杜洛克猪饲料利用效率测定阶段及RFI校正公式研究

为了解决中国猪育种过程中饲料利用效率测定期长、无校正公式等问题,本研究对应用4种不同方法计算的杜洛克猪全期和不同生长阶段的剩余采食量(RFI)进行了Pearson相关性分析,以得到可代表全期RFI的测定阶段,进而缩短测定时间。应用不同体重RFI线性插值与达100 kg真实体重RFI对杜洛克猪达100 kg体重RFI校正公式参数进行拟合求解,以得到杜洛克猪达100 kg体重RFI校正系数。结果显示,4种方法计算的RFI均为105～180 d生长阶段和全期相关性最高,相关系数均在0.92以上,适配回归方程为:全期RFI=0.9786×(105～108 d测定阶段RFI)+0.0002,最高拟合度为0.9734。杜洛克公猪及母猪达100 kg体重RFI校正系数分别为0.0519和0.0179。在此系数下,公猪70～100 kg范围内校正准确性较高,母猪40～100 kg范围内校正均比较准确。本试验结果可直接用于制定育种方案,既可缩短RFI测定的时间,又可为更准确地计算RFI提供参考,为制定优良的育种方案提供有效数据。     

种猪生长速度的联合测定评估

生长速度是猪的主要经济性状之一,生猪达100千克时日龄每缩短1天,将至少节约饲料1千克。河南省种猪联合育种协作组把这一性状作为主要测定性状来指导种猪的选育和选配,在大约克、长白和杜洛克三个品种当中都取得了良好的效果。1材料和方法河南省18家种猪场的大约克、长白和杜洛克后备种公、母猪,测定猪的体重范围在80～105千克之间(早晨空腹称重,测定数据应用中国农业大学的GBS育种软件校正处理)。2测定结果比较2.1大约克种猪2000年共测定大约克种猪354头,所测公猪和母猪达100千克体重的日龄分别为170.8天和183.9天;2004年前5个月测定种猪…     

法系皮特兰和美系杜洛克杂交试验

不同品种猪杂交对猪主要繁殖性状、生长性能可能产生很大的影响,为此对广西农垦永新畜牧集团有限公司良圻原种猪场第四原种猪场皮杜二元杂种猪（法系皮特兰公猪×美系杜洛克母猪）进行测定,并与美系杜洛克纯繁（美系杜洛克公猪×美系杜洛克母猪)生产成绩进行了比较分析。结果表明,纯繁与二元杂种猪繁殖性能差异不显著,但皮杜二元杂种猪初生重、达100 kg体重日龄、30～100 kg日增重、30～100 kg料重比等生长性能,背膘厚、眼肌面积、100 kg校正瘦肉率、体长等胴体性能上均具有明显的杂种优势,均优于纯繁杜洛克种猪。     

扬翔Ⅰ号猪配套系终端父本生长性能分析

扬翔Ⅰ号猪配套系终端父本以引进的美系杜洛克、丹系杜洛克为育种素材,进行自主培育。展示扬翔Ⅰ号猪配套系终端父本YX101公猪(丹系杜洛克)、YX102公猪(美系杜洛克)、YX106公猪(美系与丹系合成的杜洛克,称合成系杜洛克)生长性能数据,其中校正100 kg体重日龄:YX101(152.2 d)YX106(158.5 d)YX102(165.5 d);校正100 kg体重日增重:YX101(651.23 g)YX106(626.5 g)YX102(598.1 g),各品系校正100 kg体重日龄、日增重均差异极显著。扬翔Ⅰ号猪配套系终端父本生长性能优良。     

