不同比例酒糟全混合日粮对肉牛屠宰性能的影响

研究不同比例酒糟全混合日粮对肉牛屠宰性能的影响。选择西本杂牛30头,随机分为3组,即对照组(精粗分饲)、试验Ⅰ组(酒糟型全混合日粮)、试验Ⅱ组(酒糟型全混合日粮,酒糟比例提高30%)。经过9个月的育肥试验后进行屠宰测定,结果表明:⑴试验Ⅰ组的屠宰率、净肉率、肉骨比值、大理石花纹等级、眼肌面积、肉色、脂肪色、特优级肉块重、高档肉块重均为最优,试验Ⅱ组次之,对照组最低;⑵从特优级肉块重、高档肉块重占净肉重的比例来看,对照组最高,试验Ⅰ组最低(P0.05);⑶3组试验牛的屠宰性能指标差异不显著(P0.05)。结论:采用全混合日粮可提高肉牛的屠宰性能、肉的品质、特优级肉块重、高档肉块重(P0.05);提高日粮中酒糟比例,在降低饲料成本的同时,也会降低肉牛的屠宰性能、肉的品质、特优级肉块重、高档肉块重(P0.05)。     

育成期营养对育肥皖南牛产肉性能和胴体等级的影响

研究育成期日粮营养对育肥皖南牛产肉性能和胴体等级的影响。30头去势的体质量相近的7月龄皖南牛,平均随机分成5组,各组根据体质量的1.9%、1.6%、1.3%、1.0%和0.7%补充育成期精料饲养到24月龄进行育肥,各组在饲养程序相同条件下育肥期3个月后屠宰分割。结果表明:育成期的营养水平育肥期皖南的屠宰性能和胴体等级能产生影响,按体质量1%饲喂精料的G1.0组营养水平能显著提高胴体和净肉中高档肉块比例,该组育成期营养水平使5~7肋骨横切面有丰富的脂肪分布,达到优级胴体等级。     

云岭山羊产肉性能及肉质研究

本次试验测定云岭山羊的产肉性能及肉南并和陇陵黄山羊进行了比较。结果显示云岭山羊的屠宰率和净肉率较低；峪 干物质和蛋白质含量较高，干样中氨基酸含量差异不显著。蛋白质笔组氨酸含量在两个品种之间差异不显著，但均高于理想蛋白质中的含量。背最工肌和股二头肌肌纤维直径两个品种之间差异显著。肉的嫩度和膻味无差异。云岭山羊和陇陵黄山羊肉的ＰＨ２４值较高分别为６．０２和５．９２。     

基于主成分和聚类分析的牦牛部位肉品质评价

为了探讨牦牛不同部位肉的品质差异,测定了牦牛17个部位肉的L*值、a*值、b*值、失水率、蒸煮损失和剪切力6项品质指标,通过方差分析、主成分分析和聚类分析研究其品质差异。结果表明,牦牛部位肉6项品质指标均存在显著性差异(P0.01);主成分分析提取出3个主成分因子PC1(35.11%)、PC2(25.13%)、PC3(16.63%),可明显区分里脊、辣椒条、前腱、牛蹍、眼肉与其它肉块;聚类分析将17个部位肉分为前部胴体和后部胴体2大类,各类别间的差异与牦牛部位肉的持水能力和剪切力密切相关。由此得出,牦牛不同部位肉品质差异显著,且牦牛后部胴体肉在品质上优于前部胴体。     

