繁殖性状的杂种优势与基因效应分析

测定杜长大三元杂交体系和斯格配套系各杂交组合的繁殖性能,计算出繁殖性状的杂种优势率;选用5个与繁殖性状紧密连锁的微卫星标记对测定个体进行基因型检测,利用混合效应线性模型计算出繁殖性状各位点的基因效应。结果表明:斯格祖代猪与父母代猪产仔数、产活仔数、断奶仔数、断奶窝重的差异均达到极显著水平(P<0.01),父母代猪与祖代猪的初生窝重差异显著(P<0.05),斯格父母代猪的产仔数、产活仔数、断奶仔数和断奶窝重与长大母猪的差异均达到极显著水平(P<0.01),斯格父母代猪与长大母猪的初生窝重差异显著(P<0.05),初生重、断奶重杂优率低,其余各性状的杂种优势率处于较高水平。显性效应在初生窝重、断奶窝重的杂种优势中起着很重要作用,加性效应是初生重和断奶重杂种优势的主要遗传学基础,产仔数、产活仔数、断奶仔数的杂种优势的产生存在上位效应。     

N-乙酰半胱氨酸对猪肠道功能的保护作用

动物的肠道完整性在营养、代谢和机体内环境稳定中起着非常重要的作用,是机体抵御内源性和外源性有害物质的第一道屏障.肠上皮细胞的完整性是保障肠道功能的生理基础,肠上皮受损会影响营养物质的吸收,从而降低生产性能和影响动物的健康.N-乙酰半胱氨酸(NAC)是L-半胱氨酸与还原型谷胱甘肽(GSH)的前体物质,NAC的生理功能和应用效果在很大程度上与维持细胞内的GSH水平有关.饲粮中添加NAC可以缓解脂多糖应激引起的肠黏膜损伤、乙酸刺激引起的结肠炎及改善小肠吸收功能,这些与NAC促进表皮生长因子的生成、抗黏膜细胞凋亡和促进紧密连接蛋白表达有关.本文就NAC对猪肠道功能的保护作用相关研究作一综述.     

陕西省生猪规模养殖成本调查分析

通过对陕西省生猪规模养殖场户生产数据的分析,研究生猪规模养殖成本的构成,对控制生猪养殖成本提供依据,从成本投入的角度分析陕西适宜的生猪养殖规模,揭示规模化和专业化是生猪养殖的发展方向,提出推进规模化养殖的建议.     

广西规模化猪场2种主要排污模式的指标测定

应用常规的化学分析技术,测定了广西地区具有代表性的2个规模化猪场不同污水处理阶段的污染物含量,并与国家排放标准进行比较,研究每个处理环节污染指数的变化,从而为畜牧养殖业节能减排采取针对性的整改措施提供参考。污染物指标包括:悬浮物(SS)、氨氮(NH3-N)、五日生化需氧量(BOD5)和化学耗氧量(CODcr)。结果表明,2个规模化猪场排出的污水经过一定的污水处理工艺后,猪场1排放的污水不达标,猪场2排放的污水达标;植物塘对污水有明显的净化作用;沉淀调节池和二沉池环节都能有效降低悬浮物(SS)的指标。     

丹麦有机猪的生产和养猪业沙门氏菌的控制

本文介绍了丹麦有机猪的生产情况(有机猪的品种、畜舍环境和条件、畜舍卫生和饲养饲料状况)、沙门氏菌控制计划的情况(饲料、种猪群、断奶仔猪群、育肥猪群和屠宰场的监控)和效果。同时,简析了我国发展有机畜牧业的必要性,最后提出实行危害分析和关键控制点(HACCP)预防管理体系和有机养殖是我国养猪业的发展方向。     

Evaluation of smallholder pig production systems in North Vietnam: Pig production management and pig performances

This study investigated the productive adaptability of pig breeds under different smallholder production conditions in Vietnam, comparing an indigenous with a Vietnamese improved breed. Fieldwork was conducted in four villages with different remoteness in North Vietnam from 2001 to 2002, in 64 households keeping the improved Mong Cai or indigenous Ban as sow breeds and progeny for fattening. Four visits per farm yielded 234 structured interviews. Reproductive performances were derived from 135 litters. Individual weights of pigs (n = 755) were obtained. Data were analysed by regression, linear and generalised linear, especially loglinear models.

