胎次对母猪产仔性能的影响

为研究母猪胎次对产仔性能的影响,收集福建某种猪场2008-2011年总计10482胎的分娩记录,应用Excel整理数据、SPSS17.0软件比较不同胎次的大约克、长白和杜洛克母猪窝产总仔数、窝产活仔数的差异。结果表明,胎次对大约克、长白和杜洛克母猪窝产仔数和窝产活仔数的影响极显著（P<0.01）,随着胎次的增加,母猪的窝产总仔数、窝产活仔数呈逐渐上升趋势,在第4胎时达到最大值,分别为11.77头、10.54头。     

胎次对杜洛克、长白和大白母猪繁殖性能的影响

为了研究胎次对杜洛克、长白和大白母猪繁殖性能的影响,根据江苏省某国家级生猪核心育种场2009-2011年出生的繁殖母猪资料,分别选取128头杜洛克、681头长白和610头大白母猪共7280窝生产数据,统计分析不同胎次母猪的总产仔数、产活仔数、断奶仔猪数、初生窝重及校正21日龄窝重。此外,依据胎次将母猪分为3个繁殖阶段（1～2胎、3～6胎及7～8胎）来探究品种差异对母猪繁殖性能的影响。结果表明：胎次对母猪繁殖性能有显著影响（P<0.05）,母猪1～4胎的总产仔数、产活仔数、断奶仔猪数及初生窝重随胎次呈增加趋势,第4胎达到高峰,且显著高于其他胎次（P<0.05）;3～6胎繁殖性能较好,7胎之后出现迅速下降趋势;除在第4胎略有下降外,其他胎次的校正21日龄窝重随胎次递增。品种对母猪繁殖性能的影响显著（P<0.05）,长白和大白母猪的繁殖性能均极显著高于杜洛克母猪（P<0.01）;长白母猪的产活仔数和校正21日龄窝重显著高于大白母猪（P<0.05）,2个品种其他繁殖性能无显著差异（P＞0.05）。综上所述,杜洛克、长白和大白母猪的最佳繁殖胎次为3～6胎,长白猪的繁殖性能总体上优于大白猪,就本试验所在的育种场而言,长白猪可能更适合作为二元母猪生产中的母本。     

影响长白母猪产仔数胎次因素的研究

选择了890窝长白纯种母猪，对其窝产仔数、窝产活仔数、窝异常产仔数等指标进行了分析，先测定这些性状或指标不同胎次的成绩，再对每个成绩进行统计分析。结果表明，在长白母猪中，胎次对考察性状中的窝产仔数影响极显著（P〈0．01），平均窝产仔数、窝产活仔数最高均为第6胎，分别为10．28和9．81头，最少均为第1胎，分别为8．43头和7.33头。胎次对母猪异常产仔数影响极显著（P〈0．01），窝均异常产仔数最高为第7胎，较少为第2，6，4胎，异常产仔数包括死胎数和木乃伊胎数2类。疾病与胎次也有很大的关系。     

不同胎次对不同品种猪产仔数的影响

选择北京养猪育种中心某种猪场5 697窝大白母猪和2 226窝长白母猪的总产仔数和产活仔数按照胎次进行统计分析,结果表明,在大白和长白母猪中胎次对产仔数影响显著。大白母猪产仔高峰在第4胎次,总产仔数为(12.37±2.52)头,产活仔数为(11.74±2.86)头;长白母猪产仔高峰也在第4胎次,总产仔数为(12.57±2.41)头,产活仔数为(11.83±2.44)头,胎次对产仔数的影响在大白母猪和长白母猪中规律基本一致。     

