Animal Health Research Reviews最新文献

Livestock production has increased in many emerging economies, but productivity is often substantially impaired by infectious diseases. The first step towards improved livestock health and productivity is to map the presence of livestock diseases. The objective of this review was to summarize studies conducted on such diseases in an emerging economy, Vietnam, and thereby identifying knowledge gaps that may inform the design of surveillance and control programs. Few studies were found to evaluate the distribution of infectious livestock diseases other than avian influenza. Also, many regions with dense livestock populations had received little attention in terms of disease investigation. A large proportion of the studies dealt with zoonoses and food-borne infections which might be due to funding agencies priorities. On the contrary, studies targeting infections that affect livestock and their productivity were few. We think that this limitation in scientific reports on infectious diseases that only affect livestock productivity is a common phenomenon in low and lower middle income countries. More science-based data on such diseases would help policymakers to prioritize which livestock diseases should be subject to animal health programs aimed to support rural livelihoods and economic development.

Vitamin D (VD) has been reported to play multiple and significant roles in improving pig health via modulating calcium and phosphorus homeostasis, skeletal muscle development and the immune system. Apart from food, photochemical action of 7-dehydrocholesterol in the skin is the main source of this molecule for pigs. The VD from dietary intake or photosynthesized via skin can be absorbed into the liver for hydroxylation, and further hydroxylated into the hormone form of VD (1,25-dihydroxyvitamin D3 or 1,25(OH)2D3) in the kidney. As a sterol hormone, 1,25(OH)2D3 is able to bind with the VD receptor (VDR), and this ligand-receptor complex (VDR/retinoic X receptor) translocates from the cytoplasm into the nucleus to regulate gene expression, thus modulating metabolism. In this review, we summarized the recent studies regarding the non-skeletal health benefits of VD for pigs, and focused on the recent advances in the cellular and molecular mechanisms of VD that affects the immune system and reproductive health. This review provides a reference for future research and application of VD in pigs.

Odors may be pleasant or unpleasant and in practice, pleasant odors are attractive while unpleasant odors are repellent. However, an odor that is noxious to one species may be attractive to another. Plants, predators, and pathogens may enhance their transmission by manipulating these signals. This may be especially significant when odors attract arthropod disease vectors. Odor detection may also be important in small prey species for evasion of macropredators such as large carnivores. Conversely, pleasant odors may identify family members, parents, or sexual partners. They may also generate signals of good health or fitness and contribute to the process of mate selection. In this review, we seek to integrate these odor-driven processes into a coherent pattern of behaviors that serve to complement the innate and adaptive immune systems. It may be considered the 'behavioral immune system'.

Bovine respiratory disease (BRD) is the most common cause of morbidity and mortality in North American beef cattle. In recent years, isolation of strains of Mannheimia haemolytica that are resistant to multiple different classes of antimicrobials has become commonplace. New research would suggest that the routine use of antimicrobials by some cattle operations might be driving emerging resistance patterns, with the majority of the spread observed due to propagation of strains of M. haemolytica that have acquired integrative conjugative elements. To date, there is little information evaluating the impact of antimicrobial resistance on clinical outcome in cattle with BRD.

Anthropogenic activities can lead to several devastating effects on the environment. The pollutants, which include the discharge of effluents, runoffs in the form of different lethal and sub-lethal concentrations of pesticides, heavy metals, and other contaminants, can harm exposed fauna and flora. The aquatic environment is the ultimate destination for many pollutants which negatively affect aquatic biodiversity and even can cause a species to become extinct. A pollutant can directly affect the behavior of an animal, disrupt cellular systems, and impair the immune system. This harm can be reduced and even mitigated by adopting proper approaches for the conservation of the target biota. Among aquatic organisms, cetaceans, such as the Yangtze finless porpoise, Irrawaddy dolphin, Ganges River dolphin, Amazon River dolphin, and Indus River dolphin, are at a higher risk of extinction because of lack of knowledge and research, and thus insufficient information with respect to their conservation status, management, and policies. Pneumonia is one of the leading causes of mass mortalities of cetaceans. This article reviews the limited research reported on stress and pneumonia induced by pollution, stress-induced pneumonia and immunosuppression, pneumonia-caused mass mortalities of aquatic mammals, and vaccination in wildlife with a specific focus on aquatic mammals, the role of genomics in vaccine development and vaccination, and the major challenges in vaccine development for biodiversity conservation.

