Greater Longissimus Muscle Area Research Articles

187 Effect of Piglet Weaning Weight on Wean-to-Finish Growth Performance and Ultrasound Carcass Measures

Abstract The objective of this study was to evaluate the impact of variation in piglet weaning weight (WW) resulting from interventions during lactation on post-weaning performance. A split-split plot design was used with a 2 x 2 x 2 factorial arrangement of treatments: 1) Liquid milk replacer [MR; main plot; No Supplement (NS) vs. Supplement (SU)]; 2) Litter size [LS; sub-plot; LOW (4 pigs less than functional teat number) vs. HIGH (2 pigs greater than functional teat number)]; 3) WW [sub-sub-plot; LIGHT (2 lightest barrows and 2 lightest gilts within each litter) vs. HEAVY (2 heaviest barrows and 2 heaviest gilts within each litter)]. Each MR feeder was available to 2 litters, one on the LOW and one on the HIGH LS treatment. Cross-fostering was carried out at 24 h after birth to create LS treatment litters; MR treatment was applied from 24 h after birth until weaning (20 days of age). The study involved 256 pigs housed in mixed-sex pens of 4 pigs (2 barrows; 2 gilts) and was carried out from weaning to a fixed pen weight (130.0 ± 2.27 kg). Pigs were weighed at start and end of the study when ultrasound scans were collected (at the 10th rib) to measure backfat depth (BF) and Longissimus muscle area (LMA). Data were analyzed using PROC MIXED of SAS; the model accounted for fixed effects of MR, LS, WW, and all interactions, and random effects of replicate, replicate by MR interaction and replicate by MR by LS interaction. There were no treatment interactions (P > 0.05) for any measurements (Table 1). The MR treatment had no effect (P > 0.05) on WW; the SU treatment had greater (P ≤ 0.05) ADFI but had no effect (P > 0.05) on other measurements compared with the NS treatment (Table 1). Compared with the LOW LS treatment, the HIGH LS treatment had lighter WW (1.7 kg; P ≤ 0.05), and greater days on test (4 days; P ≤ 0.05); however, there were no differences (P > 0.05) for other measurements. Compared with the LIGHT WW treatment, HEAVY pigs had greater WW (1.7 kg; P ≤ 0.05), fewer days on test (7.9 days; P ≤ 0.05), greater (P ≤ 0.05) overall ADG (38 g) and ADFI (78 g), less BF (0.17 cm; P ≤ 0.05) and greater LMA (1.37 cm2; P ≤ 0.05). In conclusion, providing MR during lactation had little effect on post-weaning performance. However, increasing LS above sow functional teat number reduced WW and increased the time to reach harvest weight with no effect on post-weaning growth performance. In addition, HEAVY WW piglets had improved post-weaning growth performance and carcass lean measurements compared with LIGHT WW piglets.

