Abortion In Cattle Research Articles

Immunization with a Multivalent Listeria monocytogenes Vaccine Leads to a Strong Reduction in Vertical Transmission and Cerebral Parasite Burden in Pregnant and Non-Pregnant Mice Infected with Neospora caninum.

Neospora caninum is an apicomplexan parasite that causes abortion and stillbirth in cattle. We employed the pregnant neosporosis mouse model to investigate the efficacy of a modified version of the attenuated Listeria monocytogenes vaccine vector Lm3Dx_NcSAG1, which expresses the major N. caninum surface antigen SAG1. Multivalent vaccines were generated by the insertion of gra7 and/or rop2 genes into Lm3Dx_NcSAG1, resulting in the double mutants, Lm3Dx_NcSAG1_NcGRA7 and Lm3Dx_NcSAG1_NcROP2, and the triple mutant, Lm3Dx_NcSAG1_NcGRA7_NcROP2. Six experimental groups of female BALB/c mice were inoculated intramuscularly three times at two-week intervals with 1 × 107 CFU of the respective vaccine strains. Seven days post-mating, mice were challenged by the subcutaneous injection of 1 × 105N. caninum NcSpain-7 tachyzoites. Non-pregnant mice, dams and their offspring were observed daily until day 25 post-partum. Immunization with Lm3Dx_NcSAG1 and Lm3Dx_NcSAG1_NcGRA7_NcROP2 resulted in 70% postnatal pup survival, whereas only 50% and 58% of pups survived in the double mutant-vaccinated groups. Almost all pups had died at the end of the experiment in the infection control. The triple mutant was the most promising vaccine candidate, providing the highest rate of protection against vertical transmission (65%) and CNS infection. Overall, integrating multiple antigens into Lm3Dx_SAG1 resulted in lower vertical transmission and enhanced protection against cerebral infection in dams and in non-pregnant mice.

A preliminary study on placental damage associated to experimental neosporosis in BALB/c mice.

Neospora caninum is a protozoan parasite which can infect a range of animals, including dogs, cattle, and sheep. Bovine neosporosis, which mainly causes abortion in cattle, results in substantial economic losses worldwide. To study the effects of N. caninum infection on the placenta, a pregnant mouse model for N. caninum infection was established. The litter size (8.6 ± 1.5) and the number of live pups (6.4 ± 1.8) of infected dams were significantly lower compared with those of non-infected dams. Trophoblast cell shrinkage and a large number of apoptosomes were detected in the placentas of the infected group. The parasite load in the placental tissue was significantly higher with time after infection. Likewise, apoptosis of placental trophoblast cells significantly increased with time after infection. Among the 66 apoptotic genes detected in this study, eight genes, including Bcl-2, were significantly differentially expressed by about > tenfold in infected and uninfected mice. The expression of BAX and tumor necrosis factor-alpha (TNF-α) was upregulated in the placental cells of the infected mice, whereas the expression of BCL-2 was downregulated. Enzyme-linked immunosorbent assays (ELISAs) showed that apoptotic protease caspase-3 level was significantly increased in placental cell suspension, and insulin-like growth factor (IGF)-2 level was significantly reduced. Acetylcholine (ACH) and placental prolactin (PL) levels were initially decreased but eventually increased. In summary, infection of mice with N. caninum caused apoptotic damage to the placental tissues, cells, and genes and affected the normal physiological functions of placenta, which may largely explain the adverse pregnancy outcomes caused by N. caninum infection in mice.

