Infectious causes of embryonic and fetal mortality

Molecular detection of bacterial zoonotic abortive agents from ruminants in Turkey

Abortions in cattle and sheep are one of the major causes of economic losses worldwide. Brucella spp. are the most common infectious agent associated with these abortions. However, abortions caused by bacteria such as Listeria spp., Leptospira spp., Campylobacter spp. and Mycoplasma spp. are usually overlooked due to their sporadic nature and their status as non-priority abortion agents. In our study, we investigated the bacteria associated with abortion cases in cattle and sheep using PCR. For this purpose, we collected vaginal swab samples (n: 110) of aborted cattle and sheep, as well as stomach content samples (n: 69) of aborted calves and lambs from various cities in Turkey. The samples were analysed by bacteria-specific PCR to detect Campylobacter fetus, Leptospira spp., Listeria spp., Mycoplasma spp., and Yersinia spp. PCR analyses revealed that the investigated bacterial agents were present in 18.85% and 19.3% of the cattle and sheep samples, respectively, with an overall percentage of 18.99%. While the overall positivity rate for C. fetus, Leptospira spp., and Mycoplasma spp. was 2.79%, 10.06%, and 4.47%, respectively, the positivity rate for co-infection with Leptospira spp. and C. fetus was 1.68%. All samples were found to be negative for Yersinia spp. and Listeria spp. The high C. fetus positivity rate detected in sheep and in the stomach contents was statistically significant (p < 0.05). However, the difference in positivity rates between the cities, hosts, co-infections and causative agents was statistically insignificant (p > 0.05). This study provides preliminary data on the significant involvement of C. fetus, Leptospira spp. and Mycoplasma spp. in cattle and sheep abortions in Turkey indicating that they should not be overlooked in diagnosis. In addition, further research is needed to investigate the zoonotic potential of these pathogens for public health in Turkey.

Machine learning modeling to predict causes of infectious abortions and perinatal mortalities in cattle

A plethora of infectious and non-infectious causes of bovine abortions and perinatal mortalities (APM) have been reported in literature. However, due to financial limitations or a potential zoonotic impact, many laboratories only offer a standard analytical panel, limited to a preestablished number of pathogens. To improve the cost-efficiency of laboratory diagnostics, it could be beneficial to design a targeted analytical approach for APM cases, based on maternal and environmental characteristics associated with the prevalence of specific abortifacient pathogens. The objective of this retrospective observational study was to implement a machine learning pipeline (MLP) to predict maternal and environmental factors associated with infectious APM. Our MLP based on a greedy ensemble approach incorporated a standard tuning grid of four models, applied on a dataset of 1590 APM cases with a positive diagnosis that was achieved by analyzing an extensive set of abortifacient pathogens. Production type (dairy/beef), gestation length, and season were successfully predicted by the greedy ensemble, with a modest prediction capacity which ranged between 63 and 73 %. Besides the predictive accuracy of individual variables, our MLP hierarchically identified predictor importance causes of associated environmental/maternal characteristics of APM. For instance, in APM cases that happened in beef cows, season at APM (spring/summer) was the most important predictor with a relative importance of 24 %. Furthermore, at the last trimester of gestation Trueperella pyogenes and Neospora caninum were the most important predictors of APM with a relative importance of 22 and 17 %, respectively. Interestingly, herd size came out as the most relevant predictor for APM in multiparous dams, with a relative importance of 12 %. Based on these and other mix of predicted environmental/maternal and pathogenic potential causes, it could be concluded that implementing our MLP may be beneficial to design a more cost-effective, case-specific diagnostic approach for bovine APM cases at the diagnostic laboratory level.

The microbiome of the pregnant uterus in Holstein dairy heifers and cows assessed by bacterial culture and 16S ribosomal RNA gene sequencing

Introduction

The possibility that there is a resident and stable commensal microbiome within the pregnant uterus has been supported and refuted by a series of recent studies. One element of most of the initial studies was that they were based primarily on 16S rRNA gene sequencing from bacteria. To account for this limitation, the current study performed both bacterial culture and 16S rRNA gene sequencing in a side-by-side manner (e.g., same tissues isolated from the same animal).

Methods

The uteruses of 10 mid-pregnant (156 ± 5 d of gestation) Holstein heifers and cows were collected following slaughter. The external surface of the reproductive tract (positive control for contamination during tissue collection) as well as tissues within the pregnant uterus (placentome, inter-cotyledonary placenta, inter-caruncular endometrium, amnionic fluid, allantoic fluid, fetal abomasum content, and fetal meconium) were sampled for bacterial culture and 16S rRNA gene sequencing.

Results

There were 87 unique bacterial species cultured from the external surface of the pregnant reproductive tract (contamination control) and 12 bacterial species cultured from pregnancy tissues. Six out of 10 cattle (60%) exhibited bacterial growth in at least one location within the pregnant uterus. For the metataxonomic results (16S rRNA gene sequencing), a low targeted microbial biomass was identified. Analyses of the detected amplicon sequence variants (ASV) revealed that there were: (1) genera that were prevalent on both the external surface and within the pregnant uterus; (2) genera that were prevalent on the external surface but either not detected or had very low prevalence within the pregnant uterus; and (3) genera that were either not detected or had low prevalence on the external surface but found with relatively high prevalence within the pregnant uterus.

Conclusion

There are a small number of viable bacteria in the pregnant uterus. The 16S rRNA gene sequencing detected a microbial community within the pregnant uterus but with a low biomass. These results are consistent with recent studies of the pregnant bovine uterus and leave open the question of whether there is adequate microbial mass to significantly affect the biology of the normal healthy bovine pregnancy.

Serological Evidence and Coexposure of Selected Infections among Livestock Slaughtered at Eastern Cape Abattoirs in South Africa

Zoonotic infections were investigated in a cross-sectional study on asymptomatic livestock slaughtered in abattoirs in the Eastern Cape. Antibodies against Brucella spp., Coxiella burnetii, Toxoplasma gondii, and the coexposure were investigated in sera using serological tests. A total of 565 animals comprising of 280 cattle, 200 sheep, and 85 pigs were screened using RBT, iELISA, CFT, and AMOS-PCR. The Mast® Toxoreagent test and iELISA were used for the detection of T. gondii and C. burnetii, respectively. The Brucella positivity based on at least two tests was 4.3% (12/280), 1.0% (2/200), and 0.0% (0/85) in cattle, sheep, and pigs, respectively. Toxoplasma gondii seropositivity of 37.90% (106/280), 1.50% (3/200), and 7.10% (6/85) was observed in cattle, sheep, and pigs, respectively. Coxiella burnetii seropositivity of 26.40% (74/280), 15.00% (30/200), and 2.40% (2/85) was observed in cattle, sheep, and pigs, respectively. Coexposure was detected in cattle for positivity against C. burnetii and T. gondii 40.54%, Brucella spp. and T. gondii 1.35%, and Brucella spp. and C. burnetii 4.05%. Coexposure for Brucella spp., C. burnetii, and T. gondii 4.05% was detected in cattle. Coexposure of Brucella spp. and C. burnetii 6.67% was detected in sheep. The AMOS-PCR identified B. abortus in cattle and a mixed infection of B. abortus and B. melitensis in sheep in 64.71% seropositive samples. To our knowledge, the coexposure of Brucella spp., T. gondii, and C. burnetii in cattle has not been reported. Coexposure of Brucella spp. and C. burnetii in cattle and sheep is significant as it results in reproductive losses and constitutes an infectious risk to humans. The detection of antibodies against multiple zoonotic infections in livestock from abattoirs has implications for public health.