云岭牛不同部位肉的品质特性分析

为了探索云岭牛不同部位肉品质特性的差异,选用30月龄云岭牛霖肉、臀肉、肩肉、牛腱、黄瓜条和牛腩6个部位肉,对水分、脂肪、蛋白质和胶原蛋白含量、p H值、色差、质构、剪切力、蒸煮损失、解冻损失、凝胶特性及乳化特性进行测定。结果显示:相较于其它品种的牛,云岭牛具有蛋白质含量高,脂肪含量低的特点。肩肉的水分(75.80%)、蛋白质(24.00%)和胶原蛋白含量(13.68%)高,脂肪含量(1.05%)低,凝胶特性、嫩度和保水性均较好,但乳化特性较差;霖肉的蛋白质含量(21.30%)最低,但脂肪(5.13%)和胶原蛋白含量(17.91%)最高;臀肉的凝胶特性和乳化特性较好。结果表明,云岭牛不同部位肉间的品质特性有显著性差异,肩肉适合块状产品开发;霖肉适合烤制产品的开发;臀肉适合肠类产品开发。     

巴美肉羊与小尾寒羊杂交羔羊生长发育及屠宰性能研究

以小尾寒羊（母本）为对照,对4、6、8、12月龄的巴美肉羊（父本）和杂交后代巴寒F1美肉的生长发育和屠宰性能进行测定。结果表明：巴美肉羊胸围、胸围指标和体躯指数极显著大于小尾寒羊（P〈0.01）;巴美肉羊和巴寒F1日增质量在8月龄达到最大,12月龄开始下降。巴美肉羊和巴寒F1的屠宰性能和等级分割肉优于小尾寒羊。在6月龄巴寒F1净肉率、肉骨比和腰肉显著大于小尾寒羊（P〈0.05）,说明巴寒F1具有早期生长优势。随月龄的增加,巴美肉羊净肉质量、胴体产肉率、净肉率、肉骨比、肋肉和腹下肉极显著大于小尾寒羊（P〈0.01）,腰肉差异显著（P〈0.05）。在12月龄巴寒F1的屠宰率和净肉率极显著大于小尾寒羊（P〈0.05）。但各个月龄宰前活质量和胴体质量的差异不显著（P〉0.05）。     

科尔沁牛产肉量与净肉率预测模型建立

在活牛屠宰线上,为了较快地预测胴体产肉量和净肉率,并按照不同产肉性能对牛胴体进行等级划分,以建立科学合理的优质优价收购体系,本研究选取60头成年科尔沁牛,对其进行屠宰、冷却、分割,分别测定牛体活重(LW)、热胴体重(HCW)、眼肌面积(REA)、背膘厚度(FT)等指标,采用SPSS16.0软件对数据进行相关分析和线性回归,最终得到以牛胴体重(HCW)、牛体活重(LW)和眼肌面积(REA)三因子共同预测产肉量的线性方程Y1=-7.357+1.122×HCW-0.155×LW+0.077×REA(R2=0.986,RMSE=2.842)和预测净肉率的线性方程Y2=42.971+0.182×HCW-0.098×LW+0.021×REA(R2=0.930,RMSE=0.516),结果表明两个方程均可在实际生产中用于科尔沁牛产肉量和净肉率的预测。     

不同饲养条件对苏尼特羊背最长肌中MyomiRs表达及屠宰性能的影响

选择不同饲养条件下12月龄苏尼特羊的背最长肌为实验材料,通过测定6种mi RNAs的表达量及苏尼特羊的屠宰性能,研究不同饲养条件对mi RNAs表达量及屠宰性能的影响。结果表明:放牧苏尼特羊生长性状(体长、体高、胸围)、宰前活质量、胴体质量均显著高于圈养(P0.05),圈养苏尼特羊屠宰率、净肉率高于放牧。放牧苏尼特羊mi RNAs表达量均高于圈养苏尼特羊。放牧苏尼特羊mi R-1表达量与体高、胴体质量、净肉质量、净肉率显著正相关(P0.05),mi R-133表达量与净肉质量呈显著正相关性(P0.05),圈养苏尼特羊mi R-128表达量与净肉率显著负相关(P0.05)。说明不同饲养条件对mi RNAs的表达有影响,进一步影响屠宰性能。     

BMY牛育肥性状及胴体品质评价

本实验在云南省肉牛和牧草研究中心的小哨牧场选择6月龄左右的BMY断奶牛30头,根据月龄、体重和家系分为三组,采用三种不同的育肥方式育肥后进行屠宰测定,其结果为6～12月龄育肥日增重900g以上,12月龄的平均屠宰率为58.8%,平均净肉率为47.6%,优质肉占净肉的58.43%;12～18月龄育肥日增重650g以上,1 8月龄的平均屠宰率为59.51%,平均净肉率为48.07%,优质肉占净肉的59.79%;18～24有龄育肥日增重590g以上.24月龄的平均屠宰率为61%,平均净肉率为49.7%,优质肉占净肉的60.99%.     

