Heavier Carcass Weights Research Articles

Estimation of genetic and phenotypic parameters for ultrasound and carcass merit traits in crossbred beef cattle

Miar, Y., Plastow, G. S., Bruce, H. L., Moore, S. S., Durunna, O. N., Nkrumah, J. D. and Wang, Z. 2014. Estimation of genetic and phenotypic parameters for ultrasound and carcass merit traits in crossbred beef cattle. Can. J. Anim. Sci. 94: 273–280. Ultrasound measurements of 852 crossbred steers along with carcass merit measurements on 756 of them were used to examine their genetic and phenotypic parameters. Traits including ultrasound backfat thickness (UBF), ultrasound ribeye area (UREA), ultrasound marbling (UMAR), carcass weight (CWT), carcass grade fat (CGF), carcass average backfat thickness (CABF), carcass ribeye area (CREA), carcass marbling score (CMAR), and carcass lean meat yield (CLMY) were measured on 6 yr of residual feed intake trials from 2003 to 2008. Pairwise bivariate animal models were performed for each combination of traits using ASReml software to estimate heritability, phenotypic and genetic correlations among the traits. Significant fixed effects (contemporary group, and sire breed), covariates (age of dam, slaughter weight, and start test age of animal), and random additive effect were fitted in the models. The heritability estimates for UBF, UREA, UMAR, CWT, CGF, CABF, CREA, CMAR, and CLMY were 0.31, 0.17, 0.37, 0.40, 0.22, 0.25, 0.24, 0.38, and 0.28, respectively. Most of the phenotypic correlations were significant (P<0.05). CWT had low to moderate phenotypic correlations with most of the traits. Results show that heavier CWT tends to have more UREA, CGF, CABF, and CREA. Genetic correlations among these traits varied from weak to strong, but most of them were not significantly different from zero. Greater CREA may lead to decreased UMAR, and UBF due to negative genetic correlations (−0.56±0.32, and −0.45±0.23, respectively). The results support the potential value of ultrasound technology in crossbreed beef cattle breeding programs to generate indicator traits for carcass quality. In addition, carcass lean meat yield correlated favourably with backfat thickness and rib eye area but correlated unfavourably with UMAR. The estimated genetic parameters for ultrasound and carcass merit traits can be incorporated into breeding programs that emphasize carcass quality in Canadian crossbred beef cattle populations.

Factors influencing the incidence of high rigor temperature in beef carcasses in Australia

Beef carcasses undergoing rapid pH fall while the loin muscle temperature is still high are described as heat-shortened, heat-toughened or ‘high rigor temperature’ carcasses, with subsequent negative effects on quality traits. The aim of the study was to quantify the occurrence of high rigor temperature in beef carcasses across Australia and to identify the causative factors. Data was collected over 4–5 days at each of seven beef processing plants from 1512 beef carcasses. The beef carcasses were from both grass- and grain-fed cattle ranging in days on grain feeding from 0 (grass-fed) to 350 days and the category of cattle ranged from veal to ox and cow. Data collected on the day of slaughter included the duration of electrical inputs at the immobiliser, electrical stimulation and hide puller, longissimus muscle pH and temperature decline, hot carcass weight and P8 fat depth. At grading, ultimate pH, eye muscle area, wetness of the loin surface and colour score were also collected. The temperature at pH 6 was calculated and if it was >35°C, the carcass was defined as ‘high rigor temperature’. Modelling of the data was conducted using GLMM and REML. The occurrence of high rigor temperature across all seven beef processing plants was 74.6% ranging from 56 to 94% between beef processing plants. Increasing days in the feedlot and heavier carcass weights were highly correlated and both caused an increase in the predicted temperature at pH 6 and in the % high rigor temperature (P < 0.05 for both). Longer duration of electrical inputs at the hide puller, fatter grass-fed cattle and fatter male (castrate) carcasses had a higher temperature at pH 6 and higher % high rigor temperature. Modelling showed that if the time to reach pH 6 in the longissimus muscle was 65 v. 105 min, the % high rigor temperature carcasses reduced from 98 to 19% in grain-fed cattle and 93 to 7% in grass-fed cattle. Higher plasma insulin levels at slaughter were associated with a higher temperature at pH 6 (rigor temperature) (P < 0.001). In conclusion, in order to reduce the incidence of high rigor temperature in grain-fed beef carcasses, methods for identifying high rigor temperature carcasses will be required and while some management strategies can be implemented now, others require further research.