PROFILING AND SPECIATION OF CANDIDA SPECIES BY USING HICHROME AGAR FROM VARIOUS CLINICAL AND POSTMORTEM SAMPLES IN LIVESTOCK AND POULTRY

Animal Candidiasis is associated with oral and upper respiratory disease, pyothorax, ocular lesions, intestinal disease and urocystitis in dog and cats and causes arthritis in horses and mastitis and abortion in cattle. The present study was undertaken to determine the prevalence of Candida species among various clinical and post mortem samples of livestock and poultry. All samples were collected using aseptic precautions. After receiving in the Central University laboratory, the samples were inoculated onto both Blood agar and MacConkey agar, XLD agar and SDA agar and plates were incubated at 37 oC for 24 hours aerobically. The colonies appeared as smooth, pasty, opaque, white or beige were suspected as Candida colonies and Gram stain was done for confirmation. The speciation of the Candida isolates was performed by inoculating it on Hicrome Candida differential agar. The Hicrome agar was prepared as per the manufacturer’s instructions and incubated at 37 o C for 24 hours aerobically. The antibiotic sensitivity test was performed with Highrome agar plate. The pure culture of Candida albicans were streaked in hichrome agar plate and antibiotic disc were placed in appropriate distance and incubated at 37 oC for 24 hours aerobically. Biofilm study of yeast was performed with Sterile 96-well polystyrene plates which were inoculated with 200 µl bacterial suspension (105 CFU/ml) in BHI medium and incubated at 37 o C for 24 hrs without shaking. Species identification of Candida was done by the morphology and color of the colonies. The Candida albicans produce light green colonies, C. tropicalis metallic blue colonies, C.krusei produces purple fuzzy colonies, and C. glabrata white to cream-colored colonies. Out of 298 Candida isolates, C. Albicans was the most common species in 210 (70.46%) strains. The remaining 88 (29.5%) strains showed Non-albicans Candida. Out of 88 Non-albicans Candida isolates, Candida isolates, 20 were C. tropicalis (23%), 28 were C. glabrata (32%), 18 were Candida parapsilosis (20%) and 22 were C. krusei (25%) respectively (Table 1). Out of 298 isolates from oronasal swab (HVS), the most common species was C. Albicans followed by C. tropicalis, C. glabrata, Candida parapsilosis and C. krusei. Among the 16 urine samples, the most common species was C. Albicans followed by C. tropicalis, C. glabrata, and C. krusei were isolated.

Сальмонеллезный аборт овец: опыт предупреждения

This article discusses methods of prevention and control of Salmonella abortion in small cattle (sheep and goats), salmonellosis is a widespread infectious disease of all animal, avian and human species caused by bacteria of the genus Salmonella of the family Enterobacteriaceae. The genus Salmonella Abortusovis is adopted in sheep whose main symptom is abortion. It is a gramnegative bacterium which is prevalent in Western Asia, Europe and the Mediterranean area. Sheep can shed the bacteria through colostrum, milk or feces and can become infected through the oral, conjunctival or respiratory route. The methods studied include health and hygiene prevention, metaphylaxis and vaccination. The results of the study show that all these methods studied help to relieve breeders but they are not completely efficient and effective. And on the other hand, the use of bacteriophages is the most promising method that can be used as an alternative for the control of Salmonella Abortusovis due to its specificity, safety and effectiveness.

Citrobacter koseri related abortion and fetal septicemia in cattle.

A 31-month-old Holstein dairy cow aborted at 224 days of gestation with ejection of cheese-like lochia. Citrobacter koseri, which commonly exists in the normal flora of human and animal digestive tracts, was isolated from aborted fetal tissues (liver, spleen, kidney, heart, lung, cerebrum, and skeletal muscle) and fetal membranes. Histopathological examination revealed suppurative fibrinous meningoencephalitis of the cerebrum, cerebellum, and brainstem; suppurative bronchopneumonia; suppurative chorioamnionitis; and fibrous splenic serositis. Numerous gram-negative bacilli were detected in the cytoplasm of macrophages and/or neutrophils in these lesions. Bacteriological investigation and immunohistochemical staining identified the bacilli as C. koseri. This is the first report of cattle abortion caused by C. koseri infection in dairy cattle.

Evaluation of knowledge, attitudes and practices regarding neosporosis and toxoplasmosis among farmers and animal health practitioners in Namibia.

