Genes and proteins associated with ribeye area and meat tenderness in a commercial Nellore cattle population

Despite several studies on genetic markers and differently expressed genes related to ribeye area (REA) and tenderness traits in beef cattle, there is divergence in the results regarding the genes associated with these traits. Thirteen genes that had been associated or have biological functions that may influence such phenotypes were included in this study. A total of five genes for REA (IGF-1, IGF-2, MSTN, NEDD4, and UBE4A) and eight genes for meat tenderness (CAPN1, CAPN2, CAST, HSPB1, DNAJA1, FABP4, SCD, and PRKAG3) were selected from previously studies in beef cattle. Genes and its respective proteins expression were validated in a commercial population of Nellore cattle using quantitative real-time PCR (RT-qPCR) and advanced mass spectrometry (LC / MS-MS) techniques, respectively. MSTN gene was upregulated in animals with low REA. CAPN1, CAPN2, CAST, HSPB1, and DNAJA1 genes were upregulated in animals with tougher meat. The proteins translated by these genes were not differentially expressed. Our results could confirm the potential of some studied genes as biomarkers for carcass and meat quality in Nellore cattle.

Market weight, slaughter age, and yield grade to determine economic carcass traits and primal cuts yield of Hanwoo beef

ObjectiveThis study was conducted to evaluate the relationship between market weight, slaughter age, yield grade, and primal cut yield in Hanwoo. MethodsA total of 403 Hanwoo (Korean native cattle) was assessed for carcass traits such as carcass cold weight, backfat thickness, ribeye area, dressing percentage, yield index, and marbling score. The production yield of the individual major primal cuts of Hanwoo beef was also measured. FindingsCarcass cold weight, ribeye area, and backfat thickness, which affect meat quality increased with increased market weight (p<0.05). The production yield of the ten major primal cuts also increased with increased market weight (p<0.05). In terms of slaughter age, carcass cold weight, ribeye area, and backfat thickness all increased from 25 months to 28-29 months, and the production yield of all prime cuts also increased with increasing slaughter age. According to the meat yield grade, carcass cold weight and backfat thickness increased from grade A to grade C, although the ribeye area was not affected. The combined findings of the study suggest that slaughtering Hanwoo at the weight of 651-700 kg and 701-750 and age of 28.23 and 29.83 months might be desirable to achieve the best quality and quantity grade of Hanwoo beef. However, the positive correlation of carcass cold weight and backfat thickness, and the negative correlation of the yield index according to primal cuts yield indicated that it is necessary to couple the slaughtering management of cattle with improved genetic and breeding method of Hanwoo to increase the production yield of the major prime cuts of Hanwoo beef.

274 Comparison of Two Ultrasound Systems for Estimation of Carcass Attributes in Feedlot Steers

Sixty-eight (68) crossbred steers were evaluated using two real-time, B-mode ultrasound units to estimate final carcass attributes. The cattle were ultrasounded at the West Texas A&M research feedlot (Canyon, Texas) and carcass data was collected at the West Texas A&M Meats Laboratory (Canyon, Texas) or Tyson Fresh Meats (Amarillo, Texas). Objectives of the study were 1) to compare ultrasound live animal data to carcass attributes at harvest 2) to evaluate the performance differences between the ALOKA 500 (ALK) and the EVO ultrasound units All ultrasound images were captured by the same Ultrasound Guidelines Council (UGC) certified technician with images being processed at the UltraInsights Laboratory (Pierce, Colorado). The correlations between 12th rib fat thickness of the carcass (FTC) and ultrasound (FTU) were 0.84 for the ALK and 0.85 for the EVO, with no differences being found between the two units (P = 0.15). Correlations between the 12-13th rib carcass ribeye area (REAC) and ultrasound ribeye area (REAU) were 0.69 for the ALK and 0.66 for the EVO. There was no difference in REAU size between the two units. Carcass marbling score (MS) and ultrasound intramuscular fat (IMFU) correlations were 0.78 for the ALK and 0.84 for the EVO. The IMF data were found to be different between the two units, with the EVO measuring a mean IMFU value of 6.03 and the ALK a value of 5.26 with the change of 0.77 being different (P &lt; 0.01). It is concluded that both ultrasound units performed favorably when predicting FTC and marbling score but were not highly correlated for REAU. It was found that the predictions between the two units on FT and REA were the same, though the EVO was higher on both. The IMFU values between the ALK and EVO were different, with the EVO again predicting higher values.