大白母系种猪优良性状的选育进展

组建8个独立血统10头公猪、50头母猪含2个品系的大白核心选育群,通过场内种猪测定,应用GBS育种软件估计单项育种值,根据综合选择指数大小进行选留。经过4个年份的选育,年份平均校正增重公猪提高7.90%,母猪提高7.41%,均达到差异显著(P<0.05),达100 kg体重日龄缩短了1.176 d;平均校正背膘厚公猪下降了9.54%,母猪下降了7.54%,均达到差异显著(P<0.05%),达100 kg体重背膘厚育种值减少0.159 mm,母猪总产仔数逐年提高,产仔数育种值增加0.029头;综合选择指数提高3.84%。选育结果表明,组建优秀的核心选育群,通过不同品系间的杂交,能够培育出高性能大白专门化母系种猪。     

出生季节和胎次等因素对扬翔华系杜洛克猪生长性能的影响

猪的生长性能受性别、遗传、营养和环境因素的共同影响。分析广西扬翔股份有限公司所属3个种猪场2015—2019年的生猪生长性能数据,研究性别、出生季节、胎次、猪场等因素对扬翔华系杜洛克猪生长性能的影响。发现不同性别扬翔华系杜洛克猪的校正达115 kg体重日龄、校正达115 kg日增重、校正达115 kg背膘厚和校正达115 kg眼肌面积等均差异极显著(P<0.01)。不同季节出生的扬翔华系杜洛克公猪校正达115 kg体重日龄差异极显著(P<0.01);不同季节出生的扬翔华系杜洛克母猪校正达115 kg体重日龄春季和夏季比较差异不显著(P>0.05),秋季和冬季比较差异不显著(P>0.05),但秋季和冬季出生的母猪校正达115 kg体重极显著大于春季和夏季出生的猪。此外,第3胎次出生的猪只校正达115 kg体重日龄最小,校正达115 kg日增重最大且与其他胎次间差异显著(P<0.05);第5胎次出生的猪只校正达115 kg体重日龄最大,校正达115 kg日增重最小且与其他胎次间差异显著(P<0.05)。扬翔华系杜洛克公猪校正达115 kg体重日龄、校正达115 kg日增重、校正达115 kg背膘厚、校正达115 kg眼肌面积在3个不同猪场间差异极显著(P<0.01)。     

杜×梅杂交一代猪的生长育肥和产肉性能研究

为了解杜洛克猪对梅山猪生长育肥性状的改良效果,选择杜×梅杂交一代猪48头(26公、22母),测定体重20～100 kg阶段的平均日增重、体长、体高、屠宰率、胴体瘦肉率、后腿比例、眼肌面积等。结果:阉公猪的全期日增重为(622.30±20.93)g/d,比阉母猪的低18.2 g/d,阉公猪的全期饲料转化率为2.92∶1,比阉母猪的多0.27;宰前体尺中,阉母猪体长、体高和腿臀围均高于阉公猪(P0.01),不同屠宰体重组所测定的体尺均达到显著(P0.05)或极显著(P0.01)水平,体尺随宰前体重的增加而增加;阉母猪的胴体指标优于阉公猪,不同屠宰体重组大部分胴体指标达到显著(P0.05)或极显著(P0.01)水平。研究结果表明,杜×梅杂交一代商品猪宜公、母分栏饲养,其出栏体重控制在90～95 kg为宜。     

新老美系杜洛克猪生长性能测定

选择初始重为20kg左右的新、老美系杜洛克猪各12头进行肥育试验,体重达90kg左右结束,之后进行胴体品质测定。结果表明,新美系杜洛克猪日增重770g,老美系杜洛克猪日增重728g,差异极显著;不同性别日增重为公猪813.4g、母猪698.1g、阉公猪813.7g,母猪与公猪、阉公猪日增重差异极显著,而公猪与阉公猪日增重仅差0.3g,差异不显著;瘦肉率新美系杜洛克猪64.21%,老美系杜洛克猪61.17%,差异显著。     