Association between chronic Anaplasma marginale and Babesia spp. infection and hematological parameters of taurine heifers

The aim of this study was to investigate the association between chronic Anaplasma marginale and Babesia spp. infection and hematological parameters of pregnant and non-pregnant taurine heifers. Blood samples from 94 females were collected on the first day (D-10) of timed artificial insemination (TAI) protocol and on pregnancy diagnosis (D+34). Hematological parameters were determined and compared between pregnant (PG) and non-pregnant (NPG) heifers, and within group at different sampling days. Real-time PCR (qPCR) was used to determine A. marginale and Babesia bovis infection, and for absolute quantification of Babesia spp. between PG and NPG groups. Correlation analysis was performed between the number of gDNA copies (CN) of Babesia spp. and hematological parameters. On D-10, mean hemoglobin concentration was higher for NPG, and hematocrit and total plasma protein were higher on D+34 for both groups. There was no difference in Babesia spp. CN between groups. In the first qPCR, all heifers were positive for A. marginale and B. bovis. Significant correlations were found between hemoglobin and erythrocyte and between hemoglobin and hematocrit (r = 0.8082 and r = 0.3009, respectively). Low levels of A. marginale and Babesia spp. did not affect hematological parameters of chronically infected pregnant and non-pregnant taurine heifers.

Review: Bovine foetal mortality - risk factors, causes, immune responses and immuno-prophylaxis

This review of bovine foetal mortality (>42 d gestation) concluded that while the majority of risk factors associated with sporadic loss operate at animal-level, e.g. foetal plurality, those that operate at herd-level, e.g. some foetopathogenic infections, are more likely to result in abortion outbreaks. While the causes of foetal mortality have traditionally been classified as infectious and non-infectious, in fact, the latter category is a diagnosis of exclusion, generally without determination of the non-infectious cause. This review has also established that the traditional dichotomisation of infectious agents into primary and secondary pathogens is based on a flawed premise and these terms should be discontinued. The delicate balance of the maternal gestational immune system between not rejecting the allograft (conceptus) but rejecting (attacking) foetopathogens is stage-of-pregnancy-dependent thus the timing of infection determines the clinical outcome which may result in persistent infection or foetal mortality. Utilisation of our knowledge of the materno-foetal immune responses to foetopathogenic infection has resulted in the development of numerous mono- and polyvalent vaccines for metaphylactic or prophylactic control of bovine foetal mortality. While some of these have been shown to significantly contribute to reducing the risk of both infection and foetal mortality, others have insufficient, or conflicting evidence, on efficacy. However, recent developments in vaccinology, in particular the development of subunit vaccines and those that stimulate local genital tract immunity, show greater promise.

Disease threats to tigers and their prey

The contraction of the global tiger population over the last 100 years into small, often isolated subpopulations has made them increasingly vulnerable to the impact of disease. Despite this, the health of wild tigers continues to be insufficiently funded and explored. For example, canine distemper virus (CDV), has been associated with localized declines and increased risk of extinction, and yet has received little research attention in most tiger range countries. The emergence of new pathogenic threats has posed fresh challenges, including African swine fever virus (ASFV), which has the potential to devastate wild boar populations, and severe acute respiratory syndrome coronavirus (SARS-CoV2) with implications for tiger conservation that remain unknown. The objective of this review is to synthesize current research on the health of tigers and their prey that impacts the conservation of tigers in the wild. Published sources are interpreted based on three mechanisms through which disease can affect the viability of tiger populations: (1) by reducing the survival of adult tigers, (2) by reducing breeding productivity, and (3) by reducing the carrying capacity of tiger habitat through decreased prey abundance. Examples of CDV, SARS-CoV2, carnivore protoparvovirus 1 and ASFV are used to illustrate these processes and inform discussion of research and mitigation priorities.

Neglected zoonotic bacteria causes and associated risk factors of cattle abortion in different agro-ecological zones of southwest Ethiopia

Three zoonotic bacteria, Coxiella burnetii, Leptospira spp, and Brucella spp, cause cattle abortion and significant losses in the livestock sector. However, these infections were neglected diseases in Ethiopia. Between October 2020 and October 2021, a cross-sectional study was carried out in southwest Ethiopia to determine the prevalence of abortion and identify the major zoonotic bacterial causes and risk factors that contribute to abortion. Using an indirect ELISA, antibodies to Brucella abortus, Leptospira Hardjo, and Coxiella burnetii were detected in serum samples taken from 461 cattle. Potential risk factors for cattle abortion were found using a multivariable random effect logistic regression analysis. The prevalence of cattle abortion was found to be 22.56 % (95 % CI: 18.74-26.38) in the study areas. Leptospira Hardjo (OR=1.8, 95% CI: 1.04-3.00), Coxiella burnetii (OR=2.7, 95 % CI: 1.26-5.62), and Brucella abortus (OR=9.8, 95 % CI: 1.27-17.15) were all associated with the occurrence of abortion in cattle, as were their co-infections (OR=8.1, 95 % CI: 1.28-39.33). Other risk factors for cattle abortion included breed (OR=16.7, 95 % CI: 2.20-26.77), herd size (OR=2.5, 95 % CI: 1.16-4.68), breeding method (OR=2.3, 95 % CI: 1.33-3.90), and contact with dogs (OR=2.2, 95 % CI: 1.34-3.53). According to the findings of this study, Brucella abortus, Coxiella burnetii, and Leptospira Hardjo are serious zoonoses that cause significant production loss in cattle due to abortion. To prevent transmission of these zoonotic diseases, it is crucial to implement effective control measures and increase public awareness. The causes of cattle abortion in the study areas should also be isolated and characterized.

Optimization and Application of Real-Time qPCR Assays in Detection and Identification of Chlamydiales in Products of Domestic Ruminant Abortion

Domestic ruminant abortions due to infectious agents represent an important cause of economic losses in the agricultural industry. This study aimed to optimise and apply qPCR assays for detection of Chlamydiales in domestic ruminant abortion cases. Primers and probes for detection of the order Chlamydiales, Chlamydia abortus, Chlamydia pecorum, Parachlamydia acanthamoeba and Waddlia chondrophila were taken from the literature to create one singleplex and two duplex assays and the assays were optimised. Placentitis and pneumonia are pathological lesions associated with Chlamydiales infection. In a previous study, twenty-five clinical cases had pathological lesions of placentitis or pneumonia. These cases were investigated further by application of the qPCR assays in this study. Chlamydiales were detected in 16 cases. C. abortus, P. acanthamoeba and W. chondrophila were detected in bovine; and C. pecorum and W. chondrophila in ovine and caprine cases. Chlamydiales were detected in three previously inconclusive cases. Identification was improved from genus to species level (C. pecorum). Four cases remained inconclusive. In conclusion, detection of Chlamydiales and differentiation to species level was improved. This study reports the first detection of P. acanthamoeba and W. chondrophila in abortion cases in South Africa, indicating a potentially significant role in abortions in this country.

Safety and Immunogenicity of a Chimeric Subunit Vaccine against Shiga Toxin-Producing Escherichia coli in Pregnant Cows

Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen that causes gastroenteritis and Hemolytic Uremic Syndrome. Cattle are the main animal reservoir, excreting the bacteria in their feces and contaminating the environment. In addition, meat can be contaminated by releasing the intestinal content during slaughtering. Here, we evaluated the safety and immunogenicity of a vaccine candidate against STEC that was formulated with two chimeric proteins (Chi1 and Chi2), which contain epitopes of the OmpT, Cah and Hes proteins. Thirty pregnant cows in their third trimester of gestation were included and distributed into six groups (n = 5 per group): four groups were administered intramuscularly with three doses of the formulation containing 40 µg or 100 µg of each protein plus the Quil-A or Montanide™ Gel adjuvants, while two control groups were administered with placebos. No local or systemic adverse effects were observed during the study, and hematological parameters and values of blood biochemical indicators were similar among all groups. Furthermore, all vaccine formulations triggered systemic anti-Chi1/Chi2 IgG antibody levels that were significantly higher than the control groups. However, specific IgA levels were generally low and without significant differences among groups. Notably, anti-Chi1/Chi2 IgG antibody levels in the serum of newborn calves fed with colostrum from their immunized dams were significantly higher compared to newborn calves fed with colostrum from control cows, suggesting a passive immunization through colostrum. These results demonstrate that this vaccine is safe and immunogenic when applied to pregnant cows during the third trimester of gestation.