小麦型日粮中添加酶制剂对肉仔鸡生产性能的影响

目的是评估不同比例小麦日粮中添加复合酶制剂对肉仔鸡的生产性能的影响.试验采用4×2因子处理:四种小麦基础日粮(小麦分别替代玉米40%、60%、80%、100%)和四种日粮分别添加酶制剂0和180g/t.将800只1日龄艾维因肉仔鸡随机分为8个处理组.每组分别饲喂上述8种日粮中的一种.结果表明:各处理组肉仔鸡在21和42日龄时体重无显著差异,但四个小麦加酶组与不加酶组相比,肉仔鸡1～3周和4～6周的料重比都显著降低(P<0.05);40%和60%小麦加酶组与不加酶组相比,死淘率无显著差异(P>0.05);且80%小麦加酶组肉仔鸡死淘率降低33.3%(P<0.05);100%小麦加酶组肉仔鸡死淘率降低37.7%(P<0.05).综合分析表明,本试验肉鸡日粮中小麦替代玉米在60%以下时,对内鸡生产性能无显著影响,当日粮中小麦替代玉米比例高达80%～100%时,生产性能显著降低;肉鸡日粮中小麦替代玉米在60%以下时添加酶制剂,对生产性能和死淘率无显著影响,当日粮中小麦替代玉米比例高达80%～100%时添加酶制剂,可显著提高肉鸡的生产性能.试验各组之间屠宰率、胴体性能均差异不显著(P>0.05).     

Meat quality of Angus, Simmental, Charolais and Limousin steers compared at the same intramuscular fat content

Meat quality and marbling properties of Angus, Simmental, Charolais and Limousin steers (4×16) were compared at an average intramuscular fat content (IMF) of 3.25% in the M. longissimus dorsi. The steers were fattened on a forage-based diet until the desired, ultrasonically estimated IMF content was reached which resulted in considerably different growth and carcass characteristics. The Angus group showed a growth rate similar to Simmental and Charolais while Limousin grew slower, became oldest and provided the heaviest carcasses and best conformation. Angus carcasses showed the lowest weight but the highest fatness score. Marbling was equal for all breeds. Angus and Charolais provided pale meat with low haem iron content. Angus and Limousin beef was more tender on sensory assessment than Simmental beef, corresponding to differences found in shear force (non-significant) and myofibrillar fragmentation index measured at 48 h post mortem. Flavour was similar among breed groups while juiciness was highest for Limousin and lowest for Angus. The juicier beef simultaneously showed the highest drip but the lowest cooking losses. In conclusion, clear differences in meat quality were observed between breeds despite similar IMF contents.     

不同品种牛和部位肌肉在成熟过程中品质差异比较研究

为探究肌肉部位和成熟时间对鲁西黄杂交牛和安秦杂交牛牛肉食用品质的影响,分别选取2种牛宰后的背最长肌、腰大肌和半膜肌3个部位肉,在成熟5、7、14、21?d时测定其嫩度、肌节长度、肉色和蛋白降解程度等指标.结果表明:随着成熟时间的延长,2种牛腰大肌剪切力值较低,肌节长度较长,肉色更好,而背最长肌和半膜肌剪切力更高,肌节长...     