Two distinct pig production systems were identified, that differed in remoteness, market access, resource availability, distribution of pig breeds and pig production intensity. Higher performances of 1.4 and 1.5 litters year^− 1, 8.4 and 8.4 piglets weaned litter^− 1, 66.6 and 93.0 kg piglets weaned sow^− 1 year^− 1, and 136 and 177 g day^− 1 ADG were found in two villages near town with semi-intensive production conditions and a high rate of improved Mong Cai sows and MC and LW × MC offspring in the observed population. Lower performances of 1.1 and 1.1 litters year^− 1, 4.6 and 5.5 piglets weaned litter^− 1, 20.5 and 30.9 kg piglets weaned sow^− 1 year^− 1, and 66 and 85 g day^− 1 ADG were observed in parallel to higher incidences of indigenous Ban pigs away from town under extensive conditions. Total live weight offtake per household per year was higher near town and in one village distant to town. MC and LW × MC remained even under demand-driven conditions below the performance potential reported for improved genotypes. Under resource-driven conditions with a saving-oriented production pattern, the higher-yielding but more demanding Mong Cai might not be an efficient production alternative as a further performance reduction can be assumed. A considerable live weight output was observed under resource-driven conditions and with a higher percentage of crossbred LW × Ban offspring in the population, possibly representing a promising production alternative. Factors influencing the performance expression of pigs, and the suitability of different methods for the assessment of performance parameters on-farm are discussed.     

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.     

猪血凝性脑脊髓炎病毒抗体的调查

应用血凝和血凝抑制试验检测了从吉林省部分地区采集的猪血清中血凝性脑脊髓炎病毒（HEV）抗体。结果，212份样品中有94份呈现HEV抗体阳性反应，阳性率高达44．3％。被采集血清的猪未表现临床症状，说明该地区的猪群中存在HEV隐性感染。     

Farming strategies in organic dairy farming: Effects on breeding goal and choice of breed. An explorative study

Organic farming principles give rise to multifunctionality: different activities are combined at farm level to create ecological and economic synergies. These principles do however allow for different operationalisations and different farm development strategies, for example with regard to the use of external inputs or the decision whether or not to use advanced breeding technologies such as artificial insemination. Maintaining and improving diversity are therefore characteristic to organic farming. Since organic farming took off in the early 1990 s, many specialised dairy farms which tend to be more mono-functional in nature, have converted to organic, adding a new farming strategy to the diverse collection of farming strategies in organic dairy farming. All these farming strategies actually create different organic production environments for cows, which might result in different demands on selective breeding and breeding technology. This differential demand was explored in a survey, among 151 organic dairy farmers, on general farm strategy, milk production, breeding goal, choice of breed and approach to reproduction. Farmers were divided into one of two groups on each of three strategic options: a) diversification in farm business—Specialised Dairy Farming vs. Multifunctional Farming; b) intensity of milk production—Low Input vs. High Input Farming and c) naturalness of breeding—Farming with Artificial Insemination vs. Farming with Natural Service.A pair-wise comparison within each strategic option showed that each pair differed significantly with regard to farm characteristics, farm goal and animal production goals. However, there were only minor or no significant differences within each pair with regard to overall breeding goal. For each strategic option, big differences were found within each pair as regards preferred cattle breeds and crossbreeds. Farmers in the Specialised Dairy Farming and High Input Farming groups preferred milk-type cattle (Holstein and Holstein crossbreeds), while farmers in the Multifunctional Farming and Low Input Farming groups preferred various native Dutch breeds. But even farmers with a similar strategy (within one group) differed strongly in their choice of breeds and crossbreeds. These results indicate that organic farmers are going through process of learning by doing, experimenting as they search for breeds or crossbreeds that are optimally suited to their farm environment and that best agree with their farm development strategy. In this, the growing preference for keeping bulls on the farm for natural service is remarkable.