影响山羊屠宰率和胴体性状的因素

<正> 发展山羊增加山羊肉生产是贯彻我国“八·五”计划纲要,提高牛羊禽兔肉占肉类总产量比重的措施之一。山羊肉的生产不仅要增加数量而且要提高质量。山羊的屠宰率和胴体性状是山羊肉生产中必须考虑的问题,也是山羊肉的数量和质量的     

关于肉牛屠宰试验中增加净体屠宰率,产肉率指标的建议

1 前言在“勃海黑牛选育及其品种特性研究”科研课题实施过程中,屠宰测定渤海黑牛34头。屠宰前,根据山东农业大学郭经恂教授的提议,在按照全国第三次肉牛繁育协作会议规定的“肉牛屠宰试验方法”基础上,测定记录增加了净体重、净体屠宰率和净体产肉率3项内容。在数据统计处理过程中发现,18月龄组和24月龄组宰前平均活重基本相同,按常规统计屠宰率和净肉率,24月龄组均高于18月龄组,但按净体屠宰率和净体产肉率统计,则     

饲喂湿态发酵蛋白饲料对肉牛育肥屠宰率影响的调查报告

湿态发酵蛋白饲料是玉米经酵母发酵、提取酒精后,又经益生菌发酵、密封包装的产品。因其可溶性好、易消化吸收、所含的蛋白质量多质优,因此,用于肉牛育肥时,肉牛生长速度较快。通过对饲喂湿态发酵蛋白饲料育肥牛(15头,来自2个饲养场)的屠宰率与饲喂常规饲料育肥牛的屠宰率(425头,来自24个饲养场)进行统计对比可知,肉牛的屠宰率与屠宰时的体重成高度正相关(R2=0.9528),并且全程饲喂湿态发酵蛋白饲料育肥牛的屠宰率比饲喂常规饲料育肥牛的屠宰率平均高3.65个百分点,这样1头牛将多收入640元。因此,饲喂湿态发酵蛋白饲料会使肉牛育肥经济效益显著提高。     

微贮麦秸育肥肉牛试验

麦秸经微贮处理后,用于肉牛的短期育肥试验,结果表明,试验组牛的采食率比对照组提高11.1%,日增重提高48.4%(P<0.01),屠宰率提高11.1%,其每头育肥牛的综合经济收入比对照组多56.10元,经济效益显著.且微贮技术操作简便易行,是提高麦秸利用率、弥补冬春反刍家畜饲草不足和增加农民收入的有效途径.     

氨化麦秸对肉牛育肥及胴体渗出液的影响

秦杂一代公牛36头分3组进行90 d强度育肥,1、2组饲喂氨化麦秸与精料,3组饲喂未氨化麦秸与精料。结果表明:试验1、2组日增重840 g±90 g和820 g±76 g。对照组日增重520 g±120 g。试验组比对照组日增重提高310 g(P<0．01),屠宰率、净肉率分别提高8．305和4．945个百分点。试验组胴体渗出液平均每头507．75 mL,对照组无体液渗出。试验组每千克增重纯收入4．32元,比对照组(2．14元)高2．18元,效益显著。     

三元杂交肉牛育肥效果的比较试验

试验选择健康无病、发育正常、膘情中等、12月龄的夏利本、西利本、利西本和西杂二代肉杂牛各10头,研究相同营养水平日粮对不同杂交肉牛生产性能及屠宰性能的影响.结果表明:供试的4个肉牛品种中以西利本肉牛的育肥效果和屠宰性能为最好,18月龄时屠宰率达59.04%,净肉率达49.96%;其次为利西本,屠宰率为58.68%,净肉率为48.93%;而以西杂二代肉杂牛的育肥效果和屠宰性能为最差,18月龄时屠宰率为55.44%,净肉率为42.41%;夏利本次差,屠宰率为56.47%,净肉率为43.73%.综合分析结果发现,各供试肉牛之间的相关测定指标,西利本和利西本肉牛之间差异不显著(P＞0.05),但与其他组别之间均达显著水平(P＜0.01).     

