The aim of this study was to investigate the effect of uterine histotroph on embryo development and the expression of cysteine-rich protein 2 (CRP2), coatomer subunit gamma-2 (G2COP), myoglobin (MYG), vascular endothelial growth factor D (VEGFD), collagen alpha 4 chain (COL4) and galactoside 3-L-fucosyltransferase 4 (FUT4) proteins in porcine embryo during pre-implantation. Uterine histotroph (UH) was collected from uterine horn on corpus albican phase, and embryos were cultured in porcine zygote medium with UH for 168 hours. Cleavage and blastocyst formation of embryo were detected at 168 hours after in vitro fertilization. And CRP2, G2COP, MYG, VEGFD, COL4 and FUT4 proteins were observed using confocal laser microscope. In results, embryo cleavage rate was not significantly changed by UH, but blastocyst rate was significantly (P<0.05) decreased in UH-treated embryos. Moreover, CRP2, G2COP, MYG, VEGFD, COL4 and FUT4 proteins were expressed in blastomere. CRP2 in embryo was significantly overexpressed (P<0.05), but not G2COP, MYG, VEGFD, COL4 and FUT4 proteins. In summary, UH on corpus albican phase was increased CRP2 protein in embryo, and inhibited blastocyst formation in preimplantation porcine embryos, suggesting that CRP2 may play an interrupter on embryo development in pigs.

Growth traits, such as body weight, directly influence productivity and economic efficiency in the swine industry. In this study, we estimate heritability for body weight traits usinginformation from pedigree and genome-wide single nucleotide polymorphism (SNP) chip data. Four body weight phenotypes were measured in 1,105 F2 progeny from an intercross between Landrace and Jeju native black pigs. All experimental animals were subjected to genotypic analysis using PorcineSNP60K BeadChip platform, and 39,992 autosomal SNP markers filtered by quality control criteria were used to construct genomic relationship matrix for heritability estimation. Restricted maximum likelihood estimates of heritability were obtained using both genomic- and pedigree- relationship matrix in a linear mixed model. The heritability estimates using SNP information were smaller (0.36-0.55) than those which were estimated using pedigree information (0.62-0.97). To investigate effect of common environment, such as maternal effect, on heritability estimation, we included maternal effect as an additional random effect term in the linear mixed model analysis. We detected substantial proportions of phenotypic variance components were explained by maternal effect. And the heritability estimates using both pedigree and SNP information were decreased. Therefore, heritability estimates must be interpreted cautiously when there are obvious common environmental variance components.

This study tested the association between genotypes of the single nucleotide polymorphism (SNP) marker, rs81437607 and capric acid (FA_C10_0) compositions in longissimus dorsi muscle in pigs. Eighteen fatty acid (FA) compositions were measured in a total of 974 F2 animals among 1,106 F2 progeny produced between Landrace and Jeju Black Pig (JBP). Among FA compositions tested, we identified a cluster of highly significant SNPs for capric acid compositions on 58 Mb position of Sus scrofa chromosome 12 (SSC12) using genome-wide association study (GWAS) with F2 genotypes from SNP panel analysis. GWAS results showed that the rs81437607 was the highest trait-related SNP marker with capric acid levels. Three genotypes (C/C, C/T and T/T) of rs81437607 marker were found in F2 population by further pyrosequencing. Association analysis results showed the significant differences between rs81437607 genotypes and capric acid compositions (P<0.05). The F2 pigs harboring rs81437607 C/C (0.119±0.002%) and C/T (0.116±0.002%) genotypes showed additively higher levels of capric acid content than those of T/T homozygotes (0.109±0.002%) (P=1.30×10-12). These results suggested that the genetic variations of rs81437607 may be helpful to find causative variants and assist as molecular genetic markers for improving the capric acid contents in longissimus dorsi muscle in pigs.

This experiment was conducted to evaluate the effects of migration frequency on growth performance, blood profile, pork quality and economical analysis in growing-finishing pigs. A total of 56 growing pigs [(Yorkshire×Landrace)×Duroc] with an initial body weight 28.01±4.09 kg were used in this experiment. Pigs were randomly allocated to one of two treatments in a randomized complete block design and 7 replicates with 4 pigs per pen. Experimental treatments were 1) 1 site: growingto- finishing at 1.24 m2/head, 2) 2 site: growing facility for 6 week at 0.81 m2/head followed by move to the finishing facility at 1.24 m2/head. Feeding trial was composed by two growing phase (0-3 week, 4-6 week) and two finishing phase (7-9 week, 10-12 week). As a result, different pig flows influenced on growth performance of growing-finishing pigs and 1 site treatment showed higher average daily gain, average daily feed intake, and G:F ratio on growing phase (0-6 week, p<0.01). The 2 site treatment showed higher serum cortisol level at week 6 (p=0.03). In carcass evaluation, 1 site treatment had shorter days to slaughter 110 kg body weight (p=0.01). Consequently, 1 site system had better performance and economical profits for swine farms.

