Stop H5N1 influenza in US cattle now

The relentless march of a highly pathogenic avian influenza virus (HPAIV) strain, known as H5N1, to become an unprecedented panzootic continues unchecked. The leap of H5N1 clade 2.3.4.4b from Eurasia and Africa to North America in 2021 and its further spread to South America and the Antarctic have exposed new avian and mammalian populations to the virus and led to outbreaks on an unrivaled scale. The virus has infected wild birds across vast geographic regions and caused wildlife deaths in some of the world's most biodiverse ecosystems. Hundreds of millions of poultry have died or been culled, affecting global food security in some of the world's poorest regions. Numerous mammalian species, including sea lions and fur animals, have been infected. Outbreaks in dairy cows in the United States have been occurring for months, seemingly unchecked in most affected states. Why is there not a greater sense of urgency to control these infections?

Can 'cow flu' be eliminated-or is it too late?

Feeble government response and lack of industry cooperation hamper U.S. control efforts.

Survey assessing foot trimmer involvement in managing lameness in UK beef cattle

BACKGROUND

Cattle lameness is a significant welfare and economic problem facing the livestock industry. Published research has investigated foot trimming practices in dairy herds, but little is known about the practices in beef herds. Therefore, the objective of this study was to obtain information about the current practices of professional cattle foot trimmers concerning beef cattle within the UK.

METHODS

An online survey comprising 16 questions was created using the Joint Information Systems Committee platform. The survey was open for 3 months.

RESULTS

There was a significant difference (p < 0.05) between the proportions of dairy cattle and beef cattle receiving preventative foot trims. Digital dermatitis was the most commonly recorded cause of lameness when a lame beef animal was trimmed by the respondents, followed by white line disease. A thematic analysis of foot trimmers' opinions of barriers to engagement on beef farms is presented, in addition to their opinions on veterinary involvement with beef lameness.

LIMITATIONS

Distribution bias may have affected the results, as the survey was distributed online with support from the Cattle Hoof Care Standards Board and the National Association of Cattle Hoof Trimmers. The percentage of foot trimmers not affiliated with either professional body is not known.

CONCLUSION

Further research on the impact of lameness on suckler and finishing cattle, including investigations into preventative actions to reduce lameness in beef systems, is warranted.

Effect of doubled dose administration of foot-and-mouth disease vaccine against heterologous virus infection in cattle

Vaccination is a feasible approach for controlling foot-and-mouth disease (FMD). In FMD-free countries, vaccines are stored as a precautionary measure to control potential outbreaks. However, the challenge lies in pre-stocking optimal vaccines against the newly emerging strains. This study examined the potency of pre-stocked vaccines administered at elevated doses during emergencies. We vaccinated the cows with either a single or double trivalent vaccine dose containing two serotype O and one serotype A strains. Subsequently, vaccinated and unvaccinated cows were exposed to virulent strains of serotype O (O/JPN/2010; topotype Southeast Asia/Mya-98 lineage) or A (A/IRN/2016; topotype ASIA/G-VII lineage), which were genetically and antigenically distinct from the vaccine strains. Following challenge infections, all cows that received a single dose vaccination exhibited vesicular lesions with excreted viruses in the oral and nasal discharges. However, a substantial reduction was observed in the total clinical scores and virus titers in the sera and nasal discharges compared to those in the unvaccinated group. Cows receiving a doubled dose vaccination were completely protected from infection with O/JPN/2010 or demonstrated a significant decrease in viral shedding and clinical scores against A/IRN/2016. To note, vesicular lesions harbor significant amounts of viruses; thus, by mitigating their formation, viral transmission can be impeded, thereby slowing viral spread in the field. Furthermore, increasing the vaccine dose induced higher neutralizing antibody titers against heterologous strains. These findings suggest an alternative strategy for the effective management of future epidemics using pre-stocked vaccines.

Evaluating the impact of application of anaerobic bacterial fermentation enhancer on digital dermatitis

The control of digital dermatitis (DD) among cattle is crucial; however, effective and environmentally-sound control measures have yet to be identified. From the monitoring data of DD which were recorded during regular hoof trimmings in a farm in Hokkaido, Japan, we detected a decrease in the DD prevalence in a herd where an anaerobic bacterial fermentation enhancer (ABFE) was distributed. The possible effect of ABFE was analyzed using a retrospective repeated cross-sectional design. The prevalence of DD decreased over time in the ABFE-distributed group. Furthermore, a selected regression model indicated the time-dependent enhancement of the decreasing trend. While potential coincidental factors may influence, this study provides a basis for further research on the preventive effect of ABFE against DD.