Approaches to increase recovery of bacterial and fungal abortion agents in domestic ruminants

Abortions in domestic ruminants cause significant economic losses to farmers. Determining the cause of an abortion is important for control efforts, but it can be challenging. All available diagnostic methods in the bacteriology laboratory should be employed in every case due to the many limiting factors (autolysis, lack of history, range of samples) that complicate the investigation process. The purpose of this study was to determine whether the recovery of diagnostically significant isolates from domestic ruminant abortion cases could be increased through the use of a combination of the existing aerobic culture and Brucella selective method with methods that are commonly recommended in the literature reporting abortion investigations. These methods are examination of wet preparations and impression smears stained by the modified Ziehl-Neelsen method, anaerobic, microaerophilic, Leptospira, Mycoplasma and fungal culture. Samples of placenta and aborted foetuses from 135 routine clinical abortion cases of cattle (n = 88), sheep (n = 25) and goats (n = 22) were analysed by the new combination of methods. In 46 cases, bacteria were identified as aetiological agents and in one case a fungus. Isolation of Brucella species increased to 7.4% over two years compared with the previous 10 years (7.3%), as well as Campylobacter jejuni (n = 2) and Rhizopus species (n = 1). Salmonella species (5.9%) and Trueperella pyogenes (4.4%) were also isolated more often. In conclusion, the approach was effective in removing test selection bias in the bacteriology laboratory. The importance of performing an in-depth study on the products of abortion by means of an extensive, combination of conventional culture methods was emphasised by increased isolation of Brucella abortus and isolation of C. jejuni. The combination of methods that yielded the most clinically relevant isolates was aerobic, microaerophilic, Brucella and fungal cultures.

Descriptive cross-sectional study on major bovine diseases and associated risk factors in north-eastern Ecuadorian Amazon

Cattle raising is a crucial element of production systems in the tropics and subtropics. However, in recent years, global public health security has been threatened by disease emergence. In Orellana Province, livestock is the most important activity to generate economic income. Nevertheless, there is no available data about Animal Health status. With this objective, a study was performed to describe the major Bovine diseases recorded between 2011 to 2019, and the main Risk factors associated. Data on main Bovine diseases were retrieved from the World Animal Health Information System database. Whereas Bovine population data used to calculate the prevalence rates and confidence intervals were obtained from Ecuador's Ministry of Agriculture. By contrast, the Risk factors identified with an epidemiological questionnaire were applied to 300 livestock farmers. As a result, from 2011 to 2019 in Orellana has been confirmed: 90 cases of Infectious Bovine Rhinotracheitis (31.58%), Bovine Rabies by hematophagous bats (Desmodus rotundus), 83 cases (29.12%), Bovine viral diarrhea with 43 cases (15.10%), Brucellosis by Brucella abortus 35 cases, which was (12.28%), and 34 cases related to Enzootic bovine leukosis (11.92%). Overall, the prevalence rates ranged from (0.24 to 15.37%). In addition, farm size, presence of forest, herd, and paddock sizes, cutting frequency of forages, and other animal species were involved as Risk factors (OR = 3.15 to 11.75; 95% CI, 0.01 to 0.69). In conclusion, there are animal diseases with reproductive and neurologic symptomology and high-Risk factors implicated in the transmission. Consequently, space-temporal and seroprevalence epidemiological studies should be performed in Orellana.

The Quality and Fertilizing Potential of Red Deer (Cervus elaphus L.) Epididymal Spermatozoa Stored in a Liquid State

The aim of this study was to assess the quality and fertilizing potential of red deer epididymal spermatozoa stored in a liquid state for up to 11 days (D11). In Experiment 1, sperm quality was determined. In Experiment 2, the efficiency of in vitro fertilization (IVF) and artificial insemination (AI) of stored sperm were evaluated. An analysis of sperm quality on D5 of storage revealed a decrease (p < 0.05) in motility and morphology, and a higher proportion of apoptotic spermatozoa. On D1, D7 and D10, the total motility of sperm for IVF and AI was determined to be 82.6%, 71.0% and 64.8%, respectively. The results of IVF and AI demonstrated that the fertilizing potential of spermatozoa differs between days of storage. The percentage of blastocysts was higher when oocytes were fertilized on D1 (17.4 %) compared to D7 (8.5%) and D10 sperm (10.5%). Differences were noted in the pregnancy rates of inseminated hinds. The insemination with D1, D7 and D10 sperm led to live births (33% from D7 and D10). The results indicate that the quality of red deer epididymal spermatozoa remains satisfactory during ten days of storage in a liquid state, and that these spermatozoa maintain their fertility potential.

Developmental Programming of Fertility in Cattle-Is It a Cause for Concern?

Cattle fertility remains sub-optimal despite recent improvements in genetic selection. The extent to which an individual heifer fulfils her genetic potential can be influenced by fetal programming during pregnancy. This paper reviews the evidence that a dam's age, milk yield, health, nutrition and environment during pregnancy may programme permanent structural and physiological modifications in the fetus. These can alter the morphology and body composition of the calf, postnatal growth rates, organ structure, metabolic function, endocrine function and immunity. Potentially important organs which can be affected include the ovaries, liver, pancreas, lungs, spleen and thymus. Insulin/glucose homeostasis, the somatotropic axis and the hypothalamo-pituitary-adrenal axis can all be permanently reprogrammed by the pre-natal environment. These changes may act directly at the level of the ovary to influence fertility, but most actions are indirect. For example, calf health, the timing of puberty, the age and body structure at first calving, and the ability to balance milk production with metabolic health and fertility after calving can all have an impact on reproductive potential. Definitive experiments to quantify the extent to which any of these effects do alter fertility are particularly challenging in cattle, as individual animals and their management are both very variable and lifetime fertility takes many years to assess. Nevertheless, the evidence is compelling that the fertility of some animals is compromised by events happening before they are born. Calf phenotype at birth and their conception data as a nulliparous heifer should therefore both be assessed to avoid such animals being used as herd replacements.

Bacillus amyloliquefaciens 40 regulates piglet performance, antioxidant capacity, immune status and gut microbiota

Probiotics can improve animal growth performance and intestinal health. Bacillus species, Lactobacillus species, Bifidobacterium species, yeast etc. are the common types of probiotics. However, understanding the effects of probiotics on the immune status and gut microbiota of weaning piglets and how the probiotics exert their impact are still limited. This study aimed to investigate the effects of Bacillus amyloliquefaciens 40 (BA40) on the performance, immune status and gut microbiota of piglets. A total of 12 litters of newborn piglets were randomly divided into 3 groups. Piglets in control group were orally dosed with phosphate buffered saline; BA40 group and probiotics group were orally gavaged with resuspension BA40 and a probiotics product, respectively. The results showed that BA40 treatment significantly decreased (P < 0.05) the diarrhea incidence (from d 5 to 40), diamine oxidase, D-lactate, interleukin (IL)-1β and interferon-γ concentrations compared with control group and probiotics group. Meanwhile BA40 dramatically increased the total antioxidant capacity, IL-10 and secretory immunoglobulin-A concentrations in contrast to control group. For the microbial composition, BA40 modulated the microbiota by improving the abundance of Bacteroides, Phascolarctobacterium (producing short-chain fatty acids) and Desulfovibrio and reducing the proliferation of pathogens (Streptococcus, Tyzzerella, Vellionella and paraeggerthella). Meanwhile, a metabolic function prediction explained that carbohydrate metabolism and amino acid metabolism enriched in BA40 group in contrast to control group and probiotics group. For correlation analysis, the results demonstrated that BA40-enriched Phascolarctobacterium and Desulfovibrio provide insights into strategies for elevating the health status and performance of weaned piglets. Altogether, BA40 exerted stronger ability in decreasing diarrhea incidence and improved antioxidant activity, gut barrier function and immune status of piglets than the other treatments. Our study provided the experimental and theoretical basis for the application of BA40 in pig production.

Prospective cohort study reveals unexpected aetiologies of livestock abortion in northern Tanzania

Livestock abortion is an important cause of productivity losses worldwide and many infectious causes of abortion are zoonotic pathogens that impact on human health. Little is known about the relative importance of infectious causes of livestock abortion in Africa, including in subsistence farming communities that are critically dependent on livestock for food, income, and wellbeing. We conducted a prospective cohort study of livestock abortion, supported by cross-sectional serosurveillance, to determine aetiologies of livestock abortions in livestock in Tanzania. This approach generated several important findings including detection of a Rift Valley fever virus outbreak in cattle; high prevalence of C. burnetii infection in livestock; and the first report of Neospora caninum, Toxoplasma gondii, and pestiviruses associated with livestock abortion in Tanzania. Our approach provides a model for abortion surveillance in resource-limited settings. Our findings add substantially to current knowledge in sub-Saharan Africa, providing important evidence from which to prioritise disease interventions.