The aim of this study was to investigate growth performance of growing-finishing pigs in response to high planes of nutrition. Seventy-two Yorkshire barrows weighing approximately 26 kg were randomly allotted to one of three planes of nutrition: ‘BASAL,’ ‘high’ (HI), and ‘extra-high’ (X-HI). BASAL, HI, and X-HI grower diets contained 1.15%, 1.25%, and 1.35% lysine and 3.48, 3.54, and 3.60 Mcal DE/kg, respectively; finisher diets had 1.10%, 1.10%, and 1.20% lysine and 3.43, 3.50, and 3.57 Mcal DE/kg, respectively. The animals were placed on the grower and finisher diets for 40 and 63 days, respectively, and slaughtered. Average daily gain, which did not differ among the three dietary groups during the grower phase, was greater (p<0.05) in the X-HI group than in the other two groups during the finisher phase (811, 862, and 842 g during the grower phase and 855, 884, and 953 g during the finisher phase for the BASAL, HI, and X-HI groups, respectively). Dressing percentage of the carcass was greater in the X-HI than in the other two groups, backfat thickness tending to be less in the X-HI group vs. BASAL (p=0.09). Results suggest that the growth rate of growing-finishing barrows could be increased by placing them on a high plane of nutrition.

Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are oocyte-specific growth factors that regulate many critical processes involved in early folliculogenesis and oocyte maturation. In this study, effects of GDF9 and BMP15 treatment during in vitro maturation of porcine oocytes upon development after parthenogenetic activation were investigated. Neither GDF, BMP15 alone nor in combination affects the number and viability of cumulus cells or the rates of oocyte maturation and blastocyst development. However, the treatment of GDF9 on porcine oocytes increased the number of trophectodermal (TE) cells of blastocysts derived from activated oocytes (P<0.05). The treatment of BMP15 increased the cell numbers of both inner cell mass (ICM) and TE cells (P<0.05). The treatment with the combination of GDF9 and BMP15 further increased the numbers of ICM and TE cells, compared with GDF9 or BMP15 treatment alone (P<0.05). In conclusion, the treatment of GDF9 or BMP15 (or both) enhanced the quality of blastocysts via the increased number of ICM and/or TE cells.

This study investigated the effects of L-carnitine (LC) and nicotinic acid (NA) on sperm viability during liquid storage at 18℃ in miniature pigs. 10 μM LC and 30 mM NA, combined LC and NA (LN) were treated in fresh semen for 3, 7, and 10 days. In results, sperm survival increased in NA- and LN-treated semen on 7 and 10 days (p<0.05), mitochondrial integrity of live sperm increased in LN-treated semen on 7 days (p<0.05), but not NA-treated semen. In addition, we examined the acrosome reaction of sperm in miniature pigs. LC and NA did not influence on acrosome reaction of boar sperm. In conclusion, LC and NA effectively maintained the viability and quality of sperm during long-term storage in miniature pigs, suggesting that the combined LN may be useful for improving the semen extender for long-term liquid storage in pigs.