PSIII-8 Sire breed differences for carcass attributes in feedlot steers using ultrasound technology

Live animal ultrasound measurements were taken on thirty-two feedlot steers and heifers for estimation of carcass endpoints including 12th rib fat thickness (FTU), ribeye area (REAU) and intramuscular fat (%FatU). Ultrasound measurements were collected by an inexperienced technician using an Aloka 500 ultrasound unit using Beef Image Analysis (BIA) software. The objective of the study was to evaluate carcass differences of four sire breed types including Angus (n = 11), Ultrablack (n = 6), Nelore (n = 6), Braunvieh (n = 1) and Angus X Nelore X Braunvieh hybrid (n = 8). Carcass data collected at harvest included 12th rib fat Thickness (FTC), Ribeye area (REAC), marbling score (MS), Yield Grade (YG), and Quality Grade (QG). The data were analyzed using SAS to determine breed effects. Means for FTU, FTC, REAU, REAC, %FatU and MS were 0.59 cm, 0.57 cm, 90.80 cm2, 83.53 cm2, 4.83%, and 483.75, respectively. There was no significant difference (P &gt; 0.05) in YG and FT due to breed of sire. However, there was a trend for sire breed for ribeye area (P = 0.0728) for Angus X Nelore X Braunvieh cross and MS (P = 0.0786) for Ultrablack. Pearson correlation values between FTU and FTC, REAU and REAC, and %FatU and MS were 0.1217 (P = 0.05068), 0.3545 (P = .0465) and 0.5161 (P = 0.0025), respectively. These data suggest little differences existed in carcass attributes between various sire breeds out of a set of crossbred commercial cows.

PSIII-16 Use of soybean hulls in diets for drylot beef cows

One-hundred twenty-one Red Angus beef cows were used to evaluate the effects of soybean hull inclusion in beef cow diets throughout gestation and lactation. Cows were stratified by age, body weight (BW), and body condition score (BCS), and were randomly assigned to treatment (n = 4 pens per treatment). Treatments included 1) control diet [CON; consisted of corn silage, modified distillers’ grains plus solubles (MDGS), and wheat straw], and 2) soybean hull diet [SBH; consisted of 26 to 27% soybean hulls (DM basis) replacing portions of corn silage, MDGS, and wheat straw]. Beef cow BW, BCS, average daily gain (ADG), and back fat (BF) measurements were evaluated. Colostrum samples were collected on a subset of randomly selected cows from each pen. Weigh-suckle-weigh technique was used to evaluate milk production. Calf birth weight, weaning weight, and ADG were evaluated. At weaning, calves were ultrasounded for BF, rump fat, and ribeye area. Dam BW, BCS, BF, and ADG were not affected (P ≥ 0.12) by treatment. Colostrum fat, somatic cell count, urea nitrogen, and other solids were not altered (P ≥ 0.13) by treatment; however, colostrum protein was greater (P ≥ 0.09) in CON cows. Milk production at d 60 was greater (P = 0.03) for SBH fed cows. Calf birth and weaning weights were unaffected by treatment (P = 0.30). Ribeye area measurements were greater (P = 0.05) in SBH calves (14.6 vs. 13.7 ± 0.76 cm2), but BF and rump fat were not different (P ≥ 0.58). The present study demonstrates that soybean hulls can be included in beef cow diets at 26 to 27 % of dietary DM. Our data and previous research indicate that soybean hulls can be fed to drylot beef cows during gestation and lactation without negative impacts on cow or calf outcomes.