93 Feedlot Performance, Carcass Traits, and Feeder Calf Value of Beef × Holstein and Holstein Steers

Abstract Dairy producers are increasingly breeding their lower production cows to beef sires in hopes of increasing revenue over straightbred Holstein steers (HO). However, there are limited published data regarding feedlot finishing beef × Holstein crossbred steers (B×HO). Therefore, objectives of this study were to compare feedlot performance, carcass traits, and value of B×HO and HO. Steers were delivered to the Michigan State University Beef Center, Lansing, and after a 21-d adjustment, breed types (B×HO; n = 60 and HO; n = 60) were randomly allocated into 10 pens each. Initial weights (d 0) were 196.7 and 196.9 kg for B×HO and HO, respectively (P = 0.95). Steers remained on a growing diet until d 14 and then transitioned by d 28 to a finisher diet consisting of high moisture corn, corn silage, dried corn distillers grains with solubles, pelleted supplement with monensin, and limestone. The B×HO tended (P = 0.07) to have greater ADG (1.75 ± 0.02 vs. 1.70 ± 0.02 kg/d) compared with HO, but similar DMI (10.40 vs. 10.35 kg/d; P = 0.79). The B×HO had a greater G:F compared with HO (0.188 vs. 0.178; P = 0.02). There were no observed differences in morbidity (8.3 vs. 8.3%; P = 1.0) or mortality (1.7 vs. 1.7%; P = 1.0) for B×HO and HO, respectively. Cost of gain was similar for B×HO ($2.69/kg) when compared with HO ($2.76/kg; P = 0.14). Steers were harvested at a commercial abattoir on d 245 and 266 for B×HO and HO, respectively, after reaching an average empty body fat of 28.0% as determined by ultrasound. Following a 48-h chill, carcass data were collected. Although final live weight tended (P = 0.08) to be less for B×HO compared with HO (621.3 ± 11.5 vs. 634.8 ± 11.5 kg), carcass weights were similar between breed types (365.4 vs. 366.6 kg; P = 0.78). The B×HO had greater longissimus muscle area (87.8 vs. 73.1 cm2; P < 0.01), greater backfat thickness (1.18 vs. 0.79 cm; P < 0.01), and lesser USDA Yield Grade (2.9 vs. 3.2; P = 0.02) than HO. The B×HO and HO had similar marbling scores (Small26 vs. Small37; P = 0.63) and USDA Quality Grades (Low-Choice and greater, 52.7 vs. 59.3%; Mid-Choice and greater, 18.2 vs. 20.3%; and Low-Prime and greater, 3.6 vs. 1.7%; P > 0.40). Based on abattoir plant prices in August 2022, carcass revenue was greater for B×HO ($1,911/carcass) when compared with HO ($1,765/carcass; P < 0.01). Calculated breakeven feeder calf value was $212 greater for B×HO compared with HO ($700 vs. $488/steer; P < 0.01). Overall, B×HO were more feed efficient and produced carcasses with greater yield, resulting in greater feeder calf value when compared with HO counterparts.

Essential Oils Combined with Vitamin D3 or with Probiotic as an Alternative to the Ionophore Monensin Supplemented in High-Energy Diets for Lambs Long-Term Finished under Subtropical Climate.

Supplementation with natural additives such as essential oils (EO) or probiotics has resulted in comparable growth performance to that of supplemental monensin in fattening lambs in hot environments. Supra-supplementation levels of vitamin D3 improved the carcass weight and dressing percentage of steers fattened under tropical conditions. We hypothesized that certain combinations of these natural additives could be complementary. For this reason, a feeding trial was carried out using 48 Pelibuey × Katahdin non-castrated male lambs (107 ± 14 d age; 17.9 ± 2.51 kg LW). Lambs were fed an 88:12 concentrate to forage ratio basal diet supplemented (dry matter basis, DMI) with: (1) no additive (CON); (2) 28 mg monensin/kg diet (MON); (3) 150 mg of essential oils containing a combination of thymol, eugenol, vanillin, guaiac, and limonene plus 0.12 mg vitamin D3 (EO + D3)/kg diet; and (4) 300 mg of essential oils containing a combination of carvacrol and cynamaldehyde plus 2 g probiotic (2.2 × 108 CFU of bacillus subtilis/kg diet, EO + BS). Lambs were grouped by initial weight and assigned within six weight groupings to 24 pens (2 lambs/pen, 6 replicas per treatment) in a randomized complete block design. The experiment lasted 121 days. Daily maximal THI exceeded the 80 "danger or "emergency" range for 119 days of the 121 days of the trial. Lambs supplemented with MON had similar DMI, growth performance, and dietary energetics to those of CON lambs. Lambs supplemented with EO + BS had a greater (9.2%, p ≤ 0.05) average daily gain (ADG) than the CON and MON groups due to enhanced (10.2%, p ≤ 0.05) dry matter intake. Thus, gain efficiency (GF) and estimated dietary energy were similar for CON, MON, and EO + BS. Lambs receiving EO + D3 had similar (0.254 vs. 0.262 kg/d) ADG but a lower DMI (8%, p < 0.05) compared with EO + BS lambs. Consequently, GF and estimated dietary net energy were greater (4.9 and 3.7%, respectively; p ≤ 0.05) for EO + D3 lambs. Even when ambient heat load was elevated, the efficiency of utilization of dietary energy (observed-to-expected dietary net energy) was close to 1.00 (0.992) expected for EO + D3 lambs. In contrast, efficiency of energy utilization was depressed by -4.4% for lambs on the other treatments. Compared with the other treatments, lambs receiving EO + D3 had greater longissimus muscle area (5.6%, p < 0.05) and lower kidney pelvic fat (21.8%, p ≤ 0.05). There were no treatment effects on shoulder tissue composition or whole cuts (expressed as % of cold carcass weight). Compared to CON, lambs that were fed with natural additives showed 3.5% lower (p ≤ 0.05) intestine mass. All supplemental additives decreased visceral fat mass, which was minimal with EO + D3 treatment. Combinations of essential oils with vitamins or probiotics were superior to antibiotic monensin in finishing diets for feedlot lambs. Combining EO with probiotics promoted DM intake and gain but not gain efficiency, while combining EO with vitamin D3 supra-supplementation increased dietary energy efficiency and improved some carcass characteristics in lambs fattening under high ambient heat loads.