This study assessed the knowledge, attitudes and practices of livestock farmers in Namibia's Khomas region and animal health practitioners (veterinarians and animal health technicians) in the whole country concerning neosporosis and toxoplasmosis. Structured questionnaires were used, and a total of 63 farmers and 51 animal health practitioners responded out of an estimated 560 farmers in the Khomas region and 300 veterinarians and veterinary technicians in the country. Only 15.9% of the livestock farmers (n = 63) had heard about neosporosis or toxoplasmosis or knew how animals get infected (p < 0.0001). Only 5% of the farmers knew the risks associated with keeping dogs and cats concerning neosporosis and toxoplasmosis, respectively (p < 0.0001). None of the 51 animal health practitioners routinely requested Neospora caninum or Toxoplasma gondii laboratory tests in cases of cattle, sheep or goat abortions. Although all animal health practitioners indicated they routinely interacted with livestock farmers, none regularly discussed neosporosis or toxoplasmosis. Only 3.9% of animal health practitioners (n = 51) indicated that they had ever discussed either neosporosis or toxoplasmosis at a farmers' gathering (p < 0.0001), and only 21.6% had talked to at least one cat owner about toxoplasmosis in the previous 12months (p < 0.0001). The authors concluded that farmers in the Khomas region were generally unaware of neosporosis and toxoplasmosis but could change their attitudes and practices if educated. The animal health practitioners lacked a deeper understanding and appreciation of the two diseases, which is required to cultivate enough confidence to educate farmers. Sharing this research and other relevant information on the two diseases at farmers' meetings, veterinary congresses, journals and newsletters could help educate farmers and animal health practitioners. Such platforms are likely to succeed because both these groups use these forums to get new information.

Recombinant actin-depolymerizing factor of the apicomplexan Neospora caninum (NcADF) is susceptible to oxidation.

Neospora caninum is a member of Apicomplexa Phylum and the causative agent of neosporosis, a disease responsible for abortions in cattle. Apicomplexan parasites have a limited set of actin-binding proteins conducting the regulation of the dynamics of nonconventional actin. The parasite actin-based motility is implicated in the parasite invasion process in the host cell. Once no commercial strategy for the neosporosis control is available, the interference in the parasite actin function may result in novel drug targets. Actin-depolymerization factor (ADF) is a member of the ADF/cofilin family, primarily known for its function in actin severing and depolymerization. ADF/cofilins are versatile proteins modulated by different mechanisms, including reduction and oxidation. In apicomplexan parasites, the mechanisms involved in the modulation of ADF function are barely explored and the effects of oxidation in the protein are unknown so far. In this study, we used the oxidants N-chlorotaurine (NCT) and H2O2 to investigate the susceptibility of the recombinant N. caninum ADF (NcADF) to oxidation. After exposing the protein to either NCT or H2O2, the dimerization status and cysteine residue oxidation were determined. Also, the interference of NcADF oxidation in the interaction with actin was assessed. The treatment of the recombinant protein with oxidants reversibly induced the production of dimers, indicating that disulfide bonds between NcADF cysteine residues were formed. In addition, the exposure of NcADF to NCT resulted in more efficient oxidation of the cysteine residues compared to H2O2. Finally, the oxidation of NcADF by NCT reduced the ability of actin-binding and altered the function of NcADF in actin polymerization. Altogether, our results clearly show that recombinant NcADF is sensitive to redox conditions, indicating that the function of this protein in cellular processes involving actin dynamics may be modulated by oxidation.

Prevalence of Toxoplasma gondii, Leptospira spp., and Coxiella burnetii-associated antibodies in dairy cattle with reproductive disorders.

