仔猪初生重及断奶重对成活率的影响

影响猪场生产指标和经济效益的主要因素是仔猪成活率，其与仔猪初生重及断奶重密切相关，因此探究仔猪初生重及断奶重与成活率之间的关系，对猪场淘汰仔猪具有参考价值。本研究以四川阆中大北农桥楼猪场二元母猪所产500头仔猪为试验对象，记录、整理和分析仔猪初生重、21日龄断奶重、21日龄成活率及70日龄成活率。结果表明：仔猪初生重呈正态分布，体重过小、过大的数量较少；体重≤1.0kg的仔猪21日龄成活率较低，体重>1.3kg的仔猪21日龄成活率均在95%以上；21日龄断奶重较大仔猪的70日龄成活率较高，5.5～6.0kg的仔猪最为理想。因此，建议四川阆中大北农桥楼猪场适当淘汰初生重≤1.0kg的仔猪，提高经济效益。     

母猪乳头数及哺乳位置等对哺乳仔猪早期日增重的影响

为了解母猪乳头数、仔猪哺乳位置(前、中、后)、性别和初生重等因素对哺乳仔猪早期日增重的影响,本研究选取了预产期、胎次相近的沙乌头、杜×沙、长×大母猪各5头以及它们产后的哺乳仔猪,记录母猪左右两侧乳头数并将乳头分为前、中、后区。同时记录仔猪哺乳位置,初生重(1日龄)、3日龄、6日龄、9日龄体重。结果表明:不同品种或杂交组合母猪乳头数有显著差异;不同性别仔猪初生重无显著差异,性别对仔猪1~9日龄日增重的影响也不显著;不同哺乳位置间仔猪初生重无显著差异,但仔猪日增重与其初生重显著相关;哺乳位置对沙乌头母猪所产仔猪1~9日龄日增重影响不显著,但是对杜沙和长大母猪所产仔猪3-9日龄日增重有显著影响。     

仔猪初生重对后期生长发育的影响

据报道，初生重低于0．9kg的仔猪死亡率可达％呢，初生重在1．35－1．552g范围死亡率可下降至18％，1．8kg以上存活率可88％。另外，初生重低50％的仔猪断乳重低16．62％。本文旨在通过分析不同品种初生重的仔猪后期生长发育情况，探讨初生重大小对断奶重、60日龄重的影响规律，并对不同品种仔猪的生长发育进行比较。1背景资料和研究方法1．1本研究资料选自某种猪场1993－1996年长白和杜洛克母猪产仔哺育记录。1．2该种猪场按照工厂化生产工艺流程组织生产，猪舍按空怀一妊娠舍、分娩一保育舍、出售猪舍顺序排列，根据其生产特点与要求，分…     

仔猪初生重对21日龄断奶重的影响

研究初生重对21日龄断奶重的影响。做了两个重复试验,共统计了655头仔猪,每个试验根据初生重分为4个阶段(0.70～1.00,1.10～1.30,1.31～1.60,1.61～2.10)。结果表明,初生重在1.3kg以下,21日龄重达不到平均重。初生重在1.3kg以上,21日龄重超过平均重。     

酵母元在妊娠及哺乳母猪饲料中的应用试验

选取怀孕65天左右、产期相近的长大母猪12头,胎次为第二胎．随饥分为两组．每组6头,乳猪出生7天后开始补料．35日龄断奶称重。在妊娠及哺乳母猪日粮中使川酵母元饲料添加剂后,仔猪的初生窝重增加22．71％,35日龄断奶窝重增加20．3％,仔猪头平均初生重增加11．9％,35日龄断奶重增加8．8％．仔猪的日增重提高了8．3％。     

酵母元在妊娠哺乳母猪饲料中的应用试验

试验选取妊娠65d左右、产期相近的长大母猪12头，胎次为第2胎，随机分为2组，每组6头．乳猪出生7d后开始补料，35日龄断奶称重。试验研究了在妊娠及哺乳母猪日粮中使用酵母元饲料添加剂后，仔猪的初生窝重增加了22．71％，35日龄断奶窝重增加20．3％，仔猪头平均初生重增加11．9％，35日龄断奶重增加8．8％．仔猪的日增重提高了8．3％。     

