不同年龄秦川牛胴体性状与肉质性状的研究

【作者】 胡宝利；

【导师】 昝林森；

【作者基本信息】 西北农林科技大学 ， 动物遗传育种与繁殖， 2001， 硕士

【摘要】 本研究选用16头育肥后的健康秦川牛(均为阉牛)，按年龄分为4组(Ⅰ为18月龄，Ⅱ为24月龄，Ⅲ为30月龄，Ⅳ为36月龄)，对各年龄组测定了胴体性状及肌肉的理化和组织学特性，应用方差分析方法分析了不同年龄组秦川牛各性状的差异性。利用多元统计方法对胴体性状与肉质性状之间的相互关系进行了详细分析，并且通过回归分析建立了牛肉产量的预测模型。实验结果表明： 不同年龄组间胴体性状和肉质性状存在显著差异(P＜0.05，P＜0.01)。屠宰率在18月龄与24月龄组间差异显著(P＜0.05)，但在24月龄、30月龄、36月龄组间并未有显著差异(P＞0.05)。净肉率、胴体产肉率和肉骨比在4个年龄组间不存在显著差异(P＞0.05)，但均以24月龄组最高，分别为45.24%、83.35%和5.17。肉色在不同年龄组间差异不显著(P＞0.05)。大理石花纹在18月龄组与24月龄以上各年龄组间有极显著差异(P＜0.01)，24月龄组与30月龄组差异不显著(P＞0.05)，而与36月龄组间差异显著(P＜0.05)，即24月龄以后，年龄对脂肪沉积作用才表现出来，且随年龄的增大，大理石花纹愈丰富。嫩度在24～30月龄间最好。肌肉营养成分中，粗蛋白、油酸及不饱和脂肪酸含量随年龄的增长而显著增加(P＜0.05)，其它营养成份如水分、粗脂肪、粗灰分等在4个年龄组间差异不显著(P＞0.05)。肌肉中氨基酸含量并不随年龄的变化而变化(P＞0.05)。肌纤维直径和单根肌纤维面积都随年龄的增长而显著增加(P＜0.05)。相关分析表明，胴体性状、肉质性状间具有密切的关系。宰前活重与净肉重、胴体长、胴体后腿长、腰部肌肉厚、背脂厚、眼肌面积等有显著或极显著的正相关关系(P＜0.05，P＜0.01)，与肉色、大理石花纹、粗脂肪、氨基酸含量及肌肉组织学性状也有显著或极显著的相关性(P＜0.05，P＜0.01)，表明宰前活重对胴体、肉质特性具有一定的影响。剪切力值与大理石花纹有显著的负相关性(P＜0.05)，即大理石花纹愈丰富，剪切力值愈小，肉愈嫩。而剪切力值与肌纤维密度及肌束内肌纤维根数呈负的相关性(P＜0.05)，表明随肌纤维密度及肌束内纤维根数的减少，肌纤维与结缔组织比例增大，剪切力值增大，肉变老。此外大理石花纹与背脂厚、眼肌面积都有显著的正相关关系(P＜0.05)。用最短距离法对胴体性状与肉质性状分别进行系统聚类，在阈值T=0.7997和T=0.3461水平上，共划分12大性状<WP=9>集团，这些性状集团能较全面反映秦川牛胴体与肉质特性。从聚类划分出的性状集团中选择典型性状进行主成份析，前4个主成份综合了总信息量的87.76%，这可为秦川牛胴体和肉质性状多目标选择提供参考。优质牛肉生产要求将胴体分割成不同部位肉，并用不同部位肉产率来衡量肉牛产肉性能，在生产中具有重要意义。本研究表明，胴体高档肉产率、胴体后部肉产率、胴体优质肉产率及胴体全部切块肉产率与胴体重、净肉重、屠宰率、净肉率、肉骨比有显著或极显著的相关关系(P＜0.05，P＜0.01)，即用以上各胴体肉产率可以反映牛产肉性能。用宰前活重、年龄、胴体重、背脂厚、眼肌面积、大理石花纹6项指标对胴体产肉率建立回归方程分别为胴体高档肉产率=13.4893-0.0244×宰前活重-0.1043×眼肌面积+7.9556×背脂厚，胴体优质肉产率=35.4122-0.0958×眼肌面积，胴体后部肉产率=25.6371-0.0748×眼肌面积，胴体全部切块肉率=81.0346-0.3511×年龄-0.1405×眼肌面积+2.3924×大理石花纹。这些模型可作为制订秦川牛胴体产量级标准的参考。 此外，本研究还对秦川牛胴体进行了分割，制订了胴体分割规范，并对各分割切块统一进行了命名，这些仅供厂家参考使用。更多还原

