【作者】 陈红跃；

【导师】 左福元；

【作者基本信息】 西南农业大学 ， 动物营养与饲料科学， 2005， 硕士

【摘要】 本试验旨在研究不同营养模式对肉牛肥育性能和屠宰性能的影响,以确定南方农区肉牛适宜肥育营养模式,力求为南方农区优质牛肉生产提供可行性生产方案。 试验选用利木赞牛与本地黄牛杂交牛共30头,均为阉牛,年龄8～12月龄,采用栓系舍饲育肥方式。分两个阶段进行育肥。前期120天,后期180天,设计不同营养水平(能量和蛋白质)日粮,前期日粮由精料补充料、带穗玉米青贮和黑麦草组成,后期日粮由精料补充料和杂交狼尾草组成。 采用随机完全区组设计,以体重为区间。前期各处理组分别采用高、中、低3个营养水平饲养,后期分别采用高、中2个营养水平饲养,整个试验设6个处理组,每个处理组设5个重复,每个重复均为1头牛,6个处理组营养模式分别为高-高、高-中、中-高、中-中、低-高和低-中。测定指标有日增重、体尺、屠宰性状和肉质性状,分析指标有肥育性能、屠宰性能,并做屠宰性状和肉质性状的相关分析和主成分分析。 研究结果如下: (1)不同营养模式对肥育性能的影响显著。第一,肥育前期、后期营养水平与日增重均呈正比例关系,肥育全程日增重以高-高组最高(0.61 kg),低-中组最低(0.47 kg),且差异显著(p<0.05)。第二,肥育前期、后期营养水平越高,结束体尺越大,与肉用性能有关的体尺指数也越好,肥育结束以高-高组牛只膘情最好(胸围、胸宽最高),其次是中-高(胸深最高)、低-高组、高-中组(体高最高),且不同营养模式组间存在显著性差异(p<0.05、p<0.01)。第三,从饲料利用率来看,低-高组每1kg增重所需混合精料、总干物质、粗蛋白、综合净能均最低,分别为3.88kg、11.39kg、1.46kg、61.90MJ,其次是中-高、高-高组。第四,从经济效益来看,按出售的方式不同,所获利润不一。其中以屠宰分级出售经济效益最好;直接出售活牛、屠宰不分级及按我国“肉牛等级标准”分级均以低-高组利润最高,其次是中-高组。 (2)不同营养模式对屠宰性能的影响显著。第一,对于胴体性状:宰前活重、胴体重、屠宰率、净肉率、高档肉重、眼肌面积和背膘厚度均以高-高组最高,其次是低-高、中-高组,低-中组最低,且均达到国内同类较高水平,组间也均存在不同程度的显著性差异(p<0.05、p<0.01)。第二,对于肉质性状:营养模式对肉色、脂肪颜色、pH值及常规养分均无显著性影响:对牛肉质量的部分指标有影响,其中大理石花纹、嫩度及眼肌面积较为明显;其它指标在营养模式间也存在一定的差异,总的趋势是高-高、中-高、低-高组的大理石花纹较丰富、嫩度较好、肌纤维状况较好、系水力较强、眼肌面积较大、多汁性较好,低-中、中-中组较差。第三,综合分析,高-高组肉质达到特级标准,中-高、低-高、高-中、中-中组达到优一级标准,低-中组达到优二级标准,表明试验牛完全具有生产优质、高档牛肉的条件和良好潜力。 (3)胴体和肉质性状间的相关关系及评定指标的筛选。大理石花纹等级和剪切力值分别与肌纤维密度、肌纤维根数极呈显著负相关(p<0.01),与肌纤维面积、直径呈极显著正相关(p<0.01=;眼肌面积与背膘厚度、高档肉重极显著正相关(p<0.01);宰前活重与胴体重、净肉重、高档肉重、眼肌面积、背膘厚度、肌纤维密度之间存在显著正相关(p<0.05),与大理石花纹等级、剪切力值、肌纤维面积和肌纤维直径呈显著负相关(P<0.05);粗蛋白、粗脂肪、粗灰分和水分含量四项常规养分组间相关均不显著(P>0.05)。胴体和肉质性状在适当的水平上分成11个性状集团,这些性状集团能较全面反映试验牛胴体与肉质特性。对肉质性状(变量)的综合分析表明:肉质评定系统中更多还原