In cattle dairy farms, abortions and other reproductive problems due to major infectious diseases are overlooked, and identifying their causative agents is very challenging without a confirmatory diagnosis. Further, a prevalence study in animals will provide important hints of pathogen reservoirs and provide necessary direction to disease burden with appropriate control and biosecurity measures at the farm level. This study aimed to estimate the prevalence of Toxoplasma gondii antibodies in dairy cattle associated with reproductive problems along with coexisting antibodies against abortifacient zoonotic (Coxiella burnetii and Leptospira spp.) pathogens. Cattle sera (n = 246) from dairy farms (n = 35) situated in different locations in India were screened for anti-T. gondii and C. burnetii antibodies with enzyme-linked immunoassay and Leptospira spp. antibodies with microscopic agglutination test. The overall prevalence of 11.4% (95% confidence intervals [CIs]: 7.99%-15.96%) antibodies in cattle associated with reproductive problems (p < 0.021) with farm-level seropositivity of 43% was observed. Further, on analysis of screened sera, 49.8% (95% CI: 42.6%-55%) and 77.6% (95% CI: 72%-82.4%) of samples were found to be positive for C. burnetii and Leptospira spp. antibodies, respectively. Moreover, the seropositivity of 91.9% (226/246) for at least one of the screened zoonotic pathogens was observed, indicating antibodies against either of these organisms in association with reproductive disorders (p < 0.005). The percentage of cattle found to have T. gondii antibodies was only 1.8%, whereas 11.5% and 41.6% of cattle were found to have C. burnetii and Leptospira spp. antibodies, respectively. Nevertheless, the predominantly mixed infections observed were of Leptospira and C. burnetii (34.5%), followed by all three infections (4.9%); toxoplasmosis and leptospirosis (3.5%); and toxoplasmosis and Q fever (2.2%). The serological detection of antibodies against these pathogens in cattle may have significant implications for the livestock industry and public health, suggesting the need for continuous surveillance and monitoring of these infections to prevent their spread.

Development and application of an indirect ELISA to detect antibodies to Neospora caninum in cattle based on a chimeric protein rSRS2-SAG1-GRA7.

Neospora caninum is an important apicomplexan parasite causing neosporosis in cattle. The disease is recognized as one of the most important cause of reproductive problems and abortion in cattle worldwide. In this context, we developed an indirect enzyme-linked immunosorbent assays (ELISA) with chimeric protein rSRS2-SAG1-GRA7 to diagnose antibodies to Neospora-infection. This indirect ELISA was compared to indirect fluorescent antibody test (IFAT) and western blotting (WB), and the sensitivity and specificity results of ELISA were calculated to be 86.7 and 96.1%, respectively. The overall coincidence rate was 92.6% using IFAT and WB. Additionally, 329 aborting dairy cattle serum samples were tested using this ELISA to evaluate the prevalence of N. caninum in Ningxia, China. The positive rate of N. caninum in these farms was from 19.05 to 57.89%, and the mean rate was 41.64% (±11.01%), indicating that infection with N. caninum may be one of the important causes of cattle abortion in this region. This established rSRS2-SAG1-GRA7 indirect ELISA is capable for detecting the antibodies against N. caninum, and it could be a useful screening tool for monitoring the epidemiology of neosporosis in cattle.

Genetic diversity and known virulence genes in Listeria innocua strains isolated from cattle abortions and farm environment

Listeria innocua is considered as non-pathogenic bacteria living in an environment although several cases of immunocompromised humans and ruminant listeriosis infections have been reported. Previously, L. innocua was identified as a potential pathogen and virulence in association with L. monocytogenes PrfA dependent virulence (LIPI-1) gene cluster was demonstrated in hemolytic L. innocua. L. innocua usually considered non-pathogenic versus pathogenic L. monocytogenes and L. ivanovii because of the main virulence gene loss. There are limited studies and reports available about L. innocua-caused illness in cattle. A total of 18 STs were identified in cattle abortions while 17 STs in the farm environment with majority of STs were present in both abortions and environmental samples. Genome sequencing showed that in one farm identical L. innocua clones were represented in water, feed, soil, and faeces sample groups, suggesting that animals most likely through the faecal shedding may remain as the main source of L. innocua in a farm environment. Out of all L. innocua isolates PrfA-dependent virulence genes were not found in aborted foetuses isolates and environmental L. innocua isolate groups; however, in 20% of isolates a complete LIPI-3 pathogenicity island encoding listeriolysin S was identified. In this study, we demonstrated that genetically diverse L. innocua clones were widely distributed in cattle farm environment and certain isolates had a significant pathogenicity potential for cattle, thus causing adverse health effects, including abortions.