Factors associated with perceived Anaplasma marginale infection and clinical anaplasmosis cases on beef operations in California

Bovine anaplasmosis is a tick-borne disease caused by Anaplasma marginale in the United States. The objective of this study was to use a survey tool to generate information for beef operations in California on anaplasmosis prevention and control management, including to what extent management activities were informed by perceived herd-level exposure to A. marginale infection or occurrence of clinical anaplasmosis cases. We mailed 2,621 questionnaires with questions on Anaplasma status, herd demographics, anaplasmosis control and prevention measures, and environmental factors to beef ranchers in California in October 2020. Survey-weighted chi-square tests were used to compare management differences according to perceived Anaplasma infection status. Generalized estimating equations (GEEs) were used to analyze whether region of California, management practices, or environmental factors were associated with reported clinical cases of anaplasmosis in the previous five years. A total of 466 questionnaires describing 749 herds were obtained and used in this study. Use of management measures, including deliberate exposure of calves to ticks, vaccination for Anaplasma, infection control through antibiotics in feed, maintaining a completely closed herd, blood testing for Anaplasma on all herd additions, and taking no anaplasmosis control and prevention measures, were significantly different between herds with or without perceived A. marginale infection based on producers' self-declared status. The overall perceived prevalence for Anaplasma infection and reported clinical cases of anaplasmosis at the herd level was 26.0 % (95 % CI: 24.3-27.7 %) and 17.1 % (95 % CI: 15.6-18.6 %) respectively, with the highest perceived infection and case numbers reported in the Central Coast region. In the GEE model, higher odds of reporting clinical cases of anaplasmosis in the previous five years were observed in cattle located in the Central Coast region, cattle within a large herd, cattle that are treated with tick/fly control, cattle in a completely closed herd, and cattle receiving Anaplasma vaccine. Anaplasma infection and bovine anaplasmosis status may be underestimated in beef herds in California based on previous study results. Changing needles between cattle after injections and conducting blood testing for Anaplasma on herd additions are important Anaplasma management measures that are infrequently implemented in beef herds in California. The results show a need for producer education to improve producers' awareness of bovine anaplasmosis and implement proper measures for disease control and prevention.

Leveraging artificial intelligence and software engineering methods in epidemiology for the co-creation of decision-support tools based on mechanistic models

Epidemiological modeling is a key lever for infectious disease control and prevention on farms. It makes it possible to understand the spread of pathogens, but also to compare intervention scenarios even in counterfactual situations. However, the actual capability of decision makers to use mechanistic models to support timely interventions is limited. This study demonstrates how artificial intelligence (AI) techniques can make mechanistic epidemiological models more accessible to farmers and veterinarians, and how to transform such models into user-friendly decision-support tools (DST). By leveraging knowledge representation methods, such as the textual formalization of model components through a domain-specific language (DSL), the co-design of mechanistic models and DST becomes more efficient and collaborative. This facilitates the integration of explicit expert knowledge and practical insights into the modeling process. Furthermore, the utilization of AI and software engineering enables the automation of web application generation based on existing mechanistic models. This automation simplifies the development of DST, as tool designers can focus on identifying users' needs and specifying expected features and meaningful presentations of outcomes, instead of wasting time in writing code to wrap models into web apps. To illustrate the practical application of this approach, we consider the example of Bovine Respiratory Disease (BRD), a tough challenge in fattening farms where young beef bulls often develop BRD shortly after being allocated into pens. BRD is a multi-factorial, multi-pathogen disease that is difficult to anticipate and control, often resulting in the massive use of antimicrobials to mitigate its impact on animal health, welfare, and economic losses. The DST developed from an existing mechanistic BRD model empowers users, including farmers and veterinarians, to customize scenarios based on their specific farm conditions. It enables them to anticipate the effects of various pathogens, compare the epidemiological and economic outcomes associated with different farming practices, and decide how to balance the reduction of disease impact and the reduction of antimicrobial usage (AMU). The generic method presented in this article illustrates the potential of artificial intelligence (AI) and software engineering methods to enhance the co-creation of DST based on mechanistic models in veterinary epidemiology. The corresponding pipeline is distributed as an open-source software. By leveraging these advancements, this research aims to bridge the gap between theoretical models and the practical usage of their outcomes on the field.

