The effects of halothane sensitivity on carcass composition and meat quality in HAL-1843-normal pigs

Objectives of this study were to determine the incidence of halothane sensitivity in pigs that are homozygous normal at the ryanodine receptor nucleotide 1843 (HAL-1843-normal) and the relationships between halothane sensitivity and carcass composition or meat quality. In Exp. 1, piglets (Lines A, B, C, and D; n = 168, 170, 168, and 169, respectively) were obtained from mating a HAL-1843-normal sire line to four HAL-1843-normal dam lines. In Exp. 2, piglets from Lines A and B (n = 87 and 90, respectively) were included with piglets (Lines E, F, G, and H; n = 94, 92, 89, and 89, respectively) obtained from mating four HAL-1843-normal sire lines to a single HAL-1843-normal dam line. Pigs were subjected to 3% halothane at approximately 9 wk of age. In Exp. 1, limb rigidity, blotching of the skin, and muscle tremors were visually assessed, and based on these criteria, halothane sensitivity (HS) was observed in 48% of the pigs. To better characterize this response, a scoring system was developed and used in Exp. 2. Using this system, 25, 42, and 33% of the pigs in E and 40, 33, and 27% of the pigs in Line G were categorized as HS-low (HS-L), HS-intermediate (HS-I), and HS-high (HS-H), respectively. In Lines F and H, 13 and 18% of the pigs were HS-I, and 0 and 2% were HS-H, respectively. No consistent effects due to HS were observed in carcass composition or meat quality; however, when a subset of pigs from Exp. 2 were subjected to more extensive handling and transportation before slaughter, ultimate pH was lower and drip loss was higher in LM from HS-H compared with HS-L pigs (P < 0.05; n = 71). These results demonstrate that some pigs are sensitive to halothane anesthesia even in the absence of the known HAL-1843 polymorphism. Additionally, halothane sensitivity may be associated with inferior pork quality under adverse antemortem conditions.     

Health of non-ambulatory, non-injured pigs at processing

Loss of pigs during or after transport is a welfare concern, but also an economic concern for producers. Transport losses include animals that are dead on arrival (DOA) at the plant, pigs that are injured, and pigs which are not obviously injured but unwilling or unable to walk (non-ambulatory, non-injured or NANI). The objective of this research was to assess the health of non-ambulatory, non-injured (NANI) pigs relative to control pigs at the processing plant by looking at a range of measures, including complete blood chemistry, anatomy, and pathology to determine potential factors associated with pigs going down. Data were collected from NANI and control pigs at five plants in the midwest USA. Feet and legs and internal organs were inspected and the severity of the pathology scored. Alveolar macrophages were collected and counted. Blood was collected for analysis of hematology, blood chemistry and cortisol concentrations. Titers to common porcine respiratory viruses were measured in pigs from one plant. Hoof and pad problems did not differ overall between control and NANI pigs, however the percentage of severe foot problems was greater (P < 0.05) in NANI compared with control pigs at plants A and E. The percentage of total ulcers, rhinitis, and empty stomachs differed (P < 0.05) between control and NANI pigs at individual plants, but not overall. Blood hematology and chemistry differed (P < 0.05) between NANI and control pigs. Cortisol concentrations did not differ between NANI and control pigs. Titers to swine influenza virus (SIV) H1N1 and H3N2 and porcine circovirus (PCV) were lower (P < 0.01) among NANI compared with control pigs. However, more (P < 0.01) NANI pigs were positive for SIV H1N1 and H3N2 compared with control pigs. Blood hematology, chemistry, and pathology indicate a large difference between NANI and controls pigs. No single health problem was higher among NANI pigs compared to plant-matched control pigs. Rather, several problems appear to contribute to pigs becoming NANI which may differ from one plant too another.     