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015–2021

The aim of this work was to identify causes of abortion through laboratory investigations in sheep flocks in Uruguay. One hundred cases of abortion, comprising 58 fetuses, 36 fetuses with their placentas, and 6 placentas were investigated in 2015–2021. Cases were subjected to gross and microscopic pathologic examinations, and microbiological and serological testing for the identification of causes of abortion, including protozoal, bacterial, and viral pathogens. An etiologic diagnosis was determined in 46 (46%) cases, including 33 (33%) cases caused by infectious pathogens, as determined by the detection of a pathogen along with the identification of fetoplacental lesions attributable to the detected pathogen. Twenty-seven cases (27%) were caused by Toxoplasma gondii, 5 (5%) by Campylobacter fetus subspecies fetus, and 1 (1%) by an unidentified species of Campylobacter. Fourteen cases (14%) had inflammatory and/or necrotizing fetoplacental lesions compatible with an infectious etiology. Although the cause for these lesions was not clearly identified, T. gondii was detected in 4 of these cases, opportunistic bacteria (Bacillus licheniformis, Streptococcus sp.) were isolated in 2 cases, and bovine viral diarrhea virus 1 subtype i (BVDV-1i) was detected in another. Campylobacter jejuni was identified in 1 (1%) severely autolyzed, mummified fetus. BVDV-2b was identified incidentally in one fetus with an etiologic diagnosis of toxoplasmosis. Microscopic agglutination test revealed antibodies against ≥1 Leptospira serovars in 15/63 (23.8%) fetuses; however, Leptospira was not identified by a combination of qPCR, culture, fluorescent antibody testing nor immunohistochemistry. Neospora caninum, Chlamydia abortus, Chlamydia pecorum, Coxiella burnetii and border disease virus were not detected in any of the analyzed cases. Death was attributed to dystocia in 13 (13%) fetuses delivered by 8 sheep, mostly from one highly prolific flock. Congenital malformations including inferior prognathism, a focal hepatic cyst, and enterohepatic agenesis were identified in one fetus each, the latter being the only one considered incompatible with postnatal life. Toxoplasmosis, campylobacteriosis and dystocia were the main identified causes of fetal losses. Despite the relatively low overall success rate in establishing an etiologic diagnosis, a systematic laboratory workup in cases of abortion is of value to identify their causes and enables zoonotic pathogens surveillance.

Investigation of Toxoplasma gondii and Neospora caninum as cause of ovine abortion in affected flocks of Urmia, northwest of Iran

Toxoplasma gondii and Neospora caninum, two obligatory intracellular protozoan parasites, are important causes of neonatal mortality and abortion in farmed ruminants worldwide. Previously, protozoan abortions in small ruminants were attributed to T. gondii, but the role of N. caninum in these abortions was uncertain. The aim of this study was to investigate the role of T. gondii and N. caninum in ovine abortion in Urmia, northwest of Iran using a molecular method. Overall, 130 placenta and brain samples of aborted ovine foetuses were collected. Extracted DNA from placenta and CNS tissues of the aborted foetuses were analysed using PCR with primers specific for T. gondii and N. cani­num. The association of the frequency of T. gondii and N. caninum infection of aborted foetuses with age and breed in flocks was also studied. The results showed that out of the 130 examined ovine foetuses, 5.3 and 2.3 % were PCR-positive for T. gondii and N. caninum DNA, respectively. In this study, no significant differences were recorded relating to Toxoplasma and Neospora infection in different age groups in flocks and among sheep breeds included in the present study (P>0.05). The results of this study proved the importance of T. gondii and N. caninum as reasons of abortion in the studied area.

Toll-Like Receptor 2 is Involved in Abnormal Pregnancy in Mice Infected with Toxoplasma gondii During Late Pregnancy

Infection with Toxoplasma gondii during pregnancy causes failure of pregnancy maintenance, resulting in fetal death, abortion, stillbirth, or premature birth, but the mechanism of disease onset remains unclear. Although Toll-like receptor 2 (TLR2) is expressed on antigen-presenting cells and trophoblasts, the role of TLR2 in T. gondii infection during pregnancy is unknown. In this study, we investigated the role of TLR2 in congenital toxoplasmosis using TLR2-deficient (TLR2^−/−) mice. T. gondii infection on gestational day 12.5 (Gd12.5) induced more abnormal pregnancy, including premature birth and stillbirth, in wild-type mice than in TLR2^−/− mice. Multiple calcifications were observed in the placentas of the infected wild-type mice. At Gd18.5 (6days postinfection), the parasite numbers in the placenta and uterus and the histological changes did not differ significantly between the wild-type and TLR2^−/− mice. However, T. gondii infection reduced the mRNA expression of interleukin-12p40 (IL-12p40) and increased IL-4 and IL-10 mRNAs in the placentas of the wild-type mice. In contrast, the placentas of the TLR2^−/− mice showed no changes in the expression of these cytokines, including IL-6 and tumor necrosis factor α, in response to T. gondii infection. Serum interferon-γ levels were significantly lower in the infected TLR2^−/− mice than in the infected wild-type mice on Gd18.5. Thus, the TLR2^−/− mice were less susceptible to the induction of immune responses by T. gondii infection during late pregnancy. Therefore, TLR2 signaling may play a role in the development of disease states during pregnancy, specifically placental hypofunction.

Abortive diseases and their various associated risk factors in small ruminants in Algeria: a systematic review

Abortive infections are a major health challenge affecting productive and reproductive performance of sheep and goats. However, there is no comprehensive summary on the occurrence and distribution of these infections in Algeria. This systematic review provides a comprehensive summary on the prevalence of different abortive diseases and assesses potential risk factors in small ruminants in Algeria. Five databases were used to search epidemiological data on the prevalence of different abortive diseases (bacterial, parasitic, and viral). Data were collected from 25 papers published between 2003 and 2020. The total mean sample size was 53,080 small ruminants. The majority of the diseases/infections were diagnosed by serological and molecular tests. The overall prevalence of brucellosis was 0.39% in sheep and 5.31% in goats. Chlamydia and Q fever were observed in 32.72% and 20.62% of small ruminants, respectively. The prevalence of peste des petits ruminants was 15.76% and the overall prevalence of bluetongue in sheep and goats was, respectively, 13.41% and 44.50%. Border disease and bovine viral diarrhea were detected in 22.68% and 1.01% of sheep examined, respectively. Toxoplasma gondii infection prevalence among sheep and goats was 21.43% and 32.31% respectively. This study is a comprehensive epidemiological analysis of abortion diseases in small ruminants in Algeria and will therefore be a useful tool for researchers. Larger and more robust prevalence studies are needed to adequately support risk assessment and management of animal and public health threats.

