贵州白香猪与3种杂交猪脏器系数及血液生理指标比较

试验对贵州白香猪及贵州白香猪与大约克猪、杜洛克猪、长白猪3种杂交猪的体重、脏器系数和血液生理指标进行了比较。结果显示,贵州白香猪体重极显著低于3种杂交猪（P＜0.01）;贵州白香猪的脏器指标除心脏外与3种杂交猪均存在差异;贵州白香猪红细胞总数(RBC)和红细胞压积(HCT)极显著高于大约克猪×香猪（YX）（P＜0.01）;贵州白香猪的平均红细胞血红蛋白浓度(MCHC)、白细胞中淋巴细胞数量(LYM)、白细胞中淋巴细胞比率(LYM,%)及白细胞中中性粒细胞比率(GRA,%)与长白猪×香猪（LX）间存在显著差异（P＜0.05）。     

胰岛素样生长因子-1基因多态性与猪部分生产性能的关系

采用PCR－RFLP对南昌白猪（92头）和大约克夏猪（170头）的IGF－1基因的179bp片段进行了扩增，并用HhaI酶切，产生两个等位基因A（151＋28bp)和等位基因B（116＋35＋28bp)。分析了不同基因型对个体初生重、2月龄重、4月龄重、6月龄重、料重比、背膘厚和瘦肉率等生产性能的影响。结果表明，在南昌白猪中，AA型猪比AB型猪初生重大，差异显著（P＜0.05)；在大约克夏猪中，BB型猪比AB型猪的6月龄体重大，差异显著（P＜0.05)；AA型猪比AB型和BB型猪瘦肉率低，差异极差著（P＜0.01)。     

发酵麦麸对育肥猪生产性能、肠道菌群及免疫功能的影响

文章旨在研究发酵麦麸对育肥猪生产性能、肠道菌群和免疫功能的影响。试验将150头130日龄育肥猪随机分为3组,每组10个重复,每个重复5头猪。对照组饲喂基础日粮,试验组分别用发酵麦麸5%、10%等量替代基础日粮中的麦麸。预饲期5?d,正试期28?d。试验结果表明：（1）与对照组相比,饲喂发酵麦麸可以显著提高育肥猪的平均日增重和试验末重（P <0.05）,显著降低了育肥猪的料重比（P <0.05）,而对于育肥猪的日采食量有增加趋势,但无显著影响（P> 0.05）,不同比例发酵麦麸替代组之间无显著差异;（2）发酵麦麸替代基础日粮中未发酵麦麸可以显著提高育肥猪血清的补体C3、C4、免疫球蛋白A(IgA)、免疫球蛋白G(IgG)、免疫球蛋白M(IgM)的含量（P <0.05）,显著降低了血清中白细胞介素-2(IL-2)和白介素-10(IL-10)的含量（P <0.05）,且两试验组之间无显著差异;（3）发酵麦麸显著降低了育肥猪盲肠内大肠杆菌和沙门氏菌的数量（P <0.05）,5%组显著低于10%组（P <0.05）;发酵麦麸显著提高了育肥猪盲肠内乳酸杆菌...     

发酵饲料对生长育肥猪生长性能与免疫力的影响

试验旨在研究发酵饲料对生长育肥猪生长性能与免疫力的影响。选取100头健康、体重（23.21±2.13） kg生长育肥猪（公、母各半），随机分为2组，每组5个重复，每个重复10头猪。对照组为基础日粮，试验组为90%基础日粮+10%乳酸菌发酵饲料。试验期30 d。结果显示，试验组生长育肥猪的末重、平均日增重、平均日采食量均显著高于对照组（P<0.05），料重比显著低于对照组（P<0.05）。试验组生长育肥猪的粗蛋白、能量、干物质、粗纤维、粗脂肪表观消化率均显著高于对照组（P<0.05）。试验组生长育肥猪血清总蛋白（TP）、球蛋白（GLB）含量显著高于对照组（P<0.05），尿素氮（BUN）、胆固醇（TC）、甘油三酯（TG）、葡萄糖（GLU）含量以及谷丙转氨酶（ALT）活性显著低于对照组（P<0.05）。与对照组相比，试验组生长育肥猪血清免疫球蛋白G(IgG)、免疫球蛋白A(IgA)、免疫球蛋白M(IgM)含量显著升高（P<0.05），白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)含量显著降低（P<0.05...     

