杜洛克猪生长和繁殖性状的遗传参数估计和遗传进展分析

本研究旨在对杜洛克猪生长与繁殖性状进行遗传参数估计，评估其遗传进展和探讨群体遗传参数变化。收集江西某核心育种场杜洛克猪育种群2014—2021年共30 319条目标性状测定记录（达100 kg体重日龄、达100 kg体重背膘厚、总产仔数、产活仔数），使用DMU软件多性状动物模型估计目标性状群体遗传参数和个体育种值，并统计这些性状在多年选育中遗传参数的变化。结果表明，杜洛克猪达100 kg体重日龄和达100 kg体重背膘厚估计遗传力分别为0.31±0.02、0.29±0.07，属于中高遗传力性状，总产仔数和产活仔数估计遗传力分别为0.09±0.01、0.05±0.01，属于低遗传力性状。达100 kg体重日龄在长期的选育中取得了较大的遗传进展，而达100 kg体重背膘厚、总产仔数、产活仔数则遗传进展较小。针对上述生长性状和繁殖性状的不同特点，应制定合理的选育手段，及时有效地开展遗传评估，以获得准确的个体育种值，并指导生产应用，加快群体的遗传改良。     

优质猪育种目标的确定

以差额法和系统分析法为基础建立模型,确定了优质猪目标性状的经济加权值。结论为优质猪综合育种值应包括目标性状:窝活产仔数、达100 kg体重日龄、饲料效率、胴体瘦肉率和肌内脂肪含量,选择性状包括窝活产仔数、达100 kg体重日龄、活体背膘厚、活体眼肌面积和肌内脂肪含量。目标性状的边际效益为窝活产仔数8.06元、达100 kg体重日龄-0.87元、饲料效率-86.32元、胴体瘦肉率10.78元、肌内脂肪含量48.51元。父本父系目标性状不包括窝活产仔数,母本母系目标性状的边际效益除窝活产仔数外的所有性状都比母本父系小1/2。     

湘沙猪配套系选育及展望

湘沙猪配套系以地方良种沙子岭猪和引进品种巴克夏、大白猪为育种素材,经过5个世代的持续选育,分别育成XS1系(终端父本)、XS2系(母系父本)、XS3系(母系母本)3个专门化品系。各专门化品系主要经济技术指标达到或超过育种目标,遗传稳定。XS1系初产总仔数10.7头,产活仔数10.3头;经产总产仔数11.8头,产活仔数11.4头;公猪达100 kg日龄165.4 d,背膘厚9.9 mm;母猪达100 kg日龄166.5 d,背膘厚10.8 mm。XS2系初产总仔数10.0头,产活仔数9.5头;经产总产仔数10.2头,产活仔数9.8头;公猪达100 kg日龄168.8 d,背膘厚12.5 mm;母猪达100 kg日龄169.7 d,背膘厚13.5 mm。XS3系初产总仔数10.2头,产活仔数9.4头;经产总产仔数11.1头,产活仔数10.3头;公猪达50 kg日龄193.9 d,背膘厚15.6 mm;母猪达50 kg日龄185.7 d,背膘厚17.9 mm。配套系父母代总产仔数12.4头,产活仔数11.9头。配套系商品猪30~100 kg期间平均日增重832.44 g,料重比3.16;100.6 kg屠宰,屠宰率73.0%,胴体瘦肉率58.2%,系水力93.26%,肌内脂肪含量2.9%,肉质优良,市场前景广阔。     

猪的遗传育种研究动态

在过去的３０年间，猪育种的主要目标是降低背膘厚，提高胴体瘦肉率，提高生长速度。现在降低背膘厚这一目标已基本实现，三元杂交商品瘦肉型猪胴体瘦肉率６０％左右。遗传育种的方向正在发生变化，除要求提高瘦肉生长率、饲料报酬外，更强调提高繁殖率和肌肉品质。育种手...     