Contagious Bovine Pleuropneumonia: Global Eradication Remains a Challenging and Distant Goal

Contagious bovine pleuropneumonia (CBPP) is one of the six high impact diseases for which currently World Organization for Animal Health (WOAH) has established an official procedure for recognition of disease-free status for trade purposes. Although its exact distribution, incidence, and impact have not been well established, the disease is known to be endemic in sub-Saharan Africa, where it has a severe socio-economic impact on people's livelihoods. Control or elimination of the disease can be achieved by various strategies including vaccination, movement control, and stamping-out. Due to many factors, countries in sub-Saharan Africa are still struggling with this disease, compromising continental and global eradication. In this review, basic epidemiologic features and clinical signs of CBPP are presented and disease control challenges, particularly in endemic countries, are briefly discussed.

Rinderpest: A Disease of the Past, and a Present Threat

Rinderpest is a highly contagious viral disease that affects ungulates such as cattle, buffalo, yak, and various wildlife species, leading to significant morbidity and mortality. The global eradication of rinderpest was successfully accomplished in 2011 through extensive vaccination efforts. Today, safeguarding against the re-emergence of rinderpest in animal populations is paramount. The Food and Agriculture Organization of the United Nations and the World Organization for Animal Health are entrusted through a series of resolutions with the responsibility to prevent the re-emergence of rinderpest in animals.

Brazil's battle against Rhipicephalus (Boophilus) microplus ticks: current strategies and future directions

Ticks are parasitic arthropods that cause significant economic losses to livestock production worldwide. Although Rhipicephalus (Boophilus) microplus, the cattle tick, occurs throughout the Brazilian territory, there is no official program to control this tick, which is the vector of tick fever pathogens. We address the situation of R. (B.) microplus resistance to synthetic acaricides in Brazil, including cattle tick management; the status of tick resistance per Brazilian state; the history of resistance occurrence of different acaricides; multiple resistance occurrence; and the main strategies for integrated tick management. Tick control in Brazil is characterized by management errors. Local laboratories affiliated with federal and state research institutions and universities employ the Adult Immersion Test as a primary diagnostic method to assess acaricide resistance to topically applied drugs. Only three states (Acre, Amapá, and Amazonas) have no reports on resistant populations. Misinformation on tick control strategies, misuse of available products for tick control, no adoption of Integrated Parasite Management (IPM) practices, low technical support to producers, and the high-speed emergence of acaricide-resistant tick populations are the main problems. We also propose a list of needs and priorities for cattle tick control regarding communication, research, and policies.

Strategic control of the cattle tick Rhipicephlaus microplus applied to rotational and silvopastoral grazing systems in subtropical areas

This work evaluated if strategic control based on no more than three or four annual treatments is useful to control Rhipicephalus microplus infestations on cattle when it is applied to intensive rotational grazing and silvopastoral systems with high stocking rates in subtropical areas. In the intensive rotational grazing system, three annual treatments with chemical acaricides were applied on cattle in two different schemes: between spring and early summer and from late winter and late spring. Strategic control based on three treatments with chemical acaricides from late winter to late spring plus an additional fourth treatment in summer was tested in the silvopastoral system. In the intensive rotational grazing systems, the control schemes allow to reach a significant reduction in the tick load on cattle considering a time interval from spring to autumn. However, the efficacy levels were not high enough in some specific moments, namely, the tick counts of summer and autumn (there were not significant differences between treated and control groups). The scheme evaluated in the silvopastoral grazing system yielded better results than those tested for the intensive rotational system, because significant differences in tick load between treated and control groups were observed in all post-treatment counts and when the analysis was performed for the whole study period. However, values of efficacy in the count-by-count comparison were disparate, ranging from 64.1 to 99.7. Although the efficacy values obtained in the silvopastoral system were better than those of the rotational grazing systems, the total tick load on treated cattle in autumn was not low enough (mean abundance values 25.14 and 38.14). Ticks were more evenly distributed among hosts in late summer and autumn than in spring or early summer, where few hosts carry most of the ticks. Some management strategies as intensive rotational systems or silvopastoral structures can lead to a more efficient forage use, but they imply greater tick challenge than in extensive grazing systems. In these situations, the schemes of strategic control bases on three or four annual treatments should be complemented with additional tactical treatments in late summer or autumn.