提高肉牛胴体重的措施

在分析肉牛胴体重对肉牛生产的作用以及影响肉牛胴体重因素的基础上,借鉴国内外经验,从杂交优势利用、饲养方式转变、合理确定出栏时间等3个方面提出了提高肉牛胴体重的措施,以期为肉牛由数量增长型模式向质量效益型模式转变提供参考。     

三元杂交肉牛育肥效果的比较试验

试验选择健康无病、发育正常、膘情中等、12月龄的夏利本、西利本、利西本和西杂二代肉杂牛各10头,研究相同营养水平日粮对不同杂交肉牛生产性能及屠宰性能的影响。结果表明:供试的4个肉牛品种中以西利本肉牛的育肥效果和屠宰性能为最好,18月龄时屠宰率达59.04%,净肉率达49.96%;其次为利西本,屠宰率为58.68%,净肉率为48.93%;而以西杂二代肉杂牛的育肥效果和屠宰性能为最差,18月龄时屠宰率为55.44%,净肉率为42.41%;夏利本次差,屠宰率为56.47%,净肉率为43.73%。综合分析结果发现,各供试肉牛之间的相关测定指标,西利本和利西本肉牛之间差异不显著(P>0.05),但与其他组别之间均达显著水平(P<0.01)。     

法国肉牛胴体分割法的解读

解读了法国肉牛胴体在大分割和二级分割上的特色,同时对我国肉牛胴体的分割方法提出了建议。     

肉牛育肥的几个方面

对肉牛进行快速育肥，既可提高屠宰率、增加净肉重，又可使牛肉变得细嫩可口，改善肉的品质。     

张掖肉牛屠宰性能测定和肉品质评定

[目的]为了解张掖肉牛现阶段产肉性能,及时分析品种培育进展和成效,张掖市通过委托第三方专业检测机构开展肉牛屠宰性能测定和肉品质评价试验,根据其结果进行分析研判。[方法]从3家肉牛核心育种场选择具有继代关系的公犊牛持续育肥后根据屠宰性能测定和肉品质评定试验结果分析世代遗传进展和品种培育成效。[结果]试验历时5年,完成连续2个世代各20头育肥牛的屠宰测定和肉质评定。共测定性能指标35项,对其中25项测定值进行样本配对检验,试验B较试验A的体重、体高、胸围、胴体重、净肉重5项指标差异显著,管围、肉质大理石花纹、pH、系水力、蒸煮损失5项指标差异极显著,月龄、十字高、体斜长、腹围等其它15项指标有差异但尚未达到显著水平。而且试验B组较A组的屠宰月龄缩短1.64月,而体重增加59.91 kg,且体尺表型值相应增加。根据日增重遗传力(h²)0.42计算出宰前体重表型增加量为25.16 kg(即剔除由于育种场饲养管理改进、环境影响友好和其它有利因素叠加实现的提高量为34.75 kg),相当于产肉量增加11.6 kg。[结论]从2次结果反映出品种选育有成效,由活重体现出遗传进展。...     

Whole-genome QTL scan for ultrasound and carcass merit traits in beef cattle using Bayesian shrinkage method

Fine mapping of quantitative trait loci (QTL) for 16 ultrasound measurements and carcass merit traits that were collected from 418 hybrid steers was conducted using 1207 SNP markers covering the entire genome. These SNP markers were evaluated using a Bayesian shrinkage estimation method and the empirical critical significant thresholds (α = 0.05 and α = 0.01) were determined by permutation based on 3500 permuted datasets for each trait to control the genome-wide type I error rates. The analyses identified a total of 105 QTLs (p < 0.05) for seven ultrasound measure traits including ultrasound backfat, ultrasound marbling and ultrasound ribeye area and 113 QTLs for seven carcass merit traits of carcass weight, grade fat, average backfat, ribeye area, lean meat yield, marbling and yield grade. Proportion of phenotypic variance accounted for by a single QTL ranged from 0.06% for mean ultrasound backfat to 4.83% for carcass marbling (CMAR) score, while proportion of the phenotypic variance accounted for by all significant (p < 0.05) QTL identified for a single trait ranged from 4.54% for carcass weight to 23.87% for CMAR.     

Genetic relationships between temperament of calves at auction and carcass traits in Japanese Black cattle

Correlations of calves’ temperament with carcass traits were estimated to clarify the genetic relationships between them in Japanese Black cattle. The temperament records for 3128 calves during auction at a calf market were scored on a scale of 1 (calm) to 5 (nervous) as temperament score (TS ), and the TS were divided into two groups (TSG ): TS 1 and 2 comprised TSG 1, and 3 to 5 constituted TSG 2. Carcass data were obtained from 33 552 fattened cattle. A threshold animal model was used for analyzing the underlying liability for TSG , whereas a linear one was used for TS and carcass traits. The heritability estimates for TS and TSG were 0.12 and 0.11, respectively. On the other hand, moderate to high heritability estimates were obtained for carcass traits (0.40 to 0.68). The temperament scores were negatively correlated with carcass weight, rib thickness and subcutaneous fat thickness (?0.13 to ?0.59). In contrast, weak to moderate positive correlations were found between the temperament scores and rib eye area or yield estimate (0.16 to 0.45). The temperament scores and beef marbling score had no correlation. These results showed that it is possible to improve temperament and carcass traits simultaneously.     