长大母猪窝产活仔数对初生重、28日龄断奶重及哺育率的影响

以311窝长大母猪所产的3 148头仔猪为研究对象,探讨窝产活仔数对初生重、28日龄断奶重及哺育率的影响。结果表明,随着窝产活仔数的增加,仔猪初生窝重、28日龄断奶窝重增加,而初生个体重、哺育率降低。相近窝产活仔数间的初生重、28日龄断奶重、哺育率差异不显著(P>0.05),而不同梯度间差异极显著(P<0.01)。窝产活仔数与初生窝重、28日龄断奶窝重均成极显著正相关,相关系数分别为0.739和0.525;与初生窝均重成显著负相关,相关系数为-0.344;与28日龄断奶个体重成极显著负相关,相关系数为-0.351;与28日龄哺育率成极显著负相关,相关系数为-0.363。本试验条件下,窝产活仔数在10~11头之间可以取得较高的经济效益。     

窝产活仔数和初生重与仔猪早期断奶重及成活率的相关性研究

为研究猪窝产活仔数与初生仔猪个体重对21日龄早期断奶仔猪个体重及成活率的相关性,特选择一大型规模猪场2~6胎母猪在1个月内所产的118窝计1350头仔猪作为试验对象,要求所有初生仔猪均由亲本母猪带仔哺乳,且按窝产活仔数不同(6~17头)分组测定仔猪初生个体重和21日龄早期断奶仔猪窝个体均重,并观察断奶成活率,同时对其相关性状作方差及回归分析。结果表明,不同组间初生仔猪窝个体均重和21日龄早期断奶仔猪窝个体均重及断奶成活率差异显著(P0.05);窝产活仔数对初生仔猪窝个体均重和21日龄早期断奶仔猪窝个体均重及断奶成活率呈极显著的负相关(R=-0.802、-0.851、-0.698,P0.01);初生仔猪窝个体均重对21日龄早期断奶仔猪窝个体均重及断奶成活率呈极显著的正相关(R=0.837、0.741,P0.01)。试验结果表明,窝产活仔数越多,初生仔猪个体就越小,早期断奶也越轻,成活率也低;初生仔猪个体越大,早期断奶就越重,成活率也越高。只要通过科学合理的方法,适当控制猪窝产活仔数并提高初生仔猪个体重,能有效提高早期断奶仔猪的生长速度,并可获得更好的经济效益。     

仔猪初生重对断奶窝重的影响

提高猪的增重速度首先要从仔猪初生重、断奶重抓起 ,要取得仔猪窝重高的结果 ,除了抓好泌乳母猪的饲养管理、发挥母猪良好的泌乳性能外 ,做好仔猪补料、抓旺食、过好断奶关及疾病的预防工作是关键。1　试验材料与方法1 .1　试验猪随机选用 1 8窝“杜长上”初生仔猪 ,饲养 3 5日龄断奶。泌乳母猪、仔猪分别用申兰集团饲料厂生产的泌乳母猪料和乳猪料。母猪产前一周进产房待产 ,母猪采用高床单体限位栏 ,两侧为仔猪活动空间并配有保暖小间。1 .2　试验猪的饲养管理1 .2 .1　对临产前母猪后躯、乳房部位及分娩床面用0 .1 %高锰酸钾溶液擦拭消毒…     

皖南花猪不同头型母猪繁殖性能比较研究

皖南花猪按头型可分为狮子头型、马脸型和桩头型,为研究皖南花猪母猪不同头型母猪间的繁殖性能差异,研究通过整理安徽省皖南花猪保种场以往数据,现场记录等方法,统计皖南花猪不同头型经产母猪(370窝)的窝产仔数、窝产活仔数、初生窝重、35日龄窝断奶仔猪数和35日龄断奶窝重等繁殖性能指标,并进行比较分析。结果如下:皖南花猪马脸型母猪窝产仔数、窝产活仔数、仔猪初生窝重、35日龄断奶仔猪数、35日龄断奶窝重均显著高于狮子头型及桩头型母猪(P0.05);皖南花猪桩头型母猪在窝产仔数、窝产活仔数、仔猪初生窝重等繁殖性能上优于狮子头型母猪,但在35日龄断奶窝重这一指标中低于狮子头型母猪。研究表明皖南花猪马脸型母猪繁殖性能与狮子头型、桩头型母猪相比更为优异,为皖南花猪种质资源保护与开发利用提供了一定的参考依据。     

Effect of piglet birth weight on body weight,growth, backfat,and longissimus muscle area of commercial market swine

