Dual-component video image analysis system (VIASCAN) as a predictor of beef carcass red meat yield percentage and for augmenting application of USDA yield grades

An improved ability to quantify differences in the fabrication yields of beef carcasses would facilitate the application of value-based marketing. This study was conducted to evaluate the ability of the Dual-Component Australian VIASCAN to 1) predict fabricated beef subprimal yields as a percentage of carcass weight at each of three fat-trim levels and 2) augment USDA yield grading, thereby improving accuracy of grade placement. Steer and heifer carcasses (n = 240) were evaluated using VIASCAN, as well as by USDA expert and online graders, before fabrication of carcasses to each of three fat-trim levels. Expert yield grade (YG), online YG, VIASCAN estimates, and VIASCAN estimated ribeye area used to augment actual and expert grader estimates of the remaining YG factors (adjusted fat thickness, percentage of kidney-pelvic-heart fat, and hot carcass weight), respectively, 1) accounted for 51, 37, 46, and 55% of the variation in fabricated yields of commodity-trimmed subprimals, 2) accounted for 74, 54, 66, and 75% of the variation in fabricated yields of closely trimmed subprimals, and 3) accounted for 74, 54, 71, and 75% of the variation in fabricated yields of very closely trimmed subprimals. The VIASCAN system predicted fabrication yields more accurately than current online yield grading and, when certain VIASCAN-measured traits were combined with some USDA yield grade factors in an augmentation system, the accuracy of cutability prediction was improved, at packing plant line speeds, to a level matching that of expert graders applying grades at a comfortable rate.     

Evaluation of the E+V video image analysis system as a predictor of pork carcass meat yield

This study was conducted to assess the ability of the VCS2001 (E+V, Oranienburg, Germany) video image analysis system to predict pork carcass composition. Pork carcasses (n = 278) were selected from a commercial packing plant to differ in weight, Fat-O-Meater (FOM) predicted percentage lean, and gender. Carcasses were imaged three times with the VCS2001, chilled overnight, and then sequentially fabricated into boneless subprimals. The VCS2001 accurately predicted the weight of total saleable product (R2 = 0.88, root mean square error [RMSE] = 1.84) and fat-corrected lean (R2 = 0.92, RMSE = 1.66), but autocorrelation existed between dependent and independent variables. The VCS2001 was acceptably accurate and precise in predicting weights of bone-in ham (R2 = 0.83, RMSE = 0.80), bone-in loin (R2 = 0.74, RMSE = 1.17), loin lean (R2 = 0.77, RMSE = 0.82), belly (R2 = 0.78, RMSE = 0.94), sparerib (R2 = 0.55, RMSE = 0.28), and boneless shoulder (R2 = 0.73, RMSE = 0.79). Weights were more accurately predicted than yields (as a percentage of hot carcass weight) of total saleable product (R2 = 0.47, RMSE = 1.97) or total fat-corrected lean (R2 = 0.44, RMSE = 1.89) using VCS2002, and it did not accurately predict percentages of bone-in ham (R2 = 0.45, RMSE = 1.13), ham lean (R2 = 0.32, RMSE = 1.46), bone-in loin (R2 = 0.29, RMSE = 1.36), loin lean (R2 = 0.56, RMSE = 0.90), belly (R2 = 0.43, RMSE = 1.08), sparerib (R2 = 0.08, RMSE = 0.32), or boneless shoulder (R2 = 0.30, RMSE = 0.88). New prediction models and equations were developed using VCS2001 output variables plus hot carcass weight to predict weight of total saleable product (R2 = 0.89, RMSE = 1.72) and fat-corrected lean (R2 = 0.93, RMSE = 1.55) with very minimal increases in accuracy and precision over that achieved using E+V-programmed models and equations. Use of new prediction models and equations marginally improved accuracy and precision of estimations of total saleable product yield (R2 = 0.56, RMSE = 1.81) and fat-corrected lean yield (R2 = 0.57, RMSE = 1.67) over that achieved using E+V-programmed models and equations. The VCS2001 was not able to predict pork carcass composition more accurately than existing technology; therefore, further development is needed to assure commercial viability of this instrument.     