Knowledge, attitude, and practices to zoonotic disease risks from livestock birth products among smallholder communities in Ethiopia

Many causes of abortion in livestock are due to zoonotic pathogens that pose serious infection risks for humans. Carefully designed, empirical One Health research allows to untangle the complexity around these risks and guides the development of practical health education guidelines and best prevention practices for veterinary public health interventions. To support this, the study presented here aimed at understanding knowledge, attitudes, and practices (KAP) on zoonotic risks from livestock birth products among rural communities in Ethiopia. From July 2018 to February 2019, a cross-sectional study design was conducted with 327 randomly selected farmers and pastoralists in five districts in three regions in Ethiopia. The structured questionnaire consisted of 48 items to evaluate knowledge (24), attitude (9), and prevention practices (15) related to zoonotic diseases risks from livestock birth products. A unidimensional two-parameter logistic (2-PL) Item Response Theory (IRT) model was used for zoonotic disease risk KAP scale construction and evaluation. The 2-PL IRT model was fitted to determine the probability of a person to appropriately respond to an item with a provided zoonotic disease KAP level. We then examined differential item functioning (DIF) concerning to five important covariates. The attitude subscale had the highest total mean score (37.3, ± 28.92%) and the knowledge subscale had the lowest mean score (22.4, ± 33.6%) among the three subscales. The mixed model regression analysis indicated that region was the only apparent factor explaining differences in zoonotic diseases knowledge, attitude, and practice total mean scores. The knowledge and attitude subscales had good internal consistency with a Cronbach's α at 0.83 and 0.81, respectively, whereas the practice subscale had lower internal consistency with 0.51. There was a positive association between responding to knowledge questions correctly and a positive attitude (r2 = 0.44, p < 0.0001) and self-reported good practice (r2 = 0.307, p < 0.0001). The differential item functioning test showed that 19 of 37 (51.35%) and 12 of 37 (32.43%) items of the retained KAPs survey items had non-uniform and uniform DIF linked to at least one covariate respectively and all the covariates were related with DIF in at least one item. This study found substantial knowledge gaps, a low level of the desired attitude, and high-risk behavioural practices regarding zoonotic disease from livestock birth products. Consequently, livestock keepers are likely exposed to pathogens and thus these practices are an important contributing factor for zoonotic disease infection in people.

Retrospective study of factors associated with bovine infectious abortion and perinatal mortality

Abortion and perinatal mortality, leading causes of economic loss in cattle industry, are the consequence of both non-infectious and a wide range of infectious causes. However, the relative contribution of pathogens to bovine abortion and perinatal mortality is poorly documented, since available studies involved only a limited number of pathogens. Therefore, the objectives of the present monitoring study were to determine the prevalence of infectious agents associated with bovine abortion and perinatal mortality, and to identify differences in production type, gestation length, parity and seasonality by using mixed effect models (logistic regression). A pre-established sampling protocol based on the collection of the aborted fetus/calf and a corresponding maternal blood sample, involving diagnostic testing for 10 pathogens, was performed. At least one potential causal agent of the abortion or perinatal mortality was detected in 39 % of cases. In these diagnosed cases, Neospora caninum was the most detected pathogen, followed by Trueperella pyogenes, BVDv, Escherichia coli, and Aspergillus fumigatus. Neospora caninum [odds ratio (OR): 0.4; 95 % confidence interval (CI): 0.3-0.7] and Aspergillus fumigatus (OR: 0.1; 95 % CI: 0.1-0.3) were detected less in late versus early gestation. Aspergillus fumigatus was less common in dairy in comparison to beef abortion cases (OR: 0.2; 95 % CI: 0.1-0.6). Winter was associated with a lower positivity for Neospora caninum and BVDv in comparison to warmer seasons. Despite extensive diagnostic testing, an etiological diagnosis was not reached in 61 % of cases, highlighting the need for even more extensive (non-)infectious disease testing or more accurate tests.

Characteristics of Aerococcus viridans isolated from porcine fetuses in Korean farms

Swine abortion caused by viruses as well as bacteria has caused many economic losses in domestic farms over the years; however, bacterial abortion has not yet been studied in Korea. Several bacterial species were isolated from aborted fetuses (n = 103) for which the cause of death was not viral abortion. Among them, we focused on Aerococcus viridans, which had the highest positive rate within three provinces (Gangwon, Jeonnam and Gyeongnam). A total of 16 isolates were identified as A. viridans by matrix‐assisted laser desorption ionization‐time of flight mass spectrometry (MALDI‐TOF MS), and 13 were characterized by both antibiotic resistance and 16S rRNA gene analysis. Based on antibiotic susceptibility testing result, eight antimicrobials could not effectively eliminate the present isolation (more than 40% of isolates can resist these antibiotics), while all except two strains were susceptible to trimethoprim/sulfamethoxazole. Molecular analysis indicated genetic variation among these strains. This study is the first report detecting A. viridans from aborted fetuses in Korean domestic farms.

Causes and Flock Level Risk Factors of Sheep and Goat Abortion in Three Agroecology Zones in Ethiopia

A cross-sectional survey was conducted to estimate the incidence of small ruminant abortion and identify its major causes and potential risk factors in goat and sheep flocks in three agroecology and production systems of Ethiopia. Information on pregnancy outcomes and management risk factors were collected for 299 goat and 242 sheep flocks. Blood samples were collected from 133 sheep and 90 goat flocks and tested for Coxiella burnetii, Brucella spp., Chlamydia abortus, and Toxoplasma gondii. A causal diagram outlined relationships between potential predictor variables and abortion in the flock. The effect of management and exposure to infectious causes on the number of abortions in the flock across agroecology was tested using zero-inflated negative binomial regression. Results showed that 142 (58.68%) goats and 53 (17.73%) sheep flocks reported abortions in the 12 months before the survey. The mean annual flock abortion percentages were 16.1% (±26.23) for does and 12.6% (±23.5) for ewes. Farmers perceived infectious diseases, extreme weather conditions, feed shortage, physical traumas, and plant poisoning as the most important causes of abortion. A higher proportion of abortion was recorded during the short rainy season (March to May) and start of the short dry and cold season (June to August) in the lowland mixed crop-livestock and pastoral agroecology and production system, respectively. Overall, 65.41% sheep and 92.22% goat flocks tested positive for one or more abortion causing agents, namely, C. burnetti, C. abortus, Brucella spp., and T. gondii; mixed infection was found in 31.58% sheep and 63.33% goat flocks. Spending the night in a traditional house and providing supplementary feed for pregnant dams were important management factors which significantly (p ≤ 0.05) decreased the risk of abortion by 2.63 and 4.55 times, respectively. However, the presence of other livestock species and dogs in the household and exposure of the flock to Brucella spp. or anyone of the four tested infectious agents significantly (p ≤ 0.05) increased the risk of abortion in sheep and goat flocks. In general, abortion is a challenge for small ruminant production in the study area especially in lowland agroecology and calls for improvement in husbandry practices, health care and biosecurity practices.

CXCR3-Dependent Immune Pathology in Mice following Infection with Toxoplasma gondii during Early Pregnancy

Toxoplasmosis is a worldwide zoonosis caused by the obligate intracellular parasite Toxoplasma gondii The symptoms of congenital toxoplasmosis range from embryonic death and resorption to subclinical infection, but the mechanism of disease onset remains unclear. C-X-C motif chemokine receptor 3 (CXCR3) is highly expressed in Th1-associated immune cells and plays an important role in the trafficking and activation of immune cells. However, the roles of CXCR3 in T. gondii-induced fetal loss and the molecular mechanism of embryo resorption remain poorly understood. In this study, we investigated the role of CXCR3 in fetal wastage caused by T. gondii infection using CXCR3-deficient (CXCR3^-/-) mice. CXCR3^-/- and wild-type pregnant mice were inoculated intraperitoneally with T. gondii tachyzoites on day 3.5 of gestation (Gd3.5). Pregnancy rates decreased as the pregnancy progressed in both infected groups; however, infected CXCR3^-/- mice showed a significant fetal loss at Gd13.5 compared with that at Gd7.5. All embryos of the infected groups showed necrosis, and embryo resorption was significantly increased in infected CXCR3^-/- compared with wild-type mice at Gd13.5. The parasite load of fetoplacental tissues was significantly increased in CXCR3^-/- mice at Gd10.5. Moreover, mRNA expression levels of inducible nitric oxide synthase were significantly increased in fetoplacental tissues from infected wild-type mice compared to infected CXCR3^-/- mice following the infection. These results suggested that CXCR3-dependent immune responses provide anti-Toxoplasma activity and play an essential role in reducing embryo resorption and fetal loss caused by T. gondii infection during early pregnancy.

Emerging diseases in international trade in embryos

A significant change in cattle production and germplasm exchange has occurred over the past 50 years. The growth of artificial reproductive technologies and their broad implementation has become commonplace. The production and subsequent import and export of semen and embryos throughout the world has increased significantly. The embryo transfer industry has reached a new record of growth, with approximately 1.5 million transferrable bovine embryos collected and/or produced in 2018. Over 1 million of these embryos were produced invitro . The increased production of invitro -produced embryos leads to greater opportunities involving international trade. However, further research concerning emerging pathogens is imperative to ensure the efficacy and safety of the embryo transfer industry. Appropriate biosecurity protocols, including reliable testing methodology and effective embryo processing procedures, are key in preventing disease due to emerging and re-emerging pathogens that can be transmitted via embryo transfer.

