Recent advances in early pregnancy loss diagnosis in dairy cows: New approaches.

Early pregnancy loss is a primary cause of low reproductive rates in dairy cows, posing severe economic losses to dairy farming. The accurate diagnosis of dairy cows with early pregnancy loss allows for oestrus synchronization, shortening day open, and increasing the overall conception rate of the herd. Several techniques are available for detecting early pregnancy loss in dairy cows, including rectal ultrasound, circulating blood progesterone, and pregnancy-associated glycoproteins (PAGs). Yet, there is a need to improve on existing techniques and develop novel strategies to identify cows with early pregnancy loss accurately. This manuscript reviews the applications of rectal ultrasound, circulating blood progesterone concentration, and PAGs in the diagnosis of pregnancy loss in dairy cows. The manuscript also discusses the recent progress of new technologies, including colour Doppler ultrasound (CDUS), interferon tau-induced genes (ISGs), and exosomal miRNA in diagnosing pregnancy loss in dairy cows. This study will provide an option for producers to re-breed cows with pregnancy loss, thereby reducing the calving interval and economic costs. Meanwhile, this manuscript might also act as a reference for exploring more economical and precise diagnostic technologies for early pregnancy loss in dairy cows.

Development and application of one-step multiplex Real-Time PCR for detection of three main pathogens associated with bovine neonatal diarrhea.

Introduction: Neonatal calf diarrhea (NCD) is one of the most common diseases in calves, causing huge economic and productivity losses to the bovine industry worldwide. The main pathogens include bovine rotavirus (BRV), bovine coronavirus (BCoV), and Enterotoxigenic Escherichia coli (ETEC) K99. Since multiple infectious agents can be involved in calf diarrhea, detecting each causative agent by traditional methods is laborious and expensive. Methods: In this study, we developed a one-step multiplex Real-Time PCR assay to simultaneously detect BRV, BCoV, and E. coli K99+. The assay performance on field samples was evaluated on 1100 rectal swabs of diseased cattle with diarrhea symptoms and compared with the conventional gel-based RT-PCR assay detect BRV, BCoV, and E. coli K99+. Results: The established assay could specifically detect the target pathogens without cross-reactivity with other pathogens. A single real-time PCR can detect ~1 copy/µL for each pathogen, and multiplex real-time PCR has a detection limit of 10 copies/µL. Reproducibility as measured by standard deviation and coefficient of variation were desirable. The triple real-time PCR method established in this study was compared with gel-based PT-PCR. Both methods are reasonably consistent, while the real-time PCR assay was more sensitive and could rapidly distinguish these three pathogens in one tube. Analysis of surveillance data showed that BRV and BCoV are major enteric viral pathogens accounting for calves' diarrhea in China. Discussion: The established assay has excellent specificity and sensitivity and was suitable for clinical application. The robustness and high-throughput performance of the developed assay make it a powerful tool in diagnostic applications and calf diarrhea research. ​.

Biochemical and molecular characterization of Campylobacter fetus isolates from bulls subjected to bovine genital campylobacteriosis diagnosis in Spain.

