Abstract: Ein Klinikaufenthalt stellt für Pferde eine Stresssituation dar und viele Pferde erkranken
während eines Klinikaufenthalts an Stress-assoziierten Erkrankungen. Eine der häufigsten ist
die so genannte Colitis X, eine oft tödlich verlaufende Durchfallerkrankung. Da es im Verlauf
dieser Erkrankungen zu einem Verlust der Tiere kommen kann, hat ihre Vermeidung oberste
Priorität.
Ziel der vorliegenden Untersuchung war es, herauszufinden, inwieweit bei den Pferden der
klinisch erkennbare Stress mit Veränderungen messbarer Blutparameter (Hämatokrit,
Gesamteiweiß, Leukozyten, Glukose, Laktat, Kortisol) einhergeht und dabei einen Parameter
zu finden, mit dem Stress beim Klinikpatienten Pferd verlässlich und möglichst einfach
evaluiert werden kann. Zudem wurden in dieser Studie Freie Sauerstoffradikale („oxidativer
Stress“) und IgA im Kot bestimmt, um diese Parameter auf ihre klinische Verwendbarkeit zu
prüfen und zu untersuchen, inwieweit Stress mit dem lokalen Immunglobulingehalt
interferiert. Einigen ausgewählten Pferden wurde zudem der Paramunitätsinducer Zylexis® der
Firma Pfizer appliziert, um dessen Wirkung auf die untersuchten Parameter festzustellen.
Es wurden 110 Patienten der Klinik für Pferde untersucht, die in dem Zeitraum der Studie
zufällig hospitalisiert wurden. Die Pferde wurden in zwei Gruppen eingeteilt. Eine Gruppe
wurde in der Klinik operiert, die zweite nur stationär behandelt. Des Weiteren wurde eine
Kontrollgruppe in ihrem Heimatstall zum Vergleich miteinbezogen, die in den letzten sechs
Wochen vor der Studie nicht transportiert oder anderweitig belastet worden war.
Den Pferden wurde in definierten Abständen Blut und Kot entnommen, um den Einfluss von
Transport, Operation und Klinikstress möglichst gut zu erfassen. Die Zeitpunkte waren direkt
nach der Einlieferung, am Morgen vor der Narkose, nach der Aufstehphase und sowohl einen
als auch vier Tage nach der Narkose. Pferden, die nicht operiert wurden und der
Kontrollgruppe wurden insgesamt dreimal Blut und Kot (Tag 1, 3, Tag vor der Entlassung)
entnommen.
Für die Zylexis®-Studie wurden Vitrektomie-Patienten ausgewählt, da diese ein gutes Beispiel
für eine kurze, wenig traumatische Operation darstellen. Diese Pferde wurden mit den
anderen Pferden, die leichten Operationen unterzogen wurden, verglichen.
Bereits nach dem unterschiedlich langen Transport zeigten die Pferde signifikante Anstiege
von Gesamtleukozytenzahl, dem Verhältnis neutrophiler Granulozyten zu Lymphozyten
(N:L-Verhältnis), Glukose und den klinischen Parametern (Herzfrequenz, Atemfrequenz,
Körpertemperatur). Die IgA-Konzentration im Kot sank bei den eingelieferten Pferden nach
Einlieferung erst ab, um sich dann vermutlich durch den Kontakt mit den fremden Antigenen
in der Klinik reflektorisch zu erhöhen. Auffällig war, dass die Kortisolkonzentration nach
dem Transport bei den als „nervös, sensibel“ eingestuften Pferden signifikant höher lag als bei
den „ruhigen, ausgeglichenen“ Pferden.