猪冠尾线虫病的诊治

猪冠尾线虫病是由圆线目（Strongylata）冠尾科（Stephanu）冠尾属（Stephanurusridae)的有齿冠尾线虫（S．dentatus)寄生于猪的肾盂、肾周围脂肪和输尿管壁等处引起的一种寄生虫病，又称猪肾虫病：2004年8月上旬．辽宁省某养猪户饲养的育肥猪发生以后躯麻痹为主要特征的疾病．经综合跨断确诊为猪冠尾线虫病，现将该病的诊治情况简要报告如下。     

国家级猪遗传资源保护品种

2006年6月2日,农业部根据《畜牧法》第十二条的规定,公布了八眉猪等138个畜禽品种为国家级畜禽遗传资源保护品种,其中猪的品种有：八眉猪、大花白猪（广东大花白猪）、黄淮海黑猪（马身猪、淮猪、莱芜猪、河套大耳猪）、内江猪、乌金猪（大河猪）、五指山猪、太湖猪（二花脸、梅山猪）、民猪、两广小花猪（陆川猪）、里岔黑猪、金华猪、荣昌猪、香猪（含白香猪）、     

规模化猪场猪伪狂犬病的血清学调查

猪伪狂犬病(PR)是由猪伪狂犬病病毒(PRV)引起的一种急性传染病。采用ELISA方法对青海省西宁市及海东地区9个市（县）规模猪场(户) 776头猪进行了猪伪狂犬病的血清学检测,结果检出阳性猪35头,阳性率为4.51%（35/776）,表明青海省西宁市及周边地区部分规模化猪场仍存在猪伪狂犬病感染的潜在危害,因此对该病的防控不可忽视。     

中华人民共和国农业部公告第662号——国家级畜禽遗传资源保护名录

一、猪 八眉猪、大花白猪（广东大花白猪）、黄淮海黑猪（马身猪、淮猪、莱芜猪、河套大耳猪）、内江猪、乌金猪（大河猪）、五指山猪、太湖猪（二花脸、梅山猪）、民猪、两广小花猪（陆川猪）、里岔黑猪、金华猪、荣昌猪、香猪（含白香猪）、华中两头乌猪（通城猪）、清平猪、滇南小耳猪、槐猪、蓝塘猪、藏猪、浦东白猪、撒坝猪、湘西黑猪、大蒲莲猪、巴马香猪、玉江猪（玉山黑猪）、河西猪、姜曲海猪、关岭猪、粤东黑猪、汉江黑猪、安庆六白猪、莆田黑猪、嵊县花猪、宁乡猪。     

含不同比例梅山猪血缘杂交肉猪肉质及肌纤维组织学特性研究

选不同比例梅山猪血缘（梅山猪血缘比例为0,1/8,1/4,3/8,1/2,1)的杂种仔猪68头，采用单因子试验设计，在同一营养水平（DE：前期14.21MJ/kg，后期13.79MJ/kg；CP：15％，13％；Lys:0.75%,0.65%)下，研究不同比例梅山猪血缘对不同体重阶段生长肥育猪肉质及肌纤维组织学特性的影响。结果表明，梅山及其杂种猪与杜大猪相比，肉色好（P＜0.05)，pH正常（P＜0.01)，肌内脂肪含量高（P＜0.01)，分布均匀，系水力高（P＜0.05)，无异常肉发生，其它常规化学成分分析差异不显著（P＞0.05)；肌纤维直径随梅山猪血缘比例增加逐渐变细，而随体重增加逐渐增大。     

44个地方猪种入选《国家级畜禽遗传资源保护名录》

2014年2月14日,农业部发布第2061号公告,对《国家级畜禽遗传资源保护名录》（农业部公告第662号）（以下简称《名录）））进行了修订,确定159个畜禽品种为国家级畜禽遗传资源保护品种,其中地方猪种44个,分别为八眉猪、大花白猪、马身猪、淮猪、莱芜猪、内江猪、乌金猪（大河猪）、五指山猪、二花脸猪、梅山猪、民猪、两广小花猪（陆川猪）、里岔黑猪、金华猪、荣昌猪、香猪、华中两头乌猪（沙子岭猪、通城猪、监利猪）、清平猪、滇南小耳猪、槐猪、蓝塘猪、藏猪、浦东白猪、撒坝猪、湘西黑猪、大蒲莲猪、巴马香猪、玉江猪（玉山黑猪）、姜曲海猪、粤东黑猪、汉江黑猪、安庆六白猪、莆田黑猪、嵊县花猪、宁乡猪、米猪、皖南黑猪、沙乌头猪、乐平猪、海南猪（屯昌猪）、嘉兴黑猪、大围子猪。     

