Abstract: Finding the right horse for each rider is a difficult task as it is just as important that the temperament of the horse fits the rider as it is that the horse is of the right size. Even though it is a commonly experienced problem, no objective method of easily measuring the horse“s temperament has yet been developed. If it is possible to test horses and get an objective measure of how reactive (emotional) they are, it could be a big help in finding the right horse for each rider. It would be desirable to have a way of testing the horse”s reaction in an unfamiliar (and potentially frightening) situation. In practice this test should be just as easy as it is getting a judgement of its conformation and gaits.
The aim of the present study was to measure individual variation in HR response to different novel objects in horses of the same age, breed and reared in the same environment. We wanted to see whether certain horses (i.e. more emotional horses) react more to novel stimuli, in general, than other horses (i.e. less emotional), irrespective of the type of stimulus. We also wanted to see if different novel stimuli elicited different responses within individuals. The hypothesis was that individuals will react in a similar way to various stimuli.
Twenty four Danish warmblood horses were included in this study. All horses were 2 year-old stallions, reared under similar environmental conditions. They had received a minimum of handling prior to the experimental period. Three different stimuli were used. They were chosen because they were novel to the horses and would elicit measurable fear-reactions in all horses, but not so much that the horses did not approach the feed within the duration of the test. The visual stimulus consisted of a 1meter high orange traffic cone with reflex stripes, placed 1 m in front of the tub, the olfactory stimulus was eucalyptus oil and the auditory stimulus was a radio tuned to white noise. The control was an empty arena.
The result was that only the HR response to the auditory and visual stimuli differed significantly from the control days. The olfactory stimulus did not seem to alarm the horses the way the other stimuli did. We found a tendency towards a correlation in reaction between the olfactory and auditory stimuli and between the auditory and visual stimuli within individuals. These results indicate that horses do not generalize completely in their reaction between different stimuli.

Abstract: This thesis focuses on the relationship between innovation and social learning in the foraging context, across and within bird species, using two different sources of data: anecdotal reports from the literature, and experimental tests in the laboratory and the field. In chapter 1, I review the trends in innovation and social learning in the avian literature, and contrast them with trends in mammals, especially primates. In chapter 2, I use anecdotal reports of feeding innovation and social learning in the literature to assess taxonomic trends and to study the relationship between the two traits at the interspecific level. In chapter 3, I investigate the relationship between innovation and social learning at the intraspecific level in captive feral pigeons (Columba livia). Innovation is estimated from the ability to solve an innovative foraging problem, and social learning is measured as the number of trials required to learn a foraging task from a proficient demonstrator. (Abstract shortened by UMI.)

Abstract: In der praktischen Pferdefütterung kommen regelmäßig Substanzen zum Einsatz, die
einen erheblichen Einfluss auf den Säure-Basen-Haushalt ausüben. Andererseits können
Manipulationen des Säure-Basen-Haushaltes in der Diätetik erwünscht sein, z.B. bei
Harnsteinen oder hyperkaliämischer periodischer Paralyse. Verschiebungen im Säure-
Basen-Gleichgewicht treten – unabhängig von der Fütterung – außerdem bei starker
körperlicher Aktivität auf, eine eventuelle Prophylaxe durch die Ernährung wird
ebenfalls diskutiert. Der Einfluss der Fütterung auf den Säure-Basen-Haushalt ist beim
Pferd bisher nur wenig und nicht systematisch untersucht, während sich viele Arbeiten
mit dem Effekt körperlicher Belastung beschäftigen. Analogieschlüsse zu anderen
Spezies müssen äußerst vorsichtig betrachtet werden, da die Absorption von am Säure-
Basen-Haushalt beteiligten Substanzen beim Pferd Unterschiede zu anderen Spezies
aufweist (Meyer, 1982).
In der vorliegenden Untersuchung sollte daher der Effekt von verschiedenen Chloriden
(Natriumchlorid, Kalziumchlorid, Ammoniumchlorid) auf den Säure-Basen-Haushalt bei
Ponys geprüft werden. In den ersten Versuchsdurchgängen wurden für Kleinpferde im
Erhaltungsstoffwechsel für diesen Zweck Rationen mit sehr hohen Heuanteilen
verwendet. Trotz hoher Dosen des bei verschiedenen Spezies stark säuernden
Ammoniumchlorids traten bei den Ponys nur relativ kleine Effekte auf. Bei der weiteren
Durchsicht des Schrifttums fiel auf, dass Einzelbeobachtungen zu stark säuernden
Effekten nur bei Rationen mit hohem Anteil an Kraftfutter und geringem Anteil an
Rauhfutter auftraten. Daher wurde der Effekt von Ammoniumchlorid auf einer stark
kraftfutterhaltigen Ration nochmals überprüft.