Weitere deutliche Veränderungen zeigten sich nach den Operationen. Glukose, Kortisol und
das N:L-Verhältnis wiesen nach den unterschiedlich langen Eingriffen höhere Konzentrationen
auf. Die Laktatkonzentration stieg signifikant bereits nach der Operation und
anschließend noch weiter nach der Aufstehphase. Dies ist primär auf die Muskelbelastung
zurückzuführen, da Laktat vor allem muskulären Ursprungs ist. Hämatokrit und Gesamteiweiß
sanken nach der Narkose aufgrund der intraoperativ verabreichten Infusionen ab.
Einem starken hoch signifikanten Konzentrationsabfall unterlag auch der IgA-Gehalt im Kot.
Dabei war kein Unterschied zwischen den verschiedenen Operationstraumata festzustellen.
Ansonsten unterlagen die Pferde, die mit hochgradig gestörtem Allgemeinbefinden zu einer
Notoperation eingeliefert wurden, viel deutlicheren Veränderungen als die anderen Pferde.
Die Freien Radikale zeigten überhaupt keinen charakteristischen Verlauf. Sie schienen
allerdings bei den chronisch erkrankten Pferden erhöht zu sein. Des Weiteren zeigten sie
Erhöhungen bei bestimmten Erkrankungen („Equine Motor Neuron Disease“, Hufrehe).
Bei den Pferden, die Zylexis® verabreicht bekamen, konnte eine Tendenz zur Verbesserung
des Immunstatus nachgewiesen werden. Es fiel ein deutlich höherer Gesamteiweißgehalt auf,
der wahrscheinlich auf eine vermehrte Produktion von Immunglobulinen zurückzuführen ist.
Außerdem war die Kortisolkonzentration nach der Operation signifikant niedriger. Der IgAGehalt
zeigte einen weniger deutlichen Konzentrationsabfall, was aber statistisch nicht belegt
werden konnte.
Die Untersuchungen zeigten, dass das N:L-Verhältnis und Glukose geeignete Parameter
darstellen um zuverlässig den Stress, dem ein Pferd ausgesetzt ist, zu evaluieren. Kortisol ist
vorsichtig zu interpretieren, da es großen individuellen Schwankungen ausgesetzt ist.
Die Bestimmung von IgA im Kot gibt Aufschluss über den lokalen Immunstatus des
Intestinaltrakts. Da es bei allen Pferden postoperativ zu signifikanten Konzentrationsabfällen
kam, sind Pferde nach jeder Operation offensichtlich prädisponiert, eine Darmerkrankung,
wie beispielsweise Colitis X, zu entwickeln. Kortisol scheint auch Einfluss auf das lokale
Immunsystem zu nehmen, da hohe Kortisolwerte mit einem niedrigen IgA-Gehalt im Kot
korrelierten.
Um die Zusammenhänge der Blutparameter und der Colitis X näher zu erforschen und
insbesondere um die „kritischen“ IgA-Konzentrationen zu ermitteln, wären noch weiterführende
Untersuchungen aufschlußreich.
[Many horses in clinics display symptoms of stress-associated diseases. One of the most feared
is the so-called Colitis X, an often fatal ending diarrhea. As death occurs quite often in the
course of those diseases, their avoidance has first priority.
The aim of the following study was to find out whether signs of stress which are displayed by
the horses correlate with measurable blood parameters. Furthermore we tried to find a
parameter which was suitable to evaluate stress in hospitalized horses.
Apart from the commonly measured parameters (hematocrit, total protein, leucocytes,
glucose, lactate, corticosterone) we tried to include free oxygen radicals in this study.
Immunoglobulin A in faeces was investigated to find out how stress interfered with the local
immune system. A Paramunityinducer often used in Germany (Zylexis®) was administered to
10 selected horses to research its effect on the different parameters.
110 patients hospitalized in the horse clinic were examined. First the horses were organized
into two groups. One group underwent surgery and the other one received stationary
treatment. Furthermore a control group was taken into account which had not been
transported or subjected to stress in six weeks prior to the study.