BACKGROUND: Bovine genital campylobacteriosis (BGC) is caused by Campylobacter fetus subsp. venerealis (Cfv) including its biovar intermedius (Cfvi). This sexually transmitted disease induces early reproductive failure causing considerable economic losses in the cattle industry. Using a collection of well-characterized isolates (n = 13), C. fetus field isolates (n = 64) and saprophytic isolates resembling Campylobacter (n = 75) obtained from smegma samples of breeding bulls, this study evaluated the concordance of the most used phenotypic (H2S production in cysteine medium and 1% glycine tolerance) and molecular (PCR) methods for the diagnosis of BGC and assessed possible cross-reactions in the molecular diagnostic methods. RESULTS: Characterization at the subspecies level (fetus vs. venerealis) of C. fetus isolated from bull preputial samples using phenotypic and molecular (PCR targeting nahE and ISCfe1) methods showed moderate concordance (κ = 0.462; CI: 0.256-0.669). No cross-reactions were observed with other saprophytic microaerophilic species or with other Campylobacter species that can be present in preputial samples. Whole genome sequencing (WGS) of discrepant isolates showed 100% agreement with PCR identification. For the differentiation of Cfv biovars, comparison of the H2S test (at 72 h and 5 days of incubation) and a PCR targeting the L-cysteine transporter genes showed higher concordance when H2S production was assessed after 5 days (72 h; κ = 0.553, 0.329-0.778 CI vs. 5 days; κ = 0.881, 0.631-1 CI), evidencing the efficacy of a longer incubation time. CONCLUSIONS: This study confirmed the limitations of biochemical tests to correctly identify C. fetus subspecies and biovars. However, in the case of biovars, when extended incubation times for the H2S test (5 days) were used, phenotypic identification results were significantly improved, although PCR-based methods produced more accurate results. Perfect agreement of WGS with the PCR results and absence of cross-reactions with non-C. fetus saprophytic bacteria from the smegma demonstrated the usefulness of these methods. Nevertheless, the identification of new C. fetus subspecies-specific genes would help to improve BGC diagnosis.

A rare case of adventitious placentation (diffuse semi-placenta) in a Jersey cow.

Placental abnormalities more frequently occur during pregnancy of somatic cell clones and may lead to pregnancy loss or dystocia. Adventitious placentation, or diffuse semi-placenta, is determined by the development of areas of accessory placentation between the cotyledons due to the abnormal growth of placentomes.After a full-term pregnancy, a 3-year-old Jersey heifer was referred for dystocia which resulted in the delivery of a dead calf. The cause of dystocia was found to be foetal malposition, while the placenta was physiologically expelled after dystocia resolution.Grossly, cotyledons appeared reduced in size and number in one placental horn, while the surface of the other horn was covered with microplacentomes. Numerous villous structures without trophoblastic coating were highlighted after histopathology. The dominant sign was an inflammatory reaction. The findings were consistent with inter-cotyledonal placentitis, which led to adventitial placentation.Diffuse semi-placenta compensates for the inadequate development of placentomes and may occur as a congenital or acquired defect. The outcome depends on its severity: in the worst scenario, pregnancy may not proceed beyond midterm and may be complicated by hydrallantois. In the case under examination, the dimensions of the cotyledons (from 2 to 10 cm) allowed for the natural course of pregnancy.

Torsion of the spiral colon in cattle- a retrospective analysis of 58 cases.

BACKGROUND: Torsion of the spiral colon (TSC) describes twisting of the spiral colon around its mesentery. The present study reviewed the medical records of 58 cows and heifers with TSC and described the findings, treatment and outcome. RESULTS: All cases had an abnormal general condition, and the main vital sign abnormalities were tachycardia (72.4%), tachypnoea (67.2%) and decreased rectal temperature (51.8%). Signs of colic were seen in 62.1% of the cows. The most common intestinal abnormalities were an empty or almost empty rectum (96.6%), reduced or absent rumen motility (93.2%), positive ballottement and/or percussion and simultaneous auscultation on the right side of the abdomen (87.9%), reduced or absent intestinal motility (84.5%) and dilatation of the large intestines (spiral colon and/or caecum, 70.7%) diagnosed by transrectal palpation. The main biochemical changes were hypermagnesaemia (70.8%), hypocalcaemia (70.8%), and acidosis (66.7%). Haemoconcentration was found in 63.8%. The main ultrasonographic findings were reduced to absent small intestinal motility (83.3%), dilated small intestines (69.6%) and ascites (66.7%). The spiral colon was dilated in 44.0% of the cows and the caecum in 24.0%. The actual site of torsion could not be visualised. Based on the clinical findings, TSC was diagnosed in 22.4% and caecal dilatation in 50.0% of the cows. A tentative diagnosis of small intestinal ileus was made in another 10.3% of the cows, and a definitive diagnosis of small intestinal ileus in 17.3%. Fifty-three cows underwent right flank laparotomy, and the TSC could be reduced in 26. Twenty-six of the 58 (44.8%) cows were discharged and 32 (55.2%) were euthanased before, during or after surgery. CONCLUSIONS: Acute illness, a sparse amount of faeces in the rectum and dilated spiral colon and caecum are characteristic findings of TSC. The final diagnosis often relies on the surgical or postmortem findings. Cattle with TSC should be treated surgically without delay. The prognosis is guarded with a survival rate of 44.8%.