Seroprevalence of Neospora caninum infection and associated risk factors in cattle in Shanxi Province, north China.

Neospora caninum is an obligate intracellular parasitic protozoan that can cause abortions in cattle and pose considerable economic losses to the cattle industry. As a major livestock province, little is known of N. caninum infection in cattle in Shanxi Province, north China. In order to investigate the seroprevalence of N. caninum in cattle in Shanxi Province, 978 cattle serum samples were collected from 11 cities in three representative geographical locations in Shanxi Province, and the N. caninum-specific IgG antibodies were examined using an indirect enzyme linked immunosorbent assay (ELISA) kit commercially available. The results showed that 133 of the 978 examined cattle serum samples (13.60%, 95% CI = 11.45-15.75) were positive for N. caninum antibodies, and the seroprevalence in different cities ranged from 0 to 78.89%. The geographical location and management mode were the risk factors associated with N. caninum infection in cattle herds in Shanxi Province. Cattle in Northern and Central Shanxi Province as well as cattle whose management mode is that of large-scale cattle farming companies are more susceptible to N. caninum infection. This was the first large-scale survey of N. caninum seroprevalence and assessment of associated risk factors in cattle in Shanxi Province, which provided baseline information for the prevention and control of N. caninum infection in cattle in Shanxi Province, north China.

Neospora caninum-associated abortions in cattle from Southern Brazil: Anatomopathological and molecular characterization.

This study aimed to evaluate the N. caninum associated abortions in cattle in the state of Santa Catarina, in the southern Brazil. Aborted bovine fetuses were necropsied, submitting organ samples for histopathological evaluation. Brain fragments were analyzed by polymerase chain reaction (PCR). The diagnosis of abortion due to N. caninum was established through histopathology and molecular analysis in 53.84% (28/52) of the cases, with PCR detection in 71.42% (20/28). The histopathological evaluation showed lesions in 75% of the cases, characterized by mononuclear necrotizing encephalitis, mononuclear myocarditis, mononuclear myositis, mixed placentitis, and mononuclear pneumonia. Neospora caninum was the primary etiological agent associated with causes of abortion in cattle in the present study.

Evaluation of fetal heart serum amyloid a concentrations in infectious cattle abortion cases

Serum amyloid A (SAA) concentrations have been investigated in diseases of human and domestic animals and increased SAA levels have been reported in infectious diseases. In the present study, we determined the fetal heart blood SAA concentrations in aborted bovine fetuses and investigated the relationship between the level of SAA and causative infectious agents. A total of 46 heart blood samples were collected from aborted bovine fetuses between July 2018 and July 2019 and were assigned to two groups according to microbiological, pathological and molecular results. Group 1: An infectious disease was diagnosed by detecting a microorganism (21 cases); Group 2: An infectious or inflammatory disease was not detected (25 cases). The fetal heart blood SAA concentrations were measured by commercial ELISA test. Serum amyloid A concentrations in aborted bovine fetuses were elevated from 6.1 to ≥40 mg/L in 17 of 21 cases in group 1. In group 2, SAA concentrations were less than 2.5 mg/L in 23 of 25 cases. This difference was statistically significant between group 1 and group 2. These findings suggest that SAA concentrations in fetal heart blood from bovine fetuses is potentially a novel marker for distinguishing between infectious and non-infectious bovine abortion cases.

