| Home | << 1 2 3 4 5 6 7 8 9 10 >> [11–20] |
|
Polley, L. (1986). Strongylid parasites of horses: experimental ecology of the free-living stages on the Canadian prairie. Am J Vet Res, 47(8), 1686–1693.
Abstract: Each month for a 1-year period (October through September), equine fecal masses containing eggs of strongylid nematodes were placed outdoors on small grass plots in Saskatchewan, Canada. Thereafter, feces and grass from the plots were sampled after intervals of 1 week or longer, and the strongylid eggs and larvae recovered were counted. These observations were made over a 2-year period. Development of eggs to infective larvae occurred in all experiments, except those established in October, December, and January. Infective larvae from experiments set up in April through September survived that winter. During the summer, there was a gradual build up of infective larvae in the fecal masses, which reached a peak in August and September and then decreased into the winter. These results are discussed in the context of the control of strongylid parasites of horses on the Canadian prairie and in other areas of the world with a similar climate and similar horse management practices.
|
|
Herholz, C. P., Gerber, V., Tschudi, P., Straub, R., Imhof, A., & Busato, A. (2003). Use of volumetric capnography to identify pulmonary dysfunction in horses with and without clinically apparent recurrent airway obstruction. Am J Vet Res, 64(3), 338–345.
Abstract: OBJECTIVE: To investigate whether volumetric capnography indices could be used to differentiate between horses without recurrent airway obstruction (RAO) and horses with RAO that were in clinical remission or that had clinically apparent RAO. ANIMALS: 70 adult Swiss Warmblood horses (20 used for pleasure riding and 50 used for dressage or show jumping). PROCEDURE: Horses were allocated to 4 groups on the basis of history, clinical signs, results of endoscopy, and cytologic findings (group 1, 21 healthy horses; group 2, 22 horses with RAO that were in remission; group 3, 16 horses with mild RAO; group 4, 11 horses with exacerbated RAO). Expiratory volume and CO2 curves were recorded by use of a computerized ultrasonic spirometer. Volumetric capnograms were plotted, and derived indices were calculated. RESULTS: Dead-space volume (VD) was calculated by use of the Bohr equation (VD(Bohr)) and for physiologic VD (VD(phys)). Ratios for VD(Bohr) to expiratory tidal volume (VT) and VD(phys) to V(T) as well as an index of effective CO2 elimination were significantly different among groups of horses. Age and use of the horses also significantly affected volumetric capnography indices. CONCLUSIONS AND CLINICAL RELEVANCE: Ratios of VD(Bohr) to VT and VD(phys) to VT as well as an index of effective CO2 elimination were sufficiently sensitive measures to distinguish between healthy horses and horses with RAO in remission. To optimize the ability of volumetric capnography indices to differentiate among horses in heterogeneous populations, it is important to account for effects of age and specific use of the horses.
|
|
Grafner, G., Zimmermann, H., Karge, E., Munch, J., Ribbeck, R., & Hiepe, T. (1976). [Incidence and damages inflicted by simuliid flies in the GDR district of Schwerin]. Angew Parasitol, 17(1), 2–6.
Abstract: Systematic faunal studies in the district Schwerin showed at the present time there are 3 more or less damage-biotopes existing in the districts of Perleberg, Ludwigslust and Parchim; 5 river sources can be considered as potential sources, 5 are temporary and 2 are ephemeral whilst in 3 further areas environmental influences such as effluent impairs the flow of the river and the developmental stages of Simuliidae were not observed.--The following species were found: Boophthora erythrocephala, Wilhelmia salopiensis, Wilhelmia equina, Odagmia ornata, Eusimulium aureum and Eusimulium lundstroemi.--The damage statistics covering the period 1966--1971 showed in the district of Schwerin, due to Simuliid attacks, 38 cattle died, 170 were seriously ill; in 1967 5 horses were seriously ill; in 1971, 3 pigs died and 27 were seriously ill.--The symptoms were manifested by pathological petechiae, scabs and oedema, also by insufficiency of the heart and circulatory system, diminished performance and growth disturbance. In severe cases heart and circulation failure occurred, paresis, coma and death followed.--The real economic significance of the Simuliid attacks rest with its strong and prolonged distrubance in young animals, as well as in pronounced irreparable diminished performance in diseased dairy cattle.
|
|
KOIZUMI, R., MITANI, T., UEDA, K., & KONDO, S. (2017). Skill reading of human social cues by horses (Equus caballus) reared under year-round grazing conditions. Animal Behaviour and Management, 53(2), 69–78.