Intake of compound probiotics accelerates the construction of immune function and gut microbiome in Holstein calves

Acquired immunity is an important way to construct the intestinal immune barrier in mammals, which is almost dependent on suckling. To develop a new strategy for accelerating the construction of gut microbiome, newborn Holstein calves were continuously fed with 40 mL of compound probiotics (containing Lactobacillus plantarum T-14, Enterococcus faecium T-11, Saccharomyces cerevisiae T-209, and Bacillus licheniformis T-231) per day for 60 days. Through diarrhea rate monitoring, immune index testing, antioxidant capacity detection, and metagenome sequencing, the changes in diarrhea incidence, average daily gain, immune index, and gut microbiome of newborn calves within 60 days were investigated. Results indicated that feeding the compound probiotics reduced the average diarrhea rate of calves by 42.90%, increased the average daily gain by 43.40%, raised the antioxidant indexes of catalase, superoxide dismutase, total antioxidant capacity, and Glutathione peroxidase by 22.81%, 6.49%, 8.33%, and 13.67%, respectively, and increased the immune indexes of IgA, IgG, and IgM by 10.44%, 4.85%, and 6.12%, respectively. Moreover, metagenome sequencing data showed that feeding the compound probiotics increased the abundance of beneficial strains (e.g., Lactococcus lactis and Bacillus massionigeriensis) and decreased the abundance of some harmful strains (e.g., Escherichia sp. MOD1-EC5189 and Mycobacterium brisbane) in the gut microbiome of calves, thus contributing to accelerating the construction of healthy gut microbiome in newborn Holstein calves.

IMPORTANCE

The unstable gut microbiome and incomplete intestinal function of newborn calves are important factors for the high incidence of early diarrhea. This study presents an effective strategy to improve the overall immunity and gut microbiome in calves and provides new insights into the application of compound probiotics in mammals.

[Progress of schistosomiasis control in People's Republic of China in 2023]

To understand the progress of national schistosomiasis elimination program of China in 2023 and summarize the lessons and experiences, data on the endemic status of schistosomiasis and national schistosomiasis surveillance results in the People's Republic of China were collected and analyzed at a national level. By the end of 2023, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to consolidate the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan and Hubei provinces were identified to achieve the criteria of transmission interruption in 2020, and Anhui, Jiangxi and Hunan provinces achieved the criteria of transmission interruption in 2023. A total of 451 counties (cites, districts) were found to be endemic for schistosomiasis in China in 2023, including 26 250 endemic villages covering 73 034 500 residents at risk of infections. Among the 451 endemic counties (cities, districts), 78.49% (354/451) achieved the criteria of schistosomiasis elimination and 21.51% (97/451) achieved the criteria of transmission interruption, respectively. In 2023, a total of 4 216 643 individuals received immunological tests, with 47 794 sero-positives identified, and a total of 184 216 individuals received parasitological examinations, with 4 egg-positives detected. A total of 27 768 cases with advanced schistosomiasis were documented in China by the end of 2023. In 2023, 539 548 bovines were raised in schistosomiasis-endemic areas of China, and 125 440 bovines received immunological tests, with 124 sero-positives detected, while no egg-positives were identified among the 133 508 bovines receiving parasitological examinations. In 2023, snail survey was performed at an area of 641 339.53 hm2 and 184 819.77 hm2 snail habitats were identified, including 51.53 hm2 emerging snail habitats and 642.25 hm2 reemerging snail habitats. In 2023, there were 20 198 schistosomiasis patients receiving praziquantel chemotherapy, and 598 183 person-time individuals and 283 954 herdtime bovines were given expanded chemotherapy. In 2023, snail control with chemical treatment was performed in 116 347.95 hm2 snail habitats, and the actual area of chemical treatment was 65 690.89 hm2, while environmental improvements were performed in snail habitats covering an area of 1 334.62 hm2. The national schistosomiasis surveillance results showed that the mean prevalence of Schistosoma japonicum infections were both zero among humans and bovines in 2023, and no S. japonicum infection was detected in snails. These data demonstrated that transmission interruption of schistosomiasis had been achieved across all endemic provinces in China in 2023, and the endemic status of schistosomiasis tended to be stable, while advanced cases were predominant among all schistosomiasis cases. However, the areas of snail habitats remained high and cattle re-raising was very common in some regions. Intensified schistosomiasis surveillance and forecast and snail control in high-risk areas are needed.