Some observations on the liver copper status of pigs in the northern part of New Zealand

The copper content of the livers from 347 pigs was analysed. Two hundred and three of these samples were from animals varying in age from full term foetus to five years, which were submitted to the laboratory (laboratory cases) for a variety of diagnostic tests. The remaining 144 liver samples were obtained from pigs slaughtered at an abattoir (abattoir survey) at 75-85 kg liveweight (approximately 20-30 weeks old). Liver copper levels of 12 mg/kg D.M. (Dry Matter) or less, a level consistent with copper deficiency, were found in 6.9% of the laboratory cases and in 9.0% of the abattoir survey pigs. Liver levels less than 20 mg/kg suggesting insufficient dietary copper to produce a growth-promoting effect, were found in 21.6% of the former and 36.1% of the latter pigs. A significantly greater frequency of illthrift and anaemia was found in the laboratory cases in which liver copper levels were less than 20 mg/kg compared with animals with higher levels. Liver copper levels less than 20 mg/kg were also more common in pigs derived from dairy farms or fed garbage than in animals from pig farms or fed on meal. All of 26 samples of commercial pig meal analysed contained sufficient copper to satisfy the daily essential copper requirements of pigs (greater than 5-6 mg/kg) but 14 of these (53.8%) contained less than 125 mg/kg levels of copper and were unlikely to produce a growth-promoting effect.     

Some observations on the liver copper status of pigs in the northern part of New Zealand

The copper content of the livers from 347 pigs was analysed. Two hundred and three of these samples were from animals varying in age from full term foetus to five years, which were submitted to the laboratory (laboratory cases) for a variety of diagnostic tests. The remaining 144 liver samples were obtained from pigs slaughtered at an abattoir (abattoir survey) at 75-S kg liveweight (approximately 20–30 weeks old).

Liver copper levels of 12 mg/kg D.M. (Dry Matter) or less, a level consistent with copper deficiency, were found in 6.9% of the laboratory cases and in 9.0% of the abattoir survey pigs. Liver levels less than 20 mg/kg suggesting insufficient dietary copper to produce a growth-promoting effect, were found in 21.6% of the former and 36.1% of the latter pigs.

A significantly greater frequency of illthrift and anaemia was found in the laboratory cases in which liver copper levels were less than 20 mg/kg compared with animals with higher levels. Liver copper levels less than 20 mg/kg were also more common in pigs derived from dairy farms or fed garbage than in animals from pig farms or fed on meal.

All of 26 samples of commercial pig meal analysed contained sufficient copper to satisfy the daily essential copper requirements of pigs (greater than 5–6 mg/kg) but 14 of these (53.8%) contained less than 125 mg/kg levels of copper and were unlikely to produce a growth-promoting effect.     

2010年广西中小规模养猪户面临的问题调查分析

为了解广西中小规模养猪户面临的问题,以问卷形式对广西贵港、北海、玉林、柳州、南宁等地19个乡镇148个农户进行调查。结果显示20头母猪以上大户占75%,投入在5万元以上,从业多年,养猪是主要收入来源,户主多为中学文化水平,用工3～10人;5～20头母猪中户占17%,母猪在5头以下的小户占8%。大户对乳猪料认识好,用得多,占32%,但有50%的大户对价格比较敏感。农户饲养土杂猪的比例占60%,饲养快大猪占35%,纯土猪只有5%。大户的种猪多来自种猪场占25%,而小农户多数自己留种或在村里购买,占60%;对选种多数看外表占66%,15%的人会关注生产记录。普遍使用大猪场的精液,占80%。调查表明将中小规模养猪户并入产业链,统一规范管理,平衡合作农户的计酬,形成一站式服务是中小规模养猪户的发展趋势。     

中国6个地方猪种与3个外种猪氟烷基因PCR产物序列比较研究

本文应用PCR方法 ,体外扩增了中国地方猪和外种猪共 16个个体的氟烷基因 1814 9～ 1876 0位之间 6 12bp的片段 (包含完整的外显子 17和cDNAC1843 →T1843 突变位点 ) ,并进行了序列测定。结合网上下载的 5个中外猪种相同区段的序列进行了比较研究。结果表明 ,本文所测序列比网上公布的序列少 2bp ,在 1815 3,1815 4处有两胞嘧啶(C)缺失 ;皮特兰猪在cDNA的C1843 位点存在C1843 →T1843 突变 ;6 12bp的片段中共有 14个变异位点 ,皆为转换型突变 ,内含子 16中有 3个位点存在转换型杂合子 ;所有突变中 ,有 4处发生在外显子 17内 ,除香猪和皮特兰猪外均为同义突变 ;这些变异位点共形成 12种单倍型 ,其中扩增片段 5 14位 (全序列中为 186 6 2位 )的C→T突变为内江猪独有 ,构成了内江猪独特的单倍型 ,C18662 →T18662 突变具有品种特异性     