胎次和配种季节对长白、大白母猪繁殖性能的影响

为了分析不同胎次、配种季节对母猪繁殖性能的影响,笔者对江西省赣州市某猪场2015年长白母猪、大白母猪的繁殖记录进行统计分析,并按胎次及配种季节进行分组,分析其在不同胎次、配种季节条件下的繁殖性能差异。结果表明:长白母猪和大白母猪3~5胎繁殖性能较好,第1胎的初生均重、断奶均重最低;长白母猪第3胎窝产活仔数最高,显著高于1,2,6,7,8胎(P0.05);大白母猪第4胎窝产活仔数最高,显著高于第1,2胎(P0.05);长白母猪夏季配种窝产仔数、窝产活仔数最高,初生均重、断奶均重春季配种最高;大白母猪不同季节配种窝产仔数差异不显著(P0.05),夏季、秋季配种产活仔数显著高于冬季(P0.05)。说明不同胎次、配种季节对长白、大白母猪繁殖性能有较大影响。     

不同胎次对母猪繁殖性能的影响

通过分析EZ猪场2005-2011年7年2万多条配种分娩记录发现,胎次对大白和长白母猪的受胎率和配种分娩率影响不大;1-9胎次母猪的受胎率相对比较理想,基本上在90%以上,4-10胎次母猪的配种分娩率相对较高。胎次明显影响母猪的总产仔数和产活仔数,1-5胎母猪的总产仔数和产活仔数随胎次增加而逐渐增加,第4、5胎时总产仔数达到高峰（长白猪为11.49头,大白猪11.62头）,长白母猪7胎时产活仔数明显下降,大白母猪9胎时产活仔数明显下降;为提高繁殖性能,EZ猪场的长白母猪以6胎后、大白母猪以8胎后淘汰为宜。     

胎次对丹系大白猪繁殖性能的影响分析

对江苏省某国家生猪核心育种场丹系大白母猪各胎次的产仔数、产活仔数、断奶仔猪数及初生窝重、断奶窝重等繁殖性状进行了比较和相关性分析,旨在进一步了解丹系大白猪的繁殖性能,为后备母猪的选种选育提供参考。结果表明,丹系大白母猪第1、2胎产仔数较少,至第3胎达到最高为10.39头,后趋于稳定。不同胎次对产活仔数与断奶仔猪数的影响与产仔数的变化趋势基本一致。不同胎次的仔猪初生窝重基本持平,并以第3胎最高为14.81 kg。各胎次断奶窝重基本稳定。相关性分析表明,丹系大白母猪第3胎与第4胎产仔数、产活仔数、初生窝重呈显著正相关,第2胎与第5胎的产仔数、产活仔数、初生窝重间均呈显著负相关。第4胎与第5胎断奶仔猪数有显著负相关。第4胎和第5胎的断奶窝重有显著正相关。第3胎繁殖性能相对稳定,可以反映母猪繁殖性能,因此丹系大白母猪第3胎次的繁殖性能可作为选育后备母猪的重要依据。     

丹系与美丹大白、长白和杜洛克母猪的胎产活仔性能比较

文章主要通过比较丹系和美丹系的大白、长白和杜洛克母猪的胎产活仔性状,分析不同品种的丹系和美丹系产仔性能的差异,从而为品系的培育提供参考依据。研究整理了2017年1-11月广西某种猪场丹系和美丹系的大白、长白和杜洛克的繁殖记录,共2 301窝,其中美丹系196窝,丹系2 105窝,并对胎产活仔数性状进行统计分析。结果表明:丹系大白、丹系长白和丹系杜洛克母猪的平均胎产活仔数分别为(15.37±0.76)头、(14.30±0.54)头和(7.63±1.06)头。美丹大白、美丹长白和美丹杜洛克母猪的平均胎产活仔数分别为(12.35±1.48)头、(11.66±1.33)头和(8.59±1.06)头。丹系和美丹大白母猪差异显著(P 0.05),丹系和美丹长白母猪差异极显著(P 0.01),而丹系和美丹杜洛克则差异不显著(P 0.05)。丹系大白和长白母猪的产活仔性能优于美丹大白和长白母猪,而美丹杜洛克母猪的产活仔性能则强于丹系杜洛克母猪。研究为品系的培育提供了一定参考依据。     