Efficacy of an herbal formula Guixiong Yimu San in preventing retained placenta and improving reproductive performance in cows

Retained placenta is a common health issue, and appropriate prevention strategies are effective in postpartum health management. This study aimed to evaluate whether early intervention using GYS can prevent retained placenta and puerperal metritis, as well as enhance reproductive outcomes in cows. Each bovine in the GYS group (n = 591) received a single prophylactic dose of GYS (0.5 g/kg body weight) orally within 2 h after parturition, while those in the control group (n = 598) received no intervention. GYS treatment was associated with a decreased incidence of retained placenta (4.6% vs. 12.0%, P < 0.01, OR = 0.335), a lower puerperal metritis risk (8.8% vs. 20.1%, P < 0.01, OR = 0.369), and a reduced need for additional therapeutic antibiotics (11.2% vs. 26.1%, P < 0.01, OR = 0.342). We observed increases in the first service conception rate (59.7% vs. 49.1%, P < 0.01) and conception rate within 305 days postpartum (93.2% vs. 85.5%, P < 0.01) in the GYS group than in the control group. A significant decrease was observed in the number of services per conception (1.8 ± 1.1 vs. 2.1 ± 1.4, P < 0.01) and the calving-to-conception interval (83.6 ± 39.6 vs. 96.6 ± 52.5 days, P < 0.01) between the two groups. Additionally, GYS treatment increased milk yield on days 7, 14, and 28 postpartum without affecting milk fat, milk protein, somatic cell count (SCC), or milk urea nitrogen (MUN) on days 7 and 28 postpartum. Accordingly, the GYS was effective and safe in preventing retained placenta and to improve reproductive performance in cows. Therefore, it could be a prophylactic intervention for superior postpartum fertility in cows.

Risk factors contributing to tick-acaricide control failure in communal areas of the Oliver Tambo district eastern cape province, South Africa

Application of chemical acaricides in the control of ticks has led to the problem of tick-acaricide control failure. To obtain an understanding of the possible risk factors involved in this tick-acaricide control failure, this study investigated tick control practices on communal farms in the north-eastern part of the Eastern Cape Province (ECP) of South Africa. A semi-structured questionnaire designed to document specific farm attributes and acaricide usage practices was administered at 94 communal farms from the Oliver Tambo District municipality of the ECP. Data collected indicated that the main acaricide chemicals used at plunge dips of inland and coastal areas were synthetic pyrethroid formulations. Most (75%) farmers claimed not to have noticed a significant reduction in numbers of actively feeding and growing ticks on cattle after several acaricide treatments. Based on the farmers' perceptions, leading factors that could have led to tick-acaricide control failure included: weak strength of the dip solution (76%); poor structural state of dip tanks (42%); and irregular tick control (21%). The rearing of crossbreeds of local and exotic cattle breeds, perceived weak strength of the dip solution and high frequency of acaricide treatment, were statistically associated with proportions of farms reporting tick-acaricide control failure. Furthermore, approximately 50% of farms reported at least four tick control malpractices, which could have resulted in the emergence and spread of tick-acaricide control failure. Other sub-optimal tick control practices encountered included incorrect acaricide rotation, and failure to treat all cattle in a herd. This data will inform and guide the development of management strategies for tick-acaricide control failure and resistance in communal farming areas.

Protective immunity induced through two calving seasons following administration of live epizootic bovine abortion agent (EBAA) vaccine

A live, infectious vaccine candidate for epizootic bovine abortion, designated EBAA Vaccine, USDA-APHIS Product code #1544.00, has been reported to be both safe and effective. Previous studies established that a single dose of EBAA vaccine administered to cows at potencies of either 2000 or 500 live P. abortibovis-infected murine spleen cells (P.a.-LIC) induced protective immunity for a minimum of 5 months. The current study employed 19 pregnant cows that were challenged with P. abortibovis in their 2nd trimester of gestation; 9 were vaccinated 17.2-months earlier as 1-year-olds with 2000 P.a.-LIC and 10 served as negative controls. Eighty-nine percent of the vaccinates gave birth to healthy calves as compared to 10% of challenge controls. Vaccine efficacy was significant when analyzed by prevented fractions (87.7%; 95% CI=0.4945-0.9781). Serologic data supports previous findings that pregnant cows with detectable P. abortibovis antibodies are immune to P. abortibovis challenge as demonstrated by the birth of healthy calves.

