Browsing by Subject "Haltung"

Now showing 1 - 2 of 2

Impact of housing environment and rearing condition on the immune system and welfare of laying hens
(2021) Hofmann, Tanja Melanie; Stefanski, Volker
In recent years, consumers’ interest in modern farm animal husbandry and, above all, criticism of intensive production systems that can impair animal welfare, have increased sharply. From hatch, chickens are confronted by a wide range of environmental and social stressors that may confound homeostasis and impair their health and welfare. Not being able to deal with the environment can lead to an activation of the stress system, resulting in a release of neuroendocrine signals like glucocorticoids. These have the potential to modify the immune system and alter species-specific behavior with possible detrimental impacts on animals’ health and welfare. In this context, early-life conditions play a special role as they were shown to have long-term consequences for physiology and behavior in the later life. High stocking densities which activate the hypothalamic-pituitary-adrenal-axis are said to be one of the largest welfare concerns in the poultry industry. Previous research has primarily focused on the effects of stocking density on broilers and adult laying hens, but few studies have focused explicitly on layer pullets, and none of them investigated long-term effects on the immune system. The understanding of short- and long-term consequences of environmental conditions during rearing on the immune system and behavior of layer pullets is essential for shaping an environment that avoids allostatic overload, thus promoting animal health and welfare. This doctoral thesis aimed to identify and evaluate potential immunomodulating factors in the housing environment of chickens. In order to achieve this, it summarizes and reviews important aspects of housing environments for the immune system in chickens. Furthermore, an existing flow cytometric method for the enumeration of leukocytes and discrimination of lymphocyte subsets in blood was adapted to lymphatic tissues. Moreover, short- and longterm consequences of stocking density during rearing on the immune system, stress hormone level and behavior in layer pullets were evaluated. The results are described in detail in three peer-reviewed manuscripts published in international journals. The literature analysis identified several housing conditions as immunomodulating factors. Light management was marked as an effective tool to modulate the immune response in chickens, as long light phases were demonstrated to lower adaptive cellular and humoral immune responses while certain light colors, especially of shorter wavelengths, promote some immune functions. Moreover, particularly high ammonia and hydrogen sulfide concentrations pose a threat to chickens’ health by dampening the adaptive immune response and promoting inflammation. However, the interaction between housing environment and management is complex. Depending on the type of housing form, chickens are confronted with different social and environmental challenges, which in turn can have an impact on the immune and stress system. An understanding of immunosuppressive risk factors is essential for successful poultry management aiming to optimize health, welfare and economic efficiency. To broaden the assessment of immune status for scientific purposes, new staining- and gating strategies for avian lymphatic tissues were adapted to an existing flow cytometric method for blood. The adaptation process showed that the application of already established protocols to other tissues is possible, but has to be examined carefully as tissue-specific effects or cell-preparative procedures might lead to differences in possible combinations of antibody-fluorochrome conjugates. The results of the experimental study within this doctoral thesis demonstrate for the first time that stocking density during rearing has not only short- but also long-term impacts on the immune system in laying hens. Pullets reared at high stocking densities showed stress-related alterations in immune cell numbers and higher incidences of feather pecking that manifest in the laying period. This highlights the significance of early-life conditions for immunocompetence throughout the whole production cycle. Of particular interest is that the number of gamma-delta T cells was lower in the high-density group, which has not been investigated in any stress-related studies with chickens before. The present doctoral thesis provides a significant contribution to the improvement of health and welfare in poultry farming and forms a basis for further research about long-lasting consequences of rearing conditions on the immune system, especially in laying hens.