The objective of this study was to estimate the effect of piglet birth weight on future BW, growth, backfat, and longissimus muscle area of pigs in a commercial U.S. production system. Pigs (n = 5727) at a commercial farm were individually weighed and identified within 24 h of birth. Weights were collected prior to weaning (n = 4108), after finisher placement (n = 3439), and 7 (n = 1622) and 16 (n = 1586) weeks into finishing; hot carcass weight was also collected (n = 1693). Average daily gain during lactation, nursery, finishing, and overall (birth to 16 weeks into finishing) was calculated. During BW collection 16 weeks into finishing, real-time ultrasound backfat thickness and longissimus muscle area were measured. Sex × birth weight (linear and quadratic) interactions were observed for BW at weaning and finisher placement and daily gain during pre-weaning and nursery. Linear birth weight × cross foster interactions were observed for weaning weight and pre-weaning gain. Linear and quadratic effects of birth weight on BW at weaning, finisher placement, 7 and 16 weeks into finishing, and hot carcass weight and average daily gain during pre-weaning, nursery, finishing, and total were observed. For all measures of BW and average daily gain, as birth weight increased subsequent BW and average daily gain increased at a decreasing rate; however, for the sex × birth weight (linear and quadratic) interactions, heavier birth weight barrows were lighter and grew slower than gilts of comparable birth weight. Worth noting, the birth weight × sex interactions described very few pigs in the extreme portion of the birth weight distribution. For birth weight × cross foster interactions, non-cross fostered pigs were increasingly heavier and faster growing as birth weight increased compared to cross fostered pigs. Heavier birth weight pigs tended to have increased backfat depth (P = 0.07). Linear and quadratic effects of birth weight on longissimus muscle area were observed; as birth weight increased muscling increased at a decreasing rate. Regardless of interactions or period of production, increased birth weight resulted in heavier future BW, faster daily gain along with larger longissimus muscle area prior to harvest. In all instances the magnitude of the negative effect of birth weight increased as birth weight decreased.     

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。     

Effects of weaning on diarrhea caused by enterotoxigenic Escherichia coli in three-week-old pigs

We attempted to determine whether weaning is required for induction of diarrhea in pigs with postweaning enterotoxigenic Escherichia coli infection. Three-week-old newly weaned pigs and their suckling littermates were inoculated with the K88+ enterotoxigenic E coli strain M1823B. Fourteen of 21 weaned and 12 of 20 suckling pigs were genetically resistant to intestinal adhesion by the K88+ strain of E coli; they remained healthy, and gained weight at similar rates. Both groups of K88-resistant pigs gained weight faster, and shed fewer bacteria of strain M1823B in their feces, than did their K88-susceptible counterparts. Diarrhea developed in K88-susceptible pigs in the weaned (6 of 7 pigs) and suckling (4 of 8 pigs) groups, and 1 of the 4 affected suckling pigs died from complications resulting from diarrhea. The incidences of diarrhea, weight gain rates, and the numbers of strain M1823B shed in feces of susceptible weaned and suckling pigs were not significantly (P greater than 0.05) different. Diarrhea scores of susceptible weaned pigs were significantly (P less than 0.02) higher than those of susceptible suckling pigs on the second day after inoculation. In this experimental model, it was concluded that weaning is not required for induction of diarrhea, but may modestly increase its severity.     

Genetic determination of mothering ability and piglet growth in indigenous Mukota sows of Zimbabwe

The objective of this study was to determine genetic parameters of individual and sow records on litter size and weights at 21 and 35 days in Mukota pigs. Data gathered from 1961 pigs at the University of Zimbabwe between January 1998 and August 2003, were analysed. Individual pig traits analysed were the weight at 21 days of age (THRWT), weight at weaning (WWT) and average daily gain from birth to weaning (ADGWW). Sow performance traits considered were the litter weight after 21 days (LTHRWT), litter weight at weaning (LWWT), number of pigs weaned (NW) and mothering ability (MA). An animal model was used to estimate genetic parameters using the average information restricted maximum likelihood procedure. Individual pig records were analysed using models with or without litter effects and maternal genetic effects. Incorporating the maternal genetic variance component drastically reduced the standard errors of the heritability estimates. The heritabilities for LTHRWT, LWWT and MA were 0.18, 0.15 and 0.05, respectively. The LWWT and NW were positively correlated. There were no genetic relationships between MA and LTHRWT and LWWT. No antagonisms should be expected when selecting for MA and increasing litter weights in Mukota pigs.     

