[Stress]. / Over spanning.

Any change in the social or physical environment that threatens the needs or interests of a mammal, induces a state of tension ('stress') in the animal. Driven by this tension, the animal changes its behaviour. At the same time, alterations occur in bodily functions. All organs and regulatory systems (central and peripheral nervous systems, endocrine and immune systems) participate in these behaviour-physiological response and are affected in their activities. The character of the reactions (e.g. fight, flight, passivity) is mainly determined by the animals appraisal of the environmental change and of the possible impact of its response. Aim of the reactions is neutralising the threat and gaining control over the environment (adaptation). When this is achieved, the tension recedes. In case the response is unsuccessful, the state of tension persists ('chronic stress'). Prolonged exposure of brain and/or bodily functions to stress can result in pathological states.

The effect of stress on udder health of dairy cows.

The appropriate literature has been reviewed for the purpose of defining the phenomenon of stress in lactating dairy cattle, establishing a baseline concept of lactation stress and emphasizing the most significant aspects of the natural mammary defence mechanisms. Data on the general adaptation syndrome (GAS) make it clear that stress is essentially the rate of wear and tear of the biological system affected by a stressor either eliciting stress of the organism as a whole or partly so. Owing to the variety of stressors which may affect the dairy cow at physiological and pathological levels, a definition of stress in the broad sense is indicated. This is essential from the point of view of the anti-homeostatic effects (metabolic and immunological) of lactation stress, aggravated by anti-homeostatic effects elicited by superimposed other types of stress (e.g. heat stress). The lactating cow, as a ruminant in a state of sustained stress, requires a special profile of hormonal mediators. In high yielding cows, for example, acute and sustained heat stress promotes increased activities of prolactin, progesterone and catecholamines. Compared with the mainly glycogenic/glycogenolytic metabolism of non-ruminant mammals, the lipogenic/lipolytic and glycogenic/glycogenolytic metabolism of the dairy cow depends on hormonal mediators which differ from those of the former not so much in their nature but in their magnitude and ratios. Stressors induce the development of GAS reactions in the dairy cow. These enable the cow to create and maintain homeostasis of its integrated 3 main physio-pathological systems and thus to endure the stressor(s). The cow's compensating adjustments to a stressor are therefore the effects of stress. This means that natural lactation is the effect of the lactation stress induced by the cow's progeny (i.e. the natural lactation stressor). Artificial lactation stressors (e.g. removal of milk by hand and machine) may affect the lactation stress in magnitude but not necessarily in nature. Likewise, a range of behavioural, physiological, lactational and lacteal changes related to other stressors are the effects of different types of stress. Lactation stress, like other types of stress, shows 3 stages of development, i.e., an overcompensating alarm phase (= lactogenesis), resistance phase (= galactopoiesis) and exhaustion phase (= regression). They facilitate adjustments of the cow's homeostasis from the level of involutional homeostasis (= no lactational activity) to that of lactational homeostasis. Like other tissues in a state of stress, the lactating mammary epithelium requires a greatly increased supply of glucose.(ABSTRACT TRUNCATED AT 400 WORDS)

Use and misuse of an imprecise concept: alternative methods in animal experiments.

The concept of inhumanity of Russell & Burch in 1959 with proposals for human procedures in experiments on animals by way of replacement, reduction and refinement (the 3 R's) and the revival of these by Smyth (1978) as alternatives to animal experiments are presented. Since then under the name 'alternative methods', replacement of in vivo by in vitro methods has found great public attention and promotion. It is argued that alternative methods are a fallacy, because in the progress of research a continual control and reinvestigation of findings on each system level is required until knowledge is complete, which makes in vivo experiments irreplaceable. True alternatives exist only for refinement within a system level. On the level of the organism, refinement would be in the care of animals and experimental procedure through alleviation of stress. The possibilities which refinement offers for animal welfare have been nearly forgotten and need promotion among researchers, animal technicians and attendants.

Causes of mortality and morbidity of wild koalas, Phascolarctos cinereus (Goldfuss), in Victoria, Australia.

Between 1975 and 1980, necropsy investigations were conducted on 44 wild koalas (24 males, 20 females) from several localities in Victoria, Australia. An additional 11 (5 males, 6 females) were presented for clinical appraisal and treatment. Traumatic injuries resulting from motor vehicle accidents and intra-specific conflict were the commonest reason for submission (19 of 55; 35%). Keratoconjunctivitis (8 of 55; 15%), ascending urinary tract infections (6 of 20 females; 30%), ascending genital tract inflammation (10 of 20 females; 50%) and sarcoptic mange (2 of 55; 4%) were recognized as specific diseases or disease syndromes. A peracute syndrome characterized by lassitude, depression, anorexia and coma was identified in moribund koalas submitted from the wild and also in hospitalized animals. The condition, termed koala stress syndrome, was thought to be initiated by intercurrent disease or trauma, long term hospitalization and frequent manipulation and treatments. Hematological observations in 54 apparently healthy wild koalas from five different populations and on 17 sick or injured animals are also presented. Certain blood parameters are discussed in relation to the health status of the populations or individuals. Areas for further research into koala diseases are also discussed.

