提高外二杂母猪繁殖率综合技术初探

四川省什邡市现有LY、YL二杂母猪8000余头，占全市母猪总数的40％，其中采用提高外二杂母猪繁殖率综合技术的有3500头，推广面占外二杂母猪的81．3％，改造圈舍1625个，涉及1020个场户。通过对8个重点场户的460头外二杂母猪的跟踪观察，发现在推广本综合技术后，母猪受精率达90．3％，母猪年产仔17．8头。     

畜牧科技助农增收两项技术要点

瘦肉型猪是指商品猪体重达90～110k时,屠宰后,胴体瘦肉率达55％以上的肉猪。如用杜洛克、大约克、长白公猪或瘦肉猪配套系的终端父本与长本、约本、约长、长约等二杂母猪或瘦肉型配套系的母猪配种,所产的商品猪(包括外二杂商品瘦肉猪)都叫瘦肉型肉猪。     

如何提高农村二杂母猪"三率"

农村散养二杂母猪普遍存在配种难、受孕率低、产仔率不高的问题，严重影响了农民养猪积极性。笔根据近三年工作的实践经验，对解决农村散养二杂种母猪“三率”进行的探讨，提出的解决措施供养猪生产户参考。[第一段]     

提高二杂母猪繁殖力的配套技术

１改建圈舍农村传统的猪舍大多空间面积小，光线阴暗，配套设施不完善，不适应二杂母猪的饲养管理和繁殖配种。因此，我们对二杂母猪的圈舍组织开展了规范化的改建。改建的标准为：通风、向阳、光线充足；猪舍面积７～８m２，运动场地面积５～６m２，配套设置仔猪补饲间；地面一般采用石板，坡度２％～３％，防滑、防湿、保暖。２推广发情鉴定适时输精技术杂交母猪一般９～１１月龄、体重达９０kg左右时开始配种，成年杂交母猪每隔２１d左右出现一次发情，但发情症状普遍不如本地母猪明显，须仔细观察。其发情症状为：表现不安，食欲减退，…     

南方农村条件下PIC300配套系公猪杂交效果研究

选择PIC300配套系公猪分别与普杂母猪、洋二元母猪、新荣昌Ⅰ系母猪进行杂交,在南方农村条件下,分别测定3个杂交组合的繁殖性能及其后代的生长肥育性能、胴体品质和肉质。结果表明,3个杂交组合各项性能优良,证明PIC300配套系公猪是南方农村条件下进行经济杂交的优良父本。     

关于杂交母猪的配种技术的分析

随着生猪良种补贴项目的实施,地方民间公猪几乎绝迹,农村的母猪由本地的地方品种转变成了长内、长太等内二杂品种.大家总觉得杂交母猪的配种很难掌握,这里谈谈二杂母猪的配种技术.     

长大、长本和内江母猪繁殖成绩调查分析

本研究调查了97头农民散养哺乳母猪（其中长大二杂母猪33头,长本二杂母猪33头,内江母猪31头）的繁殖成绩,结果表明,在窝产间隔、窝产仔数、产活仔数、断奶窝重上,长本二杂母猪、内江母猪表现正常,长大二杂母猪在断奶窝重上表现较好成绩,但其余3项指标差,存在着严重的繁殖障碍,问题在于圈舍规划不合理、营养水平不科学和饲养管理技术不成熟.     

正确掌握现代瘦肉型母猪断奶前后的饲养水平

广泛被用作母系的现代长白、大白及其二元杂种母猪以及配套系母猪、具有显著的种性特点：1）产仔多、泌乳量高、仔猪生长快，因而对养分需要多；2）但其体脂肪少，能量储备少；3）所以，它很容易发生能量和营养物质摄取不足，并且反应非常敏感。此即现代瘦肉型母猪的饲养不可与本地母猪和土杂母猪等同对待的理由。     

杂种母猪繁殖性能调查

利用三元杂交是提高农户养猪生产水平的主要措施。但农户普遍反映二杂母猪发情征兆不明显,鉴定较难,配种受胎率低等。本文探讨了二杂母猪的发情排卵规律,提高其生产性能和经济效益,有利于二杂母猪的进一步推广。     

广花猪及杂交母猪的繁殖性能简介

我们从1981年开始,用大花白猪和长白猪育成我省新品系——广花猪,其生长速度和饲料转化率均比大花白猪有较大提高;在选育同时我们还进行了杂交配套利用的研究,统计1985年至1991年的资料,广花母猪与其二元杂、三元杂母猪的繁殖性能如下:     