Effects of a Blend of Live Yeast and Organic Minerals as an Alternative to Monensin on Intake, Digestibility, Performance and Beef Quality of Nellore Bulls Finished on Pasture with High Concentrate Supplementation

Effects of a blend of live yeast and organic minerals as an alternative to monensin and inorganic trace minerals for beef cattle finished on pasture with high concentrate supplementation, on growth performance, intake, digestibility, liver trace mineral and carcass characteristics were evaluated. Forty-eight Nellore bulls were blocked by initial body weight and randomly assigned to one of the two experimental diets. The animals were raised in an experimental pasture divided into 12 paddocks equipped with an electronic system for monitoring individual feeding behavior and feed intake. Treatments were: (1) Monensin (MON), 30 mg/kg supplement dry matter of sodium monensin and trace minerals supplementation from inorganic sources; (2) AdvantageTM (ADV), 1.6 g/kg supplement DM of a blend of live yeast (Saccharomyces cerevisiae strains) and organic trace minerals. The use of ADV instead of MON led to greater supplement intake and greater intake of dietary components. Bulls fed ADV also had higher digestibility of dry matter, organic matter, crude protein and non-fiber carbohydrates. Bulls fed MON had a greater number of visits to the feeder, however with a shorter time spent feeding per visit. The use of ADV resulted in higher average daily weight gain, and feed efficiency was similar between treatments. In the carcass, ADV tended toward greater Longissimus muscle area. Liver Zn concentration tended to be lower in the ADV treatment. The use of ADV generated higher meat lightness and redness. In summary, the blend of live yeast and organic minerals can be an alternative to monensin and inorganic sources of trace minerals for beef cattle finished on pasture with high concentrate supplementation, without negative effects on supplement feed efficiency and with benefits to animal growth.

Effect of grain inclusion rates in diets provided to early-weaned calves and steroidal implants utilization on growth performance and carcass characteristics of beef steers

Abstract One hundred and twenty-one Angus × SimAngus-crossbred steers (body weight (BW) = 159 ± 22 kg) were used to evaluate the effects of different grain inclusion (GI) rates in diets provided to early-weaned calves and steroidal implants (SI) utilization on growth performance and carcass characteristics, particularly intramuscular fat deposition, of beef steers. The experiment was conducted as a randomized complete block design with a 2 × 2 factorial arrangement of treatments, consisting of two GI rates (35% vs. 58%, dry matter (DM) basis), each one associated or not to steroidal implant utilization (no implants vs. 80 mg trenbolone acetate (TA) + 16 mg estradiol followed by 120 mg TA + 24 mg of estradiol). After being early-weaned (124 ± 14 d of age), steers were offered an average of 4.5 kg/d (DM basis) of a concentrate-based diet with a greater or lesser GI rate for 60 d. After being fed a concentrate-based diet with different GI rates for 60 d, steers were fed a common backgrounding diet for 56 d and subsequently fed a common high-grain diet until harvested at a constant final BW (620 kg). Steers were not implanted until the beginning of the backgrounding phase and then re-implanted when initiating the finishing phase. Data were analyzed using PROC MIXED in SAS. There were no GI × SI interactions (P ≥ 0.62) for any of the growth performance parameters throughout the experimental period. Implanted steers tended to have a greater average daily gain (P = 0.10) during the finishing phase than nonimplanted steers. For the 12th rib fat thickness and yield grade (YG), a GI × SI interaction (P = 0.03) and a tendency for a GI × SI interaction (P = 0.10) was detected, respectively. Nonimplanted steers fed diets with greater GI rates presented the greatest 12th rib fat thickness and tended to have the greatest YG among treatments. No other interactions (P ≥ 0.33) were observed for the hot carcass weight, Longissimus muscle (LM) area, quality grade, marbling score, and kidney-pelvic-heart fat content. Steers fed diets with lesser GI rates tended to have a greater LM area than steers fed diets with greater GI rates (P = 0.10). Results from this experiment indicate that varying GI rates in diets provided to early-weaned calves and subsequent implantation with steroidal hormones did not affect marbling deposition.

