Influence of Mycoplasma bovis infection on milk production and quality of Holstein dairy cows.

We wished to determine if Mycoplasma bovis infection can negatively impact milk quality and production in Holstein dairy cows. For this Research Communication, milk samples (271) from Holstein cows from 3 herds were screened for M. bovis by real-time PCR. Positive (n = 21) and negative animals (n = 21) were matched by herd, age, lactations and days in milk (DIM). Pairs were evaluated in 7 stages of lactation: D1-50, D51-100, D101-150, D151-200, D201-250, D251-300, and D ≥ 301. A mixed model was used to assess the effect of groups (M. bovis+ × M.bovis-), time (lactation) and groups × time interaction. Cows positive for M. bovis had lower average milk production per day and high somatic cells count (SCC).

An Assessment of Secondary Clinical Disease, Milk Production and Quality, and the Impact on Reproduction in Holstein Heifers and Cows from a Single Large Commercial Herd Persistently Infected with Bovine Viral Diarrhea Virus Type 2.

The aim of this study was to evaluate secondary clinical disease, milk production efficiency and reproductive performance of heifers and cows persistently infected (PI) with bovine viral diarrhea virus type 2 (BVDV type 2). PI animals (n = 25) were identified using an antigen capture ELISA of ear notch samples. They were distributed into three age groups: ≤ 12 (n = 8), 13 to 24 (n = 6) and 25 to 34 (n = 11) months old. A control group of BVDV antigen ELISA negative female cattle that were age matched to the PI animals was utilized from the same herd. The PI group had a 1.29 higher odds ratio for diarrhea than controls (p = 0.001, IC95% = 1.032-1.623) and 1.615 greater chance of developing bovine respiratory disease (BRD) (p = 0.012, IC95% = 1.155-2.259). The age at first insemination (p = 0.012) and number of insemination attempts required to establish the first pregnancy (p = 0.016) were both higher for PI than controls. Milk production was higher for control cows than PI cows during most of the sampling periods. Somatic cell counts (SCC) were higher in PI cows than the controls at all sampling points across lactation (p ≤ 0.042). PI cattle had a higher incidence of disease, produced less milk, a higher SCC, and poorer reproductive performance than control cattle in this study.

Comparison between DNA Detection in Trigeminal Nerve Ganglia and Serology to Detect Cattle Infected with Bovine Herpesviruses Types 1 and 5.

Bovine herpesviruses (BoHVs) types 1 (BoHV-1) and 5 (BoHV-5) are alphaherpesviruses of major importance to the bovine production chain. Such viruses are capable of establishing latent infections in neuronal tissues. Infected animals tend to develop a serological response to infection; however, such response-usually investigated by antibody assays in serum-may eventually not be detected in laboratory assays. Nevertheless, serological tests such as virus neutralization (VN) and various enzyme-linked immunosorbent assays (ELISAs) are widely employed to check individual or herd status of BoHV infections. The correlation between detection of antibodies and the presence of viral nucleic acids as indicatives of infection in infected cattle has not been deeply examined. In order to investigate such correlation, 248 bovine serum samples were tested by VN to BoHV-1 and BoHV-5, as well as in a widely employed (though not type-differential) gB ELISA (IDEXX IBR gB X2 Ab Test) in search for antibodies to BoHVs. Immediately after blood withdrawal, cattle were slaughtered and trigeminal ganglia (TG) excised for DNA extraction and viral nucleic acid detection (NAD) by nested PCR. Neutralizing antibodies to BoHV-1 and/or BoHV-5 were detected in 44.8% (111/248) of sera, whereas the gB ELISA detected antibodies in 51.2% (127/248) of the samples. However, genomes of either BoHV-1, BoHV-5, or both, were detected in TGs of 85.9% (213/248) of the animals. These findings reveal that the assays designed to detect antibodies to BoHV-1 and/or BoHV-5 employed here may fail to detect a significant number of latently infected animals (in this study, 35.7%). From such data, it is clear that antibody assays are poorly correlated with detection of viral genomes in BoHV-1 and BoHV-5-infected animals.