Seroprevalence and molecular detection of foot and mouth disease virus in cattle in selected districts of Wolaita Zone, Southern Ethiopia.

Foot and mouth disease (FMD) is a highly contagious, endemic, and acute viral cattle ailment that causes major economic damage in Ethiopia. Although several serotypes of the FMD virus have been detected in Ethiopia, there is no documented information about the disease's current serostatus and serotypes circulating in the Wolaita zone. Thus, from March to December 2022, a cross-sectional study was conducted to evaluate FMDV seroprevalence, molecular detection, and serotype identification in three Wolaita Zone sites. A multistage sample procedure was used to choose three peasant associations from each study region, namely Wolaita Sodo, Offa district, and Boloso sore district. A systematic random sampling technique was employed to pick 384 cattle from the population for the seroprevalence research, and 10 epithelial tissue samples were purposefully taken from outbreak individuals for molecular detection of FMDV. The sera were examined using 3ABC FMD NSP Competition ELISA to find antibodies against FMDV non-structural proteins, whereas epithelial tissue samples were analyzed for molecular detection using real-time RT-PCR, and sandwich ELISA was used to determine the circulating serotypes. A multivariable logistic regression model was used to evaluate the associated risk variables. The total seroprevalence of FMD in cattle was 46.88% (95% CI 41.86-51.88), with Wolaita Sodo Town having the highest seroprevalence (63.28%). As a consequence, multivariable logistic regression analysis revealed that animal age, herd size, and interaction with wildlife were all substantially related to FMD seroprevalence (p < 0.05). During molecular detection, only SAT-2 serotypes were found in 10 tissue samples. Thus, investigating FMD outbreaks and identifying serotypes and risk factors for seropositivity are critical steps in developing effective control and prevention strategies based on the kind of circulating serotype. Moreover, further research for animal species other than cattle was encouraged.

Evaluation of ELISA in raw milk for detection of antibodies to Mycobacterium avium subsp. paratuberculosis in dairy herd.

Paratuberculosis (PTBC) is a chronic intestinal disease of animals caused by Mycobacterium avium paratuberculosis (MAP). MAP infection is diagnosed through indirect tests based on the immune response. The aims of this study were to compare the performance of two milk ELISA for the diagnosis of PTBC and to assess the bulk tank milk (BTM) MAP exposure in dairy cattle in Argentina. A total of 357 fecal, serum, and milk samples were collected. The fecal samples were processed by culture for MAP isolation, while both, serum and milk samples were used for the detection of antibodies by two different ELISA tests, "in-house" and commercial kit. MAP was isolated in 3.9% of fecal samples. For milk ELISA, poor concordances were obtained. Optimized cut-off points were calculated. The highest sensitivity and specificity values (64% and 80% respectively) were obtained with the combination of MAP isolation and commercial milk ELISA. The results indicate that the combination of different techniques to identify of dairy cattle infected with MAP increases the efficiency of diagnosis. In addition, BTM  samples (n=98) were evaluated to determine herd status using the commercial kit during two seasons, identifying 33.3% of positive samples in autumn and 35.4% in spring.

Small intestinal volvulus in 47 cows.