Comparing Blend of Essential Oils Plus 25-Hydroxy-Vit-D3 Versus Monensin Plus Virginiamycin Combination in Finishing Feedlot Cattle: Growth Performance, Dietary Energetics, and Carcass Traits.

Simple SummaryA primary objective in livestock production is the limitation of use of conventional antibiotics as feed additives for promoting growth. Due to their antimicrobial characteristics, essential oils are “generally recognized as safe” alternatives to conventional antibiotics. In this study, dietary supplementation of finishing cattle with essential oils combined with vitamin D3 improved dietary energy utilization comparable to that of the combination of ionophore monensin and antibiotic virginiamycin. Furthermore, supplementation with essential oils combined with vitamin D3 during the finishing phase may improve carcass Longissimus muscle area and carcass yield.Ninety crossbreed bulls (349.5 ± 8.25 kg initial weight) were used in an 87day trial to compare the effects of a blend of essential oils plus 25-hydroxy-Vit-D3 (EO + HyD) versus the combination of monensin with virginiamycin (MON + VM) on feedlot growth performance and carcass characteristics. Dietary treatments (nine replicates/treatment) were supplemented with 40 mg/kg diet dry matter of MON + VM (equal parts) or with 120.12 mg/kg diet dry matter of a combination of standardized mixture of essential oils (120 mg) plus 0.12 mg of 25-hydroxy-vitamin-D3 (EO + HyD). There were no treatment effects on dry matter intake (DMI, p = 0.63). However, the coefficient of variation in day-to-day DMI was greater for EO + HyD than for MON + VM (11.4% vs. 3.88%, p = 0.04). There were no treatment effects (p ≥ 0.17) on daily weight gain, gain-to-feed ratio, and estimated dietary net energy. Cattle supplemented with EO + HyD had greater Longissimus muscle area (7.9%, p < 0.01) and estimated retail yield (1.6%, p = 0.03), and tended to have heavier (1.7%, p = 0.10) carcass weight. Differences among treatments in dressing percentage, fat thickness, kidney–pelvic–heart fat, and marbling score were not appreciable (p > 0.10). It is concluded that growth performance response and dietary energetic are similar for finishing cattle supplemented with EO + HyD vs. MON + VM. However, compared with MON + VM, supplementation with EO + HyD during the finishing phase may improve carcass Longissimus area and carcass yield.

Influence of Maternal Protein Restriction in Primiparous Beef Heifers during Mid- and/or Late-Gestation on Progeny Feedlot Performance and Carcass Characteristics.

Simple SummaryMaternal nutrient restriction in beef cows can impact developmental processes in the fetus, which may influence lifetime performance. If feed is limited, a maternal deficiency in protein and/or energy can occur. As a result, the fetus may receive inadequate levels of nutrients, potentially altering fetal development. In the present study, we evaluated the impact of a metabolizable protein restriction during mid- and/or late-gestation on progeny carcass characteristics. First-calf heifers were provided with a diet that either met their metabolizable protein requirements or caused an 80% restriction in metabolizable protein during mid- and/or late-gestation in a crossover design. Our results suggest that heifers catabolized lean body tissue, but not body fat stores, to overcome the metabolizable protein deficiency. However, restricting metabolizable protein in gestating heifers did not substantially influence the feedlot performance or carcass characteristics of their offspring. The restricted dams may have buffered their offspring from the metabolizable protein limitation during gestation.This study investigated the impacts of metabolizable protein (MP) restriction in primiparous heifers during mid- and/or late-gestation on progeny performance and carcass characteristics. Heifers were allocated to 12 pens in a randomized complete block design. The factorial treatment structure included two stages of gestation (mid- and late-) and two levels of dietary protein (control (CON); ~101% of MP requirements and restricted (RES); ~80% of MP requirements). Half of the pens on each treatment were randomly reassigned to the other treatment at the end of mid-gestation. Progeny were finished in a GrowSafe feeding system and carcass measurements were collected. Gestation treatment x time interactions indicated that MP restriction negatively influenced heifer body weight (BW), body condition score, and longissimus muscle (LM) area (p < 0.05), but not fat thickness (p > 0.05). Treatment did not affect the feeding period, initial or final BW, dry matter intake, or average daily gain of progeny (p > 0.05). The progeny of dams on the RES treatment in late gestation had a greater LM area (p = 0.04), but not when adjusted on a hot carcass weight basis (p > 0.10). Minimal differences in the animal performance and carcass characteristics suggest that the level of MP restriction imposed during mid- and late-gestation in this study did not have a significant developmental programming effect.

