大约克夏,杜洛克与长大杂母猪杂交试验报告

为筛选优化杂交组合，用大约克夏（大）、杜洛克（杜）及大杜杂公猪与长大杂母猪进行了杂交试验，测定了不同品种组合的生长速度、饲料报酬、胴体品质及肉质。采用综合评定指数评定结果表明，大长大组为本次试验的最佳杂交组合，讨论了大约克夏（英系）作为终端父本的可能性。     

不同杂交组合猪胴体品质及肉质性状的比较研究

为探讨不同杂交组合育肥猪胴体品质及肉质性状的差异,选用体重30 kg左右的长×大、巴×长×大、杜×长×大3种杂交阉猪各15头,饲养至100 kg左右,每组选6头进行屠宰试验,测定胴体品质与肉质性状.试验结果显示,3个杂交组合的猪都符合优质瘦肉型猪的要求,杜×长×大组的胴体性状最好,其屠宰率、眼肌面积、瘦肉率显著高于长×大组(P＜0.05);巴×长×大组的肉质性状最好,其肉色、大理石纹显著优于杜×长×大组和长×大组(P＜0.05).结果表明,杜×长×大组的胴体性状较好,巴×长×大组的肉质性状较好,采用杜洛克做杂交父本可提高后代猪的胴体性状,采用巴克夏做杂交父本可提高后代猪的肉质性状.     

杜×长大与杜×大长商品猪的肥育对比试验

为比较杜×长大与杜×大长商品猪的生长、胴体性状和肉质,进行了3次肥育对比试验,即2次小试,每组10头,肥育结束每组屠宰4头(2阉2母),1次中试,每组40头,肥育结束每组屠宰6头(3阉3母),测定这2个组合的生长速度、饲料转化率、胴体性状和肉质。结果表明,2个杂交组合在生长、胴体性状和肉质上没有显著差异。结合国内一些研究资料讨论了生产中对这2个组合的应用问题。     

杜洛克猪和大白猪作终端父本的杂交效果比较研究

为比较杜洛克和大白猪作终端父本的杂交效果，进行了杜×长大、大×长大、长×大的比较试验，测定了不同组合的生长速度、饲料转化率、胴体品质和肉质。采用综合评定指数评定结果表明，大×长大组的主要经济性状优于杜×长大组。根据本次试验和国内外大量试验结果，作者论述了利用大白猪，特别近几年从英国引进的大白猪作终端父本生产商品瘦肉猪，逐步替代传统的杜×长大组合的可能性     

猪育种进展及其发展趋势

根据以上分析，在今后１０年内所采用的杂交模式，可作如下安排：７．１．１为出境和东南沿海大城市需要，采用杜长大三元杂交，或者采用杜长南三元杂交。大约克×长白Ｆ１ ×杜洛克杜长大肉猪南昌白猪×长白Ｆ１×杜洛克杜长南肉猪 社长大（或杜大长）三元杂交肉猪胴体瘦肉率６４％左右，日增重８００－９００ｇ，饲料转化率２．８－２．９。杜长南三元杂交肉猪胴体瘦肉率６３％以上，日增重８００ｇ以上，饲料转化率２．８－２．９，肉质优于社长大三元杂交肉猪。杜长大、杜长南杂交模式可考虑占全省出栏肉猪的６０％左右。７．１．２为东…     

杜洛克、长白、大白及其杂种猪的生长表现和肉质比较研究

对杜洛克、长白、大白猪及其杂种长×大、大×长、大×长大、杜×长大共七个品种组合进行了肥育对比试验 ,结果表明 ,各品种组合猪有较好的胴体和肉质性状 ,但生长速度相对较慢 ,有待于通过选育和改善饲养管理提高。大×长大在瘦肉率、背膘厚、眼肌面积等性状上优于杜×长大 ,而在其它性状上基本接近。因此 ,用近几年新引进的父系大白猪作终端父本 ,生产大×长大商品猪是完全可能的     

东安土猪与两广花猪内四元杂交组合对比试验

为了开发利用东安土猪地方品种资源,为东安土猪优质高效配套杂交组合筛选提供理论依据,采用杜洛克作为终端父本,长大东(东安猪)、长大广(两广花猪)、大长东、大长广为母本进行四元杂交组合进行试验,测定其繁殖性能、育肥性能及胴体品质。结果表明:杜长大东杂交组合猪窝产仔数为10.95头,与另外3个杂交组合比较差异显著(P0.05);含地方血缘12.5%的两广花猪组合日增重、饲料转化率高于含东安猪血缘的组合,但胴体质量无明显差异;四元杂交组合商品猪瘦肉率在60.09%以上。     

