 (77.4%) and highest for those in fat class 11 (83.7%). Percentage of shoulder and ham in the carcass side decreased, while the percentage of the loin and belly increased as WC and FC increased. FC produced significant effect on the percentage of the shoulder, loin and belly, whereas WC had significant influence only on the proportion of the shoulder and belly. There was a significant WC × FC interaction (P &lt; 0.002) upon the percentage of the belly yield. The percentages of commercial yield, retail yield, lean yield and bone yield were reduced, and that of fat yield increased as WC and FC increased, but WC only produced significant effects on the percentage of lean and bone yield. Carcass composition of cull sows was better correlated to backfat thickness than carcass weight, since the increase in carcass weight as live weight increased was primarily fat. Key words: Carcass composition, sows, lean yield

Direct and maternal genetic effects for carcass traits in beef cattle.

Carcass measurements were taken on 1,537 steers produced over four generations in a rotational crossbreeding study. Breed direct and maternal additive and heterotic genetic effects were estimated for hot carcass weight (HCWT), retail yield (RY), longissimus muscle area (LM), fat thickness (FT), marbling score (MS), and Warner-Bratzler shear force (WBS). Angus (A), Brahman (B), Charolais (C), and Hereford (H) breeds were involved in straightbred, first-cross, and two-, three-, and four-breed rotational crossbred matings with each crossbred combination including the B. Breed direct (Ig) and maternal (Mg) additive genetic effects and direct (Ih) and maternal (Mh) heterotic genetic effects were estimated using a multiple-regression model. The Ig and Mg effects were expressed as deviations from the overall mean. The IgC effects (Ig for C breed) were significant for HCWT, RY, and LM and resulted in leaner, heavier carcasses. The IgA and IgH effects were, in general, negative (P < .05) for HCWT, RY, LM, and WBS, and positive (P < .01) for FT and MS. The IgB effects were large and undesirable for HCWT, RY, LM, MS, and WBS (P < .01). The majority of Ih effects were beneficial (P < .05) for HCWT, RY, LM, and WBS. The Ih effects exhibited by B combinations were of greater (P < .05) magnitude with positive influences for HCWT, RY, and LM and desirable effects for WBS. The maternal additive and heterotic effects were of lesser importance than the direct additive and heterotic effects for the carcass traits studied.

Two-, three-, and four-breed rotational crossbreeding of beef cattle: carcass traits.

Carcass data from 1,494 straightbred and rotational crossbred steers were collected over four generations. Mating systems included straightbreds (Angus [A], Brahman [B], Charolais [C], and Hereford [H]); two-breed rotations (A-B, C-B, and H-B); three-breed rotations (A-B-C, A-B-H, and B-C-H); and a four-breed rotation (A-B-C-H). Steers were randomly allocated to one of four postweaning treatments that varied in length of grazing and feeding periods. Treatment and breed group (four straightbreds and seven rotational combinations) significantly influenced hot carcass weight (HCWT), retail yield (RY), longissimus muscle area (LM), fat thickness (FT), marbling score (MS), USDA quality grade (QG), and Warner-Bratzler shear force (WBS). Feeding for longer periods resulted in greater (P < .05) HCWT, RY, FT, and MS, higher QG, and lower (P < .05) WBS values. Among the straightbreds, C was heavier and larger for HCWT, RY, and LM (P < .01), whereas A and H had greater (P < .01) FT and MS. The B was similar to H for HCWT, RY, and LM and to C for FT but ranked last (P < .01) for MS and WBS. Three- and four-breed rotational mating systems were superior (P < .05) to the two-breed rotation for HCWT, RY, and LM but were similar for FT, MS, and WBS. Rotational combinations exceeded (P < .05) the straightbreds for all carcass traits except MS.

Predicting percentage of retail yield from carcass measurements, the yield grading equation, and closely trimmed, boxed beef weights.

Over the past 3 yr, 100 carcasses (64 steers, 24 bulls, and 12 heifers) were fabricated into closely trimmed (6 mm maximum fat cover), boxed beef and further evaluated for percentage of retail yield at the Iowa State University Meat Laboratory. Hot carcass weight ranged from 235 to 399 kg with a least squares mean (LSM) and standard error across all sex classes of 318 +/- 3 kg. Additionally, fat cover ranged from .30 to 1.78 cm with an average of .91 +/- .05 cm. The LSM for longissimus muscle area (LMA) across all sex classes was 81.6 +/- 1.0 cm2. Bulls had significantly less subcutaneous fat (P less than .01) and greater LMA (P less than .01) than did either steers or heifers. Retail yield from the boxed chuck, expressed as a percentage of cold carcass weight, was 19.2 for bulls and 14.8 for steers. This difference was due primarily to a reduction of intermuscular fat. Similarly, bulls had a greater yield (P less than .01) of the boxed round than did steers. When cattle of differing frame sizes were compared, only percentage of retail yield of the boxed round was significant (P less than .01): large-framed cattle yielded 14.3 +/- .2%, compared with 12.8 +/- .2% for the small-framed cattle. When all possible regression analyses were run, sex class differences accounted for 25.7% of the variation in retail yield. The current USDA retail yield equation accounted for only 37.2% of the variation. Percentage of closely trimmed, boneless round had an R2-value of .57.(ABSTRACT TRUNCATED AT 250 WORDS)