野猪、松辽黑母猪及其杂交一代多性状功能基因分子遗传标记研究

本研究旨在应用"中芯一号"家猪分子育种基因芯片了解试验猪群重要经济性状功能基因遗传变异,为选留优秀育种个体提供有效信息。选择影响猪脂肪沉积、肉质、生长、抗病和被毛表型等性状功能基因有效突变位点作为分子遗传选育标记,以野猪、松辽黑母猪及其杂交一代共计106头个体作为实验动物模型,通过"中芯一号"猪分子育种芯片检测,对试验猪不同性状功能基因有效突变位点进行统计分析。结果表明,猪脂肪沉积性状功能基因（SCD和MYH4）有效突变位点在试验猪群中全部是肌内脂肪沉积有利基因型（CC、TT）;肉质性状功能基因（PHKG1、PRKAG3和RYR1）有效突变位点,除了21头猪携带有RYR1功能基因有效突变位点对肉质性状不利的等位基因T外（杂合基因型CT）,其他个体全部为肉质性状有利基因型（CC、GG、CC）;抗病性状功能基因MUC13有效突变位点的抗病有利等位基因纯合基因型（GG）所占比例高于杂合（GA）和不利等位基因纯合基因型（AA）;生长性状功能基因（HMGA1、VRTN和CCKAR）有效突变位点检测发现,猪群中没有增加体长趋势的HMGA1突变位点的TT基因型个体,仅有1个杂合体;肋骨数功能基因VRTN有效突变位点T等位基因频率高,对个体的胸椎数有增加趋势;功能基因CCKAR有效突变位点全部是有利于增加采食及日增重的C等位基因纯合基因型;被毛表型性状KIT功能基因有效突变位点在所有检测猪个体呈现出GG基因型,说明研究猪群中不存在影响白色被毛表型的基因突变位点,与试验猪群被毛表型结果一致。以上结果为猪群进一步育种规划提供了有益信息。     

Longitudinal study on the seroprevalence of Toxoplasma gondii infection in four German pig breeding and raising farms

There are very few current data on the prevalence of Toxoplasma (T.) gondii in German pig farms. Consequently a reliable risk assessment of human Toxoplasmosis caused by ingesting raw or improperly cooked pork and pork products is not available. The aim of this study was to show current data on T. gondii prevalence in German pig farms. In four pig farms with different management systems (three conventional, one organic) 100 animals each were selected and tested for T. gondii antibodies. The test was done four times during the period from birth to slaughtering. In one farm 20 mother sows were tested additionally. The slaughtered pigs from conventional farms showed seroprevalences between 0 and 15.2% (mean value 5.6%). At the organic system T. gondii antibodies were not detected. All slaughtered seropositive pigs (6 months old) were tested negatively at the age of 9 weeks, but shortly after birth high titres of T. gondii antibodies had been detected in the same animals. Comparing the results gained in different seasons significantly more pigs were found to be infected during the autumn/winter than in the spring/summer period. In order to assess the current risk of Toxoplasmosis more pig farms should be tested. From the point of view of consumer protection the detection of highly infected pig herds is necessary.     

Effects of halothane sensitivity on mobility status and blood metabolites of HAL-1843-normal pigs after rigorous handling

The objective of this study was to determine if HAL-1843-normal pigs that respond abnormally to halothane anesthesia were more likely to become nonambulatory (NA) when subjected to rigorous handling than pigs that exhibit a normal response to halothane. After a 1,100-km transport, pigs exhibiting low (HS-L; n = 33), intermediate (HS-I; n = 10), and high (HS-H; n = 47) sensitivity to halothane were moved through a 36.6-m long aisle that was 2.1 m wide at each end and 0.6 m wide in the middle 18.3 m. Ten groups of 8 pigs were briskly moved down the aisle and back 4 times, receiving a minimum of 1 electrical prod per pass (8 prods/pig). Before testing, rectal temperature was measured, open-mouth breathing and skin discoloration were visually evaluated, and a blood sample was collected from each pig. After the test, the pigs were returned to their pens, and the same measurements were taken immediately posttest and 1 h posttest (no blood at 1 h posttest). Pigs that were HS-H were more prone to becoming NA compared with HS-L pigs (P < 0.02). Regardless of halothane status, a greater number of pigs exhibited open-mouth breathing and skin discolorations immediately posttest than at the pretest or 1 h posttest times (P < 0.05). No differences were observed in blood metabolites between the different halothane sensitivity categories. However, pigs that became NA had elevated blood levels of creatine phosphokinase, lactate, glycerol, nonesterified fatty acids, ammonia, and urea nitrogen before testing (P < 0.05). Collectively, these data suggest HS-H pigs are more susceptible to becoming NA than HS-L. The elevated pretest blood metabolites of NA pigs suggest that they were in a hypermetabolic state that predisposed them to becoming NA.     