Retrospective study of bacterial and fungal causes of abortion in domestic ruminants in northern regions of South Africa (2006-2016)

This initial retrospective study presents information on bacterial and fungal causes of abortion in domestic ruminants in South Africa over 10 years (2006-2016). A complete set of data was collected at the Faculty of Veterinary Science through a keyword search of pathology and bacteriology laboratory registers. Additional electronic data were received from an external laboratory. A total of 288 cases were recorded from six provinces. Overall diagnostic rate was 35.1%. In 14.6% of cases, histological evidence of an infectious process was found, but no aetiological agent was detected. Several cases did not include aetiological diagnoses because applicable diagnostic techniques were not available or not applied when necessary. Increased submission of placenta, as well as additional conventional and molecular diagnostic methods, can contribute to an improved diagnostic rate. In addition, the study highlights the superior significance of Brucella abortus as a major bovine pathogen in South Africa.

Seroepidemiology of Toxoplasma gondii in small ruminants in Northwest Ethiopia

This cross-sectional study with a cluster random sampling method was undertaken from November 2018 to May 2019 to estimate the prevalence and assess the potential risk factors of T. gondii seropositivity, and to assess the association of the T. gondii seropositivity with reproductive losses in small ruminants in Northwest Ethiopia. A total of 576 blood samples from 135 small ruminant flocks were collected and assayed for T. gondii IgG antibodies using the Toxo-latex slide agglutination test. A questionnaire survey was also conducted to gather information on the potential risk factors of T. gondii seropositivity and on the status of reproductive losses in the small ruminant flocks. The study demonstrated a high flock and animal level T. gondii seroprevalence of 96.3% (95% CI: 91% - 98%) and 70.48% (95% CI: 68% - 79%), respectively. Mixed effect logistic regression analysis of the potential risk factors showed that the odds of seropositive for T. gondii was significantly higher in sheep (OR = 1.7, 95%CI: 1.19-2.46) than in goats, in adult (OR = 1.6, 95%, CI: 1.11-2.31) than in young, in the presence of cats (OR = 2, 95%CI:1.32-3.04) than in the absence of cats, in the lack of knowledge on the role of cats as a pathogen source than knowing it (OR = 1.82, 95% CI:1.21-2.77). The study also showed that the likelihoods of experiencing the abortion, neonatal death and weak birth in the previous one year in T. gondii seropositive flocks were 20.76 (95% CI: 2.2-195.1, p < 0.001), 8.90 (95% CI: 1.99-83.0, p = 0.021) and 9.33 (95% CI: 1.1-86.2, p = 0.019) times more than the seronegative flocks, respectively. In conclusion, this study revealed high flock and animal level seroprevalence of T. gondii in the small ruminant population in northwest Ethiopia, suggesting that lamb and goat might be a source of this pathogen for human infection if their infected meat is consumed undercooked or uncooked. Besides, the observed association of T. gondii seropositivity with reproductive losses may suggest the economic importance of the pathogen for the small ruminant producers. Therefore, it warrants control attention to reduce its economic and public health burden in the study areas. Further works on the economic impacts, bioassay, isolation, and genetic characterization of the pathogen are suggested.

Breed- and trait-specific associations define the genetic architecture of calving performance traits in cattle

Reducing the incidence of both the degree of assistance required at calving, as well as the extent of perinatal mortality (PM) has both economic and societal benefits. The existence of heritable genetic variability in both traits signifies the presence of underlying genomic variability. The objective of the present study was to locate regions of the genome, and by extension putative genes and mutations, that are likely to be underpinning the genetic variability in direct calving difficulty (DCD), maternal calving difficulty (MCD), and PM. Imputed whole-genome single-nucleotide polymorphism (SNP) data on up to 8,304 Angus (AA), 17,175 Charolais (CH), 16,794 Limousin (LM), and 18,474 Holstein-Friesian (HF) sires representing 5,866,712 calving events from descendants were used. Several putative quantitative trait loci (QTL) regions associated with calving performance both within and across dairy and beef breeds were identified, although the majority were both breed- and trait-specific. QTL surrounding and encompassing the myostatin (MSTN) gene were associated (P < 5 × 10⁻⁸) with DCD and PM in both the CH and LM populations. The well-known Q204X mutation was the fifth strongest association with DCD in the CH population and accounted for 5.09% of the genetic variance in DCD. In contrast, none of the 259 segregating variants in MSTN were associated (P > × 10⁻⁶) with DCD in the LM population but a genomic region 617 kb downstream of MSTN was associated (P < 5 × 10⁻⁸). The genetic architecture for DCD differed in the HF population relative to the CH and LM, where two QTL encompassing ZNF613 on Bos taurus autosome (BTA)18 and PLAG1 on BTA14 were identified in the former. Pleiotropic SNP associated with all three calving performance traits were also identified in the three beef breeds; 5 SNP were pleiotropic in AA, 116 in LM, and 882 in CH but no SNP was associated with more than one trait within the HF population. The majority of these pleiotropic SNP were on BTA2 surrounding MSTN and were associated with both DCD and PM. Multiple previously reported, but also novel QTL, associated with calving performance were detected in this large study. These also included QTL regions harboring SNP with the same direction of allele substitution effect for both DCD and MCD thus contributing to a more effective simultaneous selection for both traits.

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.

Seroprevalence and associated risk factors for chlamydiosis, coxiellosis and brucellosis in sheep and goats in Borana pastoral area, southern Ethiopia

BACKGROUND

Abortion is considered an important disease problem of small ruminants in Borana pastoral area. A cross-sectional study was conducted to estimate the prevalence and risk factors of chlamydiosis, coxiellosis (Q-fever) and brucellosis in small ruminants in selected districts of Borana zone.

RESULTS

A total of 506 sheep and goats were tested using serological tests. Fifty (9.88%; 95% CI: 7.42, 12.82), 144 (28.46%; 95% CI: 24.56, 32.61) and none (0.00%; 95% CI: 0.00, 0.59) of them were positive for chlamydiosis, coxiellosis and brucellosis, respectively. History of abortion was recorded in 136 (32.00%; CI: 27.59, 36.67) of sheep and goats in the study area. The logistic regression analysis, however, showed that statistically significant difference ccurred among districts and between the species of small ruminants. The prevalence odd of antibodies against C. abortus was significantly lower in Miyo, Dire and Teltelle districts compared to Dillo. The odd of infection with this bacterium was lower in sheep than goats. Similarly the odd of infection with C. burnettii was significantly higher in Dillo district than the rest of the districts studied, higher in goats than sheep and higher in adult animals than young ones.

CONCLUSION

High prevalence of abortion is observed in sheep and goats in the study area. High seropositivity of C. burnetii and C. abortus in both sheep and goats tested implies risks of human infection by both diseases. Thus, attention needs to be paid to further study of both diseases in animals and humans in the area.

Herd-level risk factors for cow and calf on-farm mortality in Estonian dairy herds

BACKGROUND

On-farm mortality (unassisted death and euthanasia) is the unwanted loss of animals, and it comes with negative economic consequences. On-farm mortality rates reflect a herd's animal welfare status. The objective of this historical longitudinal single cohort study was to identify the associations between herd characteristics, animal housing conditions and management routines and within-herd calf and cow mortality rates in participating Estonian dairy herds. All farmers enrolled in the voluntary production recording system with a herd size of 20 or greater cow-years in 2015-2017 were contacted by mail or telephone between October 2017 and March 2018. The survey included questions about management routines and housing conditions of calves up to 3 months of age and of cows. In total, 214 completed questionnaires were returned, corresponding to a 63.3% response rate. The within-herd mortality rate of calves (aged 21-90 days) and cows (cattle over 24 months of age) in years 2017-2018 were calculated and used as outcome variables. Negative binomial and linear regression models were applied for risk factor analysis in calf and cow datasets, respectively.