Effect of zinc source and concentration and chromium supplementation on performance and carcass characteristics in feedlot steers1,2,3.

Four hundred crossbred steers were used in a randomized complete block design to investigate the effects of supplemental Zn source and concentration, and dietary Cr on performance and carcass characteristics of feedlot steers fed a steam-flaked corn-based finishing diet. Steers were blocked by initial BW within cattle source (3 sources) and randomly assigned within block to 1 of 5 treatments. Before the initiation of the experiment, trace mineral supplement sources were analyzed for Zn and Cr. Zinc and Cr concentrations of the Zn sources were used to balance all dietary treatments to obtain correct Zn and Cr experimental doses. Treatments were the addition of: 1) 90 mg Zn/kg DM from ZnSO4 and 0.25 mg Cr/kg DM from Cr propionate (90ZS+Cr); 2) 30 mg Zn/kg DM from Zn hydroxychloride and 0.25 mg Cr/kg DM from Cr propionate (30ZH+Cr); 3) 90 mg Zn/kg DM from Zn hydroxychloride and 0.25 mg Cr/kg DM from Cr propionate (90ZH+Cr); 4) 60 mg Zn/kg DM from ZnSO4 and 30 mg Zn/kg DM from Zn methionine (90ZSM); and 5) 90 mg Zn/kg DM from Zn hydroxychloride (90ZH). Steers were individually weighed on d-2 and on 2 consecutive days at the end of the experiment. Initial liver biopsies were obtained from all steers at processing. Equal numbers of pen replicates per treatment were slaughtered at a commercial abattoir on day 162, 176, and 211; individual carcass data and final liver samples were collected. Total finishing dietary Zn and Cr concentrations were 118.4, 58.2, 114.2, 123.0, and 108.2 mg Zn/kg DM and 0.740, 0.668, 0.763, 0.767, and 0.461 mg Cr/kg DM, for treatments 1 to 5, respectively. Data were analyzed statistically using preplanned single degree of freedom contrasts. Steers receiving 90ZH+Cr had greater final BW (P < 0.04) and ADG (P < 0.03) when compared with steers receiving 90ZH. Additionally, hot carcass weight was 8.5 kg greater (P < 0.03) for 90ZH+Cr compared with 90ZH supplemented steers. Steers receiving 90ZH+Cr had greater longissimus muscle area when compared with steers receiving 90ZSM. Dry matter intake, G:F, morbidity and mortality, and all other carcass measurements were similar across treatments. These data indicate that under the conditions of this experiment, Zn source and concentration had no impact on live performance, liver Zn and Cu concentrations, and carcass characteristics. Supplemental Cr in diets containing 90 mg of supplemental Zn/kg DM from ZH improved final BW, ADG, and hot carcass weights.