Molecular characterization of Cryptosporidium isolates from pigs in Zaragoza (northeastern Spain)

A total of 142 stool specimens from pigs on 24 farms from the province of Zaragoza (northeastern Spain) were screened for Cryptosporidium spp. Samples were first analysed by routine techniques (formalin-ethyl acetate sedimentation method and modified Ziehl-Neelsen stain) selecting those microscopically positive for genetic characterization. Cryptosporidium species and genotypes were determined by a nested PCR-RFLP technique at the 18S ribosomal DNA locus and sequencing of the PCR-positive secondary products. Cryptosporidium oocysts were microscopically identified in the faeces of 32 pigs (22.5%) from 15 farms (62.5%). Infected animals included 23 weaned piglets (30.7%), 5 fattening pigs (11.9%) and 4 sows (16%). Diarrhoea was not detected in any of the infected pigs. The molecular characterization was successfully performed in 26 samples from 14 farms. Cryptosporidium suis was found in 10 specimens from 7 farms (nine weaned piglets and one sow) and the Cryptosporidium pig genotype II in 16 samples from 10 farms (13 weaned piglets and 3 fattening pigs). Both C. suis and the pig genotype II were concurrently detected on three farms.     

2016～2018年江苏省规模猪场PRRS血清学调查

为了解2016年1月~2018年12月期间江苏省规模猪场猪繁殖与呼吸障碍综合征(porcine reproductive and respiratory syndrome,PRRS)流行动态,本研究对该省27家规模猪场不同批次送检的2062份未免疫PRRS疫苗血清样本,采用ELISA方法进行了猪繁殖与呼吸障碍综合征病毒(Porcine reproductive and respiratory syndrome virus,PRRSV)抗体检测,并对抗体阳性率≥80%的猪群阶段,依据PRRSV抗体S/P分布频段选取135份血清,采用RT-qPCR方法检测并统计PRRSV阳性率,进行血清学调查。结果显示,27家未免疫PRRS疫苗猪场抗体总阳性率为68.82%。不同地区抗体阳性率较高的为宿迁和南通,分别为72.04%和71.09%,连云港地区最低为58.82%。2016~2018年呈现逐年下降的趋势,从76.41%下降至57.72%。不同猪群阶段中以公猪、后备母猪、12~16周龄育肥猪和18~25周龄育肥猪抗体阳性率较高,分别为80.95%、92.86%、86.84%和98.09%。在上述4个抗体阳性率≥80%的猪群阶段,RT-qPCR检测结果显示,24份PRRSV阳性血清样本C t值与抗体S/P值高低无相关性。血清中PRRSV阳性率以后备母猪最高为20.58%,在PRRSV抗体S/P值<0.4和S/P值≥2.5异常分布频段,血清PRRSV阳性率均≥15.38%,而0.4≤S/P值<2.5正常范围内PRRSV阳性率均≤10%,差异显著,具有统计学意义(P<0.05)。表明江苏省规模化猪场不同地区、不同规模和不同阶段猪群普遍存在 PRRSV 感染,该研究结果为规模猪场PRRS的防控提供了参考。     

Effects of breed, sex, and halothane genotype on fatty acid composition of pork longissimus muscle