Effect of breed, grazing system and concentrate supplementation on fattening performance, carcass value and meat quality of steers

Abstract. The aim of the study was to test the influence of breed, grazing system and concentrate level on fattening performance, carcass value and meat quality of steers.Ninety-six German Simmental and German Holstein steers were fattened using two different grazing systems: continuous grazing system (CGS) and rotational grazing system (RGS). They were supplemented with medium (M) or low (L) concentrate levels. The trial period involved 22 months divided into four phases: phase 1 (indoor), 2 (grazing), 3 (indoor vs. outdoor) and 4 (grazing). In phases 1 and 3 the animals were offered grass silage ad libitum. All animals were supplied with concentrate during phase 1. In phases 3 and 4 the animals were supplied with M or L. Group M consumed a total of 275 kg and group L 191 kg concentrate per steer.German Simmental steers were significantly superior in all essential parameters of the fattening performance and the carcass value (e.g. final weight: 631 kg vs. 608 kg). German Holstein steers showed better meat quality (intramuscular fat content, tenderness, meat colour) than German Simmental steers. The impact of the grazing system was only for a few parameters (carcass weight, dressing percentage and fat colour). The CGS showed higher grazing yield and higher content of nutrients than the RGS, as a consequence, CGS steers presented heavier carcass weight than RGS steers. Concentrate levels had no effects on the evaluated parameters.

제주재래흑돼지와 Landrace, 교배집단 F2에서 척추의 수적 변이와 도체형질의 상관관계

포유류 중 돼지의 척추 중 요추, 흉추의 수는 고정되지 않은 형질로 개체간의 차이를 나타내는 것으로 알려져 있다. 본 연구는 제주재래흑돼지와 Landrace, 두 품종 간 <TEX>$F_2$</TEX> 교배집단에서 경추 수, 흉추 수, 요추 수, 척추 수 등 체형관련 형질과 도체형질의 상관관계를 살펴보기 위해 수행되었다. 세 축군 모두 경추 수의 변이는 나타나지 않았으나, 흉추 수, 요추 수, 척추 수는 상이한 양상을 보였다. 도체형질의 성적과 요추 수만이 세 축군들 사이에서 통계적인 유의성을 나타내지 않았고(p>0.05), 도체중, 육색, 근내지방도, 등심단면적, 등지방두께, 도체장, 흉추수, 척추 수 등은 통계적인 유의성을 나타내었다(p<0.05). 제주재래흑돼지는 흉추 수 14-16 개, 요추 수 5-6 개, 척추 수 27-29 개의 범위, Landrace는 흉추 수 15-16 개, 요추 수 5-7 개, 전체 척추 수 28-29 개, <TEX>$F_2$</TEX> 교배집단은 흉추 수 14-17, 요추 수 5-7 개, 전체 척추 수 27-30 개로 확인되었다. <TEX>$F_2$</TEX> 교배집단에서 흉추 수와 척추 수의 증가는 도체중, 도체장, 등지방두께의 평균이 유의적으로 다른 양상을 보인다(p<0.05). 또한 척추 수의 증가는 요추 수의 증가보다 흉추 수의 증가에 더 많은 영향을 받는 것으로 나타났다. 흉추 수 및 척추 수의 증가가 등지방두께를 점점 두껍게 만들기는 하지만, 도체중과 도체장 등 경제성을 결정하는 핵심적인 도체형질을 향상시킨다는 점은 추후 제주재래흑돼지나 Landrace 품종을 활용한 양돈산업에서 체형개선을 통한 생산성 증가를 유발할 수 있는 좋은 전략이 될 것으로 판단된다. The number of thoracic and lumbar vertebrae is known to be an unfixed trait among mammals. This study focused on the relationship between numerical variations of cervical (CER), thoracic (THO), and lumbar (LUM) vertebrae and the total number of vertebrae (TNV) and carcass traits in Jejunative black pigs (JBPs), Landrace pigs, and their intercrossed <TEX>$F_2$</TEX> population. There were no numerical variations in CER vertebrae. On the other hand, the numbers of THO and LUM vertebrae and the TNV varied in all three populations. Of the traits investigated in the three populations, only the means<TEX>${\pm}$</TEX>SE of the LUM vertebrae did not show statistical significance (p>0.05). The carcass weights (CW), meat color (MC), marbling score (MS), backfat thickness (BFT), carcass length (CLE), THO vertebrae, and TNV all showed statistical significance (p<0.05). The JBP had 14-16 THO vertebrae, 5-6 LUM vertebrae, and 27-29 TNV. The Landrace pigs had 15-16 THO vertebrae, 5-7 LUM vertebrae, and 28-29 TNV. The <TEX>$F_2$</TEX> population had 14-17 THO vertebrae, 5-7 LUM vertebrae, and 27-30 TNV. In the F2 population, increased numbers of THO vertebrae and TNV were associated with a significant increase in the CW, CLE, and BFT (p<0.05). In particular, the increase in the TNV was caused by an increase in the number of THO rather than LUM vertebrae. Although the animals with a greater number of THO and TNV had thicker backfat, they had a longer CLE and a heavier CW. Both these traits are economically more important than the level of backfat when determining the productivity level. These results suggest that genetic selection to increase the number of vertebrae, especially in Landrace pigs, JBPs, and their related populations, may be an excellent strategy for improving productivity.