靖远某猪场母猪繁殖性能统计分析

母猪繁殖力是影响种猪场经济效益的重要因素。文章对靖远某猪场大白猪、长白猪、杜洛克猪的1 200窝产仔记录进行统计分析,对总产仔数、总活仔数、初生窝重、共3个繁殖性状进行单因素方差分析,分析胎次和品种对母猪繁殖性能的影响。结果表明,胎次对总产仔数、总活仔数、初生窝重的影响极显著(P0.01),而且3个品种的母猪均表现出第一胎产仔数低,2~6胎产仔数最高,7胎以后产仔数开始下降,11胎以上产仔数最低;品种对总活仔数、初生窝重的影响不显著(P0.05),对总产仔数影响极显著,其中大白母猪显著高于长白和杜洛克,杜洛克和长白差异不显著(P0.05)。研究结果为降低非传染性因素造成的种母猪产仔数低的问题以及种猪场对母猪繁殖力的选育提高提供了参考数据和理论依据。     

胎次与配种季节对丹系大白母猪繁殖性能的影响研究

通过对广西扬翔某猪场1 314头丹系大白母猪的生产数据进行统计,并从不同配种胎次和不同配种季节对繁殖性能数据进行分析。结果表明:丹系大白母猪的总产仔数、产活仔数、初生窝重、初生个体重随着胎次的增加逐渐增加到一个最大值后减小。总产仔数和产活仔数在第4胎达到高峰,总仔为17.98头,活仔为16.06头,之后随着胎次增加繁殖性能逐步下降。初生窝重和初生个体重在第3胎达到高峰,初生窝重为20.95 kg,初生个体重为1.37 kg。冬季配种的母猪产活仔数最多,初生窝重最重;夏季配种的母猪产活仔数最少,初生窝重最轻。     

Accounting for lactation length and weaning-to-conception interval in genetic evaluations for litter size in swine

Effects of lactation length and weaning-to-conception interval on the subsequent litter size of purebred sows were estimated using an animal model. Data on 2,847 Landrace sows with 7,125 litters born between January 1989 and May 1997 and on 1,234 Yorkshire sows with 2,999 litters born between January 1990 and May 1997 were obtained from two Canadian selection herds. Sows having a lactation of less than 14 d (MMEW) were usually not mated until their second estrus, whereas sows weaned after at least 14 d of lactation (later weaning) were usually mated on their first estrus. Litter size included both number of pigs born alive and those stillborn. Linear, quadratic, and logarithmic effects of lactation length were tested. The effect of weaning-to-conception interval on litter size was modeled using an approach based on threshold variables and an approach using segmented polynomials. Results indicated linear and logarithmic effects of lactation length on subsequent litter size for Yorkshire and Landrace breeds, respectively. Litter size decreased as weaning-to-conception interval increased up to 7 and 10 d for Yorkshire and Landrace, respectively, then increased with further increases in weaning-to-conception interval up to 35 and 30 d for the two breeds, and then remained constant. The MMEW sows did not have lower subsequent litter sizes than later-weaned sows because the negative effect of a shorter lactation was offset by the positive effect of a longer weaning-to-conception interval. However, average time spent open per parity was longer for MMEW sows than for later-weaned sows. Both lactation length and weaning-to-conception interval should be considered in models for the genetic evaluation of litter size in purebred swine. Segmented polynomials can be used to predict litter size as a continuous function of weaning-to-conception interval or to derive weaning-to-conception interval adjustment factors for litter size.     

猪三元杂交体系中不同二元母本繁殖性能的研究

利用长×约7头,长×杜7头杂交母猪分别与杜洛克和大约克公猪生产三元杂交猪,着重研究约×(长×杜),杜×(长×约)三元杂交体系中,长×杜和长×约杂交母猪的繁蕴性能。研究表明:长×约、长×杜杂交母猪繁殖性能各指标均达到较好水平,第二胎产仔数、泌乳力(21日龄窝重)、断奶窝重,二组合分别达到13.5和11.75头、61.83和60.28kg、130.53和130.51kg。综合繁殖性能各指标,长×约杂交母本优于长×杜母本,特别是在产仔性能上长×约母本表现突出。因此,杜×(长×约)应是三元杂交猪推广的首选组合。约×(长×杜)组合中长×杜母本繁殖性能表现不差,三元后代哺乳期长势较好,终端父本约克夏猪适应能力强,毛色易于农户接受并与以往的杂交生产具备兼容性,也不失一个良好的杂交组合。     