应用DNA指纹技术研究湖北白猪的杂种优势

本研究利用ＤＮＡ指纹技术，通过人源小卫星探针３３６分析湖北白猪Ⅲ系、Ⅳ系，长白与杜洛克的遗传纯度与遗传距离，通过分析遗传距离与杂交组合试验资料表明，湖北白猪Ⅲ系（或Ⅳ系）与杂交品种间遗传距离大时，杂交组合的日增重、饲料转化率、瘦肉率、繁殖性状的杂种优势大；反之，遗传距离小时，其主要性状的杂种优势相应较小，根据杂交组合间的遗传距离可以预测杂交组合的杂种优势。     

通城猪的两个杂交利用模式效果比较研究(初报)

对长大通和大长通两个杂交组合的生长、胴体及肉质进行比较研究,结果表明：长大通在平均背膘厚、测定期日增重、饲料利用率等方面显著优于大长通;长大通的眼肌面积、腿臀肉骨率、估计瘦肉率等极显著优于大长通组合.二者的肉质性状没有显著差异.综合评价,长大通组合是一个较理想的杂交组合,可作为通城猪杂交利用的繁育模式进行推广.     

杂交猪肥育效果的研究

以长白猪，大白猪，杜洛克猪，PIC猪四个品种的三个杂交组合长大，杜长大，杜PIC为研究对象，测定并比较了三个杂交组合的肥育效果，结果表明，长大组合在胴体直长，肉色，熟肉率等性状上优于杜长大和杜PIC组合，因此，可考虑长大杂交组合在外向型猪场推广应用。     

优质猪杂交繁育体系的构建与优化

选用杜洛克、长白、大白3个国外引进品种,冀合白猪专门化母系B1个国内培育品系,以及1个地方品种太湖猪,模拟杂交繁育体系的生物经济学过程,构建了优质猪的杂交繁育体系,并以每头后备母猪平均每年的利润、每头标准化商品猪的利润、每1000头标准商品猪相对应的母猪头数和商品代出栏猪肌内脂肪含量(肉质指标)4个评价指标对杂交繁育体系进行了优化选择,结果在4种杂交配套组合中,杜洛克×(大白×冀合白猪专门化母系B)经济效率和商品代猪肉质最优。     

4个猪种CAST基因与背膘厚关系的研究

钙蛋白酶抑制蛋白(CAST)与猪肉质性状有关,已经作为猪肉嫩度的候选基因.用PCR-RFLP 技术对CAST基因的丝氨酸(Ser) 突变为精氨酸(Arg)进行研究,并用SAS8.02研究了辽宁黑猪、大约克、长白猪和杜洛克4个品种中该突变与背膘厚的关系.结果表明:在辽宁黑猪和大约克猪中检测到AA、AC和CC 3种基因型,而长白猪和杜洛克猪中未检测到CC基因型;辽宁黑猪A的基因频率显著低于其他3个猪种(P<0.05);3种基因型间的背膘厚相比差异显著(P<0.05).     

江口萝卜猪和梅山猪的猪应急综合征主效基因RYR1的PCR-RFLP检测

猪兰尼定受体1(Ryanodine Receptor1,RYR1)基因是导致猪应激综合征、影响猪肉质的主效基因.试验采用RFLP方法,以大白猪、2个杂交猪群(杜洛克×长白猪×大白猪和长白猪×大白猪)为对照,检测了江口萝卜猪与引入的梅山猪群RYR1基因的分布类型.结果表明,对照组中,外三元、外二元杂交猪和大白猪中均检测到...     