Effect of Stocking Rate During Gestation on Subsequent Performance of Growing Beef Cattle

Beef cows in the southeastern United States are likely maintained on pasture during mid-gestation, a critical period for fetal development of traits important to performance of the growing/finishing calf. Climate projections are for increased warming with highly variable precipitation in this region. Forage quantity and quality are affected by temperature and precipitation. Thus, in order to obtain a better understanding of downstream effects from cow nutrition during gestation on subsequent performance of growing cattle, we analyzed 579 records of crossbred steers and heifers born (fall and winter) to cows grazing typical forages in Overton, Texas. Cows were involved in a long-term stocking rate study and were assigned to either high (H; 4 cow/calf ha-1) or low (L; 2 cow/calf ha-1) treatment groups. Cow body condition scores (BCS; 1–9) were collected at breeding and weaning. Calves produced were pastured from weaning to approximately 1 to 1.5 yr of age, then shipped to a commercial feedlot and subsequently slaughtered at a commercial facility. Calf data included birth weight, weaning weight (~240 d), yearling weight, on-feed weight, final pre-harvest weight, hot carcass weight (all weights in kg), dressing percentage, marbling score, yield grade, backfat thickness (cm), ribeye area (cm2), and kidney-pelvic-heart fat (%). Differences (P &lt; 0.05) between treatment groups were determined by a general linear model in SAS with stocking rate as the main effect. Mean separation was accomplished using Tukey’s test. Cow BCS (H; 4.27 ± 0.06 vs L; 5.64 ± 0.07, P &lt; 0.0001), final pre-harvest weight (H; 594.80 ± 6.18 kg vs L; 619.85 ± 6.12 kg, &lt; 0.005), hot carcass weight (H; 366.60 ± 3.89 kg vs L; 383.17 ± 3.74, P &lt; 0.003), and ribeye area (H; 90.52 ± 0.90 cm2 vs L; 93.74 ± 1.03 cm2, P &lt; 0.03) were all lower in H than L. Calf weaning weight followed a similar trend (H; 289.24 ± 2.58 kg vs L; 296.56 ± 3.08 kg, P &lt; 0.07). Diminished nutritional provision to the fetus during mid-gestation was apparently manifest as epigenetic effects on offspring performance.

276 Evaluation of a Long-acting Growth-promoting Implant (Revalor-XS) as an Initial Implant in a Re-implant Program with a revalor-200 Terminal Implant in Feedlot Cattle: A Three-study Pooled Analysis

Data from three large-pen feedlot studies were pooled to evaluate use of a long-acting implant (Revalor-XS) as an initial implant in a re-implant program. The three studies consisted of 2,764 steers in 40 pens, with an initial body weight (BW) of 271 kg. Treatments consisted of Revalor-IS [80 mg trenbolone acetate (TBA), 16 mg estradiol (E2)] administered on arrival, followed by Revalor-200 (200 mg TBA, 20 mg E2) terminal implant (IS/200) or Revalor-XS (80 mg TBA, 16 mg E2 uncoated; 120 mg TBA, 24 mg E2 coated; 200 mg TBA, 40 mg E2 total) on arrival followed by Revalor-200 terminal implant (XS/200). Steers were fed to equal days-on-feed (DOF) within study and averaged 210 DOF. Steers within treatment were re-implanted at same DOF in two studies (Day 124 on average followed by an 81-day terminal implant window). In the third study, IS/200 steers were implanted on Day 120 and XS/200 steers on Day 140 of the 217-day study. Final BW averaged 635.6 and 638.3 kg for IS/200 and XS/200, respectively (P = 0.21). There were no differences (P &gt; 0.26) in DMI, ADG and Gain:Feed between treatments. Hot carcass weight tended (P = 0.07) to be greater with XS/200 (412.7 kg) compared with IS/200 (409.1 kg). Ribeye area was greater (P &lt; 0.01) and fat thickness tended (P = 0.06) to be lower with XS/200 compared with IS/200. Distributions of USDA quality grades were not affected (P = 0.26) by treatment. Distributions of USDA yield grades (YG) were affected (P = 0.01) by treatment with a shift toward more YG 1 and 2 carcasses with XS/200 and more YG 4 and 5 carcasses with IS/200. This analysis indicates that using Revalor-XS as an initial implant leads to greater carcass weight and ribeye area and lower YG when compared with Revalor-IS.