Carcass quality and meat tenderness of Hawaii pasture-finished cattle and Hawaii-originated, mainland feedlot-finished cattle

The objective of this study was to compare the carcass quality and meat tenderness of Hawaii cattle finished on subtropical pasture with those of mainland US feedlot-finished cattle that were shipped from Hawaii after weaning. Rib-eye steak samples were collected from 30 feedlot-finished cattle harvested at a slaughter house in Washington State, USA and from 13 subtropical pasture-finished cattle harvested at a local slaughter house in Hawaii, then shipped to meat science laboratory at the University of Hawaii, Manoa. Samples were aged for 2 weeks at 4°C and frozen for later proximate analysis and meat tenderness measurement. Feedlot-finished cattle had significantly heavier carcass weight (353 vs 290 kg) and thicker backfat (13.5 vs 6.6 mm), but no significant difference was observed in rib-eye area between the two groups. Marbling score (Small) and United States Department of Agriculture quality grade (Choice) of the pasture-finished beef were not significantly (P < 0.05) different from those of feedlot-finished beef. The shear force value of pasture-finished beef (5.18 kg) was not statistically different (P < 0.05) from that of feedlot-finished beef (4.40 kg). In conclusion, results of this study suggest that Hawaii cattle finished on subtropical pasture produced as tender beef as mainland feedlot-finished cattle with less intramuscular fat.

Genetic polymorphism in regulatory region of fatty acid binding protein 4 (FABP4) and its effect on carcass weight in Hanwoo steers

Department of Animal Science, Chung Nam Nat'l University, KoreaReceived on 13 October 2011, revised on 24 October 2011, accepted on 18 December 2011Abstract : The aim of this study was to identify the polymorphism on fatty acid binding protein (FABP4) gene promoter region and its association with carcass traits in Hanwoo. We performed PCR-direct sequencing of FABP4 promoter region to identify single nucleotide polymorphism (SNPs) using unrelated 24 Hanwoo bulls. Four SNPs (-298A>G, -472A>G, -887A>G, -862A>G) were detected in the promoter region and genotyped on 583 Hanwoo steers. A linear mixed model revealed an association of three SNPs (-298A>G, -472A>G and –862A>G) with carcass weight and marbling score in dominance model (P<0.05). The animals with AA genotypes for the three SNPs were heavier carcass weight (5 kg) than animals with GG genotypes in the statistical analysis. For the marbling score, the AA genotype was lower effect of marbling score (0.21) than GG genotypes. In conclusion, this study indicates an important role for three SNPs detected in promoter region of FABP4 in determining carcass weight and marbling score in Hanwoo.Key words : Hanwoo, Promoter, FABP4, SNP, Carcass weight, Marbling score*Corresponding author: Tel: +82-33-330-0656E-mail address: khc3365@korea.kr

Growth Performances and Carcass Characteristics of Indigenous Lambs Fed Halophyte Sporobolus virginicus Grass Hay

The objective of the present study was to compare feed and water intakes, growth performance and carcass characteristics of indigenous lamb fed diets containing various levels of halophyte Sporobolus grass hay. Forty male and female lambs were randomly and equally allotted with 5 lambs of each sex per treatment to four dietary treatment groups, which were initially formulated to have 100, 70, 30 or 0.0% Sporobolus grass hay, as a source of forage replacement for conventional Rhodes grass commonly used in the region. The lambs receiving 0.0% Sporobolus grass hay (100% Rhodes grass hay) served as the control. Feed and water were offered ad libitum. Male lambs were slaughtered at the end of the feeding trials. The average daily feed intake was significantly (p<0.05) higher for the animals fed different levels of Sporobolus grass hay than for the control animals. Feed conversion ratio (FCR), i.e., kg feed/kg BW, was similar in all treatment groups. Although lambs fed the diet with 70% Sporobolus grass hay had heavier carcass weights, the differences were not significant. In conclusion, growth performance or carcass characteristics of fattening indigenous lambs were not influenced by the inclusion of different levels of Sporobolus grass hay in the diet. Because of this, Sporobolus grass hay represents an alternative forage resource for sustaining small ruminant production in the saline coastal and sub coastal areas of the world.