猪育种目标性状边际效益的估算及影响因素研究

以差额法和系统分析法为基础建立模型,确定了优质猪目标性状的边际效益为:窝活产仔数8.06元、达100 kg体重日龄-0.87元、饲料效率-86.32元、胴体瘦肉率10.78元、肌内脂肪含量48.51元。讨论了市场形势变化和猪的配种方式对优质猪目标性状边际效益的影响。结论为:饲料价格的变化会改变窝活仔数和饲料效率的边际效益;猪场非饲料费用的改变可以影响窝活仔数和达100 kg体重日龄的边际效益;胴体基本价格变化和人工授精配种方式只改变窝活仔数的边际效益,而胴体瘦肉率和肌内脂肪含量引起的胴体价格差会影响胴体瘦肉率和肌内脂肪含量2个性状的边际效益。     

大观山长白猪的选育近况

长白猪在生产中既能作为杂交父本获得很好的效果，在“洋三元”瘦肉型商品猪生产中，作为第一母本也有很好表现，因此我们的育种要求是：在保持原有背膘厚度的基础上，重点提高生长速度并兼顾繁殖性状，外貌要求：头颈清秀、背宽、腿臀丰满、四肢粗壮、体型一致，主要指标：达100kg体重日龄在160d以内，性能测定期间的饲料利用率在2，6以内。100kg体重背膘厚11mm。均产仔数提高0，5～0，8头，预计5～8年内达到选育目标。     

华农温氏Ⅰ号猪配套系的选育与应用

本项目采用配套系育种理念,利用数量遗传方法结合分子标记技术,培育出由4个专门化品系组成的华农温氏配套系猪Ⅰ号。以四系配套生产的HN401肉猪肌肉发达,生长快、瘦肉率高、肉质优良、综合经济效益好;达100kg体重日龄154d,活体背膘厚13.4mm,饲料转化率2.49∶1;100kg体重胴体瘦肉率67.2%,变异系数在10%以下。该配套系肉猪可以在规模化养猪生产中广泛应用。     

北京市种猪基因组选择育种平台的构建与应用

2006年,北京市建立了种猪遗传评估数据平台。截止到2021年底,平台共收录371.46万头种猪系谱信息,51.23万条达100 kg体重日龄记录,50.90万条达100 kg活体背膘厚记录和45.15万条窝产仔记录。2015年,北京市将常规育种与基因组育种相结合,启动了种猪基因组选择育种平台构建工作,北京市种猪遗传评估进入基因组选择时代。截止到2021年底,平台建立了大白猪基因组选择参考群体,规模达到5 335头;开发基因组遗传评估系统,实现了将复杂的基因组选择计算过程转化为“一键式”操作;利用一步法（ssGBLUP）对9个种猪场的4 631头大白猪进行基因组遗传评估。基因组选择实施后,选择准确性大幅提高。早期选择时,达100 kg体重日龄的育种值准确性由0.56提高至0.66,达100 kg活体背膘厚的基因组育种值准确性由0.56提高至0.70,总产仔数育种值准确性由0.41提高至0.60。终选时,达100 kg体重日龄的育种值准确性由0.69提高至0.79,达100 kg活体背膘厚的基因组育种值准确性由0.72提高至0.80,总产仔数性状育种值准确性由0.41提高至0.61。基因...     

猪体型评分性状的相关性分析

为了分析环山集团近2年来某核心育种场猪体型评分性状与其他生产性状之间的相关性,笔者利用R软件评估了总体评分与各部位评分以及与繁殖性状的表型相关,又利用DMU软件和动物模型估计了体型评分性状与达100 kg体重日龄和背膘厚之间的表型与遗传相关。结果表明:总体评分与四肢、生殖器官和中躯表型相关较大,分别达到0.597,0.481和0.432;与总产仔数和产活仔数表型相关接近于0,分别达到0.041和0.034;此外,体型评分与达100 kg体重日龄和背膘厚表型相关也接近于0,而遗传相关分别达到-0.16和0.05。说明体型评分还需要进一步优化,在父系和母系中应选择性应用。     