The horses were drawn blood and collected faeces in defined intervals to register the
influence of transport, operation and clinic stress. Blood samples were taken directly after the
transport, prior to the operation, right after surgery and one day and four days after the
operation. Horses which did not undergo surgery including the control group were drawn
blood and faeces three times (day 1, 3, and the day prior to discharge from the clinic).
For the paramunity investigation patients for vitrectomy were chosen as they display a good
example for short little traumatic operations. Those were compared with other horses brought
into the clinic for short operations.
After the transport to the clinic horses showed significant increases in leukocyte
concentration, N:L-ratio, glucose and the clinical parameters (heart rate, breathing rate, body
temperature). The immunoglobulin concentration decreased after the transport to rapidly rise
after contact with antigens from the clinic environment.
Horses categorized as “nervous, sensitive” displayed significantly higher corticosterone
concentrations after the transport than horses categorized as “cool, calm”. Other distinct
variations showed after the operations. The lactate concentrations increased significantly after
anaesthesia and went up even further after the horse got up afterwards. This is due to
muscular fatigue as lactate is mainly produced in the muscles. Glucose, corticosterone and the
N:L-ratio also displayed higher concentrations after the operation.
Hematocrit and total protein concentrations decreased after anaesthesia ascribed to infusions
during operation. After anaesthesia a highly significant reduction of immunoglobulin
concentrations in the faeces was determined. No influence of the different operation traumas
could be recognized.
That was surprising as in all other cases horses in very bad general condition displayed
distinct changes.
The free oxygen radicals did not show any characteristic pattern. There appeared to be a
higher concentration in horses with chronic illnesses. Furthermore some diseases, like Equine
Motor Neuron Disease and laminitis, seemed to have an increasing impact on the oxygen
radicals.
Zylexis® showed a tendency to improve the immune status of the horses in this study. The
paramunized horses had more total serum protein than the others. This could be due to an
increased production of Immunoglobulins. Additionally the corticosterone concentration after
the operation stayed on a significantly lower level. The local immunoglobulin A
concentrations did not appear to decrease as much as in the non-paramunized horses but it
was not possible to statistically prove this statement.
The results of this study show that the N:L-ratio and glucose might be suitable parameters to
reliably evaluate the stress that has an effect on the hospitalized horse. Corticosterone values
have to be interpreted carefully as they are very prone to individual variations.
Measuring immunoglobulins in faeces provides information about the local intestinal immune
status. Since all horses showed significant lower immunoglobulin concentrations after the
anesthesia/operation they obviously lack immune protection and are therefore predisposed for
developing enteritis, as Colitis X. In this study corticosterone seemed to influence the local
immune system as high concentrations of corticosterone correlated with low immunoglobulin
levels.
To understand the circumstances more thoroughly and to find out which factors have to be
present additionally in order for the horses to fall ill with Colitis X, further investigations have
to be made.]

Abstract: It has been claimed that capuchin monkeys (Cebus apella) show inequity aversion in relation to food rewards for a simple exchange task. However, other factors may affect the willingness of a monkey to consume foods of high or low value in the presence of a conspecific. In this study, pairs of monkeys were presented with unequally valued foods, but without any task-performance: they simply received the food under four experimental conditions. By looking at the rate of collection and consumption of low-valued cucumber slices we expected to see variation dependent on whether the partner either had 1) cucumber (equity), 2) grape (inequity), 3) inaccessible cucumber or 4) inaccessible grape. Testing 12 adult capuchin monkeys, our findings differed from those of other authors in that the monkeys failed to show negative reactions to inequity, but rather responded with scramble competition (i.e., fast food collection) in the presence of a conspecific without access to food. They also showed facilitated consumption in the presence of a conspecific consuming high-valued food. Possibly, (in)equity plays a different role if food serves as a reward for a task rather than if it is simply made available for consumption. Am. J. Primatol. 69:1-9, 2007. (c) 2006 Wiley-Liss, Inc.