Correlation Analysis Between Haplotypes of ApoA5 Gene on Body Weight and Meat Quality in Jinfen White Pigs

This study was aimed to explore the correlation between the haplotypes of apolipoprotein A5 (ApoA5) gene and body weight,meat quality in Jinfen White pigs.180 Jinfen White pigs were selected,PCR was used to detect the single nucleotide polymorphism (SNP) of ApoA5 gene,and the linkage of these SNPs was analyzed by Haploview software.Non-fully linked SNPs were screened to form the haplotypes of ApoA5 gene,and the frequency of different haplotypes of ApoA5 gene were calculated.The correlation between the haplotypes of ApoA5 gene and body weight,meat quality was analyzed by SPSS software to identify the haplotypes of ApoA5 gene with excellent traits.The results showed that ApoA5 gene of Jinfen White pigs contained 21 SNPs and 5 completely linked regions which included 5,2,3,4 and 2 SNPs,respectively.Ten non-completely linked tag SNPs were selected to form the haplotypes of ApoA5 gene,Hap 1 had the highest gene frequency (46.7%).The haplotypes of ApoA5 gene had a significant correlation with the birth weight,weaning weight,6-month-old body weight,intramuscular fat content,shear force and drip loss,but no significant correlation with pH_{24 h} in Jinfen White pigs.Hap 11 of ApoA5 gene in Jinfen White pigs had the highest birth weight,weaning weight,6-month-old body weight and intramuscular fat content,the lowest shear force,and the lower drip loss.Hap 6 had the lowest birth weight.Hap 2 had the lowest weaning and 6-month-old weight.Hap 3 had the lowest intramuscular fat content and the highest shear force.Hap 10 had the highest drip loss.Hap 11 of ApoA5 gene in Jinfen White pigs had excellent traits,which could be used as a molecular marker to use in molecular breeding of Jinfen White pigs and improve the breeding efficiency.     

晋汾白猪ApoA5基因单倍型与体重和肉质性状的相关性分析

试验旨在探究晋汾白猪载脂蛋白A5（apolipoprotein A5,ApoA5）基因的单倍型与体重和肉质性状的相关性。选取180头晋汾白猪为研究群体,利用PCR技术检测ApoA5基因的单核苷酸多态性（single nucleotide polymorphism,SNP）,并采用Haploview软件分析这些SNP位点的连锁不平衡程度;筛选非完全连锁的SNP位点,构建不同的ApoA5基因单倍型,统计不同单倍型的基因频率,并通过SPSS软件分析不同ApoA5基因单倍型与晋汾白猪体重和肉质性状的相关性,鉴定优良性状的ApoA5基因单倍型。结果显示,晋汾白猪ApoA5基因共检测到21个SNPs位点,其中5个完全连锁单倍型块,分别包含5、2、3、4和2个SNPs位点;另外10个非完全连锁的标签SNP组合成不同的ApoA5基因单倍型,其中Hap 1的基因频率最高,达到46.7%,远高于其他单倍型;ApoA5基因单倍型与晋汾白猪的初生重、断奶重、6月龄体重、肌内脂肪含量、剪切力和滴水损失均具有明显的相关性,而与pH_{24 h}没有明显的相关性;ApoA5基因Hap 11晋汾白猪的初生重、断奶重、6月龄体重和肌内脂肪含量均最高,且剪切力最低,滴水损失也相对较低;Hap 6的初生重最低;Hap 2的断奶重和6月龄体重均最低;Hap 3的肌内脂肪含量最低,剪切力最高;Hap 10的滴水损失最高。晋汾白猪ApoA5基因Hap 11属于优良性状单倍型,是一个具有优良性状的分子标记,可以用于晋汾白猪的分子育种,提高选种效率。     

Direct and maternal genetic effects on birth and weaning traits in multibreed cattle data and predicted performance of breed crosses

Direct and maternal additive effects and heterosis were estimated using data from straightbred Angus, Brahman, Charolais, Hereford, and four generations of rotational crosses among these breeds. Traits of interest were birth weight, Julian day of birth, average daily gain from birth to weaning, 205-d weight, and weaning weight per cow exposed. Complete data were available on 3,445 calves produced from 4,733 matings. Discrete generations of 4-yr duration were produced from 1970 through 1988. Brahman was included in each rotational crossbreeding system. Genetic effects were estimated by regression. Direct and maternal additive effects of Brahman, Charolais, and Hereford were estimated as deviations from Angus. Direct and maternal heterosis effects were assumed proportional to expected heterozygosity. The Brahman direct additive effect resulted in later-born calves (P < 0.01). Brahman, Charolais, and Hereford direct additive effects increased birth weight, and the Brahman maternal additive effect decreased birth weight compared with Angus (P < 0.05). Charolais direct and maternal additive effects were greater than Angus for average daily gain and 205-d weight (P < 0.01). The Hereford maternal additive effects on average daily gain and 205-d weight were less than those of the other breeds (P < 0.01). Breed combinations including Brahman had greater direct heterosis for birth weight, average daily gain, and 205-d weight than other combinations (P < 0.01). Angus, Charolais, and Hereford direct additive effects on weaning weight per cow exposed were greater than Brahman (P < 0.05). Predicted average daily gain, 205-d weight, and weaning weight per cow exposed were, on average, greater in four-breed rotation systems than in three- and two-breed systems. Among two-breed rotation systems, predicted average daily gain and 205-d weaning weight were greatest for Charolais-Brahman and least for Angus-Hereford. Calves from the Angus-Charolais-Hereford system weighed less at weaning than any other three-breed combination. However, weaning weight per cow exposed from the Angus-Charolais-Hereford system was greatest among three-breed systems. Within three- and four-breed rotation systems, ranges in predicted birth and weaning weights among generations varied by up to 10.0 and 25.2 kg, respectively. The choice of breeds affects performance, and the sequence of their use may affect intergenerational variation in performance.     