Development and validation of equations utilizing lamb vision system output to predict lamb carcass fabrication yields

This study was performed to validate previous equations and to develop and evaluate new regression equations for predicting lamb carcass fabrication yields using outputs from a lamb vision system-hot carcass component (LVS-HCC) and the lamb vision system-chilled carcass LM imaging component (LVS-CCC). Lamb carcasses (n = 149) were selected after slaughter, imaged hot using the LVS-HCC, and chilled for 24 to 48 h at -3 to 1 degrees C. Chilled carcasses yield grades (YG) were assigned on-line by USDA graders and by expert USDA grading supervisors with unlimited time and access to the carcasses. Before fabrication, carcasses were ribbed between the 12th and 13th ribs and imaged using the LVS-CCC. Carcasses were fabricated into bone-in subprimal/primal cuts. Yields calculated included 1) saleable meat yield (SMY); 2) subprimal yield (SPY); and 3) fat yield (FY). On-line (whole-number) USDA YG accounted for 59, 58, and 64%; expert (whole-number) USDA YG explained 59, 59, and 65%; and expert (nearest-tenth) USDA YG accounted for 60, 60, and 67% of the observed variation in SMY, SPY, and FY, respectively. The best prediction equation developed in this trial using LVS-HCC output and hot carcass weight as independent variables explained 68, 62, and 74% of the variation in SMY, SPY, and FY, respectively. Addition of output from LVS-CCC improved predictive accuracy of the equations; the combined output equations explained 72 and 66% of the variability in SMY and SPY, respectively. Accuracy and repeatability of measurement of LM area made with the LVS-CCC also was assessed, and results suggested that use of LVS-CCC provided reasonably accurate (R2 = 0.59) and highly repeatable (repeatability = 0.98) measurements of LM area. Compared with USDA YG, use of the dual-component lamb vision system to predict cut yields of lamb carcasses improved accuracy and precision, suggesting that this system could have an application as an objective means for pricing carcasses in a value-based marketing system.     

Online evaluation of a commercial video image analysis system (Computer Vision System) to predict beef carcass red meat yield and for augmenting the assignment of USDA yield grades. United States Department of Agriculture

Objective quantification of differences in wholesale cut yields of beef carcasses at plant chain speeds is important for the application of value-based marketing. This study was conducted to evaluate the ability of a commercial video image analysis system, the Computer Vision System (CVS) to 1) predict commercially fabricated beef subprimal yield and 2) augment USDA yield grading, in order to improve accuracy of grade assessment. The CVS was evaluated as a fully installed production system, operating on a full-time basis at chain speeds. Steer and heifer carcasses (n = 296) were evaluated using CVS, as well as by USDA expert and online graders, before the fabrication of carcasses into industry-standard subprimal cuts. Expert yield grade (YG), online YG, CVS estimated carcass yield, and CVS measured ribeye area in conjunction with expert grader estimates of the remaining YG factors (adjusted fat thickness, percentage of kidney-pelvic-heart fat, hot carcass weight) accounted for 67, 39, 64, and 65% of the observed variation in fabricated yields of closely trimmed subprimals. The dual component CVS predicted wholesale cut yields more accurately than current online yield grading, and, in an augmentation system, CVS ribeye measurement replaced estimated ribeye area in determination of USDA yield grade, and the accuracy of cutability prediction was improved, under packing plant conditions and speeds, to a level close to that of expert graders applying grades at a comfortable rate of speed offline.     

Leptin as a predictor of carcass composition in beef cattle

Our objective was to determine if serum concentrations of leptin could be used to predict carcass composition and merit in feedlot finished cattle. Two different groups of crossbred Bos taurus steers and heifers were managed under feedlot conditions near Miles City, MT. The first group consisted of 88 1/2 Red Angus, 1/4 Charolais, and 1/4 Tarentaise composite gene combination steers (CGC) harvested at the ConAgra processing facility in Greeley, CO. The second group (Lean Beef Project; LB) consisted of 91 F2 steers and heifers born to Limousin, Hereford, or Piedmontese by CGC F1 cows crossed to F1 bulls of similar breed composition and harvested at a local processing facility in Miles City, MT. Blood samples were collected approximately 24 h before harvest (CGC) or approximately 3 d before and at harvest (LB). No differences in serum concentrations of leptin were detected (P > 0.10) between Hereford, Limousin, or Piedmontese F2 calves nor between LB steers and heifers. Positive correlations (P < 0.01) existed between serum leptin and marbling score (r = 0.35 and 0.50), fat depth measured between the 12th and 13th rib (r = 0.34 and 0.46), kidney, pelvic, and heart fat (KPH) (r = 0.42 and 0.46), and quality grade (r = 0.36 and 0.49) in CGC and LB cattle, respectively. Serum leptin was also positively correlated with calculated yield grade for CGC steers (r = 0. 19; P = 0. 10) and LB cattle (r = 0.52; P < 0.01). Longissimus area was not correlated with serum leptin in CGC steers (r = 0.12; P > 0.10). However, a negative correlation existed between longissimus area and serum leptin in the LB cattle (r = -0.45; P < 0.01). Serum concentrations of leptin were significantly associated with carcass composition (marbling, back fat depth, and KPH fat) and quality grade in both groups of cattle studied and may provide an additional indicator of fat content in feedlot cattle.     