Xenotransplantation involves multiple steps of immune rejection. The present study was designed to produce nuclear transfer embryos, prior to the production of transgenic pigs, using fibroblasts carrying transgenes human complement regulatory protein hCD59 and interleukin-18 binding protein (hIL-18BP) to reduce hyperacute rejection (HAR) and cellular rejection in pig-to-human xenotransplantation. In addition to the hCD59-mediated reduction of HAR, hIL-18BP may prevent cellular rejection by inhibiting the activation of natural killer cells, activated T-cell proliferation, and induction of IFN-γ. Transgene construct including hCD59 and ILI-18BP was introduced into miniature pig fetal fibroblasts. After antibiotic selection of double transgenic fibroblasts, integration of the transgene was screened by PCR, and the transgene expression was confirmed by RT-PCR. Treatment of human serum did not affect the survival of double-transgenic fibroblasts, whereas the treatment significantly reduced the survival of non-transgenic fibroblasts (p<0.01), suggesting alleviation of HAR. Among 337 reconstituted oocytes produced by nuclear transfer using the double transgenic fibroblasts, 28 (15.3%) developed to the blastocyst stage. Analysis of individual embryos indicated that 53.6% (15/28) of embryos contained the transgene. The result of the present study demonstrates the resistance of hCD59 and IL-18BP double-transgenic fibroblasts against HAR, and the usefulness of the transgenic approach may be predicted by RT-PCR and cytolytic assessment prior to actual production of transgenic pigs. Further study on the transfer of these embryos to surrogates may produce transgenic clone miniature pigs expressing hCD59 and hIL-18BP for xenotransplantation.

사료이용 측면에서 유지 및 성장에 필요한 섭취량과 체내에 이용되지 않은 섭취량으로 구분할 수 있 으며, 체내에 이용되지 않은 섭취량을 잔류사료섭취량(Residual Feed Intake; RFI)이라 한다. 본 실험 은 국내 종돈의 RFI 유전모수를 추정하기 위해 2001년부터 2014년까지 태어난 Duroc종 8,696두의 검 정자료를 활용하였다. 일당증체량과 RFI의 육종가 상관관계는 -0.2로 음의 상관으로 조사되었는데 (P>0.01), RFI를 낮추면 일당증체량 개량에도 긍정적인 영향을 줄 수 있는 것으로 사료된다. 회귀추정 방식에 따른 RFI1(일당증체량)과 RFI2(일당증체량, 등지방두께)의 유전력은 각각 0.37, 0.45로 고도의 유전력을 나타내었다. 향후 국내에서도 개체단위 사료섭취량 측정으로 추정된 RFI를 개량에 활용한다면 농가 수익 개선에 많은 도움을 줄 수 있을 것으로 판단된다.

Seven outbreaks of foot-and-mouth disease (FMD) have occurred in South Korea during the period January 2000-September 2015. The Korean government changed national goal to FMD-free country with vaccination after the November 2010 outbreak when approximately 3.5 million cattle and pigs were culled. With regard to vaccination, Korean pig producers have claimed that the occurrence of injection site reaction (inflammatory or non-inflammatory granuloma) is potentially associated with intensive vaccination campaign since 2011. The present study was undertaken to assess the incidence of injection site lesions in slaughtered pigs caused by FMD vaccination and the corresponding economic losses. Data obtained from two meat packers were classified into 3 vaccination periods: non-vaccination (July-November, 2010, n=96,959); one injection (July-November, 2014, n=162,089); and two injections (March-July, 2015, n=161,928). A total of 420,976 carcasses from 6,526 farms were analyzed. The incidence of the lesions was 18.6% for non-vaccination, 46.5% for one injection, and 73.7% for two injections. Economic loss per head slaughtered due to removal of the lesions was estimated to 1,302 won (US$ 1.1) for non-vaccination, 8,286 won (US$ 7.2) for one injection, and 17,378 won (US$ 15.1) for two injections (converted using 2015 exchange rate where Korean won 1,150 = 1 US$). It was estimated that the national annual losses excluding costs of an FMD vaccine and its application is US$ 115 million for one injection and US$ 241 million for two injections. The adoption of measures that cause minimal tissue damages and economic losses would appear to be of high priority.

In the last 10 years, porcine somatic cell nuclear transfer to generate transgenic pig has been performed tremendous development with introduction and knockout of many genes. However, efficiency of porcine somatic cell nuclear transfer is still low and embryo transfer (ET) is one of important step for production efficiency. In porcine ET for production of transgenic cloned pig, we can consider many of points to increase production rates. In respect of seasonality and weather, porcine ET usually is not performed in summer and winter. Cloned transgenic embryos must be transferred into reproductive tracts of recipients where embryos are located after natural fertilization with similar estrous cycle. If cloned embryos with 2∼4 cell stage are transferred, they must be transferred into oviducts in periovulatory stage. Number and deposition sites of transferred cloned embryos are important. And we must compare the methods of ET between surgical and non-surgical ones in respect of production efficiency. Sow recipients after natural estrus is most preferred recipients however its cost is must be considered. Here we will review many of current studies about porcine embryo transfer to increase production efficiency of transgenic pigs and strategies for further studies.