ORF1 but not ORF2 dependent differences are important for in vitro replication of PCV2 in porcine alveolar macrophages singularly or coinfected with PRRSV

The objective of this study was to investigate cytokine expression and in vitro replication of porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) in pulmonary alveolar macrophages (PAMs) emphasizing PCV2 open-reading frame (ORF) origin (PCV2a or PCV2b) and PRRSV strain. Chimeric PCV2 viruses composed of different combinations of ORF1 and ORF2 of PCV2a or PCV2b (chimera PCV2a-2b and chimera PCV2b-2a) were constructed and five different PRRSV isolates were utilized: Type 1 (SD 01-08) or type 2 (NC16845b, VR-2332, MN-184, JA-142). PAMs were infected singularly or with combinations of PCV2b, PCV2a, chimera PCV2a-2b, and chimera PCV2b-2a, and one of the five PRRSV isolates. Real-time PCR was used to test PAMs (PCV2 mRNA) and supernatants (PRRSV RNA, PCV2 DNA, PCV2 mRNA) harvested at 24, 48, 72 and 96h post inoculation (hpi). Levels of IFN-γ, TNF-α and IL-10 were determined by quantitative ELISAs. PCV2 replication in PAMs was limited to groups inoculated with PCV2 strains containing ORF1 of PCV2a (PCV2a, chimera PCV2a-2b). Furthermore, in supernatants, PCV2 mRNA was only detected in groups coinfected with PRRSV regardless of strain at 48hpi supporting an enhancing effect of PRRSV on PCV2 infection. Changes in cytokine levels were minimal and associated with PRRSV strain for TNF-α. In summary, in vitro differences in PCV2 replication in PAMs inoculated with different PCV2-PRRSV combinations were independent of PCV2 ORF2 origin with minimal effects of concurrent PRRSV infection perhaps indicating that PCV2-specific changes in ORF1 may be more important than those in ORF2.     

Effect of porcine circovirus type 2 (PCV2) vaccination on PCV2-viremic piglets after experimental PCV2 challenge

The objective of this study was to evaluate the effect of porcine circovirus type 2 (PCV2) vaccines on PCV2-viremic and -seropositive piglets born from naturally PCV2-infected sows against postnatal PCV2 challenge. The experimental design was aimed at mimicking commercial swine rearing conditions to evaluate the response of the PCV2 vaccine on PCV2-viremic and -seropositive piglets after experimental PCV2 challenge. PCV2a (or 2b)-viremic piglets received a PCV2 vaccine at 21 days of age followed by a PCV2b (or 2a) challenge at 49 days of age (28 days post vaccination). The PCV2 vaccines elicited a high level of humoral (as measured by immunoperoxidase monolayer assay and neutralizing antibody titers) and cellular (as measured by the frequency of PCV2-specific interferon-γ-secreting cells) immune response in the PCV2-viremic piglets after vaccination even in the presence of maternally derived antibodies (MDA). The initial infection of PCV2 in the pigs was not affected by PCV2 vaccination, however the challenging PCV2 was reduced by PCV2 vaccination on PCV2-viremic pigs. The results from this study demonstrate that the PCV2 vaccine used in this study is effective at reducing PCV2 viremia and lymphoid PCV2 DNA, even for PCV2-viremic pigs with passively acquired MDA at the time of vaccination.     

Retrospective serological survey of antibodies to porcine circovirus type 1 and type 2.

A retrospective serological survey was performed to determine the presence of antibodies to porcine circovirus type 1 (PCV1) and porcine circovirus type 2 (PCV2) in serum samples collected from sows at slaughterhouses in Canada in 1985, 1989, and 1997. Each serum sample was tested by indirect immunofluorescence on PCV-free PK15 cells, on PCV1-infected PK15 cells and on PCV2-infected PK15 cells. For the 3 years studied, sera positive to PCV1 and PCV2 were identified and the number of sera positive for PCV2 was greater than the number of sera positive for PCV1. The results indicated 1) that PCV2 appears to be the main PCV type circulating in the Canadian pig population, 2) that PCV2 had been circulating in the Canadian pig population at least 10 years before the postweaning multisystemic wasting syndrome (PMWS) was reported, and 3) that serological evaluation using PCV1 underestimates the seroprevalence of PCV2.     