Objective: To describe the findings, treatment, and outcome of small intestinal volvulus (SIV) in 47 cows. Animals and procedure: Retrospective analysis of medical records. Comparison of the findings for 18 surviving and 29 non-surviving cows. Results: The most common abnormal vital signs were tachycardia (68.0%), tachypnea (59.6%), and decreased rectal temperature (51.1%). Signs of colic occurred in 66.0% of cows in the study. Rumen motility was reduced or absent in 93.6% of cows, and intestinal motility in 76.6%. Clinical signs on ballottement and/or percussion and simultaneous auscultation were positive on the right side in 78.7% of cows. Transrectal examination showed dilated small intestines in 48.9% of cows. The rectum contained little or no feces in 93.6% of cows. The principal laboratory abnormalities were hypocalcemia (74.1%), hypokalemia (73.8%), azotemia (62.8%), hypermagnesemia (61.6%), and hemoconcentration (60.0%). The principal ultrasonographic findings were dilated small intestines (87.1%) and reduced or absent small intestinal motility (85.2%). Forty-one of the 47 cows underwent right flank laparotomy and the SIV was reduced in 21 cows. When comparing the clinical and laboratory findings of 18 surviving and 29 non-surviving cows, the groups differed significantly with respect to severely abnormal general condition (16.7 versus 37.9%), rumen stasis (22.2 versus 79.3%), intestinal atony (16.7 versus 48.3%), serum urea concentration (6.5 versus 9.8 mmol/L), and serum magnesium concentration (0.98 versus 1.30 mmol/L). In summary, 38.3% of the cows were discharged and 61.7% were euthanized before, during, or after surgery. Conclusion and clinical relevance: An acute course of disease, little or no feces in the rectum, and dilated small intestines were characteristic of SIV in this study population.

Volvulus de l'intestin grêle chez 47 vaches. Objectif: Décrire les données, le traitement et les résultats du volvulus de l'intestin grêle (SIV) chez 47 vaches. Animaux et procédure: Analyse rétrospective des dossiers médicaux. Comparaison des résultats pour 18 vaches survivantes et 29 vaches non survivantes. Résultats: Les signes vitaux anormaux les plus courants étaient la tachycardie (68,0 %), la tachypnée (59,6 %) et la diminution de la température rectale (51,1 %). Des signes de coliques sont apparus chez 66,0 % des vaches étudiées. La motilité du rumen était réduite ou absente chez 93,6 % des vaches et la motilité intestinale chez 76,6 %. Les signes cliniques de ballottement et/ou percussion et auscultation simultanée étaient positifs du côté droit chez 78,7 % des vaches. L'examen transrectal a montré une dilatation de l'intestin grêle chez 48,9 % des vaches. Le rectum contenait peu ou pas de matières fécales chez 93,6 % des vaches. Les principales anomalies des analyses de laboratoire étaient l'hypocalcémie (74,1 %), l'hypokaliémie (73,8 %), l'azotémie (62,8 %), l'hypermagnésémie (61,6 %) et l'hémoconcentration (60,0 %). Les principaux résultats échographiques étaient une dilatation de l'intestin grêle (87,1 %) et une motilité intestinale réduite ou absente (85,2 %). Quarante et une des 47 vaches ont subi une laparotomie du flanc droit et le SIV a été corrigé chez 21 vaches. En comparant les résultats cliniques et biologiques de 18 vaches survivantes et de 29 vaches non survivantes, les groupes différaient significativement en ce qui concerne l'état général sévèrement anormal (16,7 contre 37,9 %), la stase du rumen (22,2 contre 79,3 %), l'atonie intestinale (16,7 contre 48,3 %), la concentration sérique d'urée (6,5 contre 9,8 mmol/L) et la concentration sérique de magnésium (0,98 contre 1,30 mmol/L). En résumé, 38,3 % des vaches ont reçu leur congé et 61,7 % ont été euthanasiées avant, pendant ou après l'intervention chirurgicale. Conclusion et pertinence clinique: Une évolution aiguë de la maladie, peu ou pas de selles dans le rectum et un intestin grêle dilaté étaient caractéristiques du SIV dans cette population étudiée.(Traduit par Dr Serge Messier).