RESULTS

The median within-herd mortality rate for calves aged 21 to 90 days was 0.15 per 100 calf-months (quartiles 0.00; 0.36). The median within-herd mortality rate for cattle over 24 months of age was 4.57 per 100 cow-years (quartiles 2.44; 6.86). Factors significantly associated with increased mortality of calves were larger herd size, higher proportion of stillbirths and abortions in a herd, prophylactic administration of vitamins to all calves and housing pre-weaned calves in single pens only compared with housing in both single and group pens. Also, farmers who attended more frequent trainings had higher calf mortality rates. Calving in a group pen or in a tie-stall compared with calving in multiple systems was associated with higher calf mortality rates. Higher cow mortality rates were present in herds that had a higher proportion of stillbirths and on farms where employees handled cows. Housing cows in free-stall barns, grazing cows and more frequent hoof trimming were protective for cow on-farm mortality.

CONCLUSIONS

This study identified the importance of housing conditions for on-farm cow and calf mortality rates. Our study results suggest that providing good care might ensure better health and welfare of dairy cows and calves.

Importance of Viral Disease in Dairy Cow Fertility

Many viral diseases are endemic in cattle populations worldwide. The ability of many viruses to cross the placenta and cause abortions and fetal malformations is well understood. There is also significant evidence that viral infections have additional actions in dairy cows, which are reflected in reduced conception rates. These effects are, however, highly dependent on the time at which an individual animal first contracts the disease and are less easy to quantify. This paper reviews the evidence relating to five viruses that can affect fertility, together with their potential mechanisms of action. Acute infection with non-cytopathic bovine viral diarrhea virus (BVDV) in mid-gestation increases abortion rates or causes the birth of persistently infected calves. BVDV infections closer to the time of breeding can have direct effects on the ovaries and uterine endometrium, which cause estrous cycle irregularities and early embryo mortality. Fertility may also be reduced by BVDV-induced immunosuppression, which increases the susceptibility to bacterial infections. Bovine herpesvirus (BHV)-1 is most common in pre-pubertal heifers, and can slow their growth, delay breeding, and increase the age at first calving. Previously infected animals subsequently show reduced fertility. Although this may be associated with lung damage, ovarian lesions have also been reported. Both BHV-1 and BHV-4 remain latent in the host following initial infection and may be reactivated later by stress, for example associated with calving and early lactation. While BHV-4 infection alone may not reduce fertility, it appears to act as a co-factor with established bacterial pathogens such as Escherichia coli and Trueperella pyogenes to promote the development of endometritis and delay uterine repair mechanisms after calving. Both Schmallenberg virus (SBV) and bluetongue virus (BTV) are transmitted by insect vectors and lead to increased abortion rates and congenital malformations. BTV-8 also impairs the development of hatched blastocysts; furthermore, infection around the time of breeding with either virus appears to reduce conception rates. Although the reductions in conception rates are often difficult to quantify, they are nevertheless sufficient to cause economic losses, which help to justify the benefits of vaccination and eradication schemes.

Reproductive performance in goats and causes of perinatal mortality: a review

Goat meat production is an expanding industry in Australia. However, there is limited data quantifying the levels of reproductive performance, particularly under extensively grazed rangeland conditions, which would inform interventions to improve performance. This review aimed to quantify the levels of reproduction, time and causes of reproductive wastage in goats. It considers the levels of fertility, fecundity, embryonic loss, fetal loss and post-natal survival reported under Australian conditions, and comparisons are made with international reports. Key management factors that may contribute to reproductive performance include breed, seasonality, nutritional conditions, and weather conditions at kidding. While goats are potentially prolific breeders, in Australia, the variation in weaning rate (kids/doe joined) among properties is large (51–165%), although the causes of this variation are not well defined. Generally, conception and kidding rates are high, although fetal loss associated with undernutrition is more likely in goats than sheep. As with sheep, perinatal losses are generally the largest source of wastage, with an average 20% kid mortality, but this level is influenced by litter size and appears to be higher under extensive rangeland systems. The causes of perinatal kid loss under Australian conditions are similar to those in sheep, with starvation–mismothering–exposure and dystocia or stillbirth the key causes. Studies are needed to accurately quantify the level and causes of reproductive wastage in commercial herds, including a range of management situations, to enable effective interventions to be developed.

Sanitary program to reduce embryonic mortality associated with infectious diseases in cattle

Among reproductive disorders in dairy and beef cattle worldwide, embryonic mortalities stand out as one of the most frequent. Because of the multifactorial etiology, the clinical and laboratory diagnoses of embryonic mortality causes in cattle are quite complex. Often, infectious causes may account for up to 50% of bovine embryonic mortality rates after 30 days of conception. This review will address the main causes of early and late embryonic mortality, with emphasis on infectious causes and, particularly, those more frequent in the Brazilian cattle herds. In addition, we will discuss ways of controlling and prophylaxis including those related to reproductive and sanitary management, with emphasis on immunoprophylaxis of the three most frequent reproductive infectious diseases in Brazilian dairy and beef cattle herds.

Longitudinal profiles of relaxin and progestagens during pregnancy, pregnancy loss and false pregnancy in the killer whale (Orcinus orca)

The circulating pattern of immunoreactive relaxin and progestagens based on monthly and gestational stage (early, mid, late) profiles were determined during pregnancies that resulted in live calves (LIVE, n = 30), stillbirths (STILLB, n = 3), abortions (ABORT, n = 5) and presumptive false pregnancies (FALSE, n = 8), and during the follicular (n = 34) and luteal phase (n = 58). Monthly LIVE relaxin concentrations steadily increased during gestation, but values did not significantly exceed those of the luteal phase until 9 months prior to parturition, peaking during the final month at 2356 ng/ml. Relaxin surged (P < 0.05) during the final week of gestation (36,397 ng/ml), undergoing a 3 and 9-fold increase compared with concentrations in the preceding two weeks, respectively. Monthly relaxin production did not differ among each reproductive state with the exception of months-13-16 where concentrations were higher (P < 0.001) for STILLB than LIVE. Relaxin concentration was reduced (P < 0.0001) by 849% in placental versus maternal serum collected within 1 day of labor. Mid- and late-pregnancy progestagen concentrations were lower for FALSE (P < 0.001) compared with STILLB and LIVE. Late pregnancy progestagen concentrations were reduced for FALSE (P < 0.05) and ABORT (P < 0.02) compared with LIVE and STILLB. Monthly progestagen production in ABORT tended to be lower than LIVE across a range of gestational months (Months 2, 7, 8, 11) but this difference only became significant during months 14 and 15. Results indicate that relaxin is primarily produced by the CL during pregnancy, and that concentrations could not be used to differentiate from non-pregnant females until the final 6 months of gestation. In addition, as would be expected from a primarily CL product, relaxin cannot be used to detect abnormal pregnancies. Conversely, progestagens, which are produced by both the placenta and CL can be used to differentiate FALSE from normal pregnancy and may be useful indicators of fetal health in the killer whale.

Changes in Blood Lymphocyte Subpopulations and Expression of MHC-II Molecules in Wild Mares Before and After Parturition

Introduction

Pregnancy is a physiological state in which the immune system undergoes certain changes. On the one hand, by depleting cell defence mechanisms, it favours development and maintenance of the pregnancy. At the same time cells of the immune system ensure resistance to many risk factors, including infectious agents.

Material and Methods

The study was carried out on 24 Polish Konik breed mares which were divided into two equal groups. The first group (group I) included mares living in the reserve. The second group (group II) comprised mares maintained under conventional conditions in the stables. The blood samples were collected for the first time in the perinatal period, i.e. 2 weeks before parturition (trial 0), then within the first 24 h after delivery, and then on 7^th and 21^st day after foaling. Flow cytometric analysis of lymphocyte expressing TCD4+, TCD8+, CD2+, and MHC class II antigens was performed.

Results

Before the delivery, in group I there was a significantly higher CD4:CD8 ratio compared to group II (P ≤ 0.05). Similarly, significantly increased CD4:CD8 ratio in group I was noted within 24 h after parturition (P ≤ 0.001) and it was also observed on 7^th day (P ≤ 0.03) and 21^st day after foaling (P ≤ 0.02). In the first 24 h after parturition, a significant decline of lymphocytes CD8+ (P ≤ 0.02) was noted. No significant differences in terms of lymphocytes CD2+ and CD3+ were observed. Expression of MHC-II molecules before and after the parturition was higher in group I compared to group II; however, the difference between the groups was not significant.