【Abstract】 Sixteen Qinchuan steers after fattening were used in this study and devided into 4 groups according to the age(Group:Ⅰ，Ⅱ，Ⅲ and Ⅳ.Age:18,24,30 and 36 age in month) were measured some items as follows:slaughter and carcass traits,phisical and chemical traits of muscle and histological properties of muscle fibre.The disparity in each trait were studied using variance analysis.Some detail analysis were made for the ralation of each trait,and predicted models to beef yield were established by regression analysis.The results were follows:Traits of carcass and meat ｑuality at the various age had significant differences(P＜0.05 or P＜0.01).Dressing percentage of steers of 18 and 24 age in month had significant differences(P＜0.05),but not in the steers of 24,30 and 36 age in month(P＞0.05).Net meat percentage,carcass percentage and meat-bone ratio at 4 age groups had not significant differences(P＞0.05),but these items of 24 age in month were the highest of the groups,amount to 45.24%,83.35% and 5.17.The difference of ralative values at the various age was not significant for muscle colour.Marbling between 18 and 24 or more 24 age in nonth had significant differences(P＜0.01),and the differences were not significand at the age of 24 and 30 months but at the age of 24 and 36 months,which indicated:fat deposition appeared after 24 age in month,and its ｑuality became higher with growth of age.Tenderness at 24 to 30 age in month was the best of the groups.The chemical analysis of muscles shown that the content of crude protein,oleic acid and unsaturated fatty acid inereased significantly with age (P＜0.05),but the content of water,crude fat,crude ash and amino acid in muscle had not significant differences at 4 age groups (P＞0.05).In addition,the diameter and area of muscle fibre increased significantly with age (P＜0.05).Phenotype correlation analysis shown that the traits of carcass and meat ｑuatily had very close relationship.There were significant relationship between live weight and other traits,including meat weight,carcass lenght,rear leg of carcass lenght,lion-muscle thickness,back-fat thickness,ribeye area,muscle colour,marbling,crude fat,the content of amino acid and histological traits of muscle fibre(P＜0.05 or P＜0.01),which suggested that live weight has influence on the proterties of carcass and meat <WP=11>ｑuality.The significant relationship between shear forc and marbling shown that the more rich marbling were,the more tender meat were,and the density of muscle fibre & the mount of muscle fibre indicated that the meat became older with decrease of them.Futhermore,marbling and fat thickness & ribeye area all had significant relationship (P＜0.05).The traits of carcass and meat ｑuality were classified respectively into six major characteristic groups which could reflect rather comprehensively the properties of carcass and meat ｑuality on the lever of threshold T=0.7997 and T=0.3461 by using cluster analysis.The typical traits were selected to make principal component analysis from major characteristic groups obtained by cluster,and about 87.76% total variance information was synthesized through the former 4 principal components which could provide some referance for multi-objective selection of the traits of carcass and meat ｑuality in Qinchuan Cattle.It was important that carcass were cut into different portion of meat whose percentage were used to evaluate beef performance in the product of high ｑuality beef.The studies shown that beef performance can be reflected by the retail cuts percentage which had significant relationship with carcass weight,meat weight,dressing percentage,net meat percentage and meat-bone ratio(P＜0.05 or P＜0.01).Six items,live weight,age,carcass weight,fat thickness,ribeye area and marbling were selected to predict the percentage of different retail cuts weight to carcass wetght.On the basis of this study,four eｑuations were obtained as follows:the percentage of superior ｑuality beef=13.4893-0.0244×live weight-0.1043×ribeye area+7.9556×fat thickness,更多还原