Animal performance and meat quality of crossbred young bulls

This work was carried out to evaluate animal performance and carcass characteristics of 45 young bulls of three genetic groups: Nellore, 1/2 Nellore × 1/2 European and 1/4 Nellore × 3/4 European finished in feedlot. At the beginning of feedlot, the average bull was 20 (± 2) months old, and average weight body was 356.0 (± 7.9) kg. The 1/2 Nellore × 1/2 European young bulls had greater ( P < 0.05) initial weight (381.7 kg), final weight (531.6 kg) and hot carcass weight (279.2 kg) than 1/4 Nellore × 3/4 European animals (334.6; 498.3 and 256.8 kg, respectively) and Nellore bulls (336.4; 446.4 and 234.3 kg, respectively). The crossbred bulls had greater daily weight gain (1.5 kg) as compared to the Nellore group (1.1 kg). However, carcass dressing was similar (52.3%) among groups. The superiority of crossbred animals over Nellore was observed when considering carcass conformation (good vs. regular), carcass length (136.6 vs. 130.1 cm), cushion thickness (26.6 vs. 25.0 cm), fat thickness (3.38 vs. 1.92 mm) and marbling (light vs. trace). The Nellore group had greater leg length (77.9 vs. 72.9 cm), better meat color (red vs. slightly dark red) and greater bone percentage (16.6 vs. 15.6%) than crossbred specimens. The 1/2 Nellore × 1/2 European groups had greater Longissimus muscle area (68.8 cm 2) and greater fat percentage (23.9%) than 1/4 Nellore × 3/4 European and Nellore animals. There was no difference in regards to texture (fine) and muscle percentage (62.9%). There was no difference among crossbreds for moisture (73.2%), ash (1.03%) and fat (1.81%) levels. Nellore animals had greater percentage of protein (25.3 vs. 23.8%), total cholesterol (27.5 vs. 23.0 mg/100 g muscle), stearic acid (25.0 vs. 21.6%), transvaccenic acid (1.6 vs. 1.3%) and γ-linolenic acid (0.2 vs. 0.1%) than crossbred specimens. Total saturated fatty acids (49.9%), monounsaturated fatty acids (38.1%), polyunsaturated fatty acids (12.1%), n-6 (10.0%), n-3 (1.7%), PUFA/SFA ratio (0.2) and n-6/ n-3 ratio (6.27) in the Longissimus muscle were similar among genetics groups.

초음파 진단장치를 이용한 한우 암소의 산차 및 지역별 산육특성 구명

Jae Jung Ha*, Jong Bok Kim*, Chang Woo Lee** and Young Han Song*College of Animal Life Sciences, Kangwon National University*,Research Center for Livestock Technology, Gangwon-do**ABSTRACTCurrent study was conducted to investigate the influence of parity and region variation in ultrasound live carcass traits of Hanwoo cows. A total of 1,386 heads of Hanwoo cows, spreading over six regions in Gangwon province of South Korea, were measured for longissimus muscle area, back fat thickness, marbling score and rump fat thickness by using real-time ultrasound method. The results revealed that, positive correlations were found in all ultrasound live carcass traits. All live carcass traits were increased in accordance with parity until the sixth, and then decreased thereafter. Statistical significant differences (p<0.01) were found among regions in ultrasound live carcass traits, e.g. Hanwoo cows showed highest longissimus muscle area and marbling score in Hwacheon, while the lowest back fat thickness and rump fat thickness were observed in Yanggu. Greater longissimus muscle area and marbling scores were found in Hanwoo cows which were born during autumn, 2000. Moreover, individuals born during autumn, 2005 and 2006 showed a thicker back fat and rump fat thickness. Back fat thickness had the highest positive correlation with rump fat thickness, while rib eye area and rump fat thickness had the lowest correlation. (Key words:Hanwoo cows, Region, Parity, Ultrasound, Live carcass trait)

The effect of the Halothane and Rendement Napole genes on carcass and meat quality characteristics of pigs.

The objective of this study was to determine the effects of the Halothane (N) and Rendement Napole (RN) genes on carcass and meat quality characteristics in pigs. Halothane and RN carrier (Nn/RN- rn+) Hampshire boars (n = 4) were mated to dams that were homozygous for the normal allele of both genes (NN/rn+ rn+) to produce progeny of four genotypes: 1, NN/rn+ rn+ (n = 31); 2, Nn/rn+ rn+ (n = 27); 3, NN/RN- rn+) (n = 30); and 4, Nn/RN- rn+ (n = 23). A DNA test was used to determine Halothane genotype, and longissimus glycolytic potential was used to predict the RN genotype. Pigs were reared under standard conditions to approximately 120 kg live weight and slaughtered at a commercial plant, and carcass characteristics and meat quality were evaluated. Halothane carriers (Nn/ _ _), in comparison to Halothane normal (NN/_ _) pigs, had shorter carcasses, lower longissimus ultimate pH, higher Minolta L* and b* values, and greater drip loss. Rendement Napole gene carriers (_ _/RN- rn+) had higher L* and b* values and drip and cooking loss and lower longissimus ultimate pH than homozygous recessive animals (_ _/rn+ rn+). There were Halothane x RN genotype interactions (P < 0.05) for subjective color, firmness, and marbling scores, and for shear force. Animals that were normal for both genes (NN/rn+ rn+) had the highest subjective scores for color (2.60, 1.88, 1.85, and 1.95, SE = 0.181, P < 0.05), firmness (2.53, 2.03, 2.10, and 1.89, SE = 0.182, P < 0 .05), and marbling (2.11, 1.44, 1.53, and 1.55, SE = 0.153, P < 0 .05) for genotypes 1, 2, 3, and 4, respectively, suggesting darker, firmer muscle with a higher level of marbling for this genotype. Shear force was highest for Nn/rn+ rn+ animals (3.83, 4.41, 3.79, and 3.70, respectively, SE = 0.172, P < 0.05). Gilts had less s.c. backfat thickness, greater longissimus muscle area, and lower subjective marbling scores than barrows. There was no effect (P > 0.05) of gender on other meat quality traits. This study illustrates the negative effects of the Halothane and RN genes on fresh pork quality and suggests that in combination the detrimental effects of the two genes are additive for ultimate pH, objective color, and water-holding capacity.