不同猪种ADIPOQ基因外显子2多态性及其与山西白猪体重和体尺性状的关联分析

本研究旨在检测猪脂联素（adiponectin,ADIPOQ）基因外显子2的多态性,并分析其对山西白猪体重和体尺性状的影响。采用PCR-SSCP技术检测了长白猪、大白猪、杜洛克猪、山西白猪、山西黑猪和马身猪6个猪种392个个体ADIPOQ基因外显子2的多态性,并采用GLM程序分析了ADIPOQ基因外显子2多态性与山西白猪体重和体尺性状的关联性。结果显示,在ADIPOQ基因外显子2的89 bp处检测到G→A错义突变,引起缬氨酸（Val）向异亮氨酸（Ile）的转变。ADIPOQ基因外显子2存在3种基因型：AA、AB、BB,2个等位基因：A和B。杜洛克猪中只有BB基因型,长白猪、大白猪、山西白猪和山西黑猪中BB基因型为优势基因型,马身猪中AA基因型频率最高。在引入品种长白猪、大白猪和杜洛克猪中B等位基因为优势等位基因,基因频率分别为0.96、0.96和1.00;在地方品种马身猪中A等位基因频率（0.52）略高于B等位基因（0.48）;在培育品种山西白猪和山西黑猪中B等位基因频率分别为0.76和0.78,介于引入猪种和地方品种之间。基因型频率分布在马身猪、山西白猪和山西黑猪之间无显著差异（P>0.05）,杜洛克猪与长白猪、大白猪间差异均不显著（P>0.05）,而长白猪和大白猪间差异显著（P<0.05）,任意一个引入品种与马身猪、山西白猪和山西黑猪之间的差异均达到极显著水平（P<0.01）。ADIPOQ基因外显子2多态性对断奶重有显著影响,其中BB基因型个体28日龄断奶重显著高于AA和AB基因型（P<0.05）,AA和AB基因型间无显著差异（P>0.05）,但对其他性状无显著影响,说明该位点只在个体发育早期阶段起作用。     

山西地区6个猪种氟烷敏感基因的检测

采用PCR-RFLP技术对大白猪、长白猪、杜洛克猪、山西白猪、山西黑猪和马身猪等6个品种（系）482头猪进行了氟烷敏感（Hal）基因检测。结果表明,在山西黑猪和马身猪中,只检测到氟烷敏感阴性纯合子（NN）;而在长白猪、大白猪、杜洛克猪和山西白猪群体中,均检测到NN、Nn两种类型的个体,Haln的基因频率分别4.1%、1.8%、1.4%和1.7%。在今后的育种工作中,应加强对氟烷敏感基因的检测,选育抗应激群体。     

二花脸猪及其杂种猪的肥育性能与胴体肉质

为探明二花脸种群与新引进的外种猪杂交利用的效果，试验以二花脸纯种为对照，分别对大约克猪×二花脸（大×二）、长白猪×二花脸（长×二）及杜洛克猪×二花脸（杜×二）杂种猪进行肥育与屠宰测定。结果表明：3个杂交组合中大×二的日增重585 g，料重比3.15，肥育性能相对较好；长×二组合的背膘厚2.8 cm，眼肌面积40.3 cm2，瘦肉率53.6%，胴体性状相对较好；杜×二组合的失水率33.2%，低于长×二（P〈0.05）和大×二组合（P＞0.05），肌内脂肪含量3.2%，高于长×二（P＞0.05）和大×二组合（P＞0.05），大理石纹评分3.19，肉色评分2.88，滴水损失等肉质指标也相对较好。3个杂交组合各有各的优点，在杂交生产中，可根据各地市场消费需求与养殖习惯选择相应的杂交组合。     

Effects of Duroc, Meishan, Fengjing, and Minzhu boars on productivity of mates and growth of first-cross progeny.

Meishan, Fengjing, Minzhu, and Duroc boars were mated by AI to crossbred gilts to compare the sire breeds for effects on productivity of their mates and performance of their progeny. Gilts were derived from a four-way cross of Chester White, Landrace, Large White, and Yorkshire. At weaning, litters sired by Meishan boars averaged 1.69 and 1.32 more pigs than those sired by Duroc and Minzhu boars, respectively (P less than .05). Pigs sired by Meishan and Fengjing boars averaged 1.2 to 1.8 more nipples than pigs sired by Duroc and Minzhu boars (P less than .05). Minzhu-sired pigs had a lower (P less than .05) survival rate to 14 and 28 d of age than did those sired by Meishan, Fengjing, and Duroc. Fengjing-sired pigs were heavier than Minzhu-sired pigs at birth and heavier than Minzhu- and Duroc-sired pigs at 14, 28, and 56 d of age (P less than .05). At 70 d of age, Meishan-sired pigs were heaviest, followed in order by Fengjing-, Duroc-, and Minzhu-sired pigs. At 98 d of age, Meishan-sired pigs were significantly heavier than all other breed groups and Duroc-sired pigs were significantly heavier than Minzhu-sired pigs. At 126 and 154 d of age, Duroc-sired pigs were heaviest, followed in order by Meishan-, Fengjing-, and Minzhu-sired pigs; all differences were significant. Average backfat thickness of gilts at 99.7 kg was least for Duroc-sired gilts and highest for Meishan-sired gilts. Sire breed groups did not differ significantly in feed efficiency from 70 to 98 d of age. Duroc-sired pigs were the most efficient (P less than .05) from 98 to 126 and 126 to 154 d of age. Results indicate that use of these Chinese breeds in crossbreeding programs will decrease performance traits. This decrease would have to be offset by increases in reproductive efficiency of Chinese sows, use of repartitioning agents, or other management techniques if Chinese pigs are to improve overall production efficiency of a crossbreeding program.     