Extracellular H2O2, peroxiredoxin, and glutathione reductase alter Neospora caninum invasion and proliferation in Vero cells

Neospora caninum is a protozoan member of the Apicomplexa phylum and is closely connected with abortion in cattle. The development of the parasite in host cells is characterized by the active secretion of proteins, allied to the tight control of the redox status. In this sense, elucidating the mechanisms related to the role of the redox agents and enzymes during the invasion and proliferation of N. caninum may contribute to developing novel forms of neosporosis control. In this study we verified the effects of the recombinant forms of N. caninum glutathione reductase (rNcGR) and thioredoxin-dependent peroxide reductase (rNcPrx), as well as H2O2 in the tachyzoite invasion and proliferation. rNcPrx interfered in the N. caninum invasion in a redox state manner. Oxidized rNcPrx inhibited the N. caninum invasion and proliferation with no toxic effects observed in Vero cells. In contrast, lower concentrations of H2O2 (10 μM) stimulated the N. caninum invasion, which was reverted in higher doses (>100 μM). H2O2 inhibited the parasite proliferation in lower concentrations than cytotoxicity in host cells, resulting in a positive selectivity index (1.8). Besides, rNcPrx (reduced and non-reduced) and rNcGR inhibited the parasite proliferation without affecting the host cell. Our results indicate the connection between the N. caninum development and the redox state, contributing to the elucidation of parasite propagation and control mechanisms.

Pathological and Immuno-Molecular Examination of Protozoa in Aborted Fetus's and Placenta of Iraqi Cattle (A case report)

Tissue samples of placenta and aborted fetus were collected from aborted cow and preserved in 10% formalin buffered saline for routine histopathology stained with H&amp;E and for immunohistochemistry to detect TNF-a marker. Pathological examination showed necrotic foci with abscesses mainly around site of invasive protozoa. Immuno-Molecular examination showed marked deposition of TNF marker in tissue, mainly brain of fetus, which refers to genetic damage in gene responsible for controlling TNF values. It is concluded that protozoal infection with Neospora caninum can cause abortion in cattle at advanced stage (8th month ) of gestation with severe histopathological lesions on placenta as well as the brain of fetus. This case report is an update for the information presented in the Proceedings of the 3rd Scientific Conference of the Faculty of Veterinary Medicine / University of Kerbala on 10th April 2017.

Seroepidemiology of Neospora caninum in Cattle of Pastoral Production System in Teltelle District of Borana Zone, Southern Ethiopia.

BackgroundNeosporosis is a major cause of abortion in smallholder dairy farms in Ethiopia. However, its status and impact in pastoral cattle production settings were uncovered. This study was performed with the aims of estimating the seroprevalence and associated potential risk factors for Neospora caninum in Boran cattle in Teltelle district of Borana zone, Ethiopia.Methods180 blood samples were collected from 48 randomly selected pastoral herds using a multistage sampling technique and subjected to an indirect enzyme-linked immunosorbent assay (ELISA) test to detect antibodies specific to N. caninum. A questionnaire survey was also used to identify the potential risk factors of N. caninum in the study area. Evaluation of the associated risk factors was conducted using a multivariable logistic regression model.ResultsAntibodies against N. caninum exposure were detected in 5% of cattle (95% CI: 1.816–8.184) from 180 animals tested. Similarly, the seroprevalence of N. caninum in herds with at least one positive animal was 14.6% (95% CI: 4.598–24.567) from 48 herds examined. A multivariable logistic regression model identified the following as significant risk factors: a history of abortion (AOR = 23; 95% CI: 2.354–188.702; P = 0.006), dystocia (AOR = 11; 95% CI = 22.275–55.860; P = 0.003), wells water sources (AOR = 9; 95% CI: 1.599–47.568; P = 0.012), and dogs fed with raw animal products (AOR = 6; 95% CI: 11.213–27.222; P = 0.028).ConclusionThis study revealed the first serological evidence of N. caninum exposure in cattle reared under pastoral production system. Our findings suggest N. caninum is likely to be an important cause of abortion and dystocia in cattle in Ethiopia. Management practices, such as provision of hygienic water and restriction of dogs fed with raw animal products, are likely to reduce the risk of infection. Thus, maximizing community awareness about these disease management practices is suggested.