Carcass traits of Charolais, Limousin, Black and White and crossbreeds of Charolais, Limousin and Belgian Blue x Black and White young bulls in Slovenia

The effect of crossing of Black and White (BW) cows with Charolais (CHA), Limousin (LIM) and Belgian Blue (BB) sires on carcass traits of their crossbred male offspring was evaluated. The crossbred bulls were compared with pure breed BW, CHA and LIM bulls. Bulls younger than 24 months and slaughtered in Slovenian slaughterhouses from 2005 to 2008 were included in the comparison. All crossbred genotypes had heavier carcass weight and better net daily gain than pure breed BW bulls. Within crossbred groups the CHAxBW bulls had the heaviest carcasses and the greatest net daily gain. Among all genotypes the best carcass conformation had CHA and the worst BW bulls. In the comparison to pure breeds the BBxBW bulls had for 1.1 of the class better conformation than BW and for 0.5 worse than CHA bulls. Within crossbreeds the BBxBW bulls had for 0.12 and 0.30 of the class better conformation than CHAxBW and LIMxBW bulls. Carcass fatness varied from 2.3 to 2.6 among genotypes, where the BBxBW buls had the lowest fatness score.

Influence of Angus and Belgian Blue bulls mated to Hereford × Brahman cows on growth, carcass traits, and longissimus steak shear force1,2

Steers and heifers were generated from Angus (A) and Belgian Blue (BB) sires mated to Brahman x Hereford (B x H) F(1) cows to characterize their growth, carcass traits, and LM shear force. A total of 120 B x H cows purchased from 2 herds and 35 bulls (14 A and 21 BB) produced calves during the 5-yr project. After the stocker phase, a representative sample of A- and BB-sired heifers and steers were transported to the Iberia Research Station to be fed a high-concentrate diet. The remaining cattle were transported to a commercial feedlot facility. Each pen of cattle from the commercial feedlot was slaughtered when it was estimated that heifers and steers had 10 mm of fat or greater. The BB-sired calves were heavier at birth (P < 0.01) than the A-sired calves. During the feedlot phase, the A-sired calves gained more BW (P < 0.05) than the BB-sired calves. The BB-sired calves had heavier (P < 0.01) carcass weights than the A-sired calves. This was due to a combination of a heavier final BW and greater dressing percent. Because of their greater muscling and reduced (P < 0.01) fat, carcasses from BB-sired calves had greater yield (P < 0.01) compared with carcasses from A-sired calves. Carcasses from A-sired calves had a greater (P < 0.01) marbling score and greater (P < 0.01) USDA quality grade than carcasses from BB-sired calves. Tenderness, as measured by shear force of the steaks aged for 7 d, was similar for A- and BB-sired calves. However, steaks aged for 14 d from the A-sired calves had a reduced shear force (P < 0.01) compared with steaks from the BB-sired calves. Steer calves were heavier (P < 0.01) at birth and weaning, and had more total BW gain in the feedlot, which resulted in a heavier final BW and HCW compared with the heifers. Steer carcasses also had greater marbling scores and quality grades, whereas the heifer carcasses had larger LM area per 100 kg of carcass weight. In conclusion, the BB-sired calves had heavier carcass weights and greater cutability, whereas the A-sired calves had a greater degree of marbling and greater quality grade, and steaks from carcasses of A-sired calves were more tender as measured by shear force at 14 d.

WET DISTILLERS GRAINS PLUS SOLUBLES DO NOT INCREASE LIVER‐LIKE OFF‐FLAVORS IN COOKED BEEF FROM YEARLING STEERS*

ABSTRACT One hundred eighty crossbred steers were organized in a 2 × 6 factorial arrangement to test the incidence of liver‐like off‐flavors in cattle finished on wet distillers grains plus solubles (WDGS). Cattle were finished with either 0, 10, 20, 30, 40 or 50% WDGS. Cattle finished with WDGS had heavier carcass weights (except for 50%) and a higher United States Department of Agriculture (USDA) yield grade (P &lt; 0.001 and P = 0.04, respectively). USDA Choice steaks, when compared to Select, had significantly higher trained sensory muscle fiber tenderness scores (5.90 versus 5.39; P &lt; 0.001), less detectable connective tissue (5.01 versus 4.51; P &lt; 0.001), higher juiciness scores (5.24 versus 4.87; P &lt; 0.001) and more intense off‐flavor ratings (5.51 versus 5.80; P = 0.002). USDA Choice steaks had a higher percentage of panelists denoted liver‐like (P = 0.03) and metallic off‐flavors (P &lt; 0.001). Treatment did not significantly influence off‐flavor intensity. The frequency of liver‐like notes occurred in a quartic fashion; frequencies of liver‐like off‐flavor were always numerically lower in meat from distillers grain‐fed cattle than control cattle. Results from this study indicate that WDGS can be used to finish cattle without causing detrimental effects on the sensory profile.PRACTICAL APPLICATIONSResults from this research suggest it is possible to include up to 50% wet distillers grains plus solubles (WDGS) in the diet of yearling steers with minimal effects on carcass characteristics. Generally, cattle finished on WDGS had higher U.S. Department of Agriculture yield grades and heavier carcass weights. Additionally, there were minimal effects on sensory traits (notably the incidence of liver‐like off‐flavor) when the meat was aged for 7 days. Therefore, WDGS can be used to finish cattle without causing detrimental effects on carcass or sensory attributes.