扬翔华系杜洛克猪专门化品系生长性状选育

扬翔华系杜洛克是以美系杜洛克和丹系杜洛克为育种素材,通过多个世代持续选育而成的一个瘦肉型猪专门化品系。该研究以扬翔华系杜洛克7个不同世代后备猪为对象,针对其生长性状的选育结果进行分析。结果表明,扬翔华系杜洛克后备公、母猪从第5世代开始,后面3个世代生长速度均显著优于前面各世代(P 0.05),且第7世代后备公、母猪校正115 kg体重日龄分别达到了166.28 d和171.36 d,均显著快于0世代(P 0.05)。后备公、母猪在校正115 kg体重日龄方面的平均世代改良比例分别达到了1.76%和1.72%。在校正115 kg体重背膘厚方面,扬翔华系杜洛克后备公、母猪平均世代改良比例分别达到了1.77%和2.44%。扬翔华系杜洛克在校正115 kg体重日龄及校正115 kg体重背膘厚方面取得较大遗传改良。扬翔华系杜洛克公、母猪达115 kg体重日龄平均每个世代减少2.69 d和2.49 d,115 kg体重背膘厚平均每个世代降低0.15 mm和0.20 mm。文章主要总结了扬翔华系杜洛克猪专门化品系生长性状选育的阶段性成果,为后续研究选育奠定了基础。     

北京地区猪生长和繁殖性状边际效益的研究

本研究旨在估计北京地区猪生长和繁殖性状的边际效益.以差额法和系统分析法为基础建立农场模型,模拟商品猪群的生产过程,采集了北京地区多个具有代表性的猪场的数据,确定北京地区猪6个生长和繁殖性状的边际效益为:窝产活仔数(头)20.5元、达100kg体质量日龄(d)-0.3元、肥育期日增体质量(g·d-1)0.04元、饲料转化效率(kg·kg-1)-186.4元、胴体背膘厚(mm) 15元、母猪繁殖寿命(胎)1.8元.结果表明,市场价格的变化对性状边际效益的影响很大.     

山西白猪高产仔母系育肥性能与胴体品质测定

以马身猪、太湖猪(二花脸类群)和长白猪为育种素材,采用标记辅助选择技术结合群体继代选育法,经7年6个世代育成山西白猪高产仔母系。结果发现,该品系6世代个体186.48日龄体重达100 kg,30~100 kg阶段日增重708.35 g,每千克增重耗料3.14 kg;体重100 kg屠宰,屠宰率为77.00%,胴体瘦肉率为57.93%,眼肌面积为32.20 cm²。山西白猪高产仔母系生长发育快,胴体品质好,是一个优良的专门化品系。     

苏淮猪发酵床养殖试验

苏淮猪是2011年刚通过国家畜禽遗传资源委员会审定的新品种。其在正常饲养条件下,25kg-90kg日增重650g,90kg体重的日龄约175天,料重比3．1：1,屠宰率72％,背膘厚28．7mm以下,胴体瘦肉率56％以上。在发酵床养殖条件下,达到90kg体重需190日龄,日增重为565g,屠宰率、背膘厚和胴体瘦肉率差异不显著,而料重比为2．87：1,节约饲料9％,特别是肌肉氨基酸含量明显提高,超过正常值40％以上。苏淮猪发酵床养殖效益十分显著。     

北京市种猪集中测定情况分析与展望

为掌握北京市种猪生产性能水平,文章对2015—2020年北京市种猪集中收测结果,包括达100 kg体重日龄、达100 kg体重活体背膘厚、30～100 kg平均日增重和饲料转化率相关数据进行了分析比较,并结合种猪生产企业现状,对集中测定的重要性进行探讨与展望,以期为指导种猪选育,开展联合育种工作提供更多思路。     

仔猪初生重对育肥期生长性状及采食性状的影响

本试验旨在研究杜洛克种公猪初生重对其育肥期生长性状和采食性状的影响。选取230头杜洛克仔猪,按初生重分为高初生重组和低初生重组,在同一饲养标准下饲养至(100±5)kg体重,记录生长性状和采食性状表型数据,用于后续分析。结果表明:高初生重组的30～100 kg日增重、达到100 kg体重时眼肌面积、瘦肉率、体长、体高和管围等生长性状均显著高于低初生重组(P<0.05);而低初生重组的体重达100 kg所用时间显著长于高初生重组(P<0.01);而高初生重组的100 kg体重背膘厚和100 kg体重肌内脂肪含量与低初生重组无显著差异(P>0.05);高、低初生重组的平均日采食量、日采食时间、日采食次数、平均每次采食时间、平均每次采食量和平均采食速率等采食性状无显著差异(P>0.05);低初生重组在30～100 kg的耗料增重比极显著高于高初生重组(P<0.01)。高初生重的杜洛克仔猪相较于低初生重仔猪在育肥期表现出更快的生长速度和更低的耗料增重比,且体尺特征更加优秀。     