Meat quality of Nguni, Bonsmara and Aberdeen Angus steers raised on natural pasture in the Eastern Cape, South Africa

The current study compared meat quality of Nguni, Bonsmara and Angus steers raised on natural pasture. Fifteen seven-month-old weaners of each breed were kept at the University of Fort Hare Farm for 12 months till slaughter. Monthly weights of the steers were recorded. Carcasses were electrically stimulated. The m. longissimus thoracis et lumborum was sampled for the measurement of meat colour, pH, drip loss, sarcomere length, myofibrillar fragmentation length and Warner Bratzler (WB) shear force. The Nguni had the highest (P < 0.05) average daily gain. Bonsmara and Angus steers had higher (P < 0.05) carcass weight and dressing percentage than the Nguni steers. Meat quality characteristics were similar among all the breeds except that Nguni meat was darker (L^∗) (P < 0.05) than meat from the other two breeds. The respective L^∗ values for Nguni, Bonsmara and Angus steers were 36.5, 38.6 and 39.9. There were significant (P < 0.05) correlations among some meat quality traits. There were significant (P < 0.05) correlations between WB values of meat aged for 2 and 21 days in Nguni and Bonsmara, but not in Angus. Meat quality from Nguni compares favourably with that from established breeds, when raised on natural pasture.     

3种牛皮加热过程中食用品质变化规律及其胶原蛋白结构差异性

为研究不同品种牛皮加热过程中食用品质的差异性,以安格斯牛皮、牦牛皮和西门塔尔牛皮为研究材料,分别在80 ℃条件下加热10、20、30、40、50、60 min,分析加热熟化过程中牛皮食用品质的变化,并采用酸法提取胶原蛋白,观察其微观结构。结果表明：3 种牛皮的食用品质有较大差异性,安格斯牛皮质量损失率与厚度损失率最低;从营养价值来看,蛋白质在加热过程中产生不同程度的损失,西门塔尔牛皮的蛋白质含量最高,损失率最低,安格斯牛皮的蛋白质含量最低,脂肪含量最高;3 种牛皮的质构变化趋势较为接近,峰值的大小和出现时间点均有所不同;Ⅰ型胶原蛋白的结构观察结果显示,3 种牛皮均保持了原有的交错结构;扫描电子显微镜结果表明,安格斯牛皮的胶原蛋白纤维簇直径更宽,网状结构更明显,不易被破坏。     

延边黄牛胴体质量等级的完善及不同等级肉质比较

对延边黄牛胴体质量等级进行完善,为胴体等级标准的建立提供前提条件,并比较不同等级延边黄牛肉肉质差异.结果表明:不同质量等级延边黄牛肉中水分、粗蛋白和粗灰分含量各组间均无显著差异,粗脂肪含量差异显著(P<0.05).不同质量等级延边黄牛肉中失水率、系水率、熟肉率、剪切力差异显著(P<0.05).牛肉质量等级越高,熟肉率和系水率越高,嫩度越好.     

河西肉牛脂肪酸成分比较及主成分分析

通过对河西肉牛西门塔尔和安格斯牛中脂肪酸成分测定,阐明两个品种间牛肉中脂肪酸的组成和特征差异。随机选取相同育肥方式的18个月龄发育健康的西门塔尔和安格斯公牛各9头,禁食12h后进行屠宰,取背最长肌为样本,以气象色谱内标法对西门塔尔牛和安格斯牛肉中的脂肪酸组成及其含量进行测定,最后使用主成分分析法对两个品种牛肉脂肪酸的差异进行评价分析。2种牛肉中共鉴定出17种脂肪酸,包括5种饱和脂肪酸和12种不饱和脂肪酸,饱和脂肪酸中棕榈酸含量最高,分别为21.81%和23.54%,安格斯牛肉的不饱和脂肪酸含量比西门塔尔牛高7.10%,同时肉豆蔻脑酸、二十碳一烯酸、花生四烯酸及DHA 4种不饱和脂肪酸含量显著高于西门塔尔牛;基于主成分分析法提取7个核心脂肪酸为2种牛肉中的特征脂肪酸,建立综合数学模型F=0.590×F1+0.154×F2+0.124×F3,从脂肪酸组成及综合得分上来看,安格斯牛肉要优于西门塔尔牛肉。脂肪酸测定和主成分分析揭示了两种牛肉中脂肪酸组成的特征与差异,为河西优质牛肉产品的合理开发利用提供理论依据。     