Differentiation of porcine circovirus 1 and 2 in formalin-fixed, paraffin-wax-embedded tissues from pigs with postweaning multisystemic wasting syndrome by in-situ hybridisation

Non-radioactive digoxigenin (DIG)-labelled probes that can differentiate porcine circovirus (PCV) 1 from PCV2 in formalin-fixed, paraffin-wax-embedded tissues by in-situ hybridisation were developed. A 349 base pair (bp) DNA fragment from open reading frame (ORF) 1 of PCV1 and a 481 bp DNA fragment from ORF2 of PCV2 generated by polymerase chain reaction (PCR) were used as PCV1 and PCV2 probes, respectively. A specific DIG-labelled PCV1 DNA probe did not hybridise with PCV2-infected PK-15 cells and vice versa. From the 40 field cases with postweaning multisystemic wasting syndrome tested by in-situ hybridisation, 30 (75 per cent) cases were PCV2-positive only and 10 (25 per cent) cases were positive for both PCV1 and PCV2. PCV1 and PCV2 DNAS were detected mainly in the macrophages of lymph nodes and spleens. Positive cells typically exhibited a dark brown to black reaction product mainly in the cytoplasm but also occasionally in the nucleus. In-situ hybridisation together with the differential probes developed in the present study represent an additional tool capable of differentiating of both types of PCV in formalin-fixed, paraffin-wax-embedded tissues.     

Monocyte-derived dendritic cells enhance cell proliferation and porcine circovirus type 2 replication in concanavalin A-stimulated swine peripheral blood lymphocytes in vitro

Dendritic cells (DCs) are professional antigen presenting cells cooperating with other immune cells for the activation of innate and adaptive immune responses. The objective of the present study was to investigate the replication activity of porcine circovirus type 2 (PCV2) in DCs and/or lymphocytes during their cross talk and its possible mechanism. Two models were set, herein. Swine blood monocyte (Mo)-derived DCs (MoDCs) or peripheral blood lymphocytes (PBLs) were inoculated with PCV2 prior to their co-cultivation. Bacterial lipopolysaccharide (LPS) and concanavalin A (Con A) were used to stimulate MoDCs and PBLs, respectively. During 6 days of cultivation, a high PCV2 antigen-containing rate without detectable intranuclear signals and a slight but significant increase in the copy number of PCV2 genome were detected in PCV2-inoculated MoDCs. The presence of LPS alone or PCV2-free PBLs, however, had no effect on the location of PCV2 antigens or copy number of PCV2 genome in PCV2-inoculated MoDCs. On the contrary, active PCV2 replication occurred in Con A-stimulated PCV2-inoculated PBLs. When compared with blood Mos, MoDCs induced significantly higher cell proliferation and intensified PCV2 replication in Con A-stimulated PCV2-inoculated PBLs, for which direct contact between MoDCs and lymphocytes was required. Among the cytokines secreted by Con A-activated PBLs, interleukin (IL)-2, but not IL-4 or interferon-γ, could induce cell proliferation and PCV2 replication in PCV2-inoculated PBLs. The findings suggest that although MoDCs support only limited PCV2 replication in themselves, their accessory cell function is required for cell proliferation and PCV2 replication in PCV2-infected lymphocytes.     

Porcine reproductive and respiratory syndrome virus (PRRSV) influences infection dynamics of porcine circovirus type 2 (PCV2) subtypes PCV2a and PCV2b by prolonging PCV2 viremia and shedding

