Kedzierski, W., Wilk, I., & Janczarek, I. (2014). Physiological response to the first saddling and first mounting of horses: comparison of two sympathetic training methods. Animal Science Papers and Reports, 32(3), 219–228.
Abstract: There is not much research done on the influence of sympathetic training on the emotional reaction
of horses. The aim of the present study was to evaluate the emotional response and the stress level
in horses to two sympathetic training methods: (1) with the use of the “round pen technique” (RP),
and (2) in which the RP was not applied (SH). Twenty two half-bred Anglo-Arab horses (2.5
years ±3 months of age) were subject to an initial training. Eleven horses were randomly included
to the RP method and the other 11 horses for the SH method. Heart rate (HR) and saliva cortisol
concentration were measured as indicators of horse emotional arousal and stress level, respectively.
The HR values were analysed: at rest, during the habituation period, just after the first saddling
and tightening of the girth, during the first time a human leaned over the horse’s back, and during
the mounting of the horse. Saliva samples were taken before and 15 min after each training session
studied. After saddling, the HR occurred significantly higher when the RP technique was used. The
significant increase in saliva cortisol concentration was observed only after the first mounting of
the horse. Generally, the use of the RP technique did not involve more important physiological
reactions in the trained horses than did the SH method.
|
Kristjansson, T., Bjornsdottir, S., Sigurdsson, A., Andersson, L. S., Lindgren, G., Helyar, S. J., et al. (2014). The effect of the ‘Gait keeper’ mutation in the DMRT3 gene on gaiting ability in Icelandic horses. J. Anim. Breed. Genet., , n/a-n/a.
Abstract: A nonsense mutation in DMRT3 (‘Gait keeper’ mutation) has a predominant effect on gaiting ability in horses, being permissive for the ability to perform lateral gaits and having a favourable effect on speed capacity in trot. The DMRT3 mutant allele (A) has been found in high frequency in gaited breeds and breeds bred for harness racing, while other horse breeds were homozygous for the wild-type allele (C). The aim of this study was to evaluate further the effect of the DMRT3 nonsense mutation on the gait quality and speed capacity in the multigaited Icelandic horse and demonstrate how the frequencies of the A- and C- alleles have changed in the Icelandic horse population in recent decades. It was confirmed that homozygosity for the DMRT3 nonsense mutation relates to the ability to pace. It further had a favourable effect on scores in breeding field tests for the lateral gait tölt, demonstrated by better beat quality, speed capacity and suppleness. Horses with the CA genotype had on the other hand significantly higher scores for walk, trot, canter and gallop, and they performed better beat and suspension in trot and gallop. These results indicate that the AA genotype reinforces the coordination of ipsilateral legs, with the subsequent negative effect on the synchronized movement of diagonal legs compared with the CA genotype. The frequency of the A-allele has increased in recent decades with a corresponding decrease in the frequency of the C-allele. The estimated frequency of the A-allele in the Icelandic horse population in 2012 was 0.94. Selective breeding for lateral gaits in the Icelandic horse population has apparently altered the frequency of DMRT3 genotypes with a predicted loss of the C-allele in relatively few years. The results have practical implications for breeding and training of Icelandic horses and other gaited horse breeds.
|
Krueger, K. (2014). “Pferdehaltung und Ethologie der Pferde” im Bachelorstudiengang Pferdewirtschaft. In : S. Lepp und C. Niederdrenk-Felgner (Ed.), Forschendes Lernen initiieren, umsetzen und reflektieren (pp. 54–81). Bielefeld: UniversitätsVerlag Webler.
|
Krueger, K. (2014). Die Bedeutung der Schiefe, Händigkeit und sensorische Lateralität der Pferde. In Pferdetage Baden-Württemberg 2014. Stuttgart: Matthaes Medien.
|
Krueger, K., & Koenig von Borstel, U. (2014). Grundlagen der Sinneswahrnehmung von Pferden. In Deutsche Reiterliche Vereinigung e.V. (Ed.), Pferde verstehen – Umgang und Bodenarbeit (pp. 38–54). Warendorf: FN Verlag der deutschen Reiterlichen Vereinigung GmbH.
|
Krueger, K., Farmer, K., & Heinze, J. (2014). The effects of age, rank and neophobia on social learning in horses. Anim. Cogn., 17(3), 645–655.
Abstract: Social learning is said to meet the demands of complex environments in which individuals compete over resources and co-operate to share resources. Horses (Equus caballus) were thought to lack social learning skills because they feed on homogenously distributed resources with few reasons for conflict. However, the horse’s social environment is complex, which raises the possibility that its capacity for social transfer of feeding behaviour has been underestimated. We conducted a social learning experiment using 30 socially kept horses of different ages. Five horses, one from each group, were chosen as demonstrators, and the remaining 25 horses were designated observers. Observers from each group were allowed to watch their group demonstrator opening a feeding apparatus. We found that young, low ranking, and more exploratory horses learned by observing older members of their own group, and the older the horse, the more slowly it appeared to learn. Social learning may be an adaptive specialisation to the social environment. Older animals may avoid the potential costs of acquiring complex and potentially disadvantageous feeding behaviours from younger group members. We argue that horses show social learning in the context of their social ecology, and that research procedures must take such contexts into account. Misconceptions about the horse’s sociality may have hampered earlier studies.
|
Krueger, K., Flauger, B., Farmer, K., & Hemelrijk, C. (2014). Movement initiation in groups of feral horses. Behav. Process., 103, 91–101.