The aim of the present study was to investigate the ovulation rate and its relationship to fertilization ability in Landrace, Durock and Crossbred pigs. Gilts were natural mated at a body weight of at least 120 kg under the same hormone treatment. Embryos were surgically collected 1 day after natural mating (Day 0). Embryos derived from in vivo-fertilized oocytes were cultured in medium PZM-3. The ovaries were examined and the pathological findings were recorded. The number of corpus hemorrhagicum was counted, and was assumed to equal the ovulation rate. There was no difference in the number of corpus hemorrhagicum (20.4, 28.8 and 23.2) and ovulation (13.5, 26.8 and 17.2) in the Landrace, Durock and Crossbred pigs. The two pronucleus formation was 76.0, 80.0 and 86.9%. The Day-7 embryos had blastocyst rates of 68.0, 75.0 and 73.9%. There was no difference in the number of total cells and apoptotic cells. In the future, more studies require determining relationships between ovulation and fertilization rate in different species of pigs.

To overcome the hyperacute immune rejection during pig-to-non-human primates xenotranasplantation, we have produced and bred α-1,3-galactosyltransferase knock-out (GalT —/—) pigs. In this study, the somatic cells and tissues from the GalT —/— pigs were characterized by an analysis of the expression of Galα-1,3-Gal (α-Gal) epitope. Briefly, ear fibroblast cell lines of 19 homozygous GalT —/— pigs were established and cryopreserved. The expression of α-Gal epitope in the cells was measured by fluorescence activated cell sorter (FACS) analysis using BS-I-B4 lectin. Also, the homozygous (GalT —/—) cells and tissues samples were immunostained with BS-I-B4 lectin for analysis of α-Gal epitope expression. The results showed that the expression of α-Gal epitope in GalT —/— cells (0.2 %) were significantly (p< 0.05) down-regulated to the range of cynomolgus monkey fibroblast (0.2 %) cells compared to heterozygous (GalT —/+) (9.3 %) and wild type (GalT +/+) (93.7 %) fibroblast cells. In the immunostaining results, while the expression of α-Gal epitope was detected a partly in GalT —/+ cells and mostly in GalT +/+ cells, it was almost not detected in the GalT —/— cells. Also, immunostaining results from various tissues of the GalT —/— pig showed that the expression of α-Gal epitope was not detectable, whereas various tissues from GalT +/+ pig showed a strong expression of α-Gal epitope. Our results demonstrated that α-Gal epitope expressions from GalT —/— pigs were successfully knocked out to prevent hyperacute immune rejection for further study of xenotransplantation.

본 연구는 소비자 기호에 적합한 한국형 비육돈 생산을 위해 Landrace×Yorkshire×Duroc(LYD)와 Yorkshire×Berkshire×Duroc(YBD) 삼원교잡종 돈육 등심의 육질 특성을 비교하고자 실시하였다. 돈 육은 생후 180일령, 생체중 110-120kg의 규격돈으로서 교잡종 별로 20두씩 임의로 선택하여 도축 후 24시간 동안 0±1℃ 예냉실에서 냉도체를 만든 후 좌도체로부터 돈육 등심 부위를 발골 및 정형하여 일반성분 및 이화학적 분석을 실시하였다. 일반성분 분석결과, YBD 교잡종의 수분과 지방함량이 LYD 교잡종에 비해 높았지만, 단백질 함량의 경우 LYD 교잡종 함량이 YBD 교잡종보다 더 높았다(P<0.05). pH와 보수력의 경우 YBD 교잡종이 LYD 교잡종보다 더 높은 값을 나타내었다(P<0.05). 가열감량의 경 우 YBD 교잡종이 LYD 교잡종보다 더 낮은 값을 나타내었고(P<0.05), 전단력가의 경우 교잡종간 유의 적인 차이가 발견되지 않았다. 육색지수의 경우 L*, b* 값에 있어 유의적인 차이가 발견되지 않았지만, a* 값의 경우 LYD 교잡종이 YBD 교잡종보다 더 높은 값을 나타내었다(P<0.05). 따라서 삼원교잡종간 육질 특성을 비교하였을 때 YBD 교잡종 등심육에 대한 선호도가 높을 것으로 판단된다. 본 연구 결과 를 통해 두가지 형태의 삼원교잡이 육질에 영향을 미칠 수 있음을 확인하였다.

