Abstract: A rider modifies the weight distribution and dynamic balance of the horse. But what effect does a rider have on the mechanical behaviour of the hoof during each stance phase? Does riding style have any effect on this behaviour? We attempted to answer these questions using strains recorded from 5 rosette strain gauges glued to the surface of the front hooves of 4 Warmblood horses. Comparisons were made between strains with and without a rider, and when the rider was sitting, rising at a trot, or in a forward seated position. The change in strains from trot to lead or nonlead at a canter, and the effect of turning were also studied. Changing lead at a canter had as least as much effect on strain magnitudes as did turning; strains were up to 43% higher for the nonlead foot, but with little redistribution. Perhaps surprisingly, strains were significantly lower on the quarters by up to 30% with a rider than without, with a 10% increase or decrease at the toe, depending on the individual. Riding style changed strain magnitudes by up to 20% and also caused strain redistribution: strains were higher medially for sitting, and laterally for forward seat, with strains for a rising trot being more evenly distributed and intermediate in magnitude. Studying the range of, and causes of variation in hoof wall strain gives baseline data aimed, in the long term, at providing a biomechanical definition of hoof balance.

Abstract: Virus vector studies were conducted in the States of Durango, Chihuahua, and Tamaulipas, Mexico, in June and July 1972. Apparently only a low level of Venzuelan equine encephalitis (VEE) virus transmission to equines occured at the time of the study, and the infection was restricted to areas which had not experienced overt activity during the preceding year. The low level of infection was associated with a scarcity of mosquitoes. The IB (epidemic) strain of VEE virus was isolated from two pools of Anopheles pseudopunctipennis (Theo.) and the blood of one symptomatic equine. The low mosquito population, the relatively few equine cases observed, and the absence of reports of VEE human disease from the outbreak area suggested VEE virus persistence through a low-level mosquito-equine transmission cycle. Other studies have already indicated that wild vertebrates play no more than a minor role in outbreaks of epidemic VEE. Mosquito collections made in areas of the states of Durango, Chihuahua, and Tamaulipas, where considerable epidemic activity of VEE had occurred in 1971, failed to reveal evidence of VEE virus persistence. Twenty-nine ioslations of other arboviruses were also made in these studies: including 22 of St. Louis encephalitis virus (SLE), 2 of Flanders virus, 1 of Turlock virus, 1 of Trivittatus virus of the California Group, 1 of western equine encephalitis virus (VEE), and 2 (from Santa Rose) which possibly represent a hitherto unknown virus in the Bunyamwera Group. These are the first reports of SLE virus isolations from mosquitoes in Mexico, and the first demonstration of Trivittatus, VEE Turlock and Flanders viruses in Mexico from any source.

Abstract: In dieser Untersuchung sollte überprüft werden, ob die für die Stressmessung beim Menschen angewandte „Chronopsychobiologische Regulationsdiagnostik“ (CRD) mithilfe des smardwatch®-Messsystems auch beim Pferd psychische Belastungssituationen aussagekräftig widerspiegelt. Menschen können anhand variierender physiologischer und ethologischer Reaktionen auf Stressoren aus der Umwelt in Stresstypen eingeteilt werden. Auch Pferde reagieren in identischen Situationen ganz unterschiedlich. Es stellte sich daher die Frage, ob Pferde ebenfalls bestimmten Stresstypen zugeordnet werden können.
Mit 26 dreijährigen Hengsten des Landgestüts Celle wurde ein Verhaltenstest durchgeführt. Auf der Grundlage wissenschaftlich dokumentierter und modifizierter Testsituationen (Open-Field-Test, Novel-Object-Test, Startling-Test Objekt/Geräusch, Mensch-Pferd-Interaktion, Ressourcenkontrolle) wurde das Erkundungs- und Fluchtverhalten untersucht (Goslar 2011). Während dieser Belastungssituationen wurden mit dem smardwatch®-Messgerät die elektrophysiologischen Parameter Hautwiderstand, Hautpotential und Muskelaktivität erfasst. Durch eine Zeitreihenmessung dieser physiologischen Parameter konnten die Reaktionen des übergeordneten Reglers (vegetatives Nervensystem) dargestellt werden. Der Hautwiderstand spiegelt die vegetativ-emotionalen Reaktionen wider, das Hautpotential die vegetativ-nervalen und somit laut Balzer (2009) die kognitiven Verarbeitungsweisen, und durch das Elektromyogramm werden die typischen muskulär-motorischen Reaktionen aufgezeichnet. Die vorliegenden Datenzeitreihen wurden mit Hilfe einer biorhythmometrischen Zeitreihenanalyse nach Balzer und Hecht (Hecht 2001, Balzer 2009) ausgewertet. Als Ergebnis wurden chronobiologische Regulationszustände definiert, die dann gemäß dem „Periodischen System der Regulationszustände“ (PSR) (Balzer 2000) eine Beurteilung der psychischen Belastungssituation erlauben. Zur Bestimmung von Stresstypen wurde die Untersuchung nach dem Reiz-Reaktions-Prinzip in drei Phasen unterteilt: Ruhephase, Stressreizphase und Stressverarbeitungsphase. Der Verhaltenstest wurde nach einer Woche zur gleichen Tageszeit mit jedem Hengst einmal wiederholt. Als physiologische Vergleichsparameter wurden vor, während und nach der Belastung insgesamt zehn Speichelproben zur Cortisolbestimmung entnommen.