Platelet morphology and membrane bound calcium in porcine stress syndrome.

Platelets of normal and stress susceptible pigs were subjected to electron microscopic examination and energy dispersive x-ray microanalysis in an attempt to study whether the cell membrane defect implicated in porcine stress syndrome is detectable at the platelet level. Electron microscopic studies revealed that the platelets of stress susceptible pigs are morphologically distinguishable from those of normal pigs by virtue of their highly dilated surface connected open canalicular system rendering the "Swiss cheese" appearance and the absence of the circumferential band of microtubules. A comparison of the data from spot analysis of cell membrane and the membranes of the open canalicular system using the energy dispersive microanalysis system showed that the calcium content of the plasma membrane of stress susceptible pigs is significantly lower than that of normal pigs. It would appear that the morphologic feature and the reduced levels of calcium bound to platelet membrane are related to the generalized membrane defect postulated to be the primary lesion in porcine stress syndrome and that these parameters could be included among the criteria for the detection of stress susceptible pigs.

Discussion: Implications of the stress syndrome to animal performance and health.

Similarities of blood metabolic and immunologic reactions that occur in cattle exposed to heat stress, other chronic stress-inducing environmental factors, and administration of pituitary, adrenal, and thyroid hormones have been described. Chronic stress can predispose cattle to both metabolic and infectious diseases. Improved characterization of endocrine, metabolic, and immunologic relationships offers promising means for studying effects of various treatment regimens on animal health, production, and reproduction.

[General adaptation syndrome (Selye) in cattle. 6. Influence of stress conditions on antibody levels after active and passive immunization as well as on the topographic distribution of various groups of pathogens in the gastrointestinal canal]. / Allgemeines Adaptationssyndrom (Selye) beim Kalb 6. Mitteilung: Einfluss von Stresszuständen auf den Antikörperspiegel nach aktiver und passiver Immunisierung sowie auf die topographische Verteilung einiger Keimgruppen im Magen-Darm-Kanal

The action of experimental and natural stressors on the humoral immune response of calf was studied. Particular attention was given to the H-antigen of S.dublin and equine erythrocytes,the degradation rate of passively acquired humoral antibody, as well as the quantity and topographic distribution of certain groups of germs in the gastrointestinal tract. The following results were obtained:1. Antibody formation was impededby repeated or lasting stressor effect (ACTH injections). 2. The immunological reactions of the calves involved to antigen injection immediately after transport into the rearing unit were stronger than those to antigen application three days from transfer. Immunisation of animals transferred to rearing or fattening units, therefore, should be applied immediately after arrival in the new accomodation, but no interval of three or four days should be allowed. 3. Antibody formation was no longer impaired in calves immunised two weeks from transfer, as compared to those immunised immediately after arrival in the rearing unit. This seemed to suggest that by that time adaptation of the animals to their new environment had been almost complete. 4. Lasting stress (slow drip infusion of ACTH, cortisol, colibacteria or coli-endotoxin) led to no detectable by paper electrophoresis. 5. Calves that had been given three weekly dosesof 1 IU ACTH per kilogram of live weight through four weeks,did not differ,withthe authors'method,from the controls regarding the decomposition rate of passively acquired humoral antibody. 6. ACTH slow drip infusions of calves over several days caused higher concentrations of colibacteria throughout the intestinal tract, including those proximal sections of the small intestine in which little or no colibacteria should occur under physiological conditions in calves of that age.

[General adaptation syndrome (Selye) in the calf. 5. Effect of increased glucocorticosteroid values on the phagocytosis activity of luekocytes, the function of RHS and the morphology of lymphatic organs]. / Allgemeines Adaptationssyndrom (Selye) bein Kalb 5. Einfluss erhöhter Glukokortikosteroidwerte auf die Phagozytoseaktivität von Leukozyten, die Funktion der RHS und die Morphologie lymphatischer Organe

Studies were conducted with the view to elucidating the correlations between increased glucocorticosteroid levels in the blood and the defense potential of calf organism against infectious diseases. The test animals were exposed to several substances (ACTH, cortisol, colibacteria, coliendotoxin), and even one to two days of increased 11-OHKS values were followed by marked decline in phagocytosis activity of leucocytes. In addition, RHS function was considerably reduced, after ten to thirteen days of application had elapsed, since at that point the disappearance of intravenously applied bacteria from circulating blood of test animals took place at rates which were much lower than those recorded from untreated calves. Differentiated length of stress or action (four to thirteen days) was followed by conspicuous changes in the lymphatic tissue of calf organism, with severe involution of thymus and follicular atrophy of intestine-associated lymphatic tissue having been the major findings. The results seem to suggest that rise in adrenocortical hormone level under stress may reduce potential organic defense to infection.