A total of 240 growing pigs were distributed in three treatment groups to investigate the influence of fermentation in different feeder type on the growing finishing pigs. The treatments were dry feeding (DF), wet feeding (WF) with dry-wet feeders and liquid feeding (LF) with freshly prepared 3:1 water to feed ratio fed three times a day throughout the experiment. The average daily gain (ADG) and body weight were consistently greater (p<0.05) in LF than the others. When the entire experimental period was taken under consideration the ADG and body weight was also found to be increased (p<0.05) in WF in comparison to DF. The average daily feed intake (ADFI) and growth to feed ratio (G/F) was not affected however the average daily water intake (ADWI) and water to feed ratio (W/F) were significantly reduced (p<0.01) in WF in comparison to DF and LF. The ATTD of DM, GE and CP was increased (p<0.05) in WF and LF in comparison to DF at both phase I and II (4th and 8th wk) of the experiment. Carcass characteristics and blood parameters were not affected (p>0.05) in any of the feeding type in growing finishing pigs. It can be concluded that wet feeding with dry-wet feeders is good for enhancing the growth performance in the later stages while fresh liquid feeding in ratio 3:1 is beneficial for the growing finishing pigs throughout the experiment.

The objective of this study was to estimate the effects of test seasons on backfat thickness and age at 90 kg body weight in Duroc pig populations. Data of a total of 40,228 Duroc pigs performance tested from 2005 to 2014 were used. The effects of sexes, years and seasons of the tests were significant (p<0.01) for the both traits. The least squares mean of the age at 90 kg body weight of the pigs tested in 2014 was significantly less than that of the pigs tested in the previous years. And the pigs tested in spring reached 90 kg body weight faster than the pigs tested in the other seasons. The least squares mean of backfat thickness of the pigs tested in autumn was thicker than that of the pigs tested in the other seasons. Pigs tested in spring had the thinnest backfat. There were seasonal variations in the least squares mean estimates of the age at 90 ㎏ both in male pigs (134.06 to 134.36 days), and in female pigs (139.47 to 139.65 days). Seasonal variations were also detected in least sqaures means of the backfat thicknesses in male pigs (11.31-11.34 ㎜) and in female pigs (13.05-13.07 ㎜). The simple and rank correlation coefficients between breeding values estimated using the trait values unadjusted for seasonal effects and those using the trait values pre-adjusted for seasonal effects trait values were all unity, for the both traits. These results indicate that the adjustment of the trait values with regards to seasonal variation had no effects on the estimates from genetic evaluations.

본 연구는 교잡돈의 출하일령은 약 200일 이고, 175두의 돼지를 도축하여 3개의 그룹(59 ~ 95kg, 96 ~ 110kg, 111 ~ 148kg)으로 나누어, 등심, 상완세갈래근, 대퇴두갈래근, 반막모양근의 육질 특성을 조사하였다. 콜라겐과 지방함량은 반막모양근, 대퇴두갈래근이 111 ~ 148kg 그룹에서 다름 그룹에 비 해 낮은 함량을 나타내었으며(p<0.05), 단백질함량은 반막모양근, 대퇴두갈래근과 상완세갈래근이 111 ~ 148kg 그룹에서 다른 그룹에 비해 높은 함량을 나타내었다(p<0.05). 등심과 반막모양근의 명도는 111 ~ 148kg 그룹에서 높게 나타내었으며(p<0.05), 적색도와 황색도는 유의적인 차이가 나타나지 않았 다(p>0.05). pH는 등심에서 체중이 증가함에 따라 낮은 값을 나타냈었다(p<0.05). 가열감량은 등심, 반 막모양근, 대퇴두갈래근, 상완세갈래근이 111 ~ 148kg 그룹에서 보다 59 ~ 95kg 그룹에서 낮게 나타 났으며(p<0.05), 보수력은 반막모양근과 대퇴두갈래근에서 체중이 증가할수록 높게 나타났다(p<0.05). 전단력은 등심과 상완세갈래근에서 체중이 증가할수록 낮게 나타났다(p<0.05). 등심의 지방산 분석 결 과는 96 ~ 110kg 그룹에서 oleic acid, MUFA, MUFA/SFA가 높았고(p<0.05), 111 ~ 148kg 그룹에서 trans-vaccenic acid와 SFA가 높았지만(p<0.05), UFA는 낮았다(p<0.05).등심의 관능평가는 연도와 다 즙성이 96 ~ 110kg 그룹에서 높은 점수를 받았다(p<0.05).