Die smardwatch®-Messtechnik ist prinzipiell geeignet die physiologischen Parameter Hautwiderstand, Hautpotential und Muskelaktivität auf der Haut des Pferdes aufzunehmen. Durch die biorhythmometrische Zeitreihenanalyse konnten chronobiologische Regulationszustände definiert werden.
Der Verhaltenstest führte bei allen Pferden zu einem signifikanten Anstieg der Cortisolwerte. Ein ebenfalls statistisch gesicherter Unterschied der aktivierten Cortisolwerte zwischen der ersten und zweiten Testwoche zeigt eine geringere Stressreaktion und weist auf einen Lerneffekt der Pferde hin:
Entsprechend der relativen Instabilitäten der Regulation der Körperfunktionen in Messphase 2 und 3 konnten die Pferde in vier Stressregulationstypen (nach Balzer u. Hecht 1996) eingeteilt werden: Stressbeherrscher, -bewältiger und kompensierer sowie Stressnichtbewältiger.
Anhand der Aktivierung von Sympathikus und Parasympathikus konnten zusätzlich vier verschiedene Vegetative Stresstypen unterschieden werden: Sympathikotoniker, Amphotoniker, Indifferenter Typ und Vagotoniker.
Die Cortisolreaktion der Hengste war individuell sehr unterschiedlich. Um die maximalen Anstiege vergleichen zu können, wurde der Trend der jeweiligen Cortisolverlaufskurve bestimmt. Anhand der Trend-korrigierten Cortisolkurven konnten einerseits die relativen Maxima der Cortisolreaktion besser verglichen werden, anderseits konnten die Pferde mittels des unterschiedlichen Trendes in drei Cortisolverlaufsgruppen eingeteilt werden: Tendenz fallend, gleichbleibend oder steigend.
Ein statistischer Nachweis für eine Abhängigkeit zwischen den verschiedenen Stresstypenklassifizierungen konnte anhand der geringen Stichprobenzahl nicht erbracht werden. Jedoch lassen sich Pferde, wie Menschen, unterschiedlichen Stresstypen zuordnen. Schwierig bleibt aber die objektive Beurteilung von Befindlichkeiten, da Empfindungen und Gefühle nur subjektiv wahrnehmbare Qualitäten sind, die von einer Reihe innerer und äußerer Faktoren abhängen. Die Verhaltenszuordnung emotionaler Zustände durch die „Chronopsychobiologische Regulationsdiagnostik“ (CRD) kann nicht ohne die Basis weiterer vergleichender Studien vom Mensch auf das Pferd übertragen werden.
Die CRD-Methode könnte allerdings einen interdisziplinären Ansatz ermöglichen und zukünftig neben den klassischen deskriptiven Verhaltensbeobachtungen bei der Beurteilung von Haltungs- und Umgangssituationen von Tieren wertvolle Aufschlüsse über die Fähigkeit zur Stressbewältigung und deren Konsequenzen für das Wohlbefinden der Tiere geben.
In this study we examined, whether the “Chronopsychobiological regulation diagnosis” (CRD) with the smardwatch®-system which is used to assess specific strain in humans, is also able to reflect convincingly specific strain in horses. Humans can be categorized into so-called stress types, because they react differently in physiology and behaviour to environmental stimuli. Concerning horses, it is also known that individuals react differently in identical situations. The question to be answered is, if it is possible to categorize horses into certain stress types as well.
We carried out a behavioural test with 26 three-year-old stallions of the State Stud of Celle, involving different test situations. On the basis of test situations, well known in scientific literature including slight modifications (open-field-test, novel-object-test, startling-test object/sound, human-horse-interaction, resource control) the explorative and flight behaviour of horses were examined (Goslar 2011). During these situations of strain the system smardwatch® measured the electro-physiological parameters skin resistance, skin potential and muscle activity. With time series analyses of these physiological parameters the reactions of the vegetative nervous system as superior control could be shown. The skin resistance reflects the vegetative-emotional, the skin potential the vegetative-nervous hence according to Balzer (2009) cognitive reactions and the electromyogram shows the motorized reactions. The time series of measured data was analyzed using the biorhythmometrical time series analysis of Balzer and Hecht (Hecht 2001, Balzer 2009). As a result of this, typical states of chronobiological regulation were defined. With the help of the “periodic system of regulatory states” (PSR) (Balzer 2000) these led to a classification of mental stress situations. To categorize horses into stress types the study was devided into three phases according to the stimulus-response principle: phase 1 (relaxing), phase 2 (situation of strain) and phase 3 (stimulus processing phase). The behavioural test was repeated once with each stallion exactly one week later. In addition ten samples of saliva were taken before, during and after the situations of strain from which we determined the cortisol concentration to be compared with the chronopsychobiological parameters.