The objective of this study was to determine the effect of porcine reproductive and respiratory syndrome virus (PRRSV) infection on porcine circovirus type 2 (PCV2) subtypes a (PCV2a) or b (PCV2b) viremia and shedding characteristics in oral, nasal and fecal samples in experimentally infected pigs. Twenty-three, 2- to 6-week-old pigs were randomly divided into five groups: negative control (n=3), PCV2a-I (n=5), PCV2a-PRRSV-CoI (n=5), PCV2b-I (n=5), and PCV2b-PRRSV-CoI (n=5). Blood, oral, nasal and fecal swabs were collected in regular intervals from day post inoculation (dpi) 0 until dpi 70 and tested by quantitative real-time PCR for the presence and amount of PCV2 DNA and by ELISA for the presence of PCV2-specific antibodies. The results indicate that there were significantly (P<0.05) higher loads of PCV2a and PCV2b DNA in serum, oral swabs, nasal swabs and fecal swabs and a higher prevalence of detectable PCV2 antigen in tissues of pigs concurrently infected with PCV2 and PRRSV compared to pigs singularly infected with PCV2 further confirming that PRRSV enhances replication of PCV2. Moreover, PRRSV infection significantly prolonged the presence of PCV2 DNA in serum and increased the amount of PCV2 DNA in oral and nasal secretions and fecal excretions in the later stages of infection between dpi 28 and 70. Shedding patterns were similar between groups infected with PCV2a and PCV2b, indicating that there was no subtype-specific interaction with the PRRSV isolate used in this study. The results from this study highlight the interaction between PRRSV and PCV2 and the importance of controlling PRRSV infection in order to reduce PCV2 virus loads in pig populations.     

Singular PCV2a or PCV2b infection results in apoptosis of hepatocytes in clinically affected gnotobiotic pigs

Porcine circovirus type 2 (PCV2) is clinically associated with respiratory disease, failure-to-thrive, hepatitis, and diarrhea; however, the precise pathogenesis of PCV2-associated disease and in particular its involvement in apoptosis is still controversial. The objectives of this study were (1) to determine whether PCV2 is associated with apoptosis by examining and comparing hepatic tissues from clinically affected or unaffected gnotobiotic pigs that were experimentally infected with PCV2, (2) to determine if there are differences between PCV2a and PCV2b in inducing hepatocyte apoptosis, and (3) to determine if there are differences between apoptosis detection systems. Forty-eight gnotobiotic pigs were separated into five groups based on inoculation status and development of clinical disease: (1) sham-inoculated, clinically-unaffected (n=4), (2) inoculated with PCV2a, clinically-unaffected (n=10), (3) inoculated with PCV2a, clinically-affected (n=6), (4) inoculated with PCV2b, clinically-unaffected, (n=13) and (5) inoculated with PCV2b, clinically-affected (n=15). Formalin-fixed, paraffin-embedded sections of liver from all pigs were analyzed for signs of apoptosis [presence of single strand DNA breaks in the nucleus by the terminal transferase dUTP nick end labeling (TUNEL) assay or presence of intra-nuclear cleaved caspase 3 (CCasp3) demonstrated by CCasp3 immunohistochemistry (IHC)]. In addition, the liver tissues were also tested for presence of cytoplasmic and intra-nuclear PCV2 antigen by an IHC assay. Specific CCasp3 and TUNEL labeling was detected in the nucleus of hepatocytes in PCV2a and PCV2b infected pigs with significantly (P<0.05) higher levels of apoptotic cells in clinically-affected pigs. Regardless of PCV2 subtype (PCV2a; PCV2b), there were higher levels of PCV2 antigen in clinically-affected pigs compared to clinically-unaffected pigs. There was no significant difference in detection rate of apoptotic cells between the TUNEL assay and CCasp3 IHC. When high amounts of PCV2 antigen were present, the incidence of CCasp3 and TUNEL staining also increased regardless of the PCV2 genotype. This suggests that PCV2-induced apoptosis of hepatocytes is important in the pathogenesis of PCV2-associated lesions and disease.     

Effect of porcine circovirus type 2 (PCV2) vaccination on porcine reproductive and respiratory syndrome virus (PRRSV) and PCV2 coinfection