Effects of parent‐of‐origin models with different pedigree information on beef carcass traits and fatty acid composition in Japanese Black cattle

Genomic imprinting should be considered in animal breeding systems to avoid lead in bias in genetic parameter estimation. The objective of this study was to clarify the effects of pedigree information on imprinting variances for carcass traits and fatty acid composition in Japanese Black cattle. Carcass records [carcass weight, rib eye area, rib thickness (RT), subcutaneous fat thickness and beef marbling score (BMS)] and fatty acid composition were obtained for 11,855 Japanese Black feedlot cattle. To estimate and compare the imprinting variances for the traits, two imprinting models with different pedigree information [the sire–dam gametic relationship matrix (Model 1) and the sire–maternal grandsire (MGS) numerator relationship matrix (Model 2)] were fitted. The ratio of the imprinting variance to the total additive genetic variance for RT (6.33%) and BMS (19.00%) was significant in Model 1, but only that for BMS (21.09%) was significant in Model 2. This study revealed that fitting the sire–MGS model could be useful in estimating imprinting variance under certain conditions, such as when restricted pedigree information is available. Furthermore, the present result suggested that the maternal gametic effects on BMS should be included in breeding programmes for Japanese Black cattle to avoid selection bias caused by imprinting effects.     

肉牛同期发情效果影响因素的研究

[目的]为了研究同期发情处理方法、繁殖状况、品种、体重等对肉牛同期发情效果的影响,[方法]选择140头不同繁殖状况、品种、体重的肉牛,随机分为3组,分别采用CIDR+第10天肌注PMSG+第11天肌注PGF_2α（埋栓Ⅰ组）、CIDR+第9天肌注PMSG+第11天肌注PGF_2α（埋栓Ⅱ组）、肌注PGF_2α+PMSG(PGF_2α组)的方法进行同期发情处理。[结果]3种不同处理方法相比,PGF_2α组发情率为87.10%,埋栓Ⅰ组、Ⅱ组母牛发情率分别为97.83%、98.41%,显著高于PGF_2α组（P<0.05）;PGF_2α组处理牛受胎率为83.87%,埋栓Ⅰ组、Ⅱ组处理牛受胎率分别为89.13%、84.13%,高于PGF_2α组,但差异不显著（P>0.05）;育成牛与经产牛发情时间相比,埋栓组12～24 h内出现发情症状的经产牛占比为27.27%,育成牛占比为60%,显著高于经产牛（P<0.05）,2...     

Use of molecular markers to improve relationship information in the genetic evaluation of beef cattle tick resistance under pedigree‐based models

The selection of genetically superior individuals is conditional upon accurate breeding value predictions which, in turn, are highly depend on how precisely relationship is represented by pedigree. For that purpose, the numerator relationship matrix is essential as a priori information in mixed model equations. The presence of pedigree errors and/or the lack of relationship information affect the genetic gain because it reduces the correlation between the true and estimated breeding values. Thus, this study aimed to evaluate the effects of correcting the pedigree relationships using single‐nucleotide polymorphism (SNP) markers on genetic evaluation accuracies for resistance of beef cattle to ticks. Tick count data from Hereford and Braford cattle breeds were used as phenotype. Genotyping was carried out using a high‐density panel (BovineHD ‐ Illumina^® bead chip with 777 962 SNPs) for sires and the Illumina BovineSNP50 panel (54 609 SNPs) for their progenies. The relationship between the parents and progenies of genotyped animals was evaluated, and mismatches were based on the Mendelian conflicts counts. Variance components and genetic parameters estimates were obtained using a Bayesian approach via Gibbs sampling, and the breeding values were predicted assuming a repeatability model. A total of 460 corrections in relationship definitions were made (Table 1) corresponding to 1018 (9.5%) tick count records. Among these changes, 97.17% (447) were related to the sire's information, and 2.8% (13) were related to the dam's information. We observed 27.2% (236/868) of Mendelian conflicts for sire–progeny genotyped pairs and 14.3% (13/91) for dam–progeny genotyped pairs. We performed 2174 new definitions of half‐siblings according to the correlation coefficient between the coancestry and molecular coancestry matrices. It was observed that higher‐quality genetic relationships did not result in significant differences of variance components estimates; however, they resulted in more accurate breeding values predictions. Using SNPs to assess conflicts between parents and progenies increases certainty in relationships and consequently the accuracy of breeding value predictions of candidate animals for selection. Thus, higher genetic gains are expected when compared to the traditional non‐corrected relationship matrix.     