农村示范户肉猪肥育性能观察研究

对项目承担县(市、区)的肉猪进行了肥育性能观察测定。结果如下：配套系杂优猪、外种猪的杂种肉猪、含地方猪血缘的三杂内猪、含地方猪血缘的二杂内猪的日增重分别为724、733、635、562g；达100kg体重日龄分别为175、168、178、192.3d；耗料指数分别为3.25、3．07、3．25、3.56；瘦肉率分别为61．26％、63．29％、56．47％、47．80％。并对其结果进行比较分析。表明项目推广的优质内猪组合在农村条件下表现了良好的生产成绩，具有推广的价值和可行性．应大力推广。     

不同品种或组合猪多产性研究

本文以 1 2个品种或组合猪为研究对象 ,收集了其 1胎、2胎及经产共 42 6 9窝产仔数和产活仔数的数据资料。纯种猪混合胎次窝产仔数以四川白猪Ⅰ系为最高 ,产仔数和产活仔数分别为 1 1 6 1头和 1 0 71头 ,本地猪、杜洛克猪和长白猪居中 ,分别为 1 0 86头和 1 0 0 6头、1 0 0 7头和 9 33头、9 85头和 9 2 6头 ,大白猪的产仔数和产活仔数最低 ,分别为 9 34头和 8 87头。二杂母猪的窝仔数以DL、DI、YI、DY较高 ,其产仔数和产活仔数分别为 1 1 4 9头和 1 0 80头、1 1 4 8头和 1 0 38头、1 1 36头和 1 0 4 5头、1 0 89头和 1 0 89头 ,YL、YB较低 ,分别为 1 0 2 7头和 9 6 5头、1 0 1 8头和 9 84头。二杂母猪产仔数和产活仔数的平均杂种优势率分别为 8 2 6 %和 9 4 1 % ,其中DL、DI、DY3个组合产仔数和产活仔数的平均杂种优势率分别为 1 1 1 4 %和 1 3 1 3% ,TI、YL、YB相应为 5 39%和 5 6 8%。     

Genetic relationship between purebred and crossbred sow longevity

Background: The overall breeding objective for a nucleus swine selection program is to improve crossbred commercial performance. Most genetic improvement programs are based on an assumed high degree of positive relationship between purebred performance in a nucleus herd and their relatives' crossbred performance in a commercial herd. The objective of this study was to examine the relationship between purebred and crossbred sow longevity performance. Sow longevity was defined as a binary trait with a success occurring if a sow remained in the herd for a certain number of parities and including the cumulative number born alive as a measure of reproductive success. Heritabilities, genetic correlations, and phenotypic correlations were estimated using THRGIBBS1F90.Results: Results indicated little to no genetic correlations between crossbred and purebred reproductive traits.This indicates that selection for longevity or lifetime performance at the nucleus level may not result in improved longevity and lifetime performance at the crossbred level. Early parity performance was highly correlated with lifetime performance indicating that an indicator trait at an early parity could be used to predict lifetime performance. This would allow a sow to have her own record for the selection trait before she has been removed from the herd.Conclusions: Results from this study aid in quantifying the relationship between purebred and crossbred performance and provide information for genetic companies to consider when developing a selection program where the objective is to improve crossbred sow performance. Utilizing crossbred records in a selection program would be the best way to improve crossbred sow productivity.     

Impact of dominance effects on sow longevity

The purpose of the current study was to estimate variance components, especially dominance genetic variation, for overall leg action, length of productive life and sow stayability until third and fifth parity in the Finnish pig populations. The variance components were estimated in two purebred [Landrace (LR), n = 23 602 and Large White (LW), n =22 984] and crossbred (LR × LW, n = 17 440) data sets. Five different analyses were carried out for all the traits to compare the effect of sows’ inbreeding, common litter environment and parental dominance in the statistical model when determining the genetic correlations of the traits for the two purebred and crossbred populations. Estimated heritabilities for the traits ranged from 0.04 to 0.06. The estimates for the proportion of dominance variance of phenotypic variance (d²) varied between 0.01 and 0.17, and was highest in the crossbred dataset. The genetic correlations of the same traits in purebred and crossbred were all high (>0.75). Based on current results, the effect of dominance should be accounted for in the breeding value estimation of sow longevity, especially when data from crossbred animals are included in the analyses. Because dominance genetic variation for sow longevity exists that variation should be utilized through planned matings in producing sows for commercial production.     