Evaluation of Florina (Pelagonia) sheep breed for growth and carcass traits

Two experiments were conducted to evaluate the performance of growing Florina (Pelagonia) lambs fed a high concentrate diet, as well as the effect of slaughter weight on carcass characteristics. The assessment of the growth used 12 male and 12 female individually penned weaned lambs until they reached 60% of their mature body weight (BW), while assessment of the effect of slaughter weight at weaning (42 days of age), and at 30%, 45% and 60% of the mature BW, on carcass characteristics used 40 male and 40 female weaned lambs. In experiment 1, results showed that Florina lambs have good growth. Male lambs grew faster ( P < 0.001) than female lambs, resulting in a lower ( P < 0.001) feed conversion ratio (FCR) for males. Rate of gain, feed consumption and FCR increased ( P < 0.001) as the experiment progressed. In experiment 2, results showed that degree of maturity affected ( P < 0.001) fasted body weight and carcass weight, as well as all carcass characteristics and commercial cuts, except the steaks cut which did not differ. Florina lambs can be slaughtered in heavier carcass weights, heavier than the 15 kg as the present practice. The heavier carcasses can appeal to wider range of consumers due to the excellent muscle development and the reduced visible fat cover. Florina sheep raised for heavy carcass meat production may be more economically beneficial for the breeders and the increased meat produced locally can help reduce need for importing meat from abroad.

Effect of teeth eruption on growth performance and meat quality of sheep

Two hundred and forty sheep of about 15 months of age were used in this experiment to investigate the impact of dentition category on objective and sensory meat quality. The lambs were categorised into 3 dentition classes (category 1, milk teeth; category 2, partial eruption of permanent teeth; and category 3, both permanent teeth fully erupted to the height of the central lateral milk teeth). The study was conducted on 3 farms with flocks representing the 3 genotypes that contribute to the prime lamb industry in Australia: Farm A (Merino × Merino), Farm B (first cross, Border Leicester sire × Merino ewe), and Farm C (second cross, Poll Dorset sire × Border Leicester–Merino ewe). Of the 19 meat quality attributes assessed in sheep from the 3 farms, only 1 attribute in sheep from 1 farm showed a significant deterioration in meat quality as a result of lambs progressing from dentition category 1 to 2. This was an increase in myoglobin content in lambs from Farm B (P&lt;0.05). Many of the attributes assessed showed changes that could be considered as positive for meat quality as the lambs progressed from milk teeth to partially erupted and even to fully erupted teeth. Lambs from dentition category 3 had heavier carcass weights and higher dressing percentages compared with lambs from dentition categories 1 and 2 (P&lt;0.05). The M. longissimus dorsi et lumborum (LD) of lambs from dentition category 3 had a lower surface lightness (L*) value, a higher myoglobin content and a lower cooking loss compared with lambs from dentition categories 1 and 2 (P&lt;0.05). Consumer sensory assessment found the LD from lambs in dentition category 1 to have a lower acceptability score for tenderness compared with the LD from lambs in dentition category 3 (P&lt;0.05) and a lower acceptability score for juiciness, a lower consumer rating and a lower sheep eating quality score compared with the LD from lambs in dentition categories 2 and 3 (P&lt;0.05). The results indicate that for the range of sheep studied, meat from young sheep with partially erupted teeth is unlikely to be inferior in eating quality than the meat currently classified as lamb.

Effects of Monensin and Tylosin Concentrations in Limit-fed, High-energy Growing Diets for Beef Cattle

Two experiments were conducted to evaluate the effects of monensin and tylosin concentrations in limit-fed, high-energy growing diets for beef cattle. In Experiment 1, crossbred beef steers (n = 164; mean BW = 261 kg) were offered growing diets at 1.8% of BW (DM basis) to provide 33, 44, or 55mg of monensin/kg (M33, M44, and M55, respectively) and then finished on a common diet offered ad libitum. Monensin concentration did not affect rate of DMI (P>0.71) or performance (P>0.74) during the growing period. Increasing monensin concentration during the growing period tended to increase DMI (quadratic, P<0.11) and increased ADG (linear, P<0.02) during the subsequent finishing period, resulting in heavier carcass weights (linear, P<0.05). In Experiment 2, crossbred beef heifers (n = 572; mean BW = 270 kg) were offered growing diets at 1.6% of BW (DM basis). Treatments consisted of monensin provided at 33 mg/kg (M33), 250 mg/d (M250), or a monensin/tylosin combination that provided 250 mg/d monensin and 90 mg/d tylosin (M250/T90). Heifers were finished in a manner similar to Experiment 1. During the finishing period, heifers that received M250/T90 during the growing period had less DMI (P<0.05) than those fed the M250 diet. Results suggest that concentrations of monensin and tylosin included in limit-fed, high-energy growing diets might affect subsequent finishing growth performance.