The objectives were to determine if PCV2 vaccination is effective in reducing disease and lesions associated with PRRSV and PCV2 coinfection and if there is a difference between intradermal (ID) and intramuscular (IM) route of PCV2 vaccination. Seventy-four, 21-day-old pigs were randomly allocated into one of six groups. On day 0, pigs were vaccinated with 2ml Suvaxyn((R)) PCV2 One Dose (Fort Dodge Animal Health, Inc.) by intramuscular (VAC-M-COINF) or intradermal (VAC-D-COINF) routes. On day 28, pigs were either singularly (PRRSV-only, PCV2-only) or coinfected (COINF) with PRRSV and PCV2. All pigs in all groups were necropsied on day 42. All vaccinated pigs seroconverted (IgM, IgG, and neutralizing antibodies) to PCV2 between 14 and 28 days post-vaccination. After challenge, all groups inoculated with PRRSV had reduced average daily gain compared to CONTROLS and PCV2-only (P<0.001). COINF pigs had significantly (P<0.05) reduced anti-PCV2-IgG antibody levels and neutralizing antibody levels compared to both vaccinated groups. COINF pigs had more severe lung lesions compared to VAC-M-COINF (P<0.05). COINF pigs had higher amounts of PCV2 DNA in serum samples and feces (P<0.05) and increased amounts of PCV2 in lymphoid tissues (P<0.05) compared to both vaccinated groups. In summary, PCV2 vaccination was effective at inducing a neutralizing antibody response and significantly reducing PCV2-associated lesions and PCV2 viremia in pigs coinfected with PCV2 and PRRSV. Differences between intradermal and intramuscular routes of vaccine administration were not observed.     

Genomic analysis of PCV2 isolates from Danish archives and a current PMWS case-control study supports a shift in genotypes with time

Porcine circovirus type 2 (PCV2) is the primary cause of Postweaning Multisystemic Wasting Syndrome (PMWS) in pigs. PCV2, however, is found in both PMWS-affected herds and non-affected herds. The objective of this study was to clarify if PCV2 genome nucleotide sequences isolated from pigs from PMWS-affected herds and non-affected herds cluster phylogenetically in two separate groups. All isolates (45) belonged to PCV2 group 1 and shared a nucleotide sequence identity of 99.4-100% indicating a very homogeneous PCV2 population in Denmark. Phylogenetic analysis of the PCV2 isolates revealed no distinctive clustering of case- and control-herds suggesting that there is no link between PCV2 sequences and herd disease status. The appearance of only PCV2 group 1 isolates in this study (isolates from 2003/2004) led us to determine if PCV2 nucleotide sequences had changed in Denmark over time. Interestingly, all PCV2 isolates from before the first outbreak of PMWS (2001) belonged either to a new PCV2 group identified for the first time in this study and named group 3 (isolates from 1980, 1987 and 1990) or PCV2 group 2 (isolates from 1993 and 1996). The shift from PCV2 group 2 to 1 was confirmed on a more global scale by placing all full genome PCV2 sequences submitted to GenBank from 1997 to 2006 in either of the groups by phylogenetic analysis. The analysis showed that the shift happened in 2003 or even earlier. This may indicate that PCV2 group 1 is a more adapted form of PCV2 and possibly could be more pathogenic.     

Antigenic subtyping and epitopes' competition analysis of porcine circovirus type 2 using monoclonal antibodies

Porcine circovirus type 2 (PCV2) strains have been classified into two major genotypes (PCV2a and PCV2b) and 8 genetic clusters: PCV2b-1A to PCV2b-1C and PCV2a-2A to PCV2a-2E. To date, no studies have been performed to antigenically subtype PCV2 strains enclosing eight PCV2 clusters. The present study aimed to antigenically subtype PCV2 and perform epitopes' competition analysis using monoclonal antibodies (mAbs). Fourteen PCV2 strains representative for eight clusters were tested with 20 mAbs (fifteen of them were generated against PCV2a strain Stoon-1010 and 5 of them against PCV2b strain 1147) in immunoperoxidase monolayer assays. Four mAbs reacted to all 14 PCV2 strains and one mAb reacted with all strains except for a PCV2a-2C strain. One mAb reacted with all PCV2a strains, except for a PCV2a-2C strain and one mAb reacted with all PCV2b strains, except for a PCV2b-1C strain. Nine mAbs reacted with the strains of PCV2b-1A/1B, PCV2a-2A and PCV2a-2E. Three mAbs only reacted with the strains of PCV2a-2A and PCV2a-2E. One mAb reacted specifically with the strains of PCV2b-1A/1B. This suggests that discrete antigenic differences exist between different PCV2 genetic clusters and that these clusters can be discriminated by the use of a panel of universal and cluster-specific mAbs. Six mAbs were selected for cross-competition analysis by a competitive ELISA using PCV2 strain Stoon-1010. Six overlapping epitopes were identified on the PCV2 capsid protein. The universal mAbs recognized larger epitopes than the cluster-specific mAbs. These findings are helpful in the development of diagnostic tests and new generation vaccines against PCV2.