Causes of mortality in laying hens in different housing systems in 2001 to 2004

<p>Abstract</p> <p>Background</p> <p>The husbandry systems for laying hens were changed in Sweden during the years 2001 – 2004, and an increase in the number of submissions for necropsy from laying hen farms was noted. Hence, this study was initiated to compare causes of mortality in different housing systems for commercial laying hens during this change.</p> <p>Methods</p> <p>Based on results from routine necropsies of 914 laying hens performed at the National Veterinary Institute (SVA) in Uppsala, Sweden between 2001 and 2004, a retrospective study on the occurrence of diseases and cannibalism, i.e., pecking leading to mortality, in different housing systems was carried out. Using the number of disease outbreaks in caged flocks as the baseline, the expected number of flocks with a certain category of disease in the other housing systems was estimated having regard to the total number of birds in the population. Whether the actual number of flocks significantly exceeded the expected number was determined using a Poisson distribution for the variance of the baseline number, a continuity correction and the exact value for the Poisson distribution function in Excel 2000.</p> <p>Results</p> <p>Common causes of mortality in necropsied laying hens included colibacillosis, erysipelas, coccidiosis, red mite infestation, lymphoid leukosis and cannibalism. Less common diagnoses were Newcastle Disease, pasteurellosis and botulism. Considering the size of the populations in the different housing systems, a larger proportion of laying hens than expected was submitted for necropsy from litter-based systems and free range production compared to hens in cages (<it>P </it>< 0.001). The study showed a significantly higher occurrence of bacterial and parasitic diseases and cannibalism in laying hens kept in litter-based housing systems and free-range systems than in hens kept in cages (<it>P </it>< 0.001). The occurrence of viral diseases was significantly higher in indoor litter-based housing systems than in cages (<it>P </it>< 0.001).</p> <p>Conclusion</p> <p>The results of the present study indicated that during 2001–2004 laying hens housed in litter-based housing systems, with or without access to outdoor areas, were at higher risk of infectious diseases and cannibalistic behaviour compared to laying hens in cages. Future research should focus on finding suitable prophylactic measures, including efficient biosecurity routines, to reduce the risk of infectious diseases and cannibalism in litter-based housing systems for laying hens.</p

Position paper: Inland waterways classification for South America: Core concepts and initial proposals

South America, as of yet, has not been able to take full advantage of its extensive system of naturally navigable waterways and in making them an integrated part of the region’s transport network to cater for the ever increasing demand for cargo and human mobility. Infrastructure limitations are one of the major obstacles for the development of inland navigation in the region and, to a certain extent, they are being addressed in most national and regional transport plans and projects. However, this effort, in most cases, remain isolated, and the potential and role of inland shipping as a “natural resource” in itself, but also for transporting the region’s natural resources is, in general, absent as an integral part of the countries transport, mobility and or logistics policies. In this sense the economic and social value of the region’s inland waterway system is still underestimated. A common classification of the inland waterways (rivers, canals and lakes), which currently does not exist in the region, could be instrumental for achieving greater, better and more sustainable use and governance of inland navigation. The experiences of other regions in the world demonstrate that inland waterway classifications, far from being public sector formality or a purely academic exercise, are an essential, powerful and dynamic tool for supporting and implementing inland waterways policies and projects inasmuch as they allow to identify the limitations and the economic potential of navigable waterways in the region and to encourage and monitor the development of their capacity for transport of goods and people. Against this backdrop and in order to encourage reflection on a potential inland waterways classification for the South American region, this document uses the example of the European system of classification to demonstrate the role of classifications in the inland navigation development. Specifically, it looks at the 1996 European Agreement on Main Inland Waterways of International Importance (AGN Agreement). Signed in 1996 and ratified by 18 European countries, the AGN Agreement continues to be one of the main instruments for inland water transport development in Europe, as demonstrated by the growing number of ratifications by the countries of the region.1 This Working Document describes the main elements of the European classification system of navigable waterways (Section I) and existing mechanisms for the monitoring and use of the established network of inland waterways (Section II) and then analyses the role of the classification in the development of inland water transport in Europe (Section III). It goes on to discuss lessons learned and presents a preliminary proposal for the establishment of a regional classification for South America (Section IV). The concluding section addresses the institutional processes and next steps needed to develop a classification of this kind. Bearing in mind that the process for the elaboration of the South American classification is still at an early stage and several open question still remain, the overall goal of the document is to highlight and illustrate relevant issues, which have to be discussed at national level and among the experts of the South American countries to identify and implement a harmonized scheme of classification on a regional basis

Position paper: Inland waterways classification for South America: Core concepts and initial proposals