Effect of a preweaning growth restriction on the subsequent growth andmeat quality of yearling steers and heifers

The eating quality of 3 'cuts' of meat was assessed on carcasses of steers (n = 46) and heifers (n = 33) when slaughtered at 17 months of age, following preweaning growth restriction. Growth restriction (for 115 days to weaning) was imposed on half the group ('low'; n = 39 steers and heifers), followed by 2 periods of high-quality nutrition for all animals on (i) pastures (180 days) and (ii) on a grain diet in a feedlot (85 days). Preweaning growth rates (mean and standard error of difference) of steers and heifers on the 'high' treatment (905 v. 838 ± 35.0 g/day) were effectively halved (498 v. 434 ± 35.0 g/day) in the restricted 'low' group. However, no significant compensatory growth occurred when these weight-restricted weaners grazed high-quality pastures, nor during their period in the feedlot. At slaughter, the predicted liveweight of 'high'-growth steers was higher than that of 'low'-growth steers (477 v. 416 ± 11.5 kg) and they had a heavier carcass weight (251 v. 221 ± 7.2 kg). There was no difference between the meat quality (MQ4) scores of meat samples from 'low' or 'high' carcasses in which cuts of blade (2302 'bolar blade', AUS-MEAT 1998) scored higher than rump (2110 'rostbiff', AUS-MEAT 1998) and striploin (2140 striploin, AUS-MEAT 1998) samples. The study has highlighted the persistent effect of undernutrition in early life on final liveweights of Hereford cattle and the consequent reduction in their carcass weight. However, there was no carryover effect of early nutrition on meat quality.

Effects of MGA in receiving diets on health, performance, and carcass characteristics (2003)

A trial was conducted using 723 crossbred heifers (468 lb initially) to evaluate the effects of including melengestrol acetate (MGA) in receiving diets on growth performance, morbidity, mortality, and carcass characteristics. Treatments were: 1) MGA included in the receiving diet at a rate of 0.5 mg per heifer daily or 2) no MGA in the receiving diet. Diets were fed once daily and contained 42% steam-flaked corn, 45% alfalfa hay, 6% steep liquor, and 2% tallow; monensin and tylosin were included. Receiving diets were fed for 35 days. After 35 days MGA was fed to all heifers, and cattle were stepped up to common finishing diets. Cattle exhibiting clinical signs of bovine respiratory disease (BRD) were treated with Excenel (1 ml/100 lb body weight) for 3 days. Animals requiring followup treatment received the same therapy. Cattle pulled a third time received oxytetracycline (4.5 ml/100 lb body weight) and Predef (5 ml/heifer). Initial respiratory pulls (73.9% for MGA and 77.3% for no MGA), re-treatments, and death loss were not different (P>0.40) during the first 35 days. The number of heifers requiring a third antibiotic treatment tended (P=0.09) to be higher for heifers not receiving MGA. Average daily gain (deads out) for the first 35 days tended to be higher for heifers fed MGA (P=0.06), but dry matter intake and feed efficiency were not different between treatments (P>0.17). Gain throughout the 220-day feeding period was 2.6% higher for cattle fed MGA during the receiving phase (P=0.05). Overall, feed intake and feed efficiency were not different (P>0.50) between treatments, but heifers fed MGA during the initial receiving period tended to have heavier carcass weights (P=0.13). No differences were detected in quality grade, yield grade, or marbling (P>0.23). Feeding MGA during the initial 35 days after arrival may improve gain and carcass weights.