Conclusion

The results obtained indicate that mares living in the reserve display higher activity of cell defence mechanisms.

Research on viral agents associated with feline reproductive problems reveals a high association with feline panleukopenia virus

Although reproductive failures (RF) such as abortion, stillbirth and neonatal mortality in cats are still under researched, it is known that many RF are caused by viral agents. This research surveyed the viral agent prevalence in queens with RF. Queens were excluded from the study if their RF was caused by issues other than infection, such as genetic, traumatic, hormonal or nutritional problems, or if they had a history of RF. Blood samples from 26 pregnant females with RF were collected for complete blood counts (BCC), renal/hepatic biochemistry and glycaemic analysis. Ultrasonography was performed to evaluate gestational age and foetal viability. When possible, placentas, humours and foetal tissues were collected. Blood samples were tested by PCR and qPCR for feline leukaemia virus (FeLV), feline immunodeficiency virus (FIV), feline alphaherpesvirus 1 (FeHV-1) and carnivore protoparvovirus 1 (CPPV-1). All maternal samples were negative for FeLV, FIV and FeHV-1 and positive for CPPV-1. In addition, foetuses from one queen and three females were positive for CPPV-1 by qPCR and for feline panleukopenia virus (FPV) through DNA sequencing. The BCC and biochemistry results revealed significant neutrophilia, lymphopenia, monocytosis, and liver enzymes. These results provide the first description of an FPV agent causing only RF-related clinical signs in queens.

The serostatus of Brucella spp., Chlamydia abortus, Coxiella burnetii and Neospora caninum in cattle in three cantons in Bosnia and Herzegovina

Background

Dairy production in Bosnia and Herzegovina exhibits limited productivity, which may partly, be explained by extensive reproductive problems of non-infectious and infectious origin. Brucella spp., Chlamydia abortus, Coxiella burnetii and Neospora caninum are common infectious causes of decreased reproductive outcomes in cattle worldwide. Little is, however, known about the disease status of herds with reduced reproductive performances. A cross-sectional study was designed to document the status of these pathogens in dairy cattle in Bosnia and Herzegovina. A total of 1970 serum samples were collected from cattle in farms located in three cantons (regions). Enzyme linked immunosorbent assays were used to screen for seropositivity against four selected pathogens.

Results

The overall seroprevalence was estimated at both the herd level and at individual level for each pathogen. At the individual animal level, the prevalence for C. abortus, C. burnetii, N. caninum and Brucella spp. was 52.1% (95% CI: 41.2–62.7), 8.8% (95% CI: 5.3–14.2), 9.2% (95% CI: 6.0–12.3 and 0.2% (95% CI: 0.1–0.5), respectively. The corresponding estimates for herd level were 87.9% (95% CI: 82.6–91.8), 19.6% (95% CI: 14.6–25.8), 35.2% (95% CI: 28.8–42.1), and 1.5% (95% CI: 0.5–4.6). A substantial overlap was observed in the presence of N. caninum, C. abortus and C. burnetii at individual and herd level.

Conclusion

Our study demonstrated a high level of antibodies to Chlamydia abortus. Considering the association of this agent with reproductive disorders in cattle, future studies should be directed to the epidemiological traits of this infection. Additionally, the relatively high levels of exposure to C. burnetii and N. caninum found in this study highlights the need for targeted control of infectious causes of reproductive disorders in dairy cattle of the studied areas. Given the low seroprevalence, Brucella spp. does not seem to represent a problem in the reproductive health of cattle in the studied areas.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1361-z) contains supplementary material, which is available to authorized users.

A nested-PCR strategy for molecular diagnosis of mollicutes in uncultured biological samples from cows with vulvovaginitis

Bacteria classified in Mycoplasma (M. bovis and M. bovigenitalium) and Ureaplasma (U. diversum) genera are associated with granular vulvovaginitis that affect heifers and cows at reproductive age. The traditional means for detection and speciation of mollicutes from clinical samples have been culture and serology. However, challenges experienced with these laboratory methods have hampered assessment of their impact in pathogenesis and epidemiology in cattle worldwide. The aim of this study was to develop a PCR strategy to detect and primarily discriminate between the main species of mollicutes associated with reproductive disorders of cattle in uncultured clinical samples. In order to amplify the 16S-23S rRNA internal transcribed spacer region of the genome, a consensual and species-specific nested-PCR assay was developed to identify and discriminate between main species of mollicutes. In addition, 31 vaginal swab samples from dairy and beef affected cows were investigated. This nested-PCR strategy was successfully employed in the diagnosis of single and mixed mollicute infections of diseased cows from cattle herds from Brazil. The developed system enabled the rapid and unambiguous identification of the main mollicute species known to be associated with this cattle reproductive disorder through differential amplification of partial fragments of the ITS region of mollicute genomes. The development of rapid and sensitive tools for mollicute detection and discrimination without the need for previous cultures or sequencing of PCR products is a high priority for accurate diagnosis in animal health. Therefore, the PCR strategy described herein may be helpful for diagnosis of this class of bacteria in genital swabs submitted to veterinary diagnostic laboratories, not demanding expertise in mycoplasma culture and identification.

On-farm biosecurity practices and causes of preweaning mortality in Canadian commercial mink kits

Background

Mink are an important animal commodity group in Canada and excessive kit mortality represents a significant loss to production. National biosecurity standards have been developed for Canadian mink farms, but it is unclear how well these standards have been implemented as there are no studies correlating management practices of mink producers with causes of death in mink kits. To that end, we surveyed Ontario mink producers on their biosecurity and management practices and conducted almost 5660 post mortem examinations on found-dead, preweaned kits to characterize mink farm biosecurity practices and causes of death in preweaned kits.

Results

We found that very few biosecurity and management practices were uniformly used by producers, despite good awareness of appropriate practices. Use of personal protective equipment was implemented by fewer than 50% of respondents, while control of mink shed access, disinfection of feed containers after use, and use of a rodent control program were the only practices implemented by greater than 70% of respondents. Only 18% of producers reported regular use of antimicrobials in feed or water, although 91% stated they used antimicrobials for treatment of bacterial diseases on a regular basis. On post mortem examination, no gross abnormalities were noted in 71% of the kits, 45% were thought to be stillborn or aborted, 27% had some form of abnormal fluid distribution in the body, and 2% had a congenital malformation. A subset of 69 gastrointestinal tract samples was submitted for bacterial culture, of which 45 samples yielded sufficient growth. Most interesting was the identification of Salmonella enterica serovar Heidelberg in 11% of samples.

Conclusions

The results of this study will provide a benchmark for Canadian mink producers and their veterinarians, defining the areas to which greater attention should be given to ensure more rigorous biosecurity practices are in place. Ultimately, these improvements in practices may contribute to increased mink production and animal well-being.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-017-0326-8) contains supplementary material, which is available to authorized users.

Transplacental transmission of Neospora caninum in naturally infected small ruminants from northeastern Brazil

ABSTRACT: Toxoplasma gondii and Neospora caninum are causative agents of abortion in sheep and goats. Thus, the present study aimed to describe the transplacental transmission of these protozoans in small ruminants of northeastern Brazil. Seventeen fetuses (6 goats and 11 sheep) from farms with history of abortion were necropsied and samples were collected from different tissues (brain, liver, lung, kidney and heart). The samples were analyzed by PCR, histopathology (HP) and immunohistochemistry (IHC) to evaluate whether T. gondii and/or N. caninum infection were the cause of abortion. None of the samples was positive for T. gondii according to PCR and IHC results. Some brain, liver, lung, kidney and heart samples of goat fetuses were positive for N. caninum by PCR. In the histopathology, mild mononuclear infiltration and necrosis with calcification were observed in the liver and brain of one goat fetus, respectively, that also was positive for N. caninum by PCR and IHC. The results confirmed vertical transmission of N. caninum in naturally infected goats of northeastern, Brazil.