Self-emulsifying drug delivery systems (SEDDS) containing Cymbopogon citratus essential oil: Enhancing the stability and acaricide efficacy against Rhipicephalus (Boophilus) microplus

The objectives of this study were to develop a self-emulsifying drug delivery system (SEDDS) to enhance the stability and efficacy of Cymbopogon citratus essential oil or lemongrass oil (LEO) against cattle tick larvae and engorged females. The system with the highest oil loading in SEDDS was composed of LEO (23.33%w/w), Tween 80: SGKH 4000 in a 2:1 ratio as surfactant (66.67%w/w), and propylene glycol as co-surfactant (10%w/w). The selected SEDDS-LEO has a particle size of 18.78 nm with a narrow size distribution (polydispersity index of 0.27). Notably, the stability of SEDDS was superior to that of the original oil, both during long-term storage and under accelerated conditions. SEDDS-LEO at oil concentrations ranging from 1.458% to 5.833% w/v showed a significantly higher percentage of egg-laying reduction against adult ticks compared with the original oil at the same concentrations (p < 0.05). Furthermore, SEDDS-LEO demonstrated greater larvicidal efficacy than the original oil, with lower LC50 and LC90 values of 0.91 mg/mL and 1.20 mg/mL, respectively, whereas the original oil's LC50 and LC90 values were 1.17 mg/mL and 1.74 mg/mL, respectively. Our findings indicate that SEDDS-LEO is a promising candidate for use as an acaricide in the control of tick populations in dairy cattle.

Invited review: Prevalence, risk factors, treatment, and barriers to best practice adoption for lameness and injuries in dairy cattle-A narrative review

Lameness and leg injuries are both painful and prevalent across the dairy industry, and are a major welfare concern. There has been a considerable amount of research focused on investigating the risk factors associated with lameness and injuries and how they might be prevented and treated. The objectives of this narrative review were to summarize herd-level prevalence estimates, risk factors, strategies for prevention, control, and treatment of these conditions, and the barriers to best practice adoption for lameness and injuries on dairy farms. There is a relatively high within-herd prevalence of lameness on dairy farms globally, with a recent systematic review estimating the mean prevalence at 22.8%. Similarly, there is a relatively high prevalence of hock injuries, with within-herd estimates ranging from 12% to 81% of cows affected. Knee and neck injuries have been reported to be less common, with 6% to 43% and 1% to 33%, respectively. Numerous risk factors have been associated with the incidence of lameness, notably housing (e.g., access to pasture, bedding depth, bedding type, flooring type, stall design), management (e.g., stall cleanliness, frequency of trimming, holding times, stocking density), and cow-level (e.g., body condition, parity, injured hocks) factors. Risk factors associated with hock injuries can be similarly classified into housing (e.g., bedding type and depth, outdoor access, parlor type, stall design), management (e.g., bedding depth, cleanliness), and cow (e.g., parity, days in milk, lameness) factors. Key preventative approaches for lameness include routine preventative and corrective hoof trimming, improving hoof cushioning and traction through access to pasture or adding rubber flooring, deep-bedded stalls, sand bedding, ensuring appropriate stocking densities, reduced holding times, and the frequent use of routine footbaths. Very little research has been conducted on hock, knee, and neck injury prevention and recovery. Numerous researchers have concluded that both extrinsic (e.g., time, money, space) and intrinsic (e.g., farmer attitude, perception, priorities, and mindset) barriers exist to addressing lameness and injuries on dairy farms. There are many diverse stakeholders in lameness and injury management including the farmer, farm staff, veterinarian, hoof trimmer, nutritionist, and other advisors. Addressing dairy cattle lameness and injuries must, therefore, consider the people involved, as it is these people who are influencing and implementing on-farm decisions related to lameness prevention, treatment, and control.