Bovine respiratory disease (BRD) is a frequent disease concern in dairy cattle and is most commonly diagnosed in young dairy heifers. The impact of BRD is highly variable, depending on the accuracy and completeness of detection, effectiveness of treatment, and on-farm culling practices. Consequences include decreased rate of weight gain, a higher culling risk either as heifers or as cows, delayed age at first service, delayed age at first calving, and in some cases, lower future milk production. In this data set of 104,100 dairy replacement heifers from across the USA, 36.6% had one or more cases diagnosed within the first 120 days of age with the highest risk of new cases occurring prior to weaning. Comparison of the raising cost for heifers with BRD and those without a recorded history of BRD resulted in an estimated cost per incident case occurring in the first 120 days of age of $252 or $282, depending upon whether anticipated future milk production differences were considered or not. Current market conditions contributed to a cost estimate that is significantly higher than previously published estimates, driven in part by the losses associated with selective culling of a subset of heifers that experienced BRD.

Bovine respiratory disease (BRD) is the leading cause of death in beef calves 3 weeks of age to weaning and is the leading cause of morbidity and mortality in beef feeding and finishing systems. Each outbreak of respiratory disease is the result of the completion of a sufficient cause, which might have also included components of viral and bacterial pathogens, a certain state of immunity, or other component causes of respiratory disease in cattle that we fail to understand. Disease is expressed when a sufficient cause is completed. Disease events we observe, such as the occurrence of BRD, usually have relationships with risk factors that are commonly the subject of epidemiologic research and the primary subject of this paper. However, it is important to understand that underlying systems produce those relationships and, ultimately, the occurrence of disease. The risk factors for BRD include a complex set of component causes that include bacterial and viral pathogens, level of host immunity, and environmental conditions that favor pathogen transmission and stress-induced susceptibility. During the post-weaning phase, these factors are superimposed on a system of marketing, transportation, and decisions made to support economic opportunity that further increase the risk for BRD.

Bovine respiratory disease (BRD) is an important disease in dairy calves due to its long-lasting effects. Early identification results in better outcomes for the animal, but producers struggle to identify all calves with BRD. Sickness behavior, or the behavioral changes that accompany illness, has been investigated for its usefulness as a disease detection tool. Behavioral changes associated with BRD include decreased milk intake and drinking speed, depressed attitude, and less likelihood of approaching a novel object or stationary human. Behavioral measurements are useful, as they can be collected automatically or with little financial input. However, one limitation of many BRD behavioral studies includes the use of either lung auscultation or clinical signs as reference methods, which are imperfect. Additionally, external factors may influence the expression of sickness behavior, which can affect if and when behavior can be used to identify calves with BRD. Behavioral measures available to detect BRD lack adequate sensitivity and specificity to be the sole means of disease detection, especially when detection tools, such as calf lung ultrasound, have better test characteristics. However, using behavioral assessments in addition to other detection methods can allow for a robust BRD detection program that can ameliorate the consequences of BRD.

Veterinary diagnostic labs (VDLs) are important service agencies providing essential diagnostic testing for a wide variety of domestic animal species as well as wildlife. They serve key roles in disease monitoring and diagnosis as well as surveillance for diseases of consequence. Of the many roles VDLs serve, one is being a member of the larger team of professionals dealing with the management of the bovine respiratory disease (BRD) complex. VDLs provide a number of services related to the management of BRD. These include disease outbreak investigation, abnormal morbidity characterization, routine monitoring, and biosecurity screening for a variety of infectious agents via methods such as necropsy and histopathology, bacterial culture, antimicrobial sensitivity testing, virus isolation, and serological assays. VDLs continue to look for better methods and assays as instrumentation technology also grows and improves. This is reflected in the growing proliferation of molecular-based assays that provide a high degree of sensitivity and specificity. Professional staff in VDLs work in collaboration with those in academia and private industry to conduct basic research focusing on a different aspect of the BRD complex. VDLs remain a primary source of the varied field-origin infectious agents associated with BRD that are used for research purposes.

Cattle producers and animal health professionals are increasingly frustrated by the inability to reduce the impacts of bovine respiratory disease (BRD). Improved BRD control is difficult due to the complex nature of the disease; the complexity of cattle industry structure and function; and the imbalance of economic incentives for enhanced BRD control. Success in improving BRD control will depend on an industry-wide comprehensive effort to address lifetime animal health issues as well as correcting or offsetting imbalances in economic benefits and costs for enhanced animal health management across cattle production sectors.