杜洛克公猪不同体重阶段料重比的相关性及全程料重比的预测公式建立

通过分析杜洛克公猪在不同体重区间的日采食量、日增重、料重比（F/G）等性状的相关关系,评估在较高始测重的情况下测定杜洛克公猪生长及料重比性能的有效性,探究杜洛克公猪不同体重阶段料重比与全程（30~110 kg）料重比的相关性,并建立不同体重阶段料重比与全程料重比的回归方程,以期增加测定站的年测定量,提高其利用率。使用8台奥饲本种猪生长性能测定系统,测定119头杜洛克公猪在30~110 kg体重阶段平均日增重（ADG）、平均日采食量（ADFI）及料重比,分析不同体重阶段料重比与全程料重比的相关性,并与全程料重比建立回归方程。结果表明,杜洛克公猪的日采食量、日增重及料重比在30~110 kg期间均呈增加趋势,并在90 kg出现1个生长期拐点,之后其采食量、日增重及料重比都有下降趋势。不同体重阶段的料重比与全程料重比具有一定的相关性,其中40~90 kg阶段的回归方程Y=0.316+0.873X₁的决定系数为0.76,该回归方程校正准确率高,说明可通过40~90 kg料重比来衡量全程料重比,这样既能缩短料重比测定时间,为准确估算全程料重比提供参考依据,同时能够有效提高种猪测定站的利用率。     

影响杜洛克种猪测定成绩的因素及种猪品牌建设探讨

中心测定的种猪生长性能数据可通过统计分析挖掘信息,为实际生产提供方向性参考。对57头杜洛克猪中心测定数据分析发现,校正至100 kg体重日龄与进场日龄有极显著正相关(P0.01),校正至100 kg体重日龄与进场体重呈现显著负相关性(P0.05),校正至100 kg体重日龄与开测日龄呈现极显著正相关(P0.01),校正30~100 kg体重日增重和生长性能指数均与开测日龄呈现显著正相关(P0.05)。开测日龄与进场日龄呈极显著正相关(P0.01),与进场体重呈极显著负相关(P0.01)。不同种猪企业送测的杜洛克种猪,校正至100 kg体重日龄和校正30~100 kg体重日增重的组间差异极显著(P0.01),校正至100 kg体重眼肌面积和测定期料重比也呈现组间显著差异(P0.05)。猪场间杜洛克种猪生长性能指数均值最高相差13.48,相差幅度达到15%;校正至100 kg眼肌面积平均值最高相差3.44 cm2,相差幅度达到10.8%;校正至100 kg日龄最高相差21.17 d。建立种猪品牌应根据客观的测定数据作为主要的指导。     

Comparisons of specific crosses from Yorkshire-Landrace, Chester White-Landrace and Chester White-Yorkshire sows

One hundred thirty Yorkshire-Landrace (YL), Chester White-Landrace (CL) and Chester White-Yorkshire (CY) F1 crossbred sows were mated randomly to Duroc (D), Hampshire (H), Farmers Hybrid 414 (FH414) or Farmers Hybrid 929 (FH929) boars. These matings produced 321 litters and 3,379 pigs, which were used to determine the effect of sire breeding and dam breeding on preweaning and postweaning performance of the pigs and litters. Litter size born alive, litter size at 56 d, litter weight at 56 d and litter weight per day of age to 100 kg were lower in litters sired by H boars than in those sired by D boars. However, sizes and weights of litters sired by D and H boars were not different from those sired by FH414 and FH929 boars. Litter sizes at birth were larger for litters out of CL and CY sows than those out of YL sows, but significant differences were not found for litter sizes at 21 d, 56 d or at marketing. Pigs sired by H boars were heavier at birth than pigs sired by D boars. Pigs sired by H boars did not differ significantly in weights at 21 and 56 d or in postweaning daily gains or days to 100 kg from pigs sired by D boars. Pigs out of CL dams were heavier at birth, 21 d and 56 d of age than pigs out of CY dams, but did not differ significantly in postweaning gains or in days to 100 kg. Pigs sired by D and H boars had less ultrasonic fat than pigs sired by FH414 and FH929 boars. Pigs sired by FH929 boars were leaner than pigs sired by FH414 boars.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of mass selection for increased weight at two ages on growth rate and carcass composition of Duroc-Landrace pigs