猪IGF2基因G3072A位点多态性及其与大白猪初生重和早期生长的关系

本研究采用PCR-SSCP技术对猪胰岛素样生长因子2（IGF2）基因G3072A位点在大白、长白和杜洛克猪群体的单核苷酸多态性（SNP）进行了检测，对其与大白猪初生重和早期生长的关系进行了分析。结果表明，在所分析的大白、长白和杜洛克猪群体的511个体中，IGF2基因在该位点均呈现多态性，大白、长白和杜洛克猪群体AA、AB和BB基因型均有分布，且大白和长白猪群体均显著偏离Hardy-Weinberg平衡（P〈0．01），而杜洛克猪群未偏离Hardy-Weinberg平衡（P〉0．05）。测序结果显示，等位基因A和B分别对应于核苷酸A和G，在A等位基因中，有（AG）二核苷酸的插入。关联分析表明，在大白猪群中，AA、AB和BB基因型个体的初生重差异显著（P〈0．05），AA和AB基因型个体的21、28和70日龄体重以及从出生～21日龄、21～28日龄、28～70日龄的日增重差异不显著（P〉0．1）。     

Heritability and genetic correlation estimates of semen production traits with litter traits and pork production traits in purebred Duroc pigs

We estimated heritabilities of semen production traits and their genetic correlations with litter traits and pork production traits in purebred Duroc pigs. Semen production traits were semen volume, sperm concentration, proportion of morphologically normal sperms, total number of sperm, and total number of morphologically normal sperm. Litter traits at farrowing were total number born, number born alive, number stillborn, total litter weight at birth, mean litter weight at birth, and piglet survival rate at birth. Litter traits at weaning were litter size at weaning, total litter weight at weaning, mean litter weight at weaning, and piglet survival rate from birth to weaning. Pork production traits were average daily gain, backfat thickness, and loin muscle area. We analyzed 45,913 semen collection records of 896 boars, 6,950 farrowing performance records of 1,400 sows, 2,237 weaning performance records of 586 sows, and individual growth performance records of 9,550 animals measured at approximately 5 mo of age. Heritabilities were estimated using a single-trait animal model. Genetic correlations were estimated using a 2-trait animal model. Estimated heritabilities of semen production traits ranged from 0.20 for sperm concentration to 0.29 for semen volume and were equal to or higher than those of litter traits, ranging from 0.06 for number stillborn and piglet survival rate at birth to 0.25 for mean litter weight at birth, but lower than those of pork production traits, ranging from 0.50 for average daily gain to 0.63 for backfat thickness. In many cases, the absolute values of estimated genetic correlations between semen production traits and other traits were smaller than 0.3. These estimated genetic parameters provide useful information for establishing a comprehensive pig breeding scheme.     

断奶后舍饲精喂对内蒙古呼伦贝尔短尾羊日增重的影响

为研究断奶后对家畜舍饲精喂饲料,呼伦贝尔羊中的"短尾品系"(简称呼伦贝尔短尾羊)日增重的变化,选取家庭牧场植被相似的典型牧户,典型牧户家畜数量为400只母羊和400只羔羊。试验采取与牧民合作的形式进行控制性试验,以全年传统自由放牧为对照组,哺乳期断奶后舍饲精喂饲料加自由放牧为控制组。结果表明:舍饲使得羔羊日增重差异性显著(P<0.05),公羔的平均日增重最大可达210.8±8.48 g·d^-1。不同月龄母畜对舍饲精喂的显著性差异表现不同,其中18个月以上月龄的母羊日增重差异性显著,且月龄越大,差异越显著。舍饲使得不同月龄段的母羊之间日增重差异性显著,12个月龄以下的母畜日增重最大,达到126.26±5.23 g·d^-1。因此断奶后对家畜舍饲精喂饲料对家畜个体生产性能的提高具有重要的促进作用。