South America, as of yet, has not been able to take full advantage of its extensive system of naturally navigable waterways and in making them an integrated part of the region’s transport network to cater for the ever increasing demand for cargo and human mobility. Infrastructure limitations are one of the major obstacles for the development of inland navigation in the region and, to a certain extent, they are being addressed in most national and regional transport plans and projects. However, this effort, in most cases, remain isolated, and the potential and role of inland shipping as a “natural resource” in itself, but also for transporting the region’s natural resources is, in general, absent as an integral part of the countries transport, mobility and or logistics policies. In this sense the economic and social value of the region’s inland waterway system is still underestimated. A common classification of the inland waterways (rivers, canals and lakes), which currently does not exist in the region, could be instrumental for achieving greater, better and more sustainable use and governance of inland navigation. The experiences of other regions in the world demonstrate that inland waterway classifications, far from being public sector formality or a purely academic exercise, are an essential, powerful and dynamic tool for supporting and implementing inland waterways policies and projects inasmuch as they allow to identify the limitations and the economic potential of navigable waterways in the region and to encourage and monitor the development of their capacity for transport of goods and people. Against this backdrop and in order to encourage reflection on a potential inland waterways classification for the South American region, this document uses the example of the European system of classification to demonstrate the role of classifications in the inland navigation development. Specifically, it looks at the 1996 European Agreement on Main Inland Waterways of International Importance (AGN Agreement). Signed in 1996 and ratified by 18 European countries, the AGN Agreement continues to be one of the main instruments for inland water transport development in Europe, as demonstrated by the growing number of ratifications by the countries of the region.1 This Working Document describes the main elements of the European classification system of navigable waterways (Section I) and existing mechanisms for the monitoring and use of the established network of inland waterways (Section II) and then analyses the role of the classification in the development of inland water transport in Europe (Section III). It goes on to discuss lessons learned and presents a preliminary proposal for the establishment of a regional classification for South America (Section IV). The concluding section addresses the institutional processes and next steps needed to develop a classification of this kind. Bearing in mind that the process for the elaboration of the South American classification is still at an early stage and several open question still remain, the overall goal of the document is to highlight and illustrate relevant issues, which have to be discussed at national level and among the experts of the South American countries to identify and implement a harmonized scheme of classification on a regional basis.Rivers, Ports, Waterways and Dredging Engineerin

Immune function across generations: integrating mechanism and evolutionary process in maternal antibody transmission.

The past 30 years of immunological research have revealed much about the proximate mechanisms of maternal antibody transmission and utilization, but have not adequately addressed how these issues are related to evolutionary and ecological theory. Much remains to be learned about individual differences within a species in maternal antibody transmission as well as differences among species in transmission or utilization of antibodies. Similarly, maternal-effects theory has generally neglected the mechanisms by which mothers influence offspring phenotype. Although the environmental cues that generate maternal effects and the consequent effects for offspring phenotype are often well characterized, the intermediary physiological and developmental steps through which the maternal effect is transmitted are generally unknown. Integration of the proximate mechanisms of maternal antibody transmission with evolutionary theory on maternal effects affords an important opportunity to unite mechanism and process by focusing on the links between genetics, environment and physiology, with the ultimate goal of explaining differences among individuals and species in the transfer of immune function from one generation to the next