Effects of crossbreeding Mexican Pelibuey sheep with Rambouillet and Suffolk on carcass traits

Fifty nine lambs: Pelibuey (P), Suffolk×Pelibuey (SP) and Rambouillet×Pelibuey (RP), were used to evaluate the effect of crossbreeding on carcass characteristics and composition. Following carcass evaluation, muscle, bone, subcutaneous, seam, internal, total fat and other tissues were dissected. Carcass dressing percentage was similar across the three genotypes. The genetic group did not influence the percentage of cuts, except for shoulder percentage. Pelibuey carcasses had less fat thickness than RP and more kidney, pelvic and heart fat than SP. Muscle percentage was lower for RP (51.27±0.68) compared to P (54.01±0.61) and SP (53.78±0.58) carcasses, respectively. Consequently, the RP group showed the highest proportion of total fat (19.66±1.00). In general, RP carcasses had the lowest meat cutability. In conclusion, carcass yield of Pelibuey lambs was not improved by the cross with either Rambouillet or Suffolk breeds.     

Carcass merit between and among family groups of Bos indicus crossbred steers and heifers

Differences in live and carcass traits attributable to increasing Bos indicus breed influence were compared to the differences between families with similar proportions of B. indicus influence. Families of offspring from 1/2 Angus×1/2 B. indicus mated to Angus, B. indicus, and 1/2 Angus×1/2 B.indicus were raised under similar conditions. Average daily gain, slaughter weight, and dressing percentage were measured in addition to USDA yield and quality grade factors. Breed type did not affect average daily gain, slaughter weight, dressing percentage, carcass weight, adjusted 12th-rib fat thickness, estimated percentage kidney, pelvic, and heart fat, or carcass maturity. Predominately (3/4) Angus progeny produced greater (P<0.05) longissimus muscle areas than 3/4 B. indicus animals. Predominately Angus cattle also had greater (P<0.05) marbling scores and USDA quality grades than predominately B. indicus cattle. Families within breed types differed (P<0.05) with regard to all traits measured. This is interesting in light of the lack of differences between breeds for most traits. In some instances, the differences in marbling score and longissimus muscle area between families within a given breed type were similar or greater in magnitude than the differences observed between predominately Angus and predominately B. indicus breed types. Whereas growth and carcass traits varied between levels of B. indicus breeding, the opportunity does exists to improve these traits by selecting within specific family lines.     

不同杂交牛心脏食用品质和营养成分分析

以安格斯牛与宁夏中卫秦川牛、甘肃张掖河西黄牛和湖南涟源湘西黄牛杂交F1代屠宰后心脏的食用品质和营养成分为研究对象,分别测定了3 种牛心脏食用品质和营养品质相应的指标。结果表明：安格斯×秦川牛F1代牛、安格斯×河西黄牛F1代牛、安格斯×湘西黄牛F1代牛心脏色泽呈正常的深红色,剪切力值分别为16.17、
17.54 N和16.76 N,熟肉率值分别为71.36%、60.15%和72.84%,失水率值分别为15.77%、29.37%和19.51%;3 种牛心脏的蛋白质含量分别为20.46、16.28 g/100 g和17.79 g/100 g,脂肪含量分别为3.69、3.44 g/100 g和2.42 g/100 g,灰分含量分别为1.10、0.76 g/100 g和1.01 g/100 g,3 种牛均含有一定量的常量及微量元素。不同牛种心脏在食用品质和营养品质方面存在一定的差异,但这3 种牛心脏均具有嫩度好、易咀嚼、加工性能良好、高蛋白、低脂肪、矿物质丰富等优良特点,是优质的肉类资源。