The objective of this study was to estimate the effects of breed, sex, and halothane genotype on fatty acid composition and several fatty acid indices of lipid extracted from porcine LM. Purebred Yorkshire (n = 436), Duroc (n = 353), Hampshire (n = 218), Spotted (n = 187), Chester White (n = 173), Poland China (n = 124), Berkshire (n = 256), and Landrace (n = 187) pigs (n = 1,934; 1,128 barrows and 806 gilts) from 1991, 1992, 1994, and 2001 National Barrow Show Sire Progeny Tests were used. Pigs were classified as the HAL-1843 normal (NN) genotype (n = 1,718) or the HAL-1843 carrier (Nn) genotype (n = 216). For statistical analysis, a mixed model was used that included fixed effects of breed, sex, halothane genotype, test, slaughter date, interaction of breed x sex, and random effects of sire and dam within breed. Breed significantly affected the concentration of individual fatty acids, total lipid content, and the values of several fatty acid indices of LM. Duroc pigs had the greatest (P < 0.01) content of total SFA. Total MUFA concentration in Poland China pigs was greater (P < 0.05) than in all other breeds except the Spotted (P > 0.05). The concentrations of total PUFA were greater (P < 0.01) in Hampshire, Landrace, and Yorkshire pigs compared with those of other breeds. Significant sex differences for individual fatty acids were detected. Compared with gilts, barrows had greater (P < 0.01) concentrations of SFA and MUFA but lower (P < 0.01) total PUFA. Halothane genotype was a significant source of variation for the percentages of some fatty acids. Pigs with the carrier (Nn) genotype had lower concentrations of SFA (P < 0.05) and MUFA (P < 0.01) but a greater concentration of PUFA (P < 0.01) compared with NN pigs. There were significant negative correlations between total lipid content and individual PUFA and significant positive correlations between lipid concentration and most individual SFA and MUFA. In conclusion, the results suggest that breed and sex are important sources of variation for fatty acid composition of LM.     

Pig and herd level prevalence of Toxoplasma gondii in Ontario finisher pigs in 2001, 2003, and 2004

The objective of this study was to estimate the apparent and true prevalence of exposure to Toxoplasma gondii in Ontario finisher pigs. During the study period (2001 to 2004), sera from 6048 pigs were tested with a commercial enzyme-linked immunosorbent assay (ELISA); 103 farms were included 1 to 3 times in the study. True prevalence was estimated using a Bayesian approach. Apparent prevalence at the pig level was 1.59% [95% confidence interval (CI): 0.45, 2.99] in 2001, 0.06% (95% CI: 0.00, 0.46) in 2003, and 0.26% (95% CI: 0.00, 0.82) in 2004. Apparent prevalence at the herd-level was 13.7% (95% CI: 7.5, 22.3) in 2001; 1.25% (95% CI: 0.03, 6.77) in 2003, and 3.75% (95% CI: 0.78, 10.6) in 2004. Similarly, posterior Bayesian estimates of true prevalence at the pig level were 1.7% [95% probability interval (PI): 1.2, 2.2] in 2001, 0.2% (95% PI: 0.04, 0.4) in 2003, and 0.3% (95% PI: 0.1, 0.7) in 2004. At the herd level, posterior estimates of prevalence were 11.6% (95% PI: 7.4, 16.8) in 2001, 0% (95% PI: 0.0, 2.5) in 2003, and 1.2% (95% PI: 0.0, 5.0) in 2004 when a herd cut-point > or = 1 was used. Exposure to T. gondii in finishing pig farms in Ontario appears to be infrequent.     

SNaPshot based genotyping of the RYR1 mutation in Portuguese breeds of pigs

The porcine stress syndrome or malignant hyperthermia is an inherited autosomic recessive disease, which results in neuromuscular disorders leading to death in homozygous individuals and is associated with deterioration of meat quality. The defect in susceptible animals results from modifications in the calcium release channel or Ryanodine Receptor (RYR1), with a mutation leading to a C to T transition in nucleotide 1843 of the gene. The objective of this work was to develop a method based on analysis of SNPs to detect the mutation described in the RYR1 locus in pigs, and study polymorphisms of the gene in four exotic (Large White, Landrace, Duroc and Pietrain) and three native (Bísaro, Alentejano and Malhado de Alcobaça) breeds of pigs in Portugal. The method was successful in identifying the mutation by analysis of SNPs, and results indicate a high incidence of the mutant allele in Pietrain (0.75) and, to a lesser degree, in Malhado de Alcobaça (0.34) and Landrace (0.28); frequencies in Alentejano, Bísaro and Large White ranged between 0.04 and 0.09. These results suggest the need to establish breeding programs aimed at eliminating the susceptibility allele from those populations.     

Prevalence of chromosomal aberrations in breeding pigs in Spain

The main aim of this study was to document the prevalence of chromosomal aberrations found to date on the pig population in Spain, a country in which this production sector has a critical role, being the fourth country in the world in pig production and the second one within the European Union. The total number of animals studied was 849, and the founded frequency of carrier pigs with chromosomal alterations was 3.8%. When only the structural alterations were considered, the prevalence in males was 3.3%. This percentage is far from the 0.5% of carrier boars that has been estimated in France, a country where there is a systematic cytogenetic screening of future breeding pigs since 1992. In order to avoid the productive and economic losses caused by karyotype alterations in breeding pigs, it would be important to establish a cytogenetic screening of breeding animals at artificial insemination centres and genetic selection farms.     