An outbreak of Rift Valley fever among peri-urban dairy cattle in northern Tanzania.

Human and animal cases of Rift Valley fever (RVF) are typically only reported during large outbreaks. The occurrence of RVF cases that go undetected by national surveillance systems in the period between these outbreaks is considered likely. The last reported cases of RVF in Tanzania occurred during a large outbreak in 2007-2008. Samples collected between 2017 and 2019 from livestock suffering abortion across northern Tanzania were retrospectively tested for evidence of RVF virus infection using serology and reverse transcription quantitative polymerase chain reaction (RT-qPCR). A total of 14 RVF-associated cattle abortions were identified among dairy cattle in a peri-urban area surrounding the town of Moshi. RVF cases occurred from May to August 2018 and were considered to represent an undetected, small-scale RVF outbreak. Milk samples from 3 of 14 cases (21%) were found to be RT-qPCR positive. Genotyping revealed circulation of RVF viruses from two distinct lineages. RVF outbreaks can occur more often in endemic settings than would be expected on the basis of detection by national surveillance. The occurrence of RVF cases among peri-urban dairy cattle and evidence for viral shedding in milk, also highlights potentially emerging risks for RVF associated with increasing urban and peri-urban livestock populations.

Seroprevalence and Risk Factors for Toxoplasma gondii and Neospora caninum in Cattle in Portugal

Simple SummaryNeospora caninum and Toxoplasma gondii are apicomplexan parasites with a worldwide distribution and both infect cattle. While the importance of N. caninum is mainly linked to reproductive losses, concern has been raised about the role of beef as a source of food-borne toxoplasmosis in humans. Little is known about the prevalence of these parasites in cattle in Portugal. This study aimed to evaluate the seroprevalence and risk factors for N. caninum and T. gondii in naturally exposed cattle from different geographical areas in the country. Results point to a low but widespread seroprevalence of T. gondii, while that of N. caninum was found to be in the same range as reported in other Mediterranean countries. Distribution of both parasites may be explained by common climate factors and management practices identified as significant predictors of infection in the study.Neospora caninum has a worldwide economic impact as an important cause of abortion in cattle, while Toxoplasma gondii, another abortifacient pathogen, is globally a major foodborne zoonotic threat. The study aimed to evaluate the seroprevalence and risk factors for the two parasites in cattle in Portugal. A total of 612 sera from 35 farms were tested by an in-house p30 ELISA for T. gondii and p38 ELISA for N. caninum. T. gondii positive and suspicious sera were confirmed by p30 Western blot or IFAT. T. gondii and N. caninum animal seroprevalence was 9.2% (95%CI 7.1–11.7) and 17.2% (95% CI 14.4–20.4) and herd seroprevalence was 51.4% (95% CI 35.6–67.0) and 68.6% (95% CI 52.0–81.5), respectively. At the univariable level, climate area and precipitation of wettest month, driest month, driest quarter, and warmest quarter were significant predictors of seropositivity for both. N. caninum seropositivity was more likely in the region Norte, densely populated areas, and intensive production, and the probability of T. gondii seropositivity decreased with herd size. Results confirm the need to consider neosporosis in the differential diagnosis of cattle reproductive disorders in Portugal and may be valuable to inform source attribution models for human toxoplasmosis.

Genomic Prediction for Abortion in Lactating Holstein Dairy Cows.