Evaluation of a bovine pregnancy-associated glycoprotein enzyme-linked immunosorbent assay kit for serological diagnosis of pregnancy in sheep / Avaliação de um kit de ensaio imunoenzimático na detecção de glicoproteínas associadas à prenhez bovina para o diagnóstico sorológico de gestação em ovinos

ABSTRACT: Pregnancy diagnosis is an important tool for farm management. Ultrasonography is the main technique used for pregnancy diagnosis in ewes. As an alternative, radioimmunoassay (RIA) allows accurate and early detection of pregnancy-associated glycoproteins (PAGs) in sheep blood. However, radioactive-based techniques, as RIA, have been increasingly inadvisable due to environmental risk. Homology between ovine and bovine PAGs is high, and ELISA kits used for PAGs detection in cattle are safer than RIA. Thus, this study aimed to evaluate the feasibility of PAGs detection for pregnancy diagnosis in sheep serum samples using an ELISA kit produced for cattle. The sensitivity and specificity of the ELISA kit were 93.5% and 98.9%, respectively, whereas positive and negative predictive values were 99.0% and 93.1%, respectively, in comparison to ultrasonography diagnostic (control). PAGs reached consistently detectable concentrations in ovine serum around 33 days after mating. Accuracy of the ELISA test was 96.1% from 33 days of pregnancy until lambing. After parturition, PAGs were still detectable seven days post-lambing. However, from 21 days post-parturition, PAGs from the previous pregnancy were no longer detected in serum samples. In conclusion, the bovine ELISA kit can accurately detect pregnancy in sheep 33 days following mating, while PAGs levels from the previous gestation are no longer detected from 21 days post-partum. The evaluated ELISA test is a reliable tool for pregnancy diagnosis in sheep at random stages and as a complementary exam at early gestation.

RESUMO: O diagnóstico de gestação é uma ferramenta importante no manejo da propriedade. A ultrassonografia é a principal técnica utilizada no diagnóstico de prenhez em ovelhas. Como alternativa, o radiomunoensaio (RIA) permite acurácia e a detecção precoce de proteínas associadas à prenhez (PAGs) no sangue. No entanto, as técnicas radioativas, como o RIA, têm sido cada vez mais desaconselháveis, devido ao risco ambiental. A homologia entre PAGs de ovinos e bovinos é alta, e os kits de ELISA utilizados para a detecção de PAGs em bovinos são mais seguros do que RIA. Portanto, este estudo teve como objetivo avaliar a viabilidade de detecção de PAGs no soro ovino para diagnóstico de gestação em soro ovino, utilizando um kit de ELISA produzido para bovinos. A sensibilidade e a especificidade do kit de ELISA foram de 93,5% e 98,9%, respectivamente, enquanto que os valores preditivos positivo e negativo foram de 99,0% e 93,1%, respectivamente, em comparação com a ultrassonografia (utilizada como referência). As PAGs atingiram concentrações consistentemente detectáveis no soro ovino em torno de 33 dias após o acasalamento. A acurácia do teste de ELISA foi de 96,1% a partir de 33 dias de gestação até o parto. As PAGs ainda eram detectáveis sete dias pós-parto. No entanto, a partir de 21 dias após o parto, as PAGs da prenhez anterior já não eram detectadas no soro. Em conclusão, o kit de ELISA bovino pode detectar a prenhez com precisão em ovelhas a partir de 33 dias após o acasalamento, e os níveis de PAGs da gestação anterior não são detectados a partir de 21 dias pós-parto. O teste de ELISA avaliado é uma ferramenta confiável para o diagnóstico de gestação em ovelhas em estágios aleatórios e como exame complementar no início da gestação.