补饲精料对乌珠穆沁羊生产性能、屠宰性能和肉品质的影响

试验旨在研究草颗粒和草颗粒补饲精料对乌珠穆沁羊生产性能、屠宰性能和肉品质的影响。选取20只6月龄体重为(28.83±0.19) kg乌珠穆沁羊,采用随机区组设计,随机分为2组,每组10只。设计2种日粮饲喂乌珠穆沁羊,分别为草颗粒(对照组)和草颗粒补饲精料(试验组)。结果表明:补饲精料未能显著影响羊的日增重(P>0.05),日增重分别为56.33和60.00 g。对照组和试验组的3项屠宰性能指标(宰前活重、胴体重、屠宰率)、6项化学成分指标(粗蛋白、粗脂肪、有机物、干物质、钙、磷)、6项肉品质指标(pH1、pH24、大理石纹、亮度、熟肉率、剪切力)、16项脂肪酸指标和15项氨基酸指标差异均不显著(P>0.05)。试验组羊4项屠宰性能指标(净肉重、净肉率、眼肌面积、GR值)、4项肉品质指标(红度、黄度、胆固醇、失水率)、6项脂肪酸指标(十三碳酸、肉豆蔻酸、珍珠酸、γ-亚麻酸、α-亚麻酸、花生酸)和3项氨基酸指标(异亮氨酸、酪氨酸、精氨酸)均显著高于对照组(P<0.05)。对照组7项主要脂肪酸(丁酸、月桂酸、肉豆蔻烯酸、十五碳酸、十五碳烯酸、棕榈酸、棕榈油酸、硬脂酸、油酸、n-6/n-3)、苏氨酸和谷氨酸显著高于试验组(P<0.05)。饲喂草颗粒补饲精料对乌珠穆沁羊生长性能影响不大;天然草地草颗粒饲喂能满足家畜营养需求,在促进乌珠穆沁羊生产性能、屠宰性能和肉品质方面具有重大潜力。     

4个黑山羊品种(类群)羔羊胴体性状和肉品质分析

选取乐至黑山羊等4个黑山羊品种(类群)共86只公羔集中育肥3个月。育肥期结束时,选择20只羊(每个品种5只)屠宰,测定胴体产肉性能和肉质指标。结果显示:在4个黑山羊品种(类群)间,乐至黑山羊公羔胴体产肉性能较自贡黑山羊、简阳大耳羊黑色群体和美姑黑山羊高,但差异不显著(P>0.05);自贡黑山羊公羔羊肉持水能力优于其他3个品种,肌内脂肪含量2.00%,显著高于美姑黑山羊和简阳大耳羊(P<0.05);4个品种必需氨基酸含量都较丰富,但品种间差异均不显著(P>0.05)。     

Using current on-line carcass evaluation parameters to estimate boneless and bone-in pork carcass yield as influenced by trim level.