Development potential of selenium in the prevention and treatment of bovine endometritis

Endometritis is a common postpartum disease in cows. It delays uterine involution and impairs normal physiological function. This can result in long-term or even lifelong infertility and cause significant losses to the dairy farming industry. Traditional treatments like antibiotics possess certain shortcomings, such as antibiotic residues, the abuse of antibiotics, and increased antimicrobial resistance of pathogens. Alternative treatment strategies are needed to minimize the utilization of antibiotics in dairy production. As an essential trace element in animals, selenium (Se) plays a vital role in regulating immune function, the inflammatory response, and oxidative stress, affecting the speed and completeness of tissue repair. This paper reviewed previous studies to analyse the potential of Se in the prevention and treatment of bovine endometritis, aiming to provide a new direction to increase production capacity in the future.

Designing a multiepitope mRNA-based vaccine against enterotoxigenic Escherichia coli infection in calves: Immunoinformatics and molecular modeling approach

Background

Escherichia coli is one of the serious pathogens causing various infections in the animal field, such as neonatal calf diarrhea, which is responsible for mortality associated with diarrhea during the first days of life.

Aim

Current work is aimed at designing an effective and safe multiepitope vaccine candidate against E. coli infection in calves based on the fimbrial protein K99 of Enterotoxigenic E. coli (ETEC) and Immuno-informatics.

Methods

A conserved sequence of K99 protein was generated, and then highly antigenic, nonallergic, and overlapped epitopes were used to construct a multiepitope vaccine. Five THL, six MHC II, and four beta cell epitopes were targeted to create the candidate. The candidate vaccine was produced utilizing 15 epitopes and three types of linkers, two types of untranslated region (UTR) human hemoglobin subunit beta (HBB), UTR beta-globin (Rabb), and RpfE protein as an immunomodulation adjuvant.

Results

Immuno-informatics analysis of the constructed protein showed that the protein was antigenic (antigenic score of 0.8841), stable, nonallergen, and soluble. Furthermore, the Immuno-informatics and physiochemical analysis of the constructed protein showed a stable, nonallergic, soluble, hydrophilic, and acidic PI (isoelectric point). of 9.34. Docking of the candidate vaccine with the toll-like receptor TLR3 was performed, and results showed a strong interaction between the immune receptor and the vaccine. Finally, the expression efficiency of the construct in E. coli was estimated via computational cloning of the vaccine sequence into Pet28a.

Conclusion

Results of immunoinformatics and in silico approaches reveal that the designed vaccine is antigenic, stable, and able to bind to the immune cell receptors. Our results interpret the proposed multiepitope mRNA vaccine as a good preventive option against E. coli infection in calves.

Comparison between a complete preconditioning programme and conventional conduct on behaviour, health and performance of young bulls from small cow-calf herds

Bovine respiratory diseases (BRDs) have major socioeconomic impacts in the beef sector. Antimicrobials have been traditionally used to prevent the development of BRDs upon arrival in fattening units. Currently, from a "One Health and One Welfare" perspective, alternative solutions are being investigated. Preconditioning programmes that aim at reducing stress and reinforcing immune functions have been proposed to decrease BRDs incidence. In this study, we assessed the effect of a preconditioning protocol set up in nine commercial beef herds on young bulls' behaviour, health, and performance. Preconditioned bulls (PREC) were weaned indoors 50 days before departure, and progressively fed a concentrate diet supplemented with vitamins and trace elements. They also received an anthelmintic treatment, and two doses of a trivalent vaccine against respiratory pathogens at 4-week intervals. In contrast, controls (CTRL) were kept on pasture with their dams with no vaccination or particular diets. All calves were transported together to a single sorting facility to be sorted by experimental groups, origins, and BW, forming new groups before dispatch to four fattening units. At arrival, CTRL were treated with anthelmintic drugs and received one injection of the same BRDs vaccine. No intervention was performed on PREC bulls. BRD-scores were 0.73 in PREC versus 0.07 in CTRL (P = 0.01) during the preconditioning period and 0.96 in PREC versus 0.54 in CTRL (P = 0.41) after 15 days in the fattening units. Morbidity estimates were 18% in PREC versus 1% in CTRL (P < 0.001) during the preconditioning period and 32% in PREC versus 19% (P = 0.07) in CTRL after 15 days in the fattening units. Poor housing conditions during preconditioning and a different aetiology could partly explain these results. At arrival to fattening, the average daily gain (ADG) was 1 605 g for PREC versus 1 140 g (P = 0.012) for CTRL. After fattening for 180 days, differences in BW, ADG, carcass weight and conformation were inconclusive. In Europe, preconditioning programmes including vaccination must be set up coherently with good husbandry practices and with a global adaptation of batch management of the beef sector otherwise, they may be less effective than expected.