Interactive effects of dietary chromium tripicolinate and crude protein level in growing-finishing pigs provided inadequate and adequate pen space.

An experiment was conduct to determine the interactive effects of dietary chromium tripicolinate (CrPic), CP, and pen space (PS) as a stress on growth performance, carcass traits, and plasma hormones and metabolites of crossbred growing-finishing pigs (128 pigs; initial BW 27.2 kg). A factorial arrangement of treatments included two levels of Cr (0 and 400 ppb as CrPic), two levels of CP (80 [80P] and 120% [120P] of the lysine requirement; NRC, 1988), and two levels of PS (adequate [APS] or inadequate [IPS]). In the grower phase, ADG was decreased more by IPS when pigs were fed 80P (CP x PS, P < .08). Gain/feed (G/F) was decreased by IPS in pigs fed 80P; however, in pigs fed 120P, IPS increased G/F (CP x PS, P < .01). Supplemental Cr did not affect (P > .10) ADG, ADFI, or G/F in the grower phase. In the finisher phase, pigs, fed 120P had less (P < .10) ADFI but similar (P > .10) ADG compared with pigs fed 80P. Gain/feed was higher (P < .10) in pigs fed 120P than in pigs fed 80P. Daily gain ADFI were lower (P < .03) in pigs provided IPS than in pigs provided APS. In pigs fed 80P, CrPic tended to result in higher ADG and G/F; however, in pigs fed 120P, Cr tended to result in lower ADG and G/F (CP x Cr, P < .09). Pigs fed 120P had greater (P < .03) longissimus muscle area (LMA) and percentage of muscling (PM) and less (P < .03) 10th rib fat thickness (TRF) than pigs fed 80P. Pigs provided IPS had greater LMA and PM and less TRF than pigs provided APS (P < .03). Pigs fed CrPic had higher TRF when provided IPS but lower TRF when provided APS (Cr x PS, P < .07). Feeding CrPic had minimal effect on plasma urea N, cholesterol, glucose, NEFA, insulin, or growth hormone.

Survival, body weights, feed efficiency, and carcass traits of 3/4 white composite and 1/4 Duroc, 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu pigs.

Pigs were the progeny of White Composite (WC) boars mated to F1 Duroc x WC, Meishan x WC, Fengjing x WC, and Minzhu x WC gilts. Meishan and Fengjing crosses had more (P < .05) nipples than Duroc and Minzhu crosses. Meishan and Minzhu crosses had a higher survival rate at birth (P < .05) than Duroc and Fengjing crosses, but breed types did not differ significantly (P approximately .29) for survival to 14 or 28 d of age. Duroc crosses were heavier (P < .05) than Fengjing and Minzhu crosses at 0, 28, 56, 70, 98, 126, and 154 d of age; they were heavier (P < .05) than Meishan crosses at 0, 28, 98, 126, and 154 d of age. Chinese crosses had similar weights at most ages, although Meishan crosses were heavier (P < .05) than Fengjing and Minzhu crosses at 126 and 154 d of age. Breed types did not differ significantly (P approximately .27) for feed efficiency during the nursery period. Over the entire finishing period, Duroc-cross gilts (.3310) were less efficient (P < .05) than Meishan (.3436), Fengjing (.3454), or Minzhu crosses (.3466); among barrows Meishan crosses (.3176) were least efficient (P < .05), Fengjing crosses (.3263) were most efficient (P < .05), and Duroc (.3211) and Minzhu (.3209) were intermediate but not significantly different from the Meishan or Fengjing crosses. At a constant age, Duroc crosses had longer carcasses, greater longissimus muscle area, and heavier slaughter weight, carcass weight, and weight of untrimmed cuts and trimmed cuts than the Chinese crosses (P < .05). There were few significant differences among breed types for carcass traits at a constant carcass weight. Results show that, relative to one-half Duroc females, incorporation of one-half Chinese females into a crossbreeding program will result in progeny with a significant decrease in rate of growth (approximately 9% for weight at 154 d of age) and a small, nonsignificant decrease in yield of trimmed lean cuts (approximately 5%) at a constant carcass weight.