Effect of recombinant porcine somatotropin on growth and carcass quality in growing pigs: interactions with genotype, gender and slaughter weight

Effects of recombinant porcine somatotropin (rpST) on growth, lean tissue growth, feed intake, feed conversion, lean tissue feed conversion, backfat thickness and lean percentage were examined in 96 growing pigs. The experiment used barrows and gilts from the genotypes Duroc, F1 (Dutch Yorkshire x Dutch Landrace) and Pietrain. Half the pigs received 14 mg rpST i.m. twice each week starting at 60 kg; others received a placebo. Pigs had ad libitum access to a diet containing 2,162 kcal net energy and 182 g crude protein per kilogram and were slaughtered at either 100 or 140 kg live weight. From 60 to 100 and from 100 to 140 kg, live weight responses to rpST averaged as follows: daily gain, +4.5 and +19.9%; feed intake, -4.4 and +3.5%; feed conversion, -8.4 and -13.9%; backfat thickness, -13.8 and -22.8%; lean percentage, +4.4 and +8.7%; lean tissue growth rate, +8.6 and +35.8%; and lean tissue feed conversion, -13.1 and -24.9%. No gender x rpST interaction was detected. However, a genotype x treatment interaction was significant for backfat thickness at both slaughter weights, showing a higher response to rpST in Duroc than in Pietrain and F1. Growth performance was improved more by rpST in F1 and Pietrain than in Duroc, especially at higher weights, but carcass traits were improved more by rpST in Duroc. The response to rpST in lean tissue growth rate from 60 to 100 kg was highest in fatter animals (Duroc, barrows), whereas from 100 to 140 kg, response in lean tissue growth rate to rpST was highest in leaner animals (Pietrain, F1, gilts).     

Evaluating breeding objectives for sow productivity and production traits in Large White Pigs

the objective of the study was to develop and evaluate different breeding objectives for sow productivity and for production traits, using economic selection indices. Genetic parameters were generated using a repeated records model for sow productivity traits and a maternal effects model for production traits, in ASREML. Stochastic simulation models based on a hypothetical 100-sow model were performed for each line, i.e., a dam line and a terminal sire line, respectively, to derive economic values. The traits included in the study were number born alive (NBA), 21-day litter size (D21LS), 21-day litter weight (D21LWT), average daily gain (ADG), feed conversion ratio (FCR), age at slaughter (AGES), dressing percentage (DRESS), lean content (LEAN) and backfat thickness (BFAT). The economic values for LEAN and BFAT were derived using the partial differentiation of the profit function, while those for the other traits were derived using the partial budget approach. An economic value of a trait was the change in profit per unit genetic change in that trait. Breeding objectives were developed with a corresponding selection index, for improvement of that objective. Three combinations of breeding objectives and selection indices were developed for sow productivity traits, while there were 15 combinations for production traits. Responses to selection and economic return were computed for each combination to determine the most appropriate combination for the improvement of the breeding objective traits. The most appropriate index to improve sow productivity consisted of NBA and D21LWT. For production traits, the combination that consisted of a selection index with AGES, DRESS and BFAT, and the breeding objective ADG, DRESS, FCR and LEAN, was considered the most appropriate. Age at slaughter and BFAT were, respectively, included as indicator traits for ADG and LEAN. The recommended breeding objectives were sensitive to changes in economic values, indicating that economic values for breeding goal traits should be updated periodically to ensure proper weighting of traits, hence maximization of economic return.     