【Abstract】 The research attempted to solve the effect of different nutrition patterns on the traits of carcass and meat quality, on the other hand, to decide the best preference nutrition pattern in South zone.Thirty crossbred beef steers (Limousin + local yellow ) were used in the study, form eight months to twelve months, which were fed in the crib. The cattle were divided into two stages to fattening. There was 120 days in the earlier stage of fattening and 108 days in the later stage. The different nutrition level diets were schemed which consider energy and protein. The diet was consisted of concentrated feed, silage corn and rye grass in the earlier stage of fattening, while concentrated feed and hybrid Chinese pennisetum were used in the later stage of fattening.The study was randomized complete block design and differentiated weight by block. Every group was fed low, middle and high nutrition level of diets in the earlier stage of fattening, but in the later stage of fattening middle and high nutrition level diets were adopted. The whole study was divided into six groups and there were five repetitions in each group, and every repetition was one cattle. The cattle in the six groups were fed respectively with different nutrition levels diet in the earlier and later stage of fattening. The six nutrition patterns were high-high, high-middle, middle-high, middle-middle, low-high, low-middle. Average daily gains, body size, the traits of slaughter and meat quality were tested. Some detail analysis were made for finishing performance and slaughter performance, when the relationship analysis and principal component analysis for the traits of carcass and meat quality. The results were follows:(1) Finishing performance of various nutrition patterns had significant differences. First, during the fattening time, the bigger daily gain was, the higher nutrition level were. The daily gain of high-high group was the highest, which was 0.61kg,while low-middle group was the lowest, which was 0.47kg,they had also significant differences(p<0.05).Second, in the length fattening time ,the higher the nutrition level was, the bigger total body sizes were , so were the better indexes of body sizes, which had relation to beef production performance. The cattle of the high-high group were in the best condition, whose chest girth and chest width were the biggest, fallowings were the middle-high group, the low-high group and the high-middle group. There had also significant differences in the carious nutrition types(p<0.05 or p< 0.01).Third, to the efficiency of feed utilization, the requirements of concentrated feed, total dry matter, total crude protein and total energy were the lowest for the low-high group, which were 3.88kg, 11.39kg,1.46kg and 61.90MJ respectively. Fourth, to the profit of all output, there were different profits when the cattle were sold in different ways. But the profit was the best as the beeves were graded. The profit of the low-high group was the highest in selling living cattle and beeves that was graded; following was the middle-high group.(2) The slaughter performance of the various nutrition patterns had significant differences. First, to the traits of carcass, the cattle of the high-high group was the highest in living weight, carcass weight, dressing percentage, meat percentage, high quality cuts weight, rib muscle area and back-fat thickness, followings were the low-high group and the middle-high group, but the low-middle group’s was the lowest Those results had reached a higher level in China and they also had significant differences amoug the various nutrition patterns (p<0.05 or p<0.01 ).Second, to the traits of meat quality, the effects of nutrition patterns on meat color, fat color, pH value and routine nutrient had no significant differences(p>0.05),but marbling, tenderness and rib muscle area had (p<0.05 or p<0.01).On the other hand, it had influence on the other traits of meat quality. But in all, those significant relationships showed that beef had more rich marbling, the better condition of muscle fibre, more tender beef ,more water absorption capacity, bigger rib muscle area, and more juiciness in the high-high group, the low-high group and the middle-high group, while beef in the low-middle group and the middle-middle group were worse. Third, through complex" analysis, beef quality of the high-high group reach extra grade, the middle-high group , the low-high group, the high-middle group , the middle-middle group reached the first grade, but the low-middle group was the second grade. In a word, the cattle had the ability to produce high or good quality beef.(3 ) Phenotype correlation analysis showed that the traits of carcass and,meat quality had a very close relationship. The relationship was significant respectively among shear force, marbling and density of muscle fibre & area of muscle fibre & diameter of muscle fibre(p<0.01).There were significant relationships among rib muscle area and the two traits of back-fat thickness and high quality cuts weight(p > <0.01). There were also obvious relationships living weight and other traits, including carcass weight, meat weight, high quality cuts weight, rib muscle area, back-fat thickness,marbling,shear force, ensity of muscle fibre & area of muscle fibre & diameter of muscle fibre,and et a/(p<0.05).But There were no significant relationship among crude protein, crude fat, crude ash and humidity ratio(p>0.05).The traits of carcass and meat quality were classified into eleven major characteristic groups in a adequate level, which could reflect rather comprehensively the properties of carcass and meat quality. The principal component analysis to traits of meat quality showed that the indexes of muscle fibre,total amino acid.pH value, humidity ratio, crude protein, crude fat, meat color and crude ash were selected ,which were the most important in evaluating system of meat quality,and about 88.08% total variance information was synthesized. The typical traits in carcass and meat quality which were selected to make principal component analysis showed that living weight, the indexes of muscle fibre,carcass weight, crude protein, total amino acid marbling ether extract and rib muscle area, and about 86.06% total variance information was synthesized. That analysis could provide some references to multi-objective selection of the cattle in SANXIA reservoir belt, meanwhile, it could improve beef production and beef quality.更多还原