Wohlbefinden von Mastschweinen in verschiedenen Haltungssystemen unter besonderer Berücksichtigung ethologischer Merkmale
(2003) Weber, Ragnhild E. F.; Valle Zárate, Anne
This study aims to compare practice oriented husbandry systems with regard to their effect on the welfare of fattening pigs. This should also contribute to the development of evaluation indicators for pig welfare. A literature review was conducted covering Definition of Welfare, Indicators for Welfare Assessment, Behavior of Fattening Pigs, Ethological Methods for Welfare Assessment, and Husbandry Systems for Fattening Pigs. Insights attained were significantly taken into account when developing and conducting the study. 2 husbandry systems were established, compromising on conventional pig husbandry and currently available knowledge on the welfare of fattening pigs. The investigation emphasizes on ethological traits. This research is part of a comprehensive project investigating prevalent fattening pig husbandry systems in the federal state of North Rhine-Westphalia, Germany, with regard to animal welfare and pig farmers? and consumers? attitudes towards husbandry conditions. The present study was conducted on the experimental station Frankenforst of the University of Bonn, Germany. A total of 256 Piétrain (Pi) x German Landrace (DL) or Pi x (Large White (DE) x DL) fattening pigs were investigated throughout 2 periods of time: middle of June 1998 to beginning of January 1999, and middle of April to end of September 1999. They were kept in two enriched husbandry systems. One system was equipped with heater, forced ventilation and partly slatted floor (TSP: 8 pigs/pen), the other was in an open stable with half the area deep littered (OT: 32 pigs/pen). The enrichments included chains, a wooden chewing bar, and a straw rack in the non-bedded system. Over a period of 10 weeks indirect video observations were conducted once per week between 5:30 and 8:30 a.m. and 1:30 and 4:30 p.m. The behavioral traits observed included feeding, exploration and occupation, abnormal occupation, comfort, aggression and fighting, locomotion, and resting and lying. In the second year direct observations were additionally conducted at specific times to analyse occupation and comfort behavior in more detail. Further traits investigated included: state of health, medical treatments, skin lesions, changes of extremities and claws, general condition, carcass, lung, liver, heart, kidney, and lymph node changes, fattening and slaughtering performance and housing characteristics. The results showed that rooting, which is of utmost importance for the welfare of pigs and which could only be performed in the OT, could not completely be compensated for in the TSP by the enrichment objects and the stable environment. In the TSP the behavioral disorders of pseudo-rooting and manipulation of pen-mates were clearly performed more often. In contrast, the husbandry environment of the OT (straw bedding, enrichment, more overall space, more outside stimuli) had a positive effect on the behavior of the pigs. An improvement of the pigs? welfare in the OT can particularly be concluded from the increased level of rooting, playing, alertness, and walking+standing as compared to the TSP. Comfort+wallowing, the least observed behavior, was also performed significantly more often in the OT. On the other hand, fattening pigs in the OT were also not completely free of behavioral disorders. In both husbandry systems pigs laid (with no other activity) more than 70 % of the observation time. Low lighting in the TSP probably caused a less pronounced endogenously predisposed two-phase daily rhythm of the pigs with less activity in the morning as compared to the pigs in the OT. The forced ventilation in the TSP and the non-bedded area of the OT were not completely sufficient to cool the pigs in summer. The territorial division of the pen by the pigs was disturbed to the point that no clear distinction between lying, defecation and feeding areas could be made. Cardiovascular problems occurred in the OT on some very hot days. Skin lesions, changes in the extremities and claws and the pigs? general condition did not deviate greatly from normal and healthy conditions. No obvious relation of injuries being caused by means of the husbandry system could be found. Carcass inspections showed that lung alterations and pleuritis occurred most frequently. Significant differences between the husbandry systems (OT > TSP) were found for liver and pluck findings. With regard to animal health the pigs in the TSP were better off. It can be presumed that welfare was reduced by the slight Ra. outbreak in the OT in the second year. Differences in daily gain and feed conversion were only due to a substantially lower performance of the pigs in the OT in the first year probably caused by higher thermoregulation efforts. By means of the methods and traits (indicators) used the welfare of the pigs in the two different husbandry systems could be compared. Proposals for further improvements of the methods as well as for the improvement of the husbandry systems were submitted.