The objective of this study was to develop prediction equations for estimating proportional carcass yield to a variety of external trim levels and bone-in and boneless pork primal cuts. Two hundred pork carcasses were selected from six U.S. pork processing plants and represented USDA carcass grades (25% USDA #1, 36% USDA #2, 25% USDA #3, and 14% USDA #4). Carcasses were measured (prerigor and after a 24 h chill) for fat and muscle depth at the last rib (LR) and between the third and fourth from last rib (TH) with a Hennessy optical grading probe (OGP). Carcasses were shipped to Texas A&M University, where one was randomly assigned for fabrication. Selected sides were fabricated to four lean cuts (ham, loin, Boston butt, and picnic shoulder) then fabricated progressively into bone-in (BI) and boneless (BL) four lean cuts (FLC) trimmed to .64, .32, and 0 cm of s.c. fat, and BL 0 cm trim, seam fat removed, four lean cuts (BLS-OFLC). Total dissected carcass lean was used to calculate the percentage of total carcass lean (PLEAN). Lean tissue subsamples were collected for chemical fat-free analysis and percentage carcass fat-free lean (FFLEAN) was determined. Longissimus muscle area and fat depth also were collected at the 10th and 11th rib interface during fabrication. Regression equations were developed from linear carcass and OGP measurements predicting FLC of each fabrication point. Loin muscle and fat depths from the OPG obtained on warm, prerigor carcasses at the TH interface were more accurate predictors of fabrication end points than warm carcass probe depth obtained at the last rib or either of the chilled carcass probe sites (probed at TH or LR). Fat and loin muscle depth obtained via OGP explained 46.7, 52.6, and 57.1% (residual mean square error [RMSE] = 3.30, 3.19, and 3.04%) of the variation in the percentage of BI-FLC trimmed to .64, .32, and 0 cm of s.c. fat, respectively, and 49.0, 53.9, and 60.7% (RMSE = 2.91, 2.81, and 2.69%) of the variation in the percentage of BL-FLC trimmed to .64, .32, and 0 cm of s.c. fat, respectively. Fat and loin muscle depth from warm carcass OGP probes at the TH interface accounted for 62.4 and 63.5% (RMSE = 3.38 and 3.27%) of the variation in PLEAN and FFLEAN, respectively. These equations provide an opportunity to estimate pork carcass yield for a variety of procurement end point equations using existing on-line techniques.     

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)     

平和红肉蜜柚优质丰产栽培技术

本文简要介绍了红肉蜜柚的特征、特性,并从园地选择、选用良种、高标准种植、肥水管理、土壤管理、整形修剪、花果管理、病虫害防治、适时采收等方面分述红肉蜜柚优质丰产栽培技术。     

Fermented cassava bioethanol waste as substitute of protein in diet for growth performance and carcass evaluation on meat ducks

The effect of dietary supplementation with fermented cassava bioethanol waste (FCBW) on the growth performance and meat quality was evaluated in 80 15-day-old male Cherry Valley meat ducks with an initial body weight (BW) of 250.67 ± 7.50 g. The experiment has 5 replications and 4 treatments and 4 ducks per treatment. Four groups (groups I, II, III, IV) supplemented with 0%, 5%, 10%, and 15% FCBW substituted for part of maize, soybean meal, and bran in basal diet and were fed for 29 days; the metabolizable energy and content of lysine in the four groups were equal. The results indicated that there were no significant differences in average daily weight gain and average daily feed intake among the four groups (P > 0.05). The digestibility rate of dry matter, ash, and phosphorus in group IV was significantly lower than that in group I by 5.23%, 6.25%, and 6.40% respectively (P < 0.05), but the digestibility rate of crude fat was significantly higher than that in group I by 8.30% (P < 0.05). No significant differences were presented among different levels of FCBW supplementation in carcass yield, eviscerated carcass yield, and semi-eviscerated carcass yield (P > 0.05), but 5% FCBW can improve the carcass yield relatively. In conclusion, with dietary supplementation of 5% FCBW, a better growth performance in meat ducks could be achieved.

     

Growth,carcass yield and meat quality attributes of Red Maasai sheep fed wheat straw-based diets

Thirty-two castrated Red Maasai sheep (12.7 kg initial body weight, aged 12–18 months), were used in an 84-day experiment to evaluate diets based on treated straw upon growth performance, carcass yield and meat quality. The animals were blocked by weight into four similar groups and randomly allotted into four dietary treatments, with eight individually fed animals per treatment. The dietary treatments were ad libitum untreated wheat straw (UTS), wheat straw treated with urea and lime (TS), straw and ad libitum hay (UTSH), and TS and ad libitum hay (TSH). In addition, each experimental animal received 220 g/day (on as fed basis) of a concentrate diet. Treatment of straw increased (P < 0.05) dry matter intake (42.3 vs. 33.7 g/kg W ⁷⁵/day), energy intake (4.6 vs. 3.7 MJ ME/d) and the average daily gain (40.7 vs. 23.1 g). Animals on TS produced heavier (P < 0.05) carcasses (6.6 vs. 5.4 kg) with superior conformation than animals on UTS. Percentage cooking loss was higher in carcasses from animals fed TS compared to those from other diets. Except M. longissimus dorsi and M. semitendinosus, tenderness of muscles was not affected by diet but ageing of meat improved (P < 0.001) tenderness. Overall, straw treatment increased carcass yields with limited effects on meat quality attributes.     