The smardwatch®-measurement technology is fundamentally suitable to measure the physiological parameters skin resistance, skin potential and electrical muscle activity of horses. Using the biorhythmometrical time series analysis, chronobiological regulatory states could be defined for horses as well.
For each horse the cortisol value increased significantly during the behavioural test. A remarkable difference of the cortisol values assessed in the first and second test, indicates a learning effect: The behavioural test led to a significantly lower stress reaction in the second week.
Depending on the proportions of unstable regulation processes during and after the situations of strain, four types of regulation (Balzer u. Hecht 1996) can be defined: the Control-, Cope-, Compensate- and Non-cope-type.
Using the activation of the sympathetic and parasympathetic nervous system four vegetative stress types could be determined: Sympathicotonic, Amphotonic, Indifferent Type and Vagotonic.
The stress reaction of the stallions in terms of cortisol level was quite individual. To compare the maximum increase the trend of each cortisol trajectory was analyzed. On the one hand correcting for the trend allowed a comparison of relative maxima, on the other hand the horses could be categorized into groups, according to the evolution of their cortisol level (cortisol progression groups): Tendency falling, stable or rising.
The number of samples was not considered to be sufficient in order to statistically assess some dependence among the different classifications of stress types. But to our point of view horses can be assigned to different stress types like humans. But it’s still difficult to judge the emotions of animals, because emotions are subjectively perceptible qualities dependent on many internal and external factors. The assignment of emotional behaviour to the chronopsychobiological regulation diagnosis (CRD) can’t be transferred from human to horse without further studies.
However, the CRD method could enable an interdisciplinary approach. Besides classic descriptive observations of behavior, the CRD could give further information about the coping capacity and the consequences for animal welfare in the assessment of stressful situations.

Abstract: Horses provide an interesting animal model to test short- and long-term effects of the paternal influence on the offspring under natural conditions. As a highly social animal, horse naturally is living in long-term harem groups building strong familiar bonds. Arguing that the environment of a juvenile is highly important for the development of cognitive and social functions as well as for the emotional competence, a future study on domestic horses wants to highlight the paternal influence on the offspring as well as special effects of the stallion during the first two years of the foals´ life. Nowadays, in most husbandry systems it is still common to keep the stallions separated, raising the offspring in an intact harem group is very rare. The aim of this study is to describe the role of the stallion in the early development of the foal in an extensive pasture management system living in natural harem groups. Results are going to be compared to findings of studies on groups without the male present in the rearing phase. A precise behavioural analysis is planned; direct behavioural observations are going to be supported by long-term and continuously activity measures by special telemetry collar systems. Additional physiological measures should give evidence of the investment of the stallion. The young horses will be confronted with different tests of cognitive and social abilities (exploration behaviour, fear behaviour, play behaviour). The results of this study will contribute to fundamental research in the behaviour of the horse and might display an important step to animal welfare in modern horse husbandry. It will be possible to set a time-frame in which the male does have positive influence on the offspring and therefore should be kept with the family. A detailed knowledge of the influence of the male to cognitive and social abilities could as well be applicable in the training of horses and therefore be of great importance in equestrian sports.

Abstract: Assessing the animal welfare state is a challenge given the subjective individual cognitive and emotional processing involved. Electroencephalography (EEG) spectrum analysis has proved an ecologically valid recording situation to assess the link between brain processes and affective or cognitive states in humans: a higher slow wave/fast wave ratio has been associated with a positive internal state. In particular, a high production of theta power (3-8 Hz) has been related to positive emotions. On the other hand, it has been hypothesized that a left hemisphere (LH) dominance may be associated with a better welfare state. Here, we test the hypothesis that individual differences in the resting-state quantitative EEG power spectrum of adult horses (N = 18) and its lateralization pattern may reflect individual subjective perception of their conditions of life and welfare state. The results show clear individual differences in the proportions of the different waves and their inter-hemispheric distribution. Three different EEG power spectrum profiles were highlighted, from a bilateral predominance of theta waves in horses in a more positive welfare state to a bilateral predominance of beta waves in horses with clear expressions of compromised welfare. Interestingly, particular correlations were found between wave power activity and welfare parameters. We found a negative correlation between the number of stereotypic behaviours per hour and the median proportion of theta waves in the left hemisphere. and between the overall state (total chronic stress score) of welfare and gamma production in the right hemisphere (RH). These findings go along the hypothesis of a particular involvement of the left hemisphere for positive processing and of the right hemisphere for negative processing. However, the pattern of laterality did not appear as the most important feature here as both extreme clusters in terms of welfare showed bilateral predominance of one wave type. It is possible that hemispheric specialization makes more sense during acute emotion-inducing conditions rather than in this resting-state context (i.e. in absence of any high emotion-inducing stimulation), although the opposition gamma versus theta waves between both hemispheres in the horses with an intermediate welfare state is noticeable and intriguing. It seems that bilateral but also LH theta activity is a promising neurophysiological marker of good welfare in horses, while a bilateral or RH high production of gamma waves should alert about potential welfare alterations. Quantitative resting-state EEG power spectrum appears as a highly promising tool for exploring the brain processes involved in the subjective perception of chronic welfare, as a useful complementary tool for welfare assessment.