Abstract: Abstract Herds of ungulates, flocks of birds, swarms of insects and schools of fish move in coordinated groups. Computer models show that only one or very few animals are needed to initiate and direct movement. To investigate initiation mechanisms further, we studied two ways in which movement can be initiated in feral horses: herding, and departure from the group. We examined traits affecting the likelihood of a horse initiating movement i.e. social rank, affiliative relationships, spatial position, and social network. We also investigated whether group members join a movement in dominance rank order. Our results show that whereas herding is exclusive to alpha males, any group member may initiate movement by departure. Social bonds, the number of animals interacted with, and the spatial position were not significantly associated with movement initiation. We did not find movement initiation by departure to be exclusive to any type of individual. Instead we find evidence for a limited form of distributed leadership, with higher ranking animals being followed more often.
|
Krueger, K., & Koenig von Borstel, U. (2014). Wie Pferde lernen. In Deutsche Reiterliche Vereinigung e.V. (Ed.), Pferde verstehen – Umgang und Bodenarbeit (pp. 56–82). Warendorf: FN Verlag der deutschen Reiterlichen Vereinigung GmbH.
|
Kruska, D. C. T. (2014). Comparative quantitative investigations on brains of wild cavies (Cavia aperea) and guinea pigs (Cavia aperea f. porcellus). A contribution to size changes of CNS structures due to domestication. Mamm Biol, 79(4), 230–239.
Abstract: Intraspecific allometric calculations of the brain to body size relation revealed distinct differences between 127 (67; 60) ancestral wild cavies and 82 (37; 45) guinea pigs, their domesticated relatives. The dependency of both measures from one another remained the same in both animal groups but the brains of guinea pigs were by 14.22% smaller at any net body weight. Consistent with results in other species the domestication of Cavia aperea is also characterized by a decrease of brain size. Fresh tissue sizes of the five brain parts medulla oblongata, cerebellum, mesencephalon, diencephalon and telencephalon were determined for 6 cavies and 6 guinea pigs by the serial section method. Additionally the sizes of 16 endbrain structures and those of the optic tract, the lateral geniculate body and the cochlear nucleus were measured. Different decrease values resulted for all these structures concomitant with domestication as was calculated from the amount of total brain size decrease and average relative structure values in the wild as well as the domesticated brain. The size decrease of the entire telencephalon (-13.7%) was within the range of the mean overall reduction as similarly was the case for the total neocortex (-10.7%) whereas the total allocortex (-20.9%) clearly was more strongly affected. The size decrease of the olfactory bulb (-41.9%) was extreme and clearly higher than found for the secondary olfactory structures (around -11%). The primary nuclei of other sensory systems (vision, audition) were decreased to less extent (lateral geniculate: -18.1%; cochlear nucleus: -12.6%). Mass decreases of pure white matter parts were nearly twice as high in contrast to associated grey matter parts (neocortex white versus grey matter; tractus opticus versus lateral geniculate body). The relatively great decrease values found for the limbic structures hippocampus (-26.9%) and schizocortex (-25.9%) are especially notable since they are in good conformity with domestication effects in other mammalian species. The findings of this study are discussed with regard to results of similar investigations on wild and domesticated gerbils (Meriones unguiculatus), the encephalization of the wild form, the special and species-specific mode and duration of domestication and in connection with certain behavioral changes as resulted from comparative investigations in ethology, socio-biology, endocrinology and general physiology.
|
Kundey, S. M. A., Delise, J., Los Reyes, A., Ford, K., Starnes, B., & Dennen, W. (2014). Domestic dogs’ (Canis familiaris) choices in reference to information provided by human and artificial hands. Anim. Cogn., 17(2), 259–266.
Abstract: ven young humans show sensitivity to the accuracy and reliability of informants’ reports. Children are selective in soliciting information and in accepting claims. Recent research has also investigated domestic dogs’ (Canis familiaris) sensitivity to agreement among human informants. Such research utilizing a common human pointing gesture to which dogs are sensitive in a food retrieval paradigm suggests that dogs might choose among informants according to the number of points exhibited, rather than the number of individuals indicating a particular location. Here, we further investigated dogs’ use of information from human informants using a stationary pointing gesture, as well as the conditions under which dogs would utilize a stationary point. First, we explored whether the number of points or the number of individuals more strongly influenced dogs’ choices. To this end, dogs encountered a choice situation in which the number of points exhibited toward a particular location and the number of individuals exhibiting those points conflicted. Results indicated that dogs chose in accordance with the number of points exhibited toward a particular location. In a second experiment, we explored the possibility that previously learned associations drove dogs’ responses to the stationary pointing gesture. In this experiment, dogs encountered a choice situation in which artificial hands exhibited a stationary pointing gesture toward or away from choice locations in the absence of humans. Dogs chose the location to which the artificial hand pointed. These results are consistent with the notion that dogs may respond to a human pointing gesture due to their past-learning history.
|