Molecular identification of bovine papillomaviruses associated with cutaneous warts in southern Brazil.

Bovine papillomaviruses (BPVs) are widespread pathogens mainly associated with benign, self-limiting, cutaneous lesions (warts). At least 8 viral types, defined by serology or nucleotide sequences of the L1 gene, have been identified to date. Different serotypes are associated with the specific type and morphology of the lesion and with particular geographical regions. This article describes the molecular identification of papillomaviruses from Brazilian cattle (n = 48) and horses (n = 1) through partial amplification and sequencing of the L1 gene. Bovine papillomavirus-1 (BPV-1) was identified in warts from 29 cattle (59%), BPV-6 from 9 cattle (18%), and BPV-2 in 8 lesions (16%). Warts of 2 cattle harbored L1 sequences of a new BPV type (BAA5), otherwise identified almost exclusively in healthy skin. The newly proposed BPV type "BR-UEL-4" was identified in a sarcoid tumor of a horse. Thus, the present report provides information on the main types of BPV involved in bovine papillomatosis in Brazil and reveals a new viral type associated with equine sarcoid, which to date has been attributed exclusively to BPV-1 and BPV-2.

Acute and latent infection by bovine herpesvirus type 2 in a guinea pig model.

Bovine herpetic mammillits is a self-limiting cutaneous disease of the udder and teats of cows associated with bovine herpesvirus 2 (BoHV-2) whose pathogenesis is poorly understood. This article describes the use of guinea pigs (Cavia porcellus) to study the pathogenesis of BoHV-2 infection. Twelve weanling female guinea pigs inoculated subcutaneously with BoHV-2 in the genitalia and teats developed local hyperemia, edema, vesicles, ulcers and scabs. Infectious virus was recovered between days 3 and 7 post-infection (pi) from the genital area (9/12) and teats (1/12); and all inoculated animals seroconverted (virus-neutralizing titers of 16-128). Histological examination of lesions revealed lymphoplasmacytic perivascular infiltrates and intranuclear inclusion bodies in keratinocytes. PCR examination of tissues collected at day 35 pi detected latent viral DNA predominantly in lumbosacral spinal segments. In another experiment, eight females inoculated with BoHV-2 in the genitalia and treated with dexamethasone (Dx) at day 35 pi developed mild to moderate local signs, yet no virus could be recovered from lesions. PCR examination of spinal segments from these animals confirmed the presence of latent viral DNA. These results demonstrate that guinea pigs are susceptible to BoHV-2 infection and therefore may be used to study selected aspects of BoHV-2 biology.

Prevalência de anticorpos contra o vírus da mamilite herpética em bovinos do Rio Grande do Sul, Brasil / Prevalence of antibodies to bovine herpes mammillitis virus in cattle of Rio Grande do Sul, Brazil

O herpesvírus bovino tipo 2 (BoHV-2), agente da mamilite herpética bovina (BHM), possui distribuição mundial e foi identificado no Brasil, na década de 70. A partir de então, casos de mamilite clinicamente compatíveis com a BHM têm sido relatados por técnicos e produtores, o que sugere a presença e disseminação do agente no rebanho bovino brasileiro. Este trabalho relata um inquérito sorológico da infecção pelo BoHV-2 no Estado do Rio Grande do Sul (RS), em amostras coletadas como parte do Programa Nacional de Controle e Erradicação da Brucelose e Tuberculose (PNCBT). Um total de 2.213 amostras de soro coletadas de fêmeas bovinas com idade igual ou superior a 24 meses, predominantemente de rebanhos leiteiros, de 136 municípios pertencentes a sete macrorregiões do RS, foram testadas para anticorpos anti-BoHV-2 pela técnica de soro-neutralização (SN). Anticorpos anti-BoHV-2 (títulos > 2) foram detectados em 24,5 por cento (543/2.213) das amostras. Os índices de positividade variaram entre 12,9 por cento (22/170), na região metropolitana de Porto Alegre, e 48,9 por cento (69/137), na região centro oriental do RS. Em geral, os rebanhos leiteiros apresentaram prevalência maior (32,3 por cento), seguidos dos rebanhos mistos (22 por cento) e de corte (17,6 por cento). Esses resultados demonstram uma ampla disseminação da infecção pelo BoHV-2 no rebanho bovino do Estado e sugerem a participação do agente em parte dos casos de mamilite descritos em gado leiteiro.