Duroc boars from a line previously selected over five generations for 200-d weight and those from a randomly selected control line were mated to Landrace sows either from a line previously selected for increased 70-d weight or from a randomly selected pedigree control line. From these matings, 900 pigs were farrowed to examine the effects of crossing lines of pigs mass selected for weight at two ages on growth rate, survival, and carcass composition. A greater (P less than .01) percentage of pigs farrowed survived birth from control-line sows (.974) than from select-line sows (.914). Of those pigs born alive, a greater (P less than .05) percentage of pigs out of control-line sows survived to 21 d (.893) than out of select-line sows (.829). Pigs sired by select-line boars weighed 2.1 kg heavier (P less than .05) at 70 d than pigs sired by control-line boars. Pigs out of select-line sows weighed .11 kg less (P less than .10) at birth and .3 kg less (P less than .10) at 21 d of age but grew .026 kg/d faster (P less than .10) from 70 d to slaughter, weighed 3.9 kg more at 165 d of age (P less than .05), and reached 100 kg 7.0 d sooner (P less than .05) than pigs out of control-line sows. Carcasses from barrows sired by select-line boars had .29 cm more (P less than .10) fat at the 10th-rib than carcasses from barrows sired by control-line boars. Marbling scores were .31 unit greater (P less than .05) and muscle color scores were .25 unit greater (P less than .10) for carcasses from pigs out of select-line sows than for carcasses from pigs out of control-line sows. Selection for increased 70-d weight decreased age at 100 kg without increasing fat deposition. However, survival rates up to 100 kg were reduced. Mass selection for 200-d weight effectively increased 70-d weight, but fat thickness at 100 kg also increased.     

Comparisons of specific crosses from Duroc-Landrace, Yorkshire-Landrace and Hampshire-Landrace sows managed in two types of gestation systems: pig performance

Ten thousand one hundred sixty-nine pigs were farrowed in 844 litters that were produced by mating Duroc (D), Yorkshire (Y) and Hampshire (H) boars to Duroc-Landrace (DL), Yorkshire-Landrace (YL) and Hampshire-Landrace (HL) sows to study the effect of sire breed, dam breeding and gestation environment (pasture lots vs confinement stalls) on pig weights, survival rates and feed efficiency. Pigs sired by H boars were .05 kg heavier at birth than Y-sired pigs and .2 kg heavier at 21 d than Y- and D-sired pigs, but they were .6 kg smaller at 56 d. D-sired pigs grew .028 kg/d faster from 56 d to 100 kg and reached 100 kg approximately 5 d sooner than the Y- and the H-sired pigs. At birth, pigs out of DL sows were .21 kg heavier than pigs out of YL sows. Pigs out of HL sows grew .025 and .021 kg/d slower from 56 d to 100 kg compared with pigs out of DL and YL sows, respectively. Sows in the pasture gestation system produced pigs that were .05 kg heavier at birth than pigs out of sows in gestation stalls. Three-breed-cross pigs were .9 kg heavier at 56 d, grew .039 kg/d faster and took 7.9 fewer days to reach 100 kg than backcross pigs. The H sire breed had lower survival rates of pigs at 21 d and to 100 kg of those born alive (P less than .10), compared with pigs sired by D and Y boars. Pigs out of HL dams had the highest survival rates, whereas pigs out of YL sows had the lowest survival rates at birth, 21 d and at 100 kg. Three-breed-cross pigs averaged .025, .028 and .035 greater survival rates at birth, 21 d and 56 d than backcross pigs. Feed efficiency was most desirable in pens of pigs sired by H and D boars compared with pens of pigs sired by Y boars. However, pens of pigs with YL dams were more efficient than pens of pigs with HL dams.     