不同配种模式对二元母猪繁殖性能的影响

为探讨不同配种方式对二元母猪产仔数的影响,以杜洛克猪、长白猪、大白猪、皮特兰猪四个品种公猪精液采用人工授精的方法对11654头长大二元母猪配种,对所产11654窝总产仔数、窝产活仔数、窝损失等进行统计和分析,分析不同配种模式对二元母猪繁殖性能的影响。结果表明,配种次数、不同品种公猪组合配种对二元母猪总产仔数、产活仔数以及窝损失均无显著影响（P〉0.05）,但杜洛克公猪所配二元母猪的总产仔数和窝产仔数均高于大白和长白猪（P〈0.05）;采用长×杜×大组合配种的二元母猪总产仔数和窝产活仔数均高于其它三种组合。试验结果表明,在生产中,可在长白、大白、杜洛克猪中任选两个品种,通过二次配种的方式提高母猪的产仔数。     

猪FSHβ基因多态性及其与产仔性能的相关性分析

以518头母猪（含杜洛克、长白、大白）为研究对象,以FSHβ基因为候选基因,采用PCR产物直接电泳法检测FSHβ基因位点的多态性。检出3种基因型,分剐为AA、AB、BB基因型。将基因座不同基因型与总产仔数和产活仔数进行关联分析,结果表明．FSHβ基因在杜洛克、长白猪、大白猪中主要以胎基因型形式存在,曰基因频率分别为96．67％、73．36％和86．01％．但对产仔数影响不显著（P〉0．05）。不同基因型的猪头胎产仔数差异不显著（P〉0．05）,不同基因型对总产仔数的影响差异不显著（P〉0．05）。总体而言,FSHβ基因在该位点的多态性与这3个猪种的头胎产仔数、总产仔数均无显著联系。     

Economic evaluation of alternative crossbreeding systems involving four breeds of swine. II. System efficiency

A static, deterministic computer model was used to calculate production efficiency (cost per kg of product) for four purebred and 69 alternative crossbreeding systems involving the Duroc, Yorkshire, Landrace and Spotted breeds of swine. Crossbreeding systems were defined as including all purebred, crossbred and commercial matings necessary to maintain a total of 10,000 farrowings. Driving variables for the model were predicted mean conception rates, litter size born, preweaning survival rate, postweaning average daily gain, feed-to-gain ratio and carcass backfat. Predictions were computed using breed effect and heterosis estimates obtained from experimental data involving the four breeds collected at the Oklahoma Agricultural Experiment Station between 1976 and 1979. The most efficient breed combinations for each of the nine types of crossbreeding systems evaluated were predicted to reduce cost per kg of product by 6.7 to 10.5%, relative to the most efficient purebred (Duroc). The Duroc X (Yorkshire, Landrace, Spotted) four-breed rotaterminal was predicted to be the most efficient system, followed by the Duroc X (Yorkshire, Landrace) rotaterminal. Duroc X (Spotted X Landrace) and Duroc X (Spotted X Yorkshire) static systems ranked third and fourth overall, respectively. Sensitivity analysis indicated that ranking of systems predicted to be most efficient under the default model was reasonably robust to varying input economic, genetic and management parameter values. Results of this study suggested that three- or four-breed rotaterminal or static systems should maximize effective use of heterosis and breed complementarity in swine production systems.     

农户饲养LY(长大)母猪调查报告

本调查主要对农户饲养LY(长大)母猪进行了调查,为在农村条件下大面积饲养LY母猪提供科学依据.调查结果显示,LY母猪可以在农村务件下大面积饲养,其生产性能有较佳表现.LY母猪初产仔数达9.9头,60日龄头平重达25.2kg,与种猪场饲养的纯种长白、大约克相近.经产母猪产仔数达12头,略高于种猪场纯种长白、大约克,60日龄头平重24.7kg.     