Automated dairy cattle lameness detection utilizing the power of artificial intelligence; current status quo and future research opportunities.

Lameness represents a major welfare and health problem for the dairy industry across all farming systems. Visual mobility scoring, although very useful, is labour-intensive and physically demanding, especially in large dairies, often leading to inconsistencies and inadequate uptake of the practice. Technological and computational advancements of artificial intelligence (AI) have led to the development of numerous automated solutions for livestock monitoring. The objective of this study was to review the automated systems using AI algorithms for lameness detection developed to-date. These systems rely on gait analysis using accelerometers, weighing platforms, acoustic analysis, radar sensors and computer vision technology. The lameness features of interest, the AI techniques used to process the data as well as the ground truth of lameness selected in each case are described. Measures of accuracy regarding correct classification of cows as lame or non-lame varied with most systems being able to classify cows with adequate reliability. Most studies used visual mobility scoring as the ground truth for comparison with only a few studies using the presence of specific foot pathologies. Given the capabilities of AI, and the benefits of early treatment of lameness, longitudinal studies to identify gait abnormalities using automated scores related to the early developmental stages of different foot pathologies are required. Farm-specific optimal thresholds for early intervention should then be identified to ameliorate cow health and welfare but also minimise unnecessary inspections.

Prepartum behaviors as early indicators for postpartum energy associated biomarkers status in Holstein dairy cows.

Our main aim was to investigate the predictive value of prepartum behaviors such as total daily rumination (TDR), total daily activity (TDA) and dry matter intake (DMI) as early indicators to detect cows at risk for hyperketonemia (HYK), hypoglycemia (HYG) or high non-esterified fatty acid (NEFA) status in the first (wk1) and second week (wk2) postpartum. In a case control study, 64 Holstein cows were enrolled 3 weeks before the expected time of calving and monitored until 15 days in milk (DIM). Postpartum blood samples were taken at D3 and D6 for wk1 and at D12 and D15 for wk2 to measure beta-hydroxybutyrate, NEFA and glucose concentration. Ear-mounted accelerometers were used to measure TDR and TDA. DMI and milk yield were obtained from farm records. Relationships between the average daily rate of change in prepartum TDR (ΔTDR), TDA (ΔTDA), and DMI (ΔDMI) with postpartum HYK, HYG and NEFA status in wk1 and wk2 post-partum were evaluated using linear regression models. Models were adjusted for potential confounding variables, and covariates retained in the final models were determined by backward selection. No evidence was found to support the premise that prepartum ΔTDR, ΔTDA or ΔDMI predicted postpartum HYK, HYG or NEFA status in wk1 or in wk2. Overall, prepartum ΔTDR, ΔTDA and ΔDMI were not effective predictors of HYK, HYG or NEFA status in the first 2 weeks postpartum.

Identification of miR-29a as a novel biomarker for lumpy skin disease virus exposure in cattle.

Micro RNAs (miRNAs) have been implicated in the regulation of maturation, proliferation, differentiation, and activation of immune cells. In this study, we demonstrated that miR-29a antagonizes IFN-γ production at early times post-LSDV infection in cattle. miR-29a was predicted to target upstream IFN-γ regulators, and its inhibition resulted in enhanced IFN-γ production in sensitized peripheral blood mononuclear cells (PBMCs). Further, stimulation of PBMCs with LSDV antigen exhibited lower levels of miR-29a, concomitant with a potent cell-mediated immune response (CMI), characterized by an increase in LSDV-specific CD8+ T cell counts and enhanced levels of IFN-γ, which eventually facilitated virus clearance. In addition, a few immunocompromised cattle (developed secondary LSDV infection at ~ 6 months) that failed to mount a potent cell-mediated immune response, were shown to maintain higher miR-29a levels. Furthermore, as compared to the sensitized crossbred cattle, PBMCs from sensitized Rathi (a native Indian breed) animals exhibited lower levels of miR-29a along with an increase in CD8+ T cell counts and enhanced levels of IFN-γ. Finally, we analysed that a ≥ 60% decrease in miR-29a expression levels in the PBMCs of sensitized cattle correlated with a potent CMI response. In conclusion, miR-29a expression is involved in antagonizing the IFN-γ response in LSDV-infected cattle and may serve as a novel biomarker for the acute phase of LSDV infection, as well as predicting the functionality of T cells in sensitized cattle. In addition, Rathi cattle mount a more potent CMI response against LSDV than crossbred cattle.