Comparison of growth performances,carcass characteristics,and meat qualities of Okinawan indigenous Agu pigs and crossbred pigs sired by Agu or Duroc boar

Indigenous Okinawa Agu pigs are crossed with Large White × Landrace (WL) pigs to improve their meat production, but there is little information regarding the crossbreeding effects. The study aims to compare growth, carcass characteristics, and meat qualities of Agu pigs with those of WL crossbreeds with Agu sires (WLA) or Duroc sires (WLD). WLA pigs showed better growth performance and carcass characteristics and less intramuscular fat (IMF) contents than Agu ones, but they had higher fat deposition, smaller longissimus dorsi muscle area, and higher IMF contents than WLD pigs. Agu pigs showed higher water holding capacity than the other two breeds. The inner layer of Agu backfat contains higher and lower proportions of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acid (PUFA), respectively, than that in WLD animals. WLA animals had intermediate values for the fatty acid content in the inner backfat, although MUFA contents were equal to those of Agu pigs. Fatty acid profiles in IMF were similar to those in the backfat. These results indicate that crossbreeding of Agu with WL pigs improves growth performance and carcass quality. Particularly, WLA pigs have higher IMF contents and MUFA concentrations and lower PUFA concentrations than WLD pigs.     

Effect of leg conformation on survivability of Duroc, Landrace, and Large White sows

Sow longevity influences farm economy and can be considered an important indicator of animal welfare. Body features such as leg conformation can play a key role in sow longevity, although little is known about its effect on culling decisions. Within this context, longevity data from 587 Duroc, 239 Landrace, and 217 Large White sows were analyzed with special emphasis on the effect of leg conformation. Sow longevity was analyzed twice for each breed, testing the effect of a subjective overall score for leg conformation, or the presence or absence of 6 specific leg conformation defects. Each preliminary model also included a teat conformation score with 3 levels, farm or origin, backfat thickness at 6 mo of age, and 2 continuous sources of variation, namely the age at the first farrowing and the number of piglets born alive at each farrowing. Overall leg conformation score influenced (P < 0.01) sow longevity in Duroc, Landrace, and Large White sows, with a greater hazard ratio (HR) for poorly conformed sows (1.56, 2.16, and 1.79, respectively) than for well-conformed sows (0.32, 0.66, and 0.68, respectively). Abnormal hoof growth reduced survivability in Duroc (HR = 2.78; P < 0.001) and Landrace sows (HR = 1.88; P < 0.01); the presence of splayed feet (P < 0.05) or bumps and injuries (P < 0.001) increased the risk of culling in Duroc sows (HR = 2.08 and 3.57, respectively), whereas the incidence of straight pastern increased the HR in Large White sows (HR = 2.49; P < 0.01). In all 3 breeds, longevity decreased for plantigrade sows, with a greater HR in Duroc (HR = 3.38; P < 0.001) than in Landrace (HR = 1.53; P < 0.10) and Large White sows (HR = 1.73; P < 0.05). Teat conformation did not influence sow longevity (P > 0.10). Estimates of heritability for longevity in Duroc sows ranged from 0.05 to 0.07 depending on the algorithm applied. Leg conformation had a substantial effect on sow longevity, where an accurate removal of poorly leg-conformed candidate gilts before first mating could improve sow survival and reduce culling costs. These moderate estimates of heritability indicated that survivability of Duroc sows could be genetically improved by direct selection for leg conformation.