An embryo transfer study of reciprocal cross differences in growth and carcass traits of Duroc and Landrace pigs.

Reciprocal cross differences have been reported for growth rate and carcass traits in F1 pigs with the Duroc (D) as a parent breed. Such differences are synonymous with maternal effects if effects of sex linkage and genomic imprinting are negligible. In the present study, transfer of embryos (ET) to paternal breed recipients partitioned effects occurring at or before fertilization from postfertilization effects for growth and carcass traits in F1 D-Landrace (L) pigs. Fifteen boars sired 115 F1 litters, 49 produced by ET. Growth rate of 349 barrows and 361 gilts and carcass measurements on 256 barrows and 159 gilts were analyzed assuming mixed linear models with animal and litter as random effects. Contrasts among genotype (D x L, L x D)- treatment (ET, non-ET) means were tested. Reciprocal cross differences were not detected for growth rate or for carcass weight, length, average backfat thickness, estimated carcass lean, or lean per day of age. Reciprocal cross differences for 10th rib backfat thickness (BF) and longissimus muscle area (LMA) were detected only in barrows. The sexual dichotomy for reciprocal cross differences followed expectations for a Y-linked gene(s), consistent with the fact that reciprocal D-L crossbred barrows exhibited a paternal effect, with responses more like the sire breed than the dam breed. Barrows that were non-ET from D sires and L dams had 3.9 cm2 larger LMA and 5.8 mm less BF than barrows from L sires and D dams (P less than .001). Barrows from ET sired by D boars had 3.8 cm2 larger LMA than did barrows from ET sired by L boars (P less than .001), although no difference was detected for BF. Barrows sired by D boars reared in a D postfertilization environment (ET) had 6.2 cm2 greater LMA and 4.1 mm less BF (P less than .05) than barrows sired by L boars gestated and reared by D dams (non-ET). Barrows sired by D boars reared by L dams (non-ET) had 1.5 cm2 greater LMA and 2.3 mm less BF (P greater than .10) than barrows sired by L boars reared by L dams (ET). In conclusion, reciprocal cross differences detected for BF and LMA in barrows were established before or at fertilization and seemed to be Y-linked.

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)

Effects of Dietary Protein Level and Feed Restriction on Performance and Carcass Characteristics of Swine

Sixty crossbred pigs were randomly assigned to five replicates of three treatments to determine effects of dietary protein level and feed restriction on rate and efficiency of gain and quantitative and qualitative carcass characteristics. Growth rate of pigs fed 16 to 14% protein diets ad libitum was significantly faster than that of pigs fed either 12 to 10% protein diets ad libitum or 16 to 14% protein diets at a restricted level of feed intake. Significantly less feed per unit of gain was required by pigs fed high protein diets at either level of feed intake. Carcasses from pigs fed high protein diets either ad libitum or at a restricted level had significantly larger longissimus muscle areas and higher percentages of ham, loin, shoulder and lean cuts than carcasses of pigs fed low protein diets. Carcasses did not differ in backfat thickness, carcass length or dressing percent because of dietary protein or feeding level. Longissimus muscle from pigs fed high protein diets contained more protein and moisture and less ether extract and had lower marbling and juiciness scores. Cooking characteristics of the meat were not significantly different among dietary treatments. Restricted feed intake of the high protein diet resulted in an 18-day increase in age at slaughter and further improved carcass leanness as indicated by less backfat, greater longissimus muscle area, lower percent belly and higher percentages of ham, ham and loin and lean cuts. Backfat of pigs fed for equal gains contained more palmitoleic and lineoleic acids and less oleic acid when pigs were fed high protein diets at a restricted level compared to low protein diets ad libitum.