Revisiting the Importance of Orthobunyaviruses for Animal Health: A Scoping Review of Livestock Disease, Diagnostic Tests, and Surveillance Strategies for the Simbu Serogroup.

Orthobunyaviruses (order Bunyavirales, family Peribunyaviridae) in the Simbu serogroup have been responsible for widespread epidemics of congenital disease in ruminants. Australia has a national program to monitor arboviruses of veterinary importance. While monitoring for Akabane virus, a novel orthobunyavirus was detected. To inform the priority that should be given to this detection, a scoping review was undertaken to (1) characterise the associated disease presentations and establish which of the Simbu group viruses are of veterinary importance; (2) examine the diagnostic assays that have undergone development and validation for this group of viruses; and (3) describe the methods used to monitor the distribution of these viruses. Two search strategies identified 224 peer-reviewed publications for 33 viruses in the serogroup. Viruses in this group may cause severe animal health impacts, but only those phylogenetically arranged in clade B are associated with animal disease. Six viruses (Akabane, Schmallenberg, Aino, Shuni, Peaton, and Shamonda) were associated with congenital malformations, neurological signs, and reproductive disease. Diagnostic test interpretation is complicated by cross-reactivity, the timing of foetal immunocompetence, and sample type. Serological testing in surveys remains a mainstay of the methods used to monitor the distribution of SGVs. Given significant differences in survey designs, only broad mean seroprevalence estimates could be provided. Further research is required to determine the disease risk posed by novel orthobunyaviruses and how they could challenge current diagnostic and surveillance capabilities.

Inter-laboratory ring trial to compare four quantitative polymerase chain reaction assays employed for detection of Mycobacterium avium subspecies paratuberculosis.

Johne's disease is an infectious enteric disease caused by Mycobacterium avium subspecies paratuberculosis (MAP) affecting ruminant species worldwide. In Project 1, an independent performance comparison ring trail was conducted between three different commercial MAP quantitative polymerase chain reaction (qPCR) assay services (B, C, and D) currently marketed in Great Britain by three separate laboratories against each other and against a fourth assay (A) not available commercially in Great Britain. A total of 205 individual ovine and bovine samples from five farms were analyzed to give 41 sets of pooled results (pool size five) from each laboratory according to their specific protocols. The numbers of positive pools for assays A-D were 18, 12, 11, and 1 (43.9%, 29.2%, 26.8%, and 2.4%), respectively. Assessment of interrater reliability produced a Fleiss' kappa coefficient of 0.15, indicating very poor overall agreement between the four laboratories. Laboratories A-D diagnosed 4, 3, 2, and 1 flocks at the farm level, respectively, as MAP positive. In Project 2, 38 pooled ovine samples from 10 flocks were analyzed to compare the performance of laboratories A and B. The numbers of positive results for laboratories A and B were 24 (63.1%) and 17 (44.7%), respectively (Cohen's kappa 0.54), indicating that laboratory A was more sensitive than B in line with results from Project 1. Variation between laboratories offering MAP qPCR assays is a significant concern, and further work is warranted to validate and standardize the performance of assays between laboratories for both ovine and bovine samples.IMPORTANCEOur study reports the findings of an inter-laboratory ring trial comparing the performance of four different quantitative polymerase chain reaction (qPCR) assay services for detecting Mycobacterium avium subspecies paratuberculosis (MAP) infection in cattle and sheep. MAP is the causative agent of Johne's disease (also known as paratuberculosis), a significant production-limiting disease in livestock populations with a worldwide distribution. The content of this paper is significant and novel as it is the first to highlight the marked variation between the diagnostic sensitivity and reproducibility of the three principal commercial laboratories offering MAP qPCR diagnostic and screening services in Great Britain. The low sensitivity and high variability between the laboratories are of great concern and relevance to veterinary practitioners and livestock producers.