Associations between the proportion of Salmonella seropositive slaughter pigs and the presence of herd level risk factors for introduction and transmission of Salmonella in 34 Danish organic, outdoor (non-organic) and indoor finishing-pig farms

This paper evaluates the association between herd level risk factors for introduction and transmission of Salmonella in farms with three different production systems: organic, outdoor (non-organic) and indoor finishing-pig farms, and the presence of seropositive animals in the herds. Potential risk factors for Salmonella in the three pig production systems were identified through a literature review, and management information as well as serological data were collected in 34 pig farms: 11 organic farms, 12 outdoor farms, and 11 indoor farms. There were no general differences in the proportion of Salmonella seropositive animals in the organic, outdoor, and indoor pig farms. Correspondence analysis showed that the occurrence of seropositive animals in the herds was mostly associated to the risk of introducing Salmonella in the herds by purchasing and transporting growing pigs. No associations between herd risk factors for transmission and survival of Salmonella and seropositive animals in the herds were found.     

规模化种猪场猪瘟免疫情况调研

猪瘟是由猪瘟病毒引起的一种以高热、出血为主要特征的烈性、高度接触性传染病,至今仍在中国广泛流行。接种疫苗是防控该病发生的最根本的方法,为了查清山西省规模化种猪场猪瘟疫苗免疫情况,课题组采用ELISA试剂盒,对8个地市42个规模化种猪场465头哺乳猪、456头保育猪、436头育肥猪、419头母猪进行了猪瘟免疫抗体检测。查明了哺乳猪抗体阳性率平均为70.11%,保育猪抗体阳性率平均为40.57%,育肥猪抗体阳性率平均为50.22%,母猪抗体阳性率平均为69.69%,证明被检猪群免疫抗体不理想,尤其是保育猪抗体水平较低。同时对12个规模化种猪场,4类不同免疫方法免疫猪瘟疫苗的133头哺乳猪、110头保育猪、105头育肥猪、135头母猪进行了免疫抗体检测。结果表明:乳猪在吃奶前超免猪瘟高效细胞苗6头份,21日龄时二免猪瘟高效细胞苗4头份,60日龄三免猪瘟高效细胞苗2头份,母猪产后21 d跟胎免疫效果最好,使保育猪免疫抗体阳性率达到89.29%,有些猪场使用该方法免疫后,使保育猪的死亡率有了明显的降低,生长发育逐渐走向正常;而采用仔猪在断奶后28日龄至35日龄时首免猪瘟普通细胞苗4头份,60日龄二免猪瘟普通细胞苗2头份,母猪产后28 d跟胎免疫的方法效果最差,不宜推广应用。通过对山西一些规模化种猪场猪瘟免疫情况的调研,基本查清了规模化种猪场猪瘟免疫效果和最佳免疫方法,可为养猪场防控猪瘟提供依据。     

Effect of Pseudorabies Purification on the Production Performance in Pig

In order to identify the effect of pseudorabies purification on pig production performance, this paper based on the survey of 63 large-scale pig farms in 9 provinces of China, analyzed the effects of pseudorabies purification on the mortality of pigs, the positive rate of gE, the maternal abortion rate and so on, and compared pig production performance between purification and non-purifucation farms in different scale and different stages of purification. The results showed that the pig production performance was improved by the implementation of vaccine immunization, quarantine diagnosis, elimination of positive animals and culture of healthy animals; Pseudorabies purification had the best effect of improving production performance for the farms with the scale of 16 500 to 84 700 head. The longer the time of pseudorabies purification, the greater the production performance of pigs.     

猪伪狂犬病净化对猪生产性能影响的研究

为了评定猪伪狂犬病净化对猪生产性能的影响,作者调查了中国9个省63个规模化猪养殖场,以调查数据为基础,统计分析了伪狂犬病净化对猪死亡率、猪群伪狂犬gE阳性率、母猪流产率等生产性能的影响,对比了不同规模、不同净化阶段养殖场的猪生产性能的差异。统计结果表明,通过实施疫苗免疫、检疫诊断、淘汰阳性动物、培养健康动物等净化措施,生猪的生产性能明显提高;养殖规模在1.65~8.47万头的养殖场其生产性能提高的效果最优;伪狂犬病净化时间越长,猪的生产性能提高的幅度越大。