Breeding Values for Carcass Traits at Calf Markets as Determinant of Feeding Length in Japanese Black Cattle: an Exploratory Study

Japanese Black cattle (Wagyu) are fed for a long period to produce high quality beef, however, extended feeding often causes inefficiency and greater environmental load mainly derived from their manure. The objectives of this study were to analyze changes in feeding length by listing breeding values (BVs) at calf markets and the relationships between BVs and carcass characteristics of 4,052 Japanese Black cattle, and to examine the feasibility of optimizing feeding length by referring to listed BVs. BV classes A, B, and C were defined based on BVs of cows in Shimane Prefecture as follows: an upper quarter of BVs was classified as A, a second quarter as B, and under the average as C. For cattle sold at calf markets in the first term of 1996, just before the start of BV listing, the feeding length of cattle with class B BVs for the beef marbling standard (BMS) was longer (p>0.05) than that of class A cattle. However, in the second term of 1996, just after the start of BV listing, the feeding length of class B cattle became shorter (p<0.001) than that of class A cattle. Then, the feeding lengths of both classes showed no significant differences. Feeding lengths of both class A and B BVs for carcass weight (CW) changed similarly to the corresponding BV classes for BMS. The analysis of the relationships among the listed BV classes and the actual carcass characteristics showed that class A cattle had a higher (p<0.001) BMS than class B cattle, and that the higher-class cattle had a heavier CW (p<0.05). On the basis of previous reports, the cattle, particularly those with lower genetic marbling ability, seem to only increase marbling at markedly low efficiency for a few months before slaughter. Therefore, the finding that carcass characteristics corresponded to their class of BVs suggests that an optimum feeding length based on listed BVs not only increases the efficiency of beef production, but also reduces the environmental load. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 5 : 635-638)

Alternative housing systems for pigs: Influences on growth, composition, and pork quality1

Effects of pig birth (first 3-wk period) and rearing environments on growth and muscle quality characteristics of loins were evaluated in three experiments over seasons in west Texas and central Missouri. Housing systems included indoor slatted-floor buildings, indoor deep-bedded buildings, outdoor housing on dirt, and outdoor housing on alfalfa pasture. Experiments were conducted during the growing/finishing phases and pigs were slaughtered at the same age. Loins were collected, vacuum-packaged, and stored for 14 d at 2 degrees C. Pigs born and finished in an outdoor environment during the summer months (Exp. 1) had a greater ADG (0.92 vs 0.82+/-0.06 kg/d, P < 0.05) and had heavier carcass weights (87.9 vs 78.4+/-2.4 kg, P < 0.05) than pigs born and finished in an indoor environment with a slatted-floor finishing building. Carcasses from the outdoor-reared group measured a larger (P < 0.05) loineye area and were fatter (P < 0.01) at the first rib, last rib, and last lumbar vertebra measurements than carcasses from the indoor-reared group. Loin chops from outdoor-reared pigs had darker color scores in the retail display case throughout the 4-d period, measured lower L* values on d 1, and had more discoloration and browning on d 4 than loin chops from the indoor-reared group. During the winter months (Exp. 2), no difference was detected in ADG, carcass measurements, sensory characteristics, or shear force values from indoor-born pigs placed in either an outdoor or indoor finishing environment. Pigs finished on deep bedding (Exp. 3) had heavier carcass weights and more backfat (P < 0.01) than pigs finished on slats, but no differences were detected in sensory panel or shear force results. Overall, carcass measurements, pH, drip loss, sensory panel, and shear force values were similar among the groups finished in different housing systems. Outdoor or deep-bedded systems may increase growth rates of pigs if suitable land area and resources are available, but pork quality of loins will be similar for pigs finished in either conventional or alternative systems.

Diverse birth and rearing environment effects on pig growth and meat quality.

Birth and rearing conditions were evaluated for their effects on pig growth, body composition, and pork quality using 48 barrows during the spring and summer months. Pigs were either farrowed in indoor crates or outdoor huts. At weaning, indoor-born and outdoor-born pigs were randomly allotted to indoor or outdoor treatments for growing/finishing. Body weight data were collected. Pigs were transported 5 h to a commercial processing plant, allowed 2 h of rest, and then processed as a group under commercial conditions. Boneless loins were collected from the left side of each carcass and aged for 14 d. Objective and subjective color measurements were taken on the longissimus muscle at the 10th rib on d 14 postmortem. Loin chops were evaluated for sensory attributes, shear force, and retail display features. Pigs born outdoors were heavier and had greater ADG at all growth intervals after weaning (d 28, 56, 112, and final weight, P < 0. 05) than pigs born indoors. Outdoor-born pigs had heavier carcass weights (91.2 vs 81.3+/-3.4 kg, P < 0.001), larger loineye areas (54.6 vs 49.7+/-0.2 cm , P < 0.05), and higher pork flavor intensity scores (6.5 vs 6.1+/-0.10, P < 0.01) than indoor-born pigs. Birth x rearing environment interactions were not significant for most measures. Backfat measurements at the last rib were greater (3.2 vs 2.8+/-0.05 cm, P < 0.05) for the pigs reared outdoors than for the pigs reared indoors. Pigs finished outdoors had more reddish pink color scores, lower shear force values, and lower L* values, indicating darker-colored pork, compared with pigs finished indoors (P < 0.05). Pig birth environment played a significant role in improving growth rates of outdoor-born pigs and increasing pork flavor intensity scores of loin chops from pigs born outdoors. Finishing pigs outdoors may improve pork color and tenderness but also may increase backfat thickness when they are fed conventional diets.