Use of fidget and drinking behaviour in combination with facial infrared thermography for diagnosis of bovine respiratory disease in a spontaneous model.

Bovine respiratory disease (BRD) is a highly prevalent multi pathogen infectious disease (70-80%) in newly received feedlot cattle, causing significant economic losses and reduced animal welfare. Current BRD diagnosis involves stressful and invasive methods that can increase the incidence and transmission of BRD. An alternative is the use of an automated infrared thermography (IR) platform that can monitor facial temperature and behaviour traits to diagnose BRD in a non-invasive manner. The objective of this study was to investigate the use of fidget and drinking behaviours in conjunction with facial temperature as method of BRD diagnosis in beef calves. Sixty-five weaned calves (N = 65) were monitored over a 21-d period after 6 h transportation to predispose calves to BRD infection. Data collected from an automated IR platform placed at a water station included the number of IR frames during drinking (Fidget), number of drinking visits (Drinking bouts), total drinking duration, average drinking duration, average cheek temperature (AVG temp), and maximum orbital temperature (Max temp). Fidget, drinking behaviours, and IR were compared to a clinical score assessment based on respiratory, digestive, and lethargy signs (visual observation) and haematology analysis using a receiver operating characteristics curve analysis to identify the accuracy of each metric and combinations of metrics for BRD diagnosis. The greater accuracies observed were Fidget, Youden's index (J): 0.25 J), Drinking bout (0.28 J), and Total drinking duration (0.22 J). The average IR temperature accuracy resulted in 0.88 J and Max temp 0.77 J. Thirty-five combinations of drinking behaviour and facial IR metrics were evaluated to identify BRD calves. Optimum accuracy (100%) was achieved when combining Fidget, Drinking bout, Average drinking duration, AVG temp, and Max temp 1.00 J. Similar evaluations were performed at 48 and 24 h before d 0 using the most accurate Fidget, Drinking behaviour, and IR combination, resulting in 0.44 J 48 h prior to d 0 and 0.45 J 24 h prior to d 0. Combining fidget and drinking behaviour metrics increased the sensitivity to detect the onset of BRD infection and the specificity to discriminate true positive BRD calves from true negative BRD calves.

Expression of sex-specific molecular markers by Babesia bovis gametes.

BACKGROUND: Bovine babesiosis caused by Babesia bovis is one of the most important tick-borne diseases of cattle in tropical and subtropical regions. Babesia bovis parasites have a complex lifecycle, including development within the mammalian host and tick vector. In the tick midgut, extracellular Babesia parasites transform into gametes that fuse to form zygotes. To date, little is known about genes and proteins expressed by male gametes. METHODS AND RESULTS: We developed a method to separate male gametes from in vitro induced B. bovis culture. Separation enabled the validation of sex-specific markers. Collected male gametocytes were observed by Giemsa-stained smear and live-cell fluorescence microscopy. Babesia male gametes were used to confirm sex-specific markers by quantitative real-time PCR. Some genes were found to be male gamete specific genes including pka, hap2, α-tubulin II and znfp2. However, α-tubulin I and ABC transporter, trap2-4 and ccp1-3 genes were found to be upregulated in culture depleted of male gametes (female-enriched). Live immunofluorescence analysis using polyclonal antibodies confirmed surface expression of HAP2 by male and TRAP2-4 by female gametes. These results revealed strong markers to distinguish between B. bovis male and female gametes. CONCLUSIONS: Herein, we describe the identification of sex-specific molecular markers essential for B. bovis sexual reproduction. These tools will enhance our understanding of the biology of sexual stages and, consequently, the development of additional strategies to control bovine babesiosis.