Simple SummaryPregnancy losses in dairy cattle result in impaired animal health and welfare, as well as economic losses due to increased culling, reduced milk production, calf losses, and increased reproductive costs, among others. Advances in the last few decades have allowed the dairy industry to make significant progress in reproductive efficiency, but pregnancy losses continue to be an unresolved problem. The origin of abortions can be infectious disease, metabolic disorders, heat stress, and a genetic predisposition among many others. We have developed genomic predictions (Z_Abort) to identify Holstein dairy cows with a greater risk of abortion. This allows dairy producers and veterinarians to select more productive and profitable cows. The objectives of the study were to (1) describe the development of the genomic predictions for cow abortions in lactating Holstein dairy cattle based on producer-recorded data and ssGBLUP methodology and (2) evaluate the efficacy of genomic predictions for cow abortions in commercial herds of US Holstein cows using data from herds that do not contribute phenotypic information to the evaluation. The results of the present study show that the genomic predictions for cow abortion trait (Z_Abort) can effectively predict the risk of abortion of lactating Holstein dairy cows and, hence, allow genetic selection towards healthier and more profitable cows.Abortion in dairy cattle causes great economic losses due to reduced animal health, increase in culling rates, reduction in calf production, and milk yield, among others. Although the etiology of abortions can be of various origins, previous research has shown a genetic component. The objectives of this study were to (1) describe the development of the genomic prediction for cow abortions in lactating Holstein dairy cattle based on producer-recorded data and ssGBLUP methodology and (2) evaluate the efficacy of genomic predictions for cow abortions in commercial herds of US Holstein cows using data from herds that do not contribute phenotypic information to the evaluation. We hypothesized that cows with greater genomic predictions for cow abortions (Z_Abort STA) would have a reduced incidence of abortion. Phenotypic data on abortions, pedigree, and genotypes were collected directly from commercial dairy producers upon obtaining their permission. Abortion was defined as the loss of a confirmed pregnancy after 42 and prior to 260 days of gestation, treated as a binary outcome (0, 1), and analyzed using a threshold model. Data from a different subset of animals were used to test the efficacy of the prediction. The additive genetic variance for the cow abortion trait (Z_Abort) was 0.1235 and heritability was 0.0773. For all animals with genotypes (n = 1,662,251), mean reliability was 42%, and genomic predicted transmitting abilities (gPTAs) ranged from −8.8 to 12.4. Z_Abort had a positive correlation with cow and calf health traits and reproductive traits, and a negative correlation with production traits. Z_Abort effectively identified cows with a greater or lesser risk of abortion (16.6% vs. 11.0% for the worst and best genomics groups, respectively; p < 0.0001). The inclusion of cow abortion genomic predictions in a multi-trait selection index would allow dairy producers and consultants to reduce the incidence of abortion and to select high-producing, healthier, and more profitable cows.

Reactivation and Foetal Infection in Pregnant Heifers Infected with Neospora caninum Live Tachyzoites at Prepubertal Age.

Neospora caninum is recognised for causing cattle abortion, provoking severe economic losses in the livestock industry worldwide. The aim of the present study was to evaluate the reactivation and foetal infection in pregnant heifers inoculated with live N. caninum tachyzoites before puberty. A total of 15 30-month-old pregnant heifers were allocated into four groups: animals inoculated with live tachyzoites of NC-Argentina LP1 isolate before puberty and challenged with live tachyzoites of NC-1 strain at 210 days of gestation (DG) (Group A); animals mock inoculated before puberty and challenged with NC-1 strain at 210 DG (Group B), animals inoculated before puberty but not subsequently challenged (Group C); and noninfected and nonchallenged animals (Group D). The results of this study showed that 100% of animals infected before puberty (Groups A and C) suffered reactivation of the infection at the seventh month of gestation. In addition, in three and two calves from Groups A and C, respectively, congenital infection was confirmed. Interestingly, we provide evidence that the use of live N. caninum tachyzoites in young animals as a strategy to induce protection is neither safe nor effective.