国外牛肉产量级发展及我国产量级制度建立问题探讨

完善的牛肉分级体系一般都包括质量等级标准和产量等级标准。产量等级主要描述胴体的产肉性能,如产肉量、产肉率等,与胴体重、背膘厚、眼肌面积等指标密切相关。详细介绍各国产量等级标准,提出我国产量等级标准的制订必须遵循通用性、可操作性和前瞻性原则。     

发酵木薯渣替代部分玉米对湖羊生长性能、血清生化指标、屠宰性能和肉品质的影响

本研究旨在探索发酵木薯渣在湖羊日粮中替代部分能量饲料(玉米)的可行性,并确定最佳替代比例。选择48只体重为(18.35±1.39) kg的湖羊公羔,随机分成4组,每组4个重复,每个重复3只羊,分别用发酵木薯渣替代0%(对照组)、20%(A组)、40%(B组)、60%(C组)玉米的日粮进行饲喂,试验期60 d。在试验开始和结束时测定羔羊生长性能,并采集血液样品进行分析,同时在试验结束时进行屠宰试验,测定屠宰性能以及肉品质。研究结果表明,A组湖羊的平均采食量(ADFI)显著高于对照组和B组(P<0.05),日增重(ADG)的变化趋势为A组>B组>对照组(P>0.05),A组和B组的料重比(F/G)有低于对照组的趋势(P>0.05)。而C组湖羊由于腹泻严重,于试验开始2周后将其淘汰。A组的宰前活重、胴体重、肝、瓣胃和肾的重量显著大于对照组和B组(P<0.05),而各组其他内脏器官无显著差异(P>0.05)。各组湖羊的血液生化指标和肉品质均无显著差异(P>0.05)。B组的肉豆蔻酸、棕榈酸等饱和脂肪酸的含量显著低于A组(P<0.05),而B组的十七烷酸和花生酸的含量显著高于A组和对照组(P<0.05),其他种类的脂肪酸无显著差异(P>0.05)。由此可见,利用发酵木薯渣替代20%玉米对湖羊公羔的生长发育和健康无不良影响,且能降低饲料成本,育肥效果最好。因此,将发酵木薯渣作为湖羊的饲料来源是完全可行的。     

Genetic evaluation of carcass yield using ultrasound measures on young replacement beef cattle

Live weight and ultrasound measures of fat thickness and longissimus muscle area were available on 404 yearling bulls and 514 heifers, and carcass measures of weight, longissimus muscle area, and fat thickness were available on 235 steers. Breeding values were initially estimated for carcass weight, longissimus muscle area, and fat thickness using only steer carcass data. Breeding values were also estimated for weight and ultrasound muscle area and fat thickness using live animal data from bulls and heifers, with traits considered sex-specific. The combination of live animal and carcass data were also used to estimate breeding values in a full animal model. Breeding values from the carcass model were less accurate and distributed more closely around zero than those from the live data model, which could at least partially be explained by differences in relative amounts of data and in phenotypic mean and heritability. Adding live animal data to evaluation models increased the average accuracy of carcass trait breeding values 91, 75, and 51% for carcass weight, longissimus muscle area, and fat thickness, respectively. Rank correlations between breeding values estimated with carcass vs live animal data were low to moderate, ranging from 0.16 to 0.43. Significant rank changes were noted when breeding values for similar traits were estimated exclusively with live animal vs carcass data. Carcass trait breeding values estimated with both live animal and carcass data were most accurate, and rank correlations reflected the relative contribution of carcass data and their live animal indicators. The addition of live animal data to genetic evaluation of carcass traits resulted in the most significant carcass trait breeding value accuracy increases for young replacements that had not yet produced progeny with carcass data.     

Back-fat thickness as a primary index reflecting the yield and overall acceptance of pork meat

Predicting aspects of lean meat yield and eating quality of pork based on some particular carcass traits become increasingly important from an economic profitability point of view. The present study aimed to determine the relationship between the back-fat (BF) thickness with lean meat yield and meat quality traits of crossbred pigs. A total of 220 crossbred pigs [(Landrace × Yorkshire) ♀ × Duroc ♂] reared under identical conditions and harvested at 180 days old were slaughtered and screened for BF thickness. Four BF thickness groups: 12–15, 16–20, 21–25, and 26–30 mm were classified, and longissimus dorsi (LD) muscles from these groups were used to analyze meat quality characteristics. Results showed that increasing BF thickness decreased the lean meat yield and loin lean area. Increasing BF thickness up to 26–30 mm increased intramuscular fat content and pH of LD muscles. The LD muscles of the thicker BF (21–30 mm) groups received significantly higher flavor, juiciness, and overall acceptability scores than those of the thinner back-fat (12–20 mm) groups. Overall, when all the pre-harvest factors are kept the same, BF thickness could be considered as a primary index for predicting lean meat yield, and the minimal back-fat thickness of 21–30 mm is required to improve the overall acceptability of pork meat.     