Monitoring ventral tail base surface temperature for fever detection in calves.

In this study, we investigated whether monitoring the ventral tail base surface temperature (ST) using a wearable wireless sensor could be effective for fever detection in calves with experimentally induced pneumonia after inoculation with Histophilus somni strain 2336. We found a significant difference in the changes in ST values between the control and H. somni-inoculated groups after 24 h of inoculation and detected fever; however, the rectal temperature showed a significant difference between the groups after 12 h of inoculation. When a significant difference in the ST between the two groups was observed, serum haptoglobin concentration and exacerbation of clinical score increased in the H. somni-inoculated group compared with those in the control group. Pneumonia was observed in the H. somni-inoculated group at necropsy, indicating that the changes in ST may reflect fever with inflammation caused by H. somni infection. Our results demonstrated that monitoring ST using a sensor attached to the ventral tail base can detect fever in calves and may be a useful and labor-saving tool for the health management of calves.

Electron microscopic observation of Mycobacterium avium subsp. paratuberculosis in cattle feces after a novel purification using liquid paraffin.

We developed a novel method for purifying acid-fast bacteria from feces. The method enabled the observation of characteristic clumps of Mycobacterium avium subsp. paratuberculosis (MAP) under electron microscopy by removing contaminants and other bacteria. Further refinement of this method will contribute to efficient and effective MAP detection.

[Intradermal and serologic testing for insect bite hypersensitivity in a Dahomey-Ox]. / Intradermaler und serologischer Allergietest zur Abklärung einer Insektenstich-Hypersensitivität bei einem Dahomey-Ochsen.

This case report describes an eosinophilic dermatitis on the prepuce of a Dahomey-Ox caused by an insect bite hypersensitivity against Culicoides spp. To the best of the authors' knowledge, this is the first report describing intradermal allergy and serological testing in cattle.

Evaluation of LAMP for Fasciola hepatica detection from faecal samples of experimentally and naturally infected cattle.

Fasciola hepatica causes liver fluke disease in production animals and humans worldwide. Faecal egg counts (FEC) are the most common diagnostic tool for the diagnosis of liver fluke disease. However, FEC has low sensitivity and is often unreliable for the detection of patent infection. In this study, loop-mediated isothermal amplification (LAMP) was optimised and evaluated for the detection of Fasciola hepatica infection, with the aim of increased sensitivity and making it suitable for on-farm application. LAMP was initially conducted under laboratory conditions, optimised to enable visual detection using calcein dye. DNA extraction based on bead-beating was developed to enable on-farm application. LAMP results were compared to FEC and polymerase chain reaction (PCR). Under laboratory conditions, LAMP was conducted using two incubation methods: a conventional PCR thermocycler and a field-deployable LAMP instrument. When compared to a 'rigorous' FEC protocol consisting of multiple counts using a comparatively large volume of faeces and with infection confirmed post-mortem, LAMP was highly sensitive and specific (using silica membrane DNA extraction sensitivity 88 %, specificity 100 %; using sieving and beat-beating DNA extraction sensitivity 98.9 %, specificity 100 %). When applied on-farm, LAMP was compared to conventional FEC, which suggested high sensitivity but low specificity (sensitivity 97 %, specificity 37.5 %). However, further analysis, comparing field LAMP results to laboratory PCR, suggested that the low specificity was likely the outcome of the inability of conventional FEC to detect all true F. hepatica positive samples. Based on the high sensitivity and specificity of LAMP compared to a 'rigorous' FEC protocol and its ability to be used in field settings, the study demonstrates the potential of LAMP for diagnosing F. hepatica infection in agriculture.