양돈 농가의 모돈 1두당 연간 출하두수(MSY; Marketted-pigs per Sow per Year)를 향상시키기 위 해 돼지의 폐사율을 줄이는 것은 매우 중요하다. 본 연구는 2014년 6월 초부터 2015년 2월 말까지(여 름, 가을, 겨울철) 총 10곳의 양돈 농가에서 각 사육단계별 돼지의 폐사율에 영향을 미치는 계절별 각 환경요인의 기여도를 분석하기 위해 수행되었다. 그 결과,‘여름+가을+겨울’에는 일교차가 분만사와 이유자돈사에서의 폐사율에 영향을 미치고(p<0.05),‘가을+겨울’에는 일교차만이 분만사에서의 페사율 에 영향을 미치는 반면에 평균기온 및 일교차가 이유자돈사에서의 폐사율에 영향을 미치는 것을 알 수 있었다(p<0.05). 하지만, 육성·비육사에서의 폐사율에는 어떠한 계절별 환경요인도 유의적으로 작용하 지 않음을 알 수 있었다(p>0.05). 따라서 계절에 상관없이 분만사와 이유자돈사의 경우에는 일교차를 적정수준인 2℃ 이하로 유지하고, 상대적으로 기온이 낮은 가을·겨울철에는 예열과정을 거쳐 외부의 찬 공기가 직접 돈사 내부로 유입되는 것을 방지하고, 난방 등을 통해 돈사 내 평균기온을 적절하게 유 지한다면 이유자돈의 폐사율을 낮춤으로써 농장의 모돈 1두당 연간 출하두수를 향상시킬 수 있을 것으 로 판단된다.

Human hepatitis B virus (HBV) infection remains a serious public health problem worldwide, as it is one of the main risk factors for hepatocellular carcinoma (HCC). Cross-species transmission of HBV has been reported in non-human primates, and pigs may also be infected with HBV or an HBV-like agent. The purpose of this study was to demonstrate the presence of HBV antigens and anti-HBV antibodies in pig sera, providing further support for the existence of HBV or an HBV-like agent in pig populations. The HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) in pig serum samples were detected using HBsAg and HBeAg ELISA Kits, respectively. Antibodies to HBsAg and the Hepatitis B core antigen (HBcAg) in serum samples were also detected using anti-HBsAg and anti-HBcAg antibody ELISA Kits, respectively. HBsAg and HBeAg were detected in 7 of 442 (1.6%) and 7 of 184 (3.8%) pig serum samples, respectively. Furthermore, antibodies specific to HBsAg and HBcAg were identified in 45 of 442 (10.2%) and 39 of 434 (9.0%) pig serum samples, respectively. However, neither HBV DNA nor antibodies to HBeAg were detected in 409 and 298 pig serum samples, respectively. HBV antigens and anti-HBV antibodies were both present in a considerable number of pig serum samples, suggesting that pigs could be infected with a variant HBV or an HBV-like agent. Further studies will be necessary to confirm cross-species infection of pigs with HBV.

Mycoplasma hyorhinis (M. hyorhinis) is considered an etiological agent of arthritis in suckling pigs. Recently, some M. hyorhinis strains were shown to produce pneumonia that is indistinguishable from the mycoplasmosis caused by M. hyopneumoniae. In this study, we developed a sensitive and specific PCR assay to detect M. hyorhinis and applied the developed PCR assay for detection of Mycoplasma infection in clinical piglets infected with M. hyorhinis. We developed a new PCR assay using a M. hyorhinis-specific primer pair, Mrhin-F and Mrhin-R, designed from the Mycoplasma 16S-23S rRNA internal transcribed spacer (ITS) region. The primers and probe for the assay were designed from regions in the Mycoplasma 16S-23S rRNA ITS unique to M. hyorhinis. The developed PCR assay was very specific and sensitive for the detection of M. hyorhinis. The assay could detect the equivalent of 1 pg of target template DNA, which indicates that the assay was very sensitive. In addition, M. hyorhinis PCR assay detected only M. hyorhinis and not any other Mycoplasma or bacterial spp. of other genera. The new developed PCR assay effectively detected M. hyorhinis infection in pigs. We suggest that this PCR assay using a M. hyorhinis-specific primer pair, Mrhin-F and Mrhin-R, could be useful and effective for monitoring M. hyorhinis infection in pigs.