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: OBJECTIVE: To assess the effects of a single intravenous dose of butorphanol (0.1 mg kg(-1)) on the nociceptive withdrawal reflex (NWR) using threshold, suprathreshold and repeated subthreshold electrical stimuli in conscious horses. STUDY DESIGN: 'Unblinded', prospective experimental study. ANIMALS: Ten adult horses, five geldings and five mares, mean body mass 517 kg (range 487-569 kg). METHODS: The NWR was elicited using single transcutaneous electrical stimulation of the palmar digital nerve. Repeated stimulations were applied to evoke temporal summation. Surface electromyography was performed to record and quantify the responses of the common digital extensor muscle to stimulation and behavioural reactions were scored. Before butorphanol administration and at fixed time points up to 2 hours after injection, baseline threshold intensities for NWR and temporal summation were defined and single suprathreshold stimulations applied. Friedman repeated-measures analysis of variance on ranks and Wilcoxon signed-rank test were used with the Student-Newman-Keul's method applied post-hoc. The level of significance (alpha) was set at 0.05. RESULTS: Butorphanol did not modify either the thresholds for NWR and temporal summation or the reaction scores, but the difference between suprathreshold and threshold reflex amplitudes was reduced when single stimulation was applied. Upon repeated stimulation after butorphanol administration, a significant decrease in the relative amplitude was calculated for both the 30-80 and the 80-200 millisecond intervals after each stimulus, and for the whole post-stimulation interval in the right thoracic limb. In the left thoracic limb a decrease in the relative amplitude was found only in the 30-80 millisecond epoch. CONCLUSION: Butorphanol at 0.1 mg kg(-1) has no direct action on spinal Adelta nociceptive activity but may have some supraspinal effects that reduce the gain of the nociceptive system. CLINICAL RELEVANCE: Butorphanol has minimal effect on sharp immediate Adelta-mediated pain but may alter spinal processing and decrease the delayed sensations of pain.

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: Animal group sizes may exert important effects on various cognitive mechanisms. Group
size is believed to exert pressures on fundamental brain structures that correlate with the
increased social demands placed on animals living in relatively large, complex and dynamic
social organizations. There is strong experimental evidence connecting social complexity,
social learning and development of other cognitive abilities in a broad range of wild and
domesticated animal species. In particular, group size seems to have significant effects on
animals? abilities to derive concrete and abstract relationships. Here, we review the literature
pertaining to cognitive processes and behaviours of various animal species relative to group
size, with emphasis on social learning. It is suggested that understanding the relationship
between group size and cognition in animals may yield practical animal management
benefits, such as housing and conservation strategies, and may also have implications for
improved animal welfare.

Abstract: We observed the behaviour of six stabled horses (stallions n = 3; geldings n = 3) in an attempt to identify behavioural measures of eating satisfaction. The horses were required to perform an operant response (pressing a button with the muzzle) in order to access a food reward in an experimental box stall. After each horse had successfully learned the experimental situation, it participated in the experimental protocol on 4 days. Horses were brought to the experimental box stall for the operant response sessions (1 h duration per session), and upon completion, they were returned to their own (home) box stalls. The number of presses for the reward was a Fixed Ratio schedule of either 3 or 12 muzzle presses (FR3, FR12) and the FR procedure for each horse was as follows: FR3 FR12 FR12 FR3 or FR12 FR3 FR3 FR12. Number of rewards obtained during each session, and behaviour and heart rate after each session were recorded for each horse. A repeated measures ANOVA showed that the number of rewards obtained in FR3 was higher than in FR12 (P < 0.05). The horses spent more time in standing-rest, (with ears rotating laterally and exhibiting a low neck position) indicating sleep, in the home box stall, after FR3 compared to FR12 treatments (P < 0.05). Mean heart rate after standing-sleep was significantly lower than mean heart rate in the home box stall (P < 0.01). These results suggest that eating satisfaction induces sleep in stabled horses, and that episodes of standing-sleep behaviour may be a useful indicator of appropriate or enhanced welfare in the horse.