Comparative evaluation of carcass traits and meat quality in native Aseel chickens and commercial broilers

1. A comprehensive study was conducted to analyse the meat quality attributes, composition and carcass traits in Aseel chickens and commercial broilers at market age on the basis of physiological age. A total of 20 Aseel (26 and 56 weeks) and 20 broiler (6 weeks) chickens were divided into two groups on a live weight basis, i.e. large (≥2.5 kg) and small (<2.5 kg) with 10 birds in each subgroup.

2. The pH of meat did not show any significant variation between Aseel and broiler chickens. The meat from heavier birds had significantly higher pH. Shear force value and hydroxyproline contents were significantly higher in Aseel chickens. Aseel birds had significantly higher red (a*) colouration and lower lightness (L*) than broiler chickens.

3. The texture and acceptability of Aseel meat were significantly higher.

4. Scanning electron microscopy revealed that muscle fibres in Aseels were arranged in a more coiled pattern making the muscle tough. A larger amount of connective tissue was also observed between the muscle fibres compared with the broiler chickens.

5. The dressing percentage was significantly higher in larger chickens. Commercial broilers recorded significantly higher meat proportion and lower proportion of bone. The meat:bone ratio was 1.07:1.0 in Aseel and 1.31–1.0 in broiler chicken. Breast muscle content was significantly lower in smaller Aseel chickens. Aseel chicken had stronger and heavier backs and shanks. Abdominal fat percentage was significantly lower in Aseel (0.73–0.78%).

6. The study concluded that the firm texture of Aseel meat was due to the high collagen content and interlocking connective tissue between the muscle fibres. The texture and acceptability of Aseel meat was higher. Aseel cocks had strong legs, lean meat and less abdominal fat, making them a high-value meat bird in addition to their aggressive fighting ability.

     

Influence of management system on litter size, lamb growth, and carcass characteristics in sheep.

Three management systems (winter, spring, and late summer) distinguished by season of lambing and management practices were compared for litter size born and weaned and growth and carcass characteristics of lambs. Three sire breeds (Cheviot, Rambouillet, and Suffolk) and three dam breeds (Florida Native, Native-X, and Synthetic-X) were used in 698 matings over a 3-yr period. System affected (P < .01) litter size born. Spring lambing yielded more lambs (1.62) than winter (1.49) and late summer (1.12). The winter-born lambs were lighter but fatter (P < .05), and spring-born lambs were leaner with higher leg conformation and carcass quality scores. The late summer-born lambs were not different from spring-born lambs. Wethers had higher (P < .01) weights off test than ewe lambs (43.9 vs 42 kg) but had lower (P < .01) leg conformation scores, percentage kidney and pelvic fat, yield grade, and dressing percentages. Dam breed effects were significant (P < .05) for average preweaning daily gains with 249+/-5, 201+/-9, and 191+/-9 g for progeny of Native-X, Florida Native, and Synthetic-X, respectively. Single-born lambs had higher daily gains (P < .05) than twins in a preweaning period in all management systems and higher postweaning and lifetime daily gains for winter and spring management systems.     

九神曲对肉鸡胴体和肌肉品质的影响

试验研究了九神曲(枯草芽孢杆菌)对肉鸡胴体和肌肉品质的影响。选用90羽7日龄的肉仔鸡,随机分成三个处理组,每个处理设三个重复。A组饲喂基础日粮,B组饲喂基础日粮加0.05%的硫酸新霉素制剂,C组饲喂基础日粮加0.1%的九神曲。试验期35d。结果表明,C组肉鸡胴体品质的各项指标与两对照组相比,除了腿肌率有显著性的差异外(P<0.05),其余各项指标均无明显差异(P>0.05)。C组鸡肌肉氨基酸总量、必需氨基酸和鲜味氨基酸含量均高于两对照组。结果表明九神曲对肉鸡胴体和鸡肉品质不但没有不良的影响,而且可增加鸡肉氨基酸总量、必需氨基酸和鲜味氨基酸的含量。