272 Managing for Efficiency and Quality Through Diet and Implant Strategies on Steers Selected for Superior Marbling

A 144-day study assessed the effects of dietary energy and implant potency to determine optimum strategies for managing feed conversion (F:G) and marbling. Fifty-four Angus steers (327 ± 8 kg) from Iowa State University’s herd genetically selected for enhanced marbling were stratified by initial bodyweight (BW), ultrasound intramuscular fat, and age to a 2 × 3 factorial. Dietary treatments included: low energy (1.30 Mcal NEg/kg DM, 18% roughage level; LE) or high energy finishing ration (1.39 Mcal NEg/kg DM, 8% roughage; HE). Implant treatments (IMP; Merck) included: no implant (NOIMP), Revalor-IS (RIS), or Revalor-200 (R200) on d 0 and 74. Steers were fed via bunks capturing daily individual feed disappearance (n = 9 steers/treatment). Steers were weighed on d 0, 74, and 144 and harvested on d 145. Data were analyzed in Proc Mixed of SAS with fixed effects of diet, IMP, and interaction. No interactions were observed for feedlot performance (P &gt; 0.17). Steers fed HE had greater average daily gain (ADG) and final BW than LE steers (P &lt; 0.01) while LE steers had greater F:G (P = 0.04). Final BW and ADG were greatest for R200, intermediate for RIS, and lowest for NOIMP (P &lt; 0.01). F:G was greatest for NOIMP, intermediate for RIS, and lowest for R200 (P &lt; 0.01). Steers fed HE had increased ribeye area (P &lt; 0.01) and tended to have greater marbling score (P = 0.06; 809) than LE steers (769). While ribeye area increased in response to implant potency (P &lt; 0.01), marbling score was not impacted (P = 0.21) by IMP (815, 771, 782, for NOIMP, RIS, R200, respectively). Overall, steers graded 100% Choice or higher and 55% Prime. These data suggest implants, when used appropriately, improve growth performance and efficiency in beef steers without compromising carcass quality.

PSX-29 Late-Breaking Abstract: The effectiveness of in vivo determination of meat quality using an ultrasonic scanning device in Kazakhstan

Improving beef quality is important task for livestock in Kazakhstan. Almost all indicators characterizing the quality of carcasses and beef are evaluated after slaughter. Their use in breeding is limited (Legoshin G.P. 2010). For lifetime assessment of carcasses in pedigree and slaughter cattle, Aloka 500B, EXAGO, EVO ultrasonographs are used, using which there is a high coincidence of the lifetime forecast of muscular development over the eye muscle area with the indicator in carcasses after slaughter of animals (Bisembaev A.T. 2019). A high correlation of prognosis of ribeye area with live weight of animals was noted (Lisitsyn A.B. 2010). The aim of the project is to study the effectiveness of in vivo determination of meat quality using an ultrasonic scanning device. Tasks: to determine the ribeye area, the fat of the cattle using an EXAGO ultrasonograph; compare the ribeye area, the fat of the slaughter cattle, determined using an EXAGO ultrasonograph and measured on the carcass after slaughter. The studies were carried out on pedigree bull-calves of the Kazakh white head (85 animals), Auliekol (101 animals) breeds aged 14–15 months and on the feeding stock (6 animals) with a live weight of more than 943 lb. The ribeye area, the fat were obtained: Kazakh white head had 23.2 sq.in and 0.10 in, Auliekol – 20.4 sq.in and 0.09 in. The animals studied after slaughter yielded full-bodied carcasses, while the slaughter yield averaged 56.3%. The correlation between live weight level and ribeye was r=0.97. The coincidence of ribeye, measured by an ultrasonograph with a post-mortem measurement averaging 93.8%. The introduction of ultrasound methods for determining beef productivity in beef industry will allow livestock husbandry to become cost-effective and improve the beef quality. The results of ultrasound images for the carcass traits will be applied in selection and breeding work.