Influence of slaughter weight and sex on yield and quality grades of Hanwoo (Korean native cattle) carcasses.

To assess the effects of slaughter weight and sex on APGS (Animal Products Grading Service) quality and APGS yield grade of Korean Hanwoo (n = 20,881) cattle, data were collected from cow, bull, and steer carcasses during a 1-yr period. Factors used to determine quality grade (marbling, meat color, fat color, texture, and overall maturity score) and yield grade (cold carcass weight, adjusted fat thickness, and longissimus muscle area) by the Korean grading system were recorded. Both yield and quality grades were improved (P < 0.01) with heavier slaughter weight, but there was no difference in yield grade for Hanwoo cattle classes heavier than 551 kg (P > 0.01). Longissimus muscle area, adjusted fat thickness, and marbling score increased (P < 0.01) with carcass weight. Bull carcasses showed higher yield but lower quality than those of cows or steers (P < 0.01). The quality grade of steer carcasses was higher (P < 0.01) than that of cow carcasses due to higher marbling scores, lower maturity scores, and heavier carcass weights. Hanwoo carcasses with larger longissimus muscle areas in relation to their carcass weight had lower APGS quality grades. The APGS quality grades were different between yield grade A and B carcasses (P < 0.01), but quality grade was not improved by increased fat thickness beyond the point of yield grade B. Adjusted fat thickness and marbling score showed significant (P < 0.01) differences among all yield grade classes, and this resulted in increased quality grade as yield grade decreased. Adjusted fat thickness showed the strongest correlation (r = -0.63) with yield grade, whereas marbling score had the strongest correlation (r = 0.81) with quality grade. Results showed a negative effect of castration on yield but a positive effect on quality. Also, data showed that Hanwoo carcasses with heavier weights had higher quality grades than those of lighter weight.

Sustained growth promotion, carcass and meat quality of steers slaughtered at three liveweights

The experiment measured the effect of a sustained growth promotion strategy on growth rate, carcass characteristics, and meat quality of Brahman and F 1 Brahman crossbred steers. Meat quality was assessed objectively by laboratory measurement and a subset of samples evaluated subjectively by consumer taste panels. Steers were allocated to one of 12 treatment groups; 2 implant strategies × 3 liveweights at slaughter × 2 nutritional finishing strategies. The 2 implant strategies were unimplanted controls and implantation with 20 mg oestradiol-17β (Compudose) every 100 days. The target carcass weights at slaughter were about 220 kg (Australian domestic market), about 280 kg (Korean market) and about 320 kg (Japanese market). Steers were finished either at pasture or on a grain-based diet in a feedlot. For every treatment group except where steers were finished in a feedlot for the domestic market, the implant strategy resulted in significantly (P&lt;0.01) heavier final liveweights, significantly (P&lt;0.01) greater cumulative liveweight gains and significantly (P&lt;0.05) heavier carcass weights. The magnitudes of the significant liveweight responses ranged from 30 kg for pasture fed steers for the domestic market to 47 kg for pasture fed steers for the heavier weight Japanese market. Repeated treatment with oestradiol-17β had no significant effect on carcass composition as determined by indices of carcass lean and carcass fat. The additional yield of retail beef from implanted steers was principally associated with increased carcass weight. The magnitude of the increase in beef yield was 8 kg (n.s.) for domestic, feedlot steers; 15 kg (P&lt;0.01) for Korean, feedlot steers and 18 kg (P&lt;0.001) for Japanese, feedlot steers. In steers finished in the feedlot for the Korean and Japanese markets, sustained growth promotion was associated with a significant (P&lt;0.01) decrease in meat tenderness as measured by peak force. In contrast there was no such effect in other groups measured (domestic market, feedlot finished and Japanese market, pasture finished). Consumer assessment of eating quality was conducted on steaks from steers, finished in a feedlot for the Korean and Japanese markets. At both slaughter weights there was no significant effect of treatment on tenderness, juiciness, flavour, overall acceptability or meat quality score which combined tenderness, juiciness, flavour and overall quality. However, mean preference scores from implanted steers were consistently lower than those from control steers. It was concluded that the aggressive implant strategy resulted in substantial increases in weight gain that were more pronounced during periods of moderate growth rate relative to periods of very low rates of gain. During periods of low weight gains or weight stasis there was little advantage from implantation. Carcass composition was not significantly modified by treatment with oestradiol. The effect of the aggressive implantation strategy on eating quality of the beef was equivocal and further investigation is certainly warranted.