两种饲喂方式对哺乳母猪生产性能的影响研究

选取年龄、胎次、品种基本一致的哺乳母猪20头,随机分成对照组和试验组,试验分两批进行,每批10头。在相同的环境条件下,母猪自由饮水,饲喂同一哺乳母猪料。母猪分娩后4d内,采用原场饲养制度,逐步增加哺乳母猪采食量,第5天开始,对照组采用不限量饲喂,试验组采用限量和添加哺乳母猪补充料的饲喂方式,仔猪21日龄断奶。结果显示:两组仔猪21日龄的断奶窝重、母猪断奶后再发情时间和母猪哺乳失重等差异均不显著(P>0.05)。     

RYRl基因对母猪繁殖性能的影响

用 PCR- RFL P法检测 2 2 5头大约克母猪的 RYR1(ryanodine receptor,RYR1)基因 ,它具有 NN、Nn和 nn3种基因型 ,其频率分别为 0 .76、0 .14和 0 .10 ;等位基因 N和 n的基因频率分别为 0 .83和 0 .17。该基因处于遗传不平衡状态 (P<0 .0 1)。具有 NN、Nn和 nn基因型母猪第 1胎产仔数分别为 10 .2 1、9.6 2和 8.2 2头 ;断奶仔猪数分别为9.2 1、8.13和 7.11头。等位基因 n使仔猪断奶应激效应具上升趋势 ,对增重有不利影响 ;降低母猪的产仔数和仔猪成活率 ,对繁殖性能有不良的遗传效应 ,有必要从母猪群中清除该等位基因。     

Effect of Early Weaning,Split-Weaning and Nursery Feeding Programmes on the Growth of Landrace×Desi Pigs

An experiment using 164 crossbred pigs born to 20 first-parity sows was conducted to evaluate the growth performance of piglets in four weaning management regimens: T1, conventional weaning at 56 days; T2, early weaning at 28 days; T3, split-weaning of the heavier half of the litter at day 28, the remaining half being weaned at 56 days; and T4, split-weaning of the lighter half of the litter at 28 days, with the animals kept on a special nutrient diet up to 56 days, and the heavier half being weaned at 56 days. Split-weaning of the lighter half in combination with feeding a special nutrient diet resulted in an increase of average daily gain of 21% from day 28 to day 140 compared to conventional weaning and of 36% compared to early weaning at day 28. Compared to the control (T1), the average weights of piglets at the 140th day in groups T4 and T3 were 19.6% and 6.16%, respectively, higher, whereas that of the T2 was 8% lower. It is concluded that feeding a special nutrient diet to lighter pigs is beneficial in overcoming the post-weaning lag and enables maximal weight gain.     

Factors to adjust litter weight of pigs to a standard 21 days of age

Factors to standardize litter weights of nursing pigs to 21 d of age were calculated from daily weights measured on 64 crossbred litters from 10 to 32 d of age. The results were compared to published factors derived from a data set of Duroc pigs weighed every 3 to 4 d. Dams in the present study were white crossbred sows and gilts, and sires were maternal or terminal breed types. Multiplicative factors were calculated by dividing the mean 21-d litter weight (LW21) by mean daily litter weight. Linear and quadratic regression coefficients of LW21 on age at weighing were fitted to the factors (R2 = .997). The final equation for adjusting litter weights to a 21-d basis was 2.5246 - .1041 x (d of age) + .0015 x (d of age)2. There were good agreement with published factors for d 19 to 25, but divergence for younger and older litters resulted in significant differences between the linear coefficients. These differences may be due to departure from a linear growth curve, which daily measurements would incorporate, or differences in sow populations. Thus, use of the new factors should be considered for white crossbred sow populations. A least squares analysis indicated that LW21 was significantly altered by parity, not by the number of pigs allowed to nurse or by breed of sire. After adjustment to 21 d, litter weights also should be adjusted for differences in parity before evaluating sow productivity, by using additive factors such as those recommended by the National Swine Improvement Federation.     

我国母猪生产现状及酵母培养物对母猪生产性能的影响

作者通过应用酵母培养物饲料添加剂饲喂哺乳母猪的试验研究,结果发现酵母培养物能够改善母猪窝产活仔数、仔猪断奶重、哺乳期间仔猪成活率等生产性能,同时与前人的研究报告做了对比,其试验结果具有相似之处。因此,本试验具有指导生产实践,提高母猪生产效率及猪场经济效益的作用。     

秦川牛改良神木当地牛效果调查研究

秦川牛是我国优良的地方黄牛品种之一。用秦川牛改良土种牛（蒙古牛），其改良后代体格变大，变结实，役用性增强，并且产肉性、早熟性提高。通过改良，经济效益和社会效益显著提高，改良1、2代效果最好。