Production traits of litters in 2 crossbred Duroc pig lines

Genetics of different pig lines affects litter size, birth weight, and neonatal losses. Low birth weight has long been associated with neonatal losses, but piglet body mass index is reported to show stronger correlation with stillbirth. The aim of this study was to investigate differences in litter size, number of stillborn piglets, piglet BW gain, and body mass index between 2 different Duroc crossbred lines. Landrace × Yorkshire sows in 2 farms (n = 89) were divided into 2 groups on each farm. One group of sows on each farm was inseminated with semen from Landrace × Duroc boars (boar group LD, n = 48), and the other was inseminated with semen from purebred Duroc boars (boar group DD, n = 41). Piglets were monitored from birth to weaning at the age of 5 wk. Litter size in boar group LD was larger than in boar group DD (P = 0.03). Number of stillborn piglets in boar group LD tended to be greater than in boar group DD (P = 0.07). Piglets in boar group DD had a greater BW at birth (P = 0.02) and at 3 wk (P = 0.01) than those in boar group LD. Body mass index from birth to weaning was greater in piglets in boar group DD vs. LD (P < 0.01), and both BW and body mass index of liveborn piglets at birth for both groups combined showed a positive correlation with survival at weaning (P < 0.01). In conclusion, breeding for larger litter size in boar group DD may be one approach to increase the number of vigorous piglets in production, but the inverse relationship between litter size and birth weight was more pronounced for this group than for boar group LD (P = 0.03). Further studies of the impact of litter size on BW gain are necessary before a final conclusion can be reached.     

Breed differences in return to estrus after PGF2 alpha-induced abortions in swine

Fifty-seven Duroc, 41 Landrace and 38 Yorkshire purebred sows in d 10 to 53 of pregnancy were aborted to synchronize estrus by using prostaglandin F2 alpha (PGF2 alpha). Breed differences in time between injection of two 10-mg doses of PGF2 alpha and return to estrus were observed in these three breeds of pregnant sows during two breeding seasons. Duroc sows returned to estrus .9 d faster (P less than .01) than Yorkshire and 1.3 d faster (P less than .01) than Landrace sows. Seasonal differences were also observed. The mean days from injection to estrus were 1.8 d fewer (P less than .01) for the spring season than in the fall season. All sows expressed estrus 5 to 11 d after injection. Normal gestation, parturition and piglet survival were observed in the sows after the treatment. Genetic differences in response to induced abortion and return to estrus could have implications in planned breeding and farrowing systems.     

Effects of genetic line and supplemental dietary fat on lactation performance of Duroc and Landrace sows.

A total of 124 Duroc and 99 Landrace primiparous and multiparous sows were assigned, within breed and contemporary group, to control (N) or 10% added fat (F) diets on d 105 of gestation based on parity and genetic line (control or selected for improved sow productivity), to determine the effects of genetic line and fat addition to the lactation diet on sow and litter performance. Weekly feed intake was not affected (P greater than .10) by genetic line for Duroc and Landrace sows but feed intake was reduced (P = .08) during wk 1 to 4 for Duroc sows and during wk 1 and 4 for Landrace sows (P less than .05) when they were fed diet F compared with diet N. Select (S)-line Duroc and Landrace sows lost more weight during lactation (P less than .01) than did control (C)-line sows. Select-line Landrace sows lost more backfat during lactation (P less than .05) than did C-line sows. Landrace sows lost less weight during lactation (P less than .05) when fed diet F than when fed diet N. The total number of pigs born, born alive, and alive at 21 d and at weaning were higher (P less than .01) for S-line Duroc sows, and litter size at 21 d and at weaning was higher (P less than .01) for S-line Landrace sows than for C-line litters within each breed. Pig survival from birth to weaning was increased (P = .07) for Duroc sows fed diet F but not for Landrace sows.(ABSTRACT TRUNCATED AT 250 WORDS)