Bovine herpesvirus type 2 (BoHV-2), the agent of bovine herpetic mammillitis (BHM), has a worldwide distribution and was identified in Brazil in the 70's. Thereafter, cases of bovine mammillitis clinically compatible with BHM have been frequently reported by cattle owners and veterinarians, mainly in dairy herds, suggesting the dissemination of BoHV-2 among Brazilian cattle. This article reports a serologic survey for BoHV-2 antibodies in cattle from Rio Grande do Sul (RS), using serum samples obtained upon a statistically planned sampling as a part of the Program of Control/Eradication of Brucellosis and Tuberculosis (PNCBT). A total of 2.213 serum samples from cows with 24 months or older, predominantly from dairy herds, from 136 counties located in seven geographical regions of RS were tested by virus neutralization (VN). Serum samples with VN titers > 2 were detected in 24.5 percent (543/2.213) of the animals. Prevalence rates varied from 12.9 percent (22/170) in Porto Alegre metropolitan area to 48,9 percent (69/137) in the central-eastern region. In most regions, the highest prevalence rates were observed in dairy herds (32.3 percent), followed by double proposit (22 percent) and beef herds (17.6 percent). These results demonstrate that BoHV-2 infection is widespread among cattle in RS, and potentially involved in cases of mammillitis described in dairy cows.

Soroneutralização e imunofluorescência utilizando anticorpos monoclonais no diagnóstico rápido de infecções pelo herpesvírus bovino tipos 1 e 5 (BHV-1 e BHV-5) / Serum neutralizing and fluorescent antibody assays using monoclonal antibodies in rapid diagnostic tests for bovine herpesvirus types 1 (BHV-1) and 5 (BHV-5) infections

Anticorpos monoclonais (AcMs) produzidos com uma amostra brasileira do herpesvírus bovino tipo 5 (BHV-5) foram utilizados na adaptação e padronização de técnicas rápidas para o diagnóstico de infecções pelo BHV-1 e BHV-5. A detecção de antígenos virais por imunofluorescência em células descamativas (IFCD) foi comparada com o isolamento viral, em secreções nasais de 16 bezerros, sendo 6 inoculados com o BHV-1 e 10 com o BHV-5. De 203 amostras testadas, 182 (89,6 por cento) apresentaram resultados concordantes nos dois testes (143 positivas; 39 negativas). Comparando-se com o isolamento, a IFCD apresentou sensibilidade de 96,6 por cento, especificidade de 70,9 por cento, e precisão de 89,6 por cento. Os AcMs também foram utilizados para detectar antígenos do BHV-5 em impressões frescas do cérebro de bezerros acometidos de enfermidade neurológica e em células de cultivo utilizadas na técnica de soroneutralização (SN), permitindo a obtenção dos resultados em 24 horas. A técnica, denominada de soroneutralização rápida (SNR), apresentou sensibilidade de 97,3 por cento; especificidade de 95,5 por cento e precisão de 96,2 por cento em comparação com a SN tradicional; e sensibilidade de 94,7 por cento, especificidade de 97,3 por cento e precisão de 96,1 por cento em comparação com um ELISA comercial. Esses resultados demonstram que esses AcMs podem ser muito úteis para uso em técnicas rápidas de diagnóstico de infecções suspeitas de BHV-1 ou de BHV-5, sobretudo em situações de surto, quando a tomada de decisões adequadas depende de um diagnóstico rápido e confiável.