Turkey research, 1974

Implications of selecting poultry for high and low adrenal response to stress / K. I. Brown and K. E. Nestor -- Effects of stress on rate of gain and feed conversion of Ohio low and high adrenal response turkey lines / K. I. Brown and K. E. Nesto -- Effects of sperm number on onset and duration of fertility in turkeys / K. I. Brown -- Acrosomal proteolytic enzymes and seminal plasma inhibitors: their implications in semen preservation / B. A. Lessley and K. I. Brown -- Selection for semen yield in the turkey / K. E. Nestor -- The influence of genetic changes in several traits of economic importance on semen production in the turkey / K. E. Nestor -- Effects of genetic changes in egg production traits, growth rate, and response to cold stress on reproduction in the turkey / K. E. Nestor -- Influence of the initial stimulatory lighting program on fighting and semen production of turkey males / K. E. Nestor, Y. M. Saif and P. A. Renner -- Intermittent lighting for the production of turkey hatching eggs / K. E. Nestor and W. L. Bacon -- Attempts to reduce broodiness of turkey hens by special light treatments / K. E. Nestor and W. Bacon -- The genetic association of growth and egg production in the turkey / K. E. Nestor -- Yolk production in turkeys differing in egg production level and growth rate / K. E. Nestor, W. L. Bacon, P. A. Renner and D. A. Ehlhardt -- Influence of strain and feed restriction on egg production, egg quality, and hatchability of cage hens / K. I. Brown, K. E. Nestor, S. P. Touchburn and D. A. Ehlhardt -- Egg shell quality according to clutch size and position in clutch and its relationship to hatchability / K. E. Nestor and D. A. Ehlhardt -- Association of certain body measurements on live birds with the amount of leg muscle in the turkey / K. E. Nestor, P. A. Renner and D. A. Ehlhardt -- Influence of plumage color pattern genes on growth and reproduction in the turkey / K. E. Nestor -- Inheritance of livability during the early growing period of turkeys / K. E. Nestor, P. A. Renner and K. I. Brown -- Influence of genetic changes in several traits on poult mortality during the early growing period / K. E. Nestor, K. I. Brown and P. A. Renner -- Influence of dipping eggs in gentamicin on growth and leg weakness of turkeys / K. E. Nestor and Y. M. Saif -- Changes in free fatty acid and neutral lipid concentrations with reproductive state in turkey hens / W. L. Bacon and M. A. Musser -- Estrogens and neutral lipids in turkey hens at different reproductive states / W. L. Bacon, K. I. Brown, M. A. Musser and D. W. Long -- Calcium and phosphorus concentrations in the plasma of turkey hens at various reproductive states / W. L. Bacon and M. A. Musser -- Variation in plasma calcium during egg formation in the turkey / M. A. Musser, W. L. Bacon and S. P. Touchburn -- Withdrawal of plasma calcium by the shell gland of the turkey / M. A. Musser, W. L. Bacon, S. P. Touchburn and K. E. Nestor -- Calcium-binding protein in the turkey hen / M. A. Musser, K. E. Nestor and W. L. Bacon -- A study of normal and abnormal shell formers among caged breeeders / M. Musser, W. Bacon and D. Long -- Selenium supplements for turkey rations / A. H. Cantor -- Cage confinement for growing, finishing, and breeding turkeys / A. H. Cantor, K. I. Brown and K. E. Nestor -- Predator control on the OARDC turkey ranges / P. A. Renner and K. E. Nestor -- Effects of relative humidity on aspergillus infection in turkey poults / Y. M. Saif -- Aeromonas and salmonella infections in turkey poults / Y. M. Saif and W. F. Busch -- Isolation and characterization of the turkey immunoglobulins M and G / Y. M. Saif and J. E. Dohms -- Observations on the serologic response of the turkey to Mycoplasma meleagridis antigens / Y. M. Saif and J. E. Dohms -- Comparative protein-amino acid level responses of broad white and medium white turkeys / P. E. Waibel and B. R. Behrends -- Influence of ambient environment and nutrition on development of growing turkeys and their subsequent reproductive performance / M. E. El Halawani, P. E. Waibel, W. H. Burke and R. N. Shoffner -- Comparative performance of turkey breeder hens in cages and floor pens / P. E. Waibel, M. E. El Halawani and W. H. Burk

Understanding stress-induced immunosuppression: Exploration of cytokine and chemokine gene profiles in chicken peripheral leukocytes

At present, the poultry meat and egg industry has gained a lot of ground, being viewed as a provider of a healthy alternative to red meat and other protein sources. If this trend is to be maintained, solutions must be found to improve resistance of chickens to disease, which often is weakened by stressful conditions. In poultry, stress-induced immunosuppression is manifested by failures in vaccination and increased morbidity and mortality of flocks. Currently, several modern cellular and molecular approaches are being used to explore the status of the immune system during stress and disease. It is likely that these new techniques will lead to the development of new strategies for preventing and controlling immunosuppression in poultry. Using quantitative reverse transcription-PCR assays, a broad spectrum of cytokine, chemokine, and their receptor genes can be quantified in birds and then be used as markers to assess the effects of stress on the immune system. Currently, we are investigating immune and endocrine interactions in the chicken, in particular the cells and molecules that are known to be involved in such interactions in mammals. We have evaluated the effects of corticosterone administration in drinking water on peripheral lymphocyte and heterophil cytokine and chemokine gene profiles. In particular, there seems to be effects on cytokine and chemokine mRNA expression levels in both lymphocytes and heterophils, especially expression of the proinflammatory cytokines interleukin (IL)-1 beta, IL-6, and IL-18 and chemokines C-C motif, ligand 1 inflammatory (CCLi1); C-C motif, ligand 2 inflammatory (CCLi2); C-C motif, ligand 5 (CCL5); C-C motif, ligand 16 (CCL16); C-X-C motif ligand 1 inflammatory (CXCLi1); and C-X-C motif ligand 2 inflammatory (CXCLi2), which are initially upregulated and are potentially involved in modulating the adaptive immune response. A chronic treatment with corticosterone downregulates proinflammatory cytokines and chemokines, suggesting that the delayed effects of chronic stress can suppress the immune response. Messenger RNA expression levels of transforming growth factor-beta 4 (TGF-beta 4) are also upregulated in cortisosterone-treated birds. It appears that the balance between T-helper (Th) 1 and Th2/T regulatory cytokine production is altered in conditions associated with significant changes in plasma corticosterone concentration. Experiments are underway to decipher the cytokine and chemokine responses to vaccination and bacterial challenge on the background of stress-induced immunosuppression