Abstract: OBJECTIVE: To investigate whether training for show jumping that is commenced early after birth affects the characteristics of equine locomotory muscle. ANIMALS: 19 Dutch Warmblood horses. PROCEDURES: Horses were assigned to a trained or not trained (control) group. After weaning, training (free jumping [2 d/wk] that was alternated with a 20-minute period of exercise in a mechanical rotating walker [3 d/wk]) was started and continued until horses were 3 years old. Fiber type composition (determined from myosin heavy chain [MyHC] content), fiber area, diffusion index (area supplied by 1 capillary), citrate synthase activity, and Na(+),K(+)-ATPase content were assessed in gluteus medius muscle specimens collected at 0.5, 1, 2, and 3 years. RESULTS: Developmental changes included an increase in MyHC fiber type IIa and a decrease in type IIad; increases in fiber area, diffusion index, and citrate synthase activity; and a decrease in Na(+),K(+)-ATPase content. The MyHC fiber type I and type IId were detected in high and low proportions, respectively. Training increased Na(+),K(+)-ATPase content, but did not affect other variables. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, show jumping training at an early age resulted in increased Na(+),K(+)-ATPase content of the deep portions of the gluteus medius muscle. The lack of training effects on the other muscle characteristics can partly be explained by the fact that an appropriate (aerobic) fiber type composition was already established at training commencement. These data also suggested that the developmental changes in equine muscle represent sufficient adaptation to meet the demands of this specific training.

Abstract: How animals use space has important consequences for feeding ecology, social organization, mating strategies and conservation management. In white rhinoceros, female home ranges are much larger than male territories, suggesting that movement patterns are influenced by factors other than resource distribution. In this study we placed radiotransmitters on 15 female white rhinoceros, recording 1758 locations and collecting behavioural data during 1671 observation sessions, making this the largest data set of its kind in this species. We investigated how habitat variables and male territories influenced female movement and reproductive behaviour. Female home ranges were approximately 20 km2 and core areas were 5 km2, with male territories roughly the same size as female core areas. Female range size did not vary with season, but the pattern of space use did vary. Females used grassland habitat preferentially, utilizing these areas significantly more than expected based on availability. Findings relevant to the mating strategy include: (1) the amount of grassland in a male's territory predicted female use of the territory; (2) the time that a female spent in a male's territory was a significant predictor of reproductive activity with the male, indicating that females probably mate with the most familiar male; and (3) the temporal pattern of female space use suggests that females did not increase mate sampling behaviour nor did they become more choosy about which males they visited when reproductively active. These findings suggest that males may maximize reproductive success by defending areas containing more grassland habitat.

Abstract: According to the socioecological framework, transitivity (or linearity) in dominance relationships is related to competition over critical resources. When a population is structured into groups, the intensity of between- versus within-group competition influences the form and function of its social organization. Few studies have compared the type and relative intensity of competition at these two levels. African elephants have well-structured social relations, providing an exemplary system for such a study. We report on dominance hierarchies among free-ranging elephants and evaluate the factors that drive their socioecological structure to lie in a region of the three-dimensional nepotism/despotism/tolerance space rarely observed among social species; namely, where non-nepotistic, transitive dominance hierarchies within groups emerge despite kin-based philopatry and infrequent agonistic interactions over widely distributed resources. We found significant transitivity in dominance hierarchies between groups. Dominance relations among the matriarchs of different social groups were primarily age based, rather than driven by physical or group size, and group matriarch rank influenced the dominance relationships among nonmatriarchal females in the population. Our results suggest that between-group dominance relationships induce tolerance among group members, which in combination with high group relatedness, reduces the benefits of nepotism. We postulate that cognitive abilities and high risk of injury in contests enhance winner and loser effects, facilitating the formation of transitive dominance relationships, despite widely distributed resources over which infrequent competition occurs. The interplay of cognitive abilities, winner and loser effects, resource distribution, and within- and between-group dominance relationships may produce behaviour in other strongly social mammals that differs from that predicted by a superficial application of current socioecological models.