Genetic parameters for measures of the efficiency of gain of boars and the genetic relationships with its component traits in Duroc pigs

Genetic parameters for the efficiency of gain traits on 380 boars and the genetic relationships with component traits were estimated in 1,642 pigs (380 boars, 868 gilts, and 394 barrows) in 7 generations of a Duroc population. The efficiency of gain traits included the feed conversion ratio (FCR) and residual feed intake (RFI) and their component traits, ADG, metabolic BW (MWT), and daily feed intake (FI). The RFI was calculated as the difference between the actual and expected FI. The expected FI was predicted by the nutritional requirement and by the residual of phenotypic (RFI(phe)) and genetic (RFI(gen)) regressions from the multivariate analysis for FI on MWT and ADG. The means for RFI(phe) and RFI(gen) were close to zero, and the mean for nutritional RFI was negative (-0.11 kg/d). The traits studied were moderately heritable (ranging from 0.27 to 0.53). The genetic and phenotypic correlations between ADG and FI were moderate to high, whereas the genetic correlation between MWT and FI was moderate, and the phenotypic correlation between them was low. The corresponding correlations between RFI(phe) and RFI(gen) were > 0.95, implying that they can be regarded as the same trait. The genetic and phenotypic correlations of FCR with measures of RFI were high but lower than unity. The RFI(phe) was phenotypically independent of its component traits, MWT (r(p) = 0.01) and ADG (r(p) = 0.03). The RFI(gen) was genetically independent of MWT (r(g) = -0.04), whereas there was a weak genetic relationship (r(g) = 0.15) between RFI(gen) and ADG. Residual FI was more heritable than FCR, and the genetic and phenotypic correlations of RFI(phe) and RFI(gen) with FI were positive and stronger than that of FCR with FI. These results provide evidence that RFI(phe) or RFI(gen) should be included in breeding programs for Duroc pigs to make genetic improvement in the efficiency of gain.     

利用后裔测定验证大白猪基因组选择实施效果研究

旨在通过测定基因组选择选留的大白公猪的后裔生产性能,探究基因组选择实际育种效果。本研究选用913头大白猪构建参考群体,利用ssGBLUP对新出生的823头大白公猪在去势前进行第一次基因组评估,待生产性能测定后进行第二次基因组评估,最终选留10头性能差异显著的公猪留种,比较其后代生长性状表型和育种值及综合选择指数差异。结果表明,两次基因组遗传评估,达100 kg体重日龄、100 kg活体背膘厚和总产仔数3个性状基因组育种值（GEBV）估计准确性分别由0.56、0.67和0.64提高至0.73、0.73和0.67,两次基因组选择基因组母系指数相关系数为0.82,表明在去势前进行公猪基因组选择具有较高的准确性,可实现种猪早期选择。根据各性状GEBV和基因组母系指数,10头公猪被划分为高、低生产性能组,后裔测定成绩表明,两组公猪后代100 kg体重日龄表型均值之差为2.58 d,育种值之差为3.08 d,100 kg活体背膘厚表型均值之差为1.15 mm,育种值之差为1.03 mm,综合母系指数均值之差为9.3,除后代100 kg体重日龄表型均值之差外,其他差异均达到极显著水平。本研究证明,在基因组评估中具有显著差异的公猪其后代在表型值和育种值等方面均存在显著差异,通过基因组选择能够挑选出优秀种公猪,可将其遗传优势传递给后代。     

Using Progeny Testing to Evaluate the Efficiency of Genomic Selection in Large White Pigs