活牛、牛肉与生产原料比价关系分析

【目的】为掌握肉牛生产及其产品市场价格波动规律,了解牛产业各环节收益和波动情况,及时为生产指导提供科学依据。 【方法】选择在张掖市辖区内设置10个畜产品价格监测点,按日汇总,以最近一个监测周期（410天）数据为总体,选择近3个月和去年同期3个月数据为样本,按统计学原理分析其均值、标准差、误差区间、变异系数、波动趋势概率（P）和增幅等,进行总比、同比分析。【结果】本监测期玉米价格2.890.03、活牛32.772.26、牛肉72.271.97、M 11.410.65 、R 2.210.11;确定以活牛/玉米（M值）为参数,将原料与产品结合起来作活牛成本分析;用牛肉/活牛比价（R值）分析养殖与屠宰消费环节营销利益分配关系。根据M、DP（屠宰率）均值11.41、55.81%确定3个盈亏平衡点为：活牛成本32.97元,牛肉成本59.08元,活牛屠宰到消费端营销成本R值为1.8;根据 R均值2.21确定活牛屠宰到消费端营销临界利润率为 22.7%,当R≧2.21时营销利润率≧22.7%,效益增加,R≦2.21时营销利润率≦22.7%效益降低。【结论】与肉牛生产息息相关的4个临界点分别为M值为11.41,基于M值的活牛成本32.97元、牛肉成本59.08元、活牛屠宰到消费端营销成本R值2.21利润率22.7%。近期M值连续下降溢出正常区间下限值10.65达66天,R值上升溢出正常区间上限2.32达52天,养殖环节收益缩减呈现亏损状态,屠宰消费环节营销利率高达30%。 M、R值变化呈不同步状态, R滞后。     

Detection and molecular characterization of bovine leukemia virus in beef cattle presented for slaughter in Egypt

Bovine leukemia virus (BLV) is the etiological agent of enzootic bovine leukosis, the most common neoplastic disease of cattle worldwide and a serious problem for the cattle industry. Previous studies have shown the molecular prevalence of BLV and the coexistence of BLV genotype-1 and -4 in Egyptian dairy cattle; however, the molecular characteristics of BLV in Egyptian beef cattle are unknown. Therefore, we collected blood samples of 168 beef cattle from slaughterhouses in three governorates in Egypt. Based on BLV-CoCoMo-qPCR-2 targeting long terminal repeats and nested PCR targeting the env-gp51 gene, the BLV provirus infection rates were found to be 47/168 (28.0%) and 42/168 (25.0%), respectively. Phylogenetic analysis based on 501 bp of the BLV env-gp51 gene from 42 BLV isolates revealed that at least six distinctive strains (b, e, f, g, x, and z) were prevalent in cattle across the examined regions. Furthermore, phylogenetic analysis of the 420 bp sequence of the BLV env-gp51 region of the six strains against 11 known genotypes showed that the strains b, e, f, and g were clustered into genotype-1, and strains x and z were clustered into genotype-4. Our results also indicated that strains b and x exist in both dairy and beef cattle in Egypt. The present study is the first to detect and genotype BLV among beef cattle in Egypt.     

突破肉牛产业发展效益瓶颈问题的探讨

随着肉牛产业从持续火热期逐渐回落,加上饲料价格的新一轮上涨,出栏育肥牛盈利空间被极度压缩,一度出现一定比例的亏损和弃养现象。这是市场规律调节的结果,是养殖业必然要经历的市场阵痛期。所以仅仅依靠高行情去获得盈利,促进肉牛产业的发展是不可能长久的。本文阐述了从提高种牛品质、提高母牛繁殖性能、抓好犊牛培育及早期断奶、粗饲料储备等几方面着手,抓技术提质增效,抓管理降低成本,理顺养牛投资理念,使肉牛产业安全走出低谷期,以突破肉牛产业发展效益瓶颈。这是市场规律调节的结果,是养殖业必然都要经过的市场阵痛期。所以仅仅依靠高行情去获得盈利,促进肉牛产业的发展是不可能长久的。文章阐述了从提高种牛品质、提高母牛繁殖性能、抓好犊牛培育及早期断奶、粗饲料储备等几方面着手,抓技术提质增效,抓管理降低成本,理顺养牛投资理念,使肉牛产业安全走出低谷期,以突破肉牛产业养殖效益瓶颈。     

肉牛添加剂的研究与应用

用本课题组研制的肉牛添加剂育肥体重230kg、330kg、400kg和530kg的肉牛，可使日增重分别提高25．5％、7．3％、25．4％和16.7％，效果显著（P＜0．05），可使饲料报酬最多提高25．8％（P＜0.05）；投入产出比最大为1：8，用该添加剂育肥高档肉牛时屠宰率可达57.2％，眼肌面积43cm2、皮下脂肪覆盖面积为优级，大理石状评分为优级。