长白和大白猪主要生长性状的遗传参数估计

旨在分析母猪的出生年份、出生季节、初生重、开测日龄等固定效应对长白、大白猪主要生长性状的影响,并对目标生长性状进行遗传参数估计（遗传力、遗传方差、表型相关和遗传相关）,为猪的遗传改良提供基本依据。本试验利用GLM模型分析试验猪群（398头长白猪和1 176头大白猪）的固定效应对猪生长性状的影响,并采用多性状动物模型对目标性状进行遗传参数估计。目标生长性状包括达100 kg体重日龄（age to 100 kg,AGE）、达100 kg背膘厚（backfat to 100 kg,BF）、100 kg平均日增重（average daily gain to 100 kg,ADG）。研究表明,在大白和长白猪中,猪的出生年、出生季、初生重以及开测日龄对生长性状均具有极显著的影响（P<0.001）;长白猪的AGE、ADG和BF的遗传力分别为0.321、0.327和0.324,大白猪对应性状的遗传力分别为0.454、0.469和0.408;长白猪的ADG和AGE之间的遗传相关、表型相关分别为-0.990、-0.995,大白猪的ADG和AGE之间的遗传相关、表型相关分别为-0.993、-0.998,均呈现较强的负相关。长白、大白猪的生长性状（AGE、ADG、BF）均属于中等遗传力性状,其出生年份、出生季节、初生重和开测日龄对猪的生长性状影响较大。在遗传参数估计分析时,提高样本数量并提升表型数据质量,可以增加遗传参数估计的可靠性。本研究中的生长性状遗传参数估计结果较为可靠,可为后续的遗传改良提供参考。     

Effect of Lactation Diet Fat Level on Sow and Litter Performance

The primary objective of this study was to determine the effects of supplemental dietary fat during lactation on sow BW, sow backfat thickness, sow feed consumption, litter size, and pig growth rate. Dietary treatments included 0, 3, 6, and 9% supplemental low acid yellow fat in a traditional corn-soybean meal basal lactation diet. A total of 160 Landrace and crossbred sows (approximately 40 per treatment) were included in the study. Sows fed 3 and 6% supplemental fat had greater (P<0.10) average backfat thickness at weaning. Sow weight change and feed consumption were inconsistent among dietary fat levels. Dietary fat level during lactation did not affect number of pigs born alive or number of stillborns. However, the 9% fat level was associated with more mummified pigs at birth. Number of pigs weaned was greater for the 0% supplemental fat than for the 9% fat level. The largest average pig weights at 21 (5.8±0.29 kg) and 28 (7.48±0.38) d of age were those from sows fed the 3% added fat diet. Sows with ≤25.4 mm backfat at farrowing had more pigs born alive (P<0.05), had less backfat at 21 and 28 d of lactation (P<0.05), and consumed more feed during wk 2 and 3 of lactation. Of all sows fed the control diet, sows with >25.4 mm backfat at farrowing consistently had heavier pigs throughout the lactation phase (P<0.05). Backfat loss during lactation was lower (P<0.05) for sows with ≤25.4 mm at farrowing within all dietary treatments. Consistent significant differences were not observed in sow weight loss or feed consumption between low and high backfat sows for each dietary treatment. Sow backfat loss during lactation is dependent on body condition at farrowing, in that, fatter sows at farrowing have greater backfat loss during lactation. Sows with ≤25.4 mm of backfat at farrowing responded to added dietary fat treatments and produced heavier pigs throughout the lactation period.     

应用超声背膘测定技术提高母猪繁殖性能

背膘厚是提高猪群生产力和生产效率的重要指标,可评估动物胴体成分,特别是胴体脂肪。动物能量储存主要以脂肪组织形式存在,而体重损失主要是因脂肪代谢所引起。在现代化养猪过程中,母猪繁殖性能是衡量养猪业经济效益的重要指标之一。膘情是衡量母猪体况的一个重要指标,膘情与母猪体内脂肪含量密切相关,可有效反映母猪的营养储备情况;母猪膘情体况与其繁殖性能密切相关,而母猪繁殖性能的高低直接决定猪场养殖效益。随着规模化养猪业快速发展,越来越多的养猪场开始通过母猪的背膘测定精准调整母猪体况,以背膘测定为依据,结合母猪所处不同生理阶段,制定相应的饲喂标准和营养标准,提高母猪繁殖性能,改良动物遗传性状,达到生产效益最大化。综述了超声背膘测定技术及其关键点、母猪背膘厚度与繁殖性能的关系,以及超声测定技术与选育方面的作用,以期为提高母猪繁殖性能和肉质性状的遗传改良提供参考。