This study aimed to evaluate the actual genetic improvement effect of genomic selection in Large White boars through progeny testing in production performance. Nine hundred and thirteen Large White pigs were used to construct a reference group, and 823 new-born Large White boars were used to implement the first genomic selection through ssGBLUP before castration. The second genomic selection were carried out after performance testing, then 10 boars with significant difference in production performance were selected and their offsprings were compared in phenotypic values, estimated breeding values of growth traits and selection index. The results showed that the accuracies of genomic prediction on age at 100 kg body weight, 100 kg backfat thickness and total number born increased from 0.56, 0.67 and 0.64 in the first genomic selection to 0.73, 0.73 and 0.67 in the second genomic selection, respectively. The correlation coefficient of maternal selection index between the two genomic selection before castration and after performance testing was 0.82, which indicated that the first genomic selection before castration was accurate enough to make early selection on boars. According to the genomic breeding values and maternal selection index of 10 selected boars, two groups with high and low production performance were set up. The progeny testing showed that the difference of average phenotypic value between groups was 2.58 days, and the difference of average evaluated breeding value(EBV) between groups was 3.08 days in age at 100 kg body weight, those were 1.15 mm and 1.03 mm in 100 kg backfat thickness, respectively, and the difference in the mean of the comprehensive maternal index was 9.3, all the differences(except age at 100 kg body weight) were extremely significant. This study prove that the offspring of boars with significant differences in genomic evaluation have significant differences in phenotypic values and breeding values, which indicate that, through genomic selection, excellent breeding boars can be selected and their genetic superiority can be passed to their offsprings.     

The energy preservation requirements of growing pigs of different sexes fed normal and high protein diets. 5. Comparison with the results obtained from castrated pigs, sows and boars

In one experiment each with castrated pigs, sows and boars (hybrid pigs of line 150), two groups of six animals received rations containing 17 and 45% crude protein resp. over the complete test period from 35 to 130 kg (castrated pigs), 150 kg (sows), 170 kg live weight (boars) and passed alternatively through a total of 60 metabolism periods on growth and 48 on maintenance level. There were significant differences between the 3 categories of animals with regard to energy maintenance requirement in the relation of 100:105:110 for castrated pigs less than sows less than boars. In contrast to the estimated values derived from previous studies for energetic maintenance requirement of 650 kJ/kg LW0.62.d the measured values for all 3 animal categories are by approximately 50% higher. The protein content did not have an influence on the maintenance requirement of metabolizable energy of the animals. The utilization of metabolizable energy of the two rations for body energy retention corresponds to the expectations with regard to its dependence on nutrients. The requirement of metabolizable energy for protein and fat retention is 1.7:1.0. The energy content of the weight gain of boars was, on average, 85% of that of castrated pigs and sows. The studies of blood parameters did not show any deviations in the parameters tested.     

Genetic parameters for feed efficiency traits and their relationships with growth and carcass traits in Duroc pigs

Genetic parameters for feed efficiency traits of 380 boars and growth and carcass traits of 1642 pigs (380 boars, 868 gilts and 394 barrows) in seven generations of Duroc population were estimated. Feed efficiency traits included the feed conversion ratio (FCR), and nutritional (RFI(nut)), phenotypic (RFI(phe)) and genetic (RFI(gen)) residual feed intake. Growth and carcass traits were the age to reach 105-kg body weight (A105), loin eye muscle area (EMA), backfat (BF), intra-muscular fat (IMF) and meat tenderness. The mean values for RFI(phe) and RFI(gen) were close to zero and for RFI(nut) was negative. All the measures of feed efficiency were moderately heritable (h(2) = 0.31, 0.38, 0.40 and 0.27 for RFI(nut), RFI(phe), RFI(gen) and FCR respectively). The heritabilities for all growth and carcass traits were moderate (ranged from 0.37 to 0.45), except for BF, which was high (0.72). The genetic correlations of RFI(phe) and RFI(gen) with A105 were positive and high. Measures of RFI were correlated negatively with EMA. BF was more strongly correlated with measures of RFI (r(g) > or = 0.73) than with FCR (r(g) = 0.52). Selection for daily gain, EMA, BF and IMF caused favourable genetic changes in feed efficiency traits. Results of this study indicate that selection against either RFI(phe) or RFI(gen) would give a similar correlated response in carcass traits.     

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。