Analysis of within-pen and between-pen fenceline temporal contact networks in confined feedlot cattle

Though contact networks are important for describing the dynamics for disease transmission and intervention applications, individual animal contact and barriers between animal populations, such as fences, are not often utilized in the construction of these models. The objective of this study was to use contact network analysis to quantify contacts within two confined pens of feedlot cattle and the shared "fenceline" area between the pens at varying temporal resolutions and contact duration to better inform the construction of network-based disease transmission models for cattle within confined-housing systems. Two neighboring pens of feedlot steers were tagged with Real-Time Location System (RTLS) tags. Within-pen contacts were defined with a spatial threshold (SpTh) of 0.71 m and a minimum contact duration (MCD) of either 10 seconds (10 s), 30 seconds (30 s), or 60 seconds (60 s). For the fenceline network location readings were included within an area extending from 1 m on either side of the shared fence. "Fenceline" contacts could only occur between a steer from each pen. Static, undirected, weighted contact networks for within-pen networks and the between-pen network were generated for the full study duration and for daily (24-h), 6-h period, and hourly networks to better assess network heterogeneity. For the full study duration network, the two within-pen networks were densely homogenous. The within-pen networks showed more heterogeneity when smaller timescales (6-h period and hourly) were applied. When contacts were defined with a MCD of 30 s or 60 s, the total number of contacts seen in each network decreased, indicating that most of the contacts observed in our networks may have been transient passing contacts. Cosine similarity was moderate and stable across days for within pen networks. Of the 90 total tagged steers between the two pens, 86 steers (46 steers from Pen 2 and 40 steers from Pen 3) produced at least one contact across the shared fenceline. The total network density for the network created across the shared fenceline between the two pens was 17%, with few contacts at shorter timescales and for MCD of 30 s or 60 s. Overall, the contact networks created here from high-resolution spatial and temporal contact observation data provide estimates for a contact network within commercial US feedlot pens and the contact network created between two neighboring pens of cattle. These networks can be used to better inform pathogen transmission models on social contact networks.

A bird flu vaccine for cows? It's complicated

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Developing a PmSLP3-based vaccine formulation that provides robust long-lasting protection against hemorrhagic septicemia-causing serogroup B and E strains of Pasteurella multocida in cattle

Background

Pasteurella multocida is a bacterial pathogen that causes a variety of infections across diverse animal species, with one of the most devastating associated diseases being hemorrhagic septicemia. Outbreaks of hemorrhagic septicemia in cattle and buffaloes are marked by rapid progression and high mortality. These infections have particularly harmful socio-economic impacts on small holder farmers in Africa and Asia who are heavily reliant on a small number of animals kept as a means of subsistence for milk and draft power purposes. A novel vaccine target, PmSLP-3, has been identified on the surface of hemorrhagic septicemia-associated strains of P. multocida and was previously shown to elicit robust protection in cattle against lethal challenge with a serogroup B strain.

Methods

Here, we further investigate the protective efficacy of this surface lipoprotein, including evaluating the immunogenicity and protection upon formulation with a variety of adjuvants in both mice and cattle.

Results

PmSLP-3 formulated with Montanide ISA 61 elicited the highest level of serum and mucosal IgG, elicited long-lasting serum antibodies, and was fully protective against serogroup B challenge. Studies were then performed to identify the minimum number of doses required and the needed protein quantity to maintain protection. Duration studies were performed in cattle, demonstrating sustained serum IgG titres for 3 years after two doses of vaccine and full protection against lethal serogroup B challenge at 7 months after a single vaccine dose. Finally, a serogroup E challenge study was performed, demonstrating that PmSLP-3 vaccine can provide protection against challenge by the two serogroups responsible for hemorrhagic septicemia.

Conclusion

Together, these data indicate that PmSLP-3 formulated with Montanide ISA 61 is an immunogenic and protective vaccine against hemorrhagic septicemia-causing P. multocida strains in cattle.

To probe outbreak, BSL-3 labs plan to infect cows with flu virus

Novel effort comes as study finds key receptor for avian flu virus in udders, where the virus flourishes.