Abstract: Animals use communicative signals, such as gesture or gaze, to communicate to someone the intention or expression of the sender, which is called social cue. In the previous studies, it was suggested the skill of reading human social cue in domestic animals are influenced to the domestication, the experience contacting with human and training to obey human. In this present study, we tested the skill for horses (Equus caballus) kept in year-round grazing conditions using 33 horses differed from breed and the degree of the experience with human by object-choice task subjects choosing either of bait boxes located at the end of experimenter. As results, non-socialized horses hardly responded to human social cues. Habituated horses that were both of trained and untrained responded to human social cues, but their accuracy rates were not more than 50% except for two trained subjects. For the skill of reading human social cues, there was high individual variation in responding to human social cues in horses kept in year-round grazing conditions. The individual characteristics influenced to it more than domestication, the experience with human, and training to obey human.
|
|
Hopkins, W. D., Taglialatela, J. P., & Leavens, D. A. (2007). Chimpanzees differentially produce novel vocalizations to capture the attention of a human. Anim. Behav., 73(2), 281–286.
Abstract: Chimpanzees, Pan troglodytes, produce numerous species-atypical signals when raised in captivity. We examined contextual elements of the use of two of these vocal signals, the `raspberry' and the extended grunt. Our results demonstrate that these vocalizations are not elicited by the presence of food, but instead function as attention-getting signals. These findings reveal a heretofore underappreciated category of animal signals: attention-getting sounds produced in novel environmental circumstances. The invention and use of species-atypical signals, considered in relation to group differences in signalling repertoires in apes in their natural habitats, may index a generative capacity in these hominoid species without obvious corollary in other primate species.
Keywords: acoustic signals; chimpanzee; cognition; Pan troglodytes; vocal communication
|
|
Beecher, M. D., Burt, J. M., O'Loghlen, A. L., Templeton, C. N., & Campbell, S. E. (2007). Bird song learning in an eavesdropping context. Anim. Behav., 73(6), 929–935.
Abstract: Bird song learning is a major model system for the study of learning with many parallels to human language development. In this experiment we examined a critical but poorly understood aspect of song learning: its social context. We compared how much young song sparrows, Melospiza melodia, learned from two kinds of adult `song tutors': one with whom the subject interacted vocally, and one whom the subject only overheard singing with another young bird. We found that although subjects learned from both song models, they learned more than twice as many songs from the overheard tutor. These results provide the first evidence that young birds choose their songs by eavesdropping on interactions, and in some cases may learn more by eavesdropping than by direct interaction.
|
|
Palagi, E. (2008). Sharing the motivation to play: the use of signals in adult bonobos. Anim. Behav., 75(3), 887–896.
Abstract: Gestures and facial displays are involved in regulating many aspects of mammal social life such as aggression, dominance-subordinate relationships, appeasement and play. Playful activity is an interesting behaviour for examining the role of signals as intentional communication systems. When animals play they perform patterns that are used in other serious contexts. To avoid miscommunication, many species have evolved signals to maintain a playful mood. Bonobos, Pan paniscus, with their flexible social relationships and playful propensity, may represent a good model species to test some hypotheses on adult play signalling. I analysed the potential roles of facial play expressions and solitary play in soliciting and regulating social play and found that adult bonobos used the play face (relaxed open-mouth display) in a selective manner. Play faces were more frequent during social than solitary play and, within social play, polyadic sessions (even though less frequent than dyadic sessions) were characterized by a higher frequency of signals. Following the rule of play intensity matching, play faces were more frequent when the two players matched in age and size (sessions among adults). Moreover, among dyads there was a positive correlation between the frequency of aggressive interactions performed and the frequency of play signals used, thus suggesting that signals are crucial in play negotiations among individuals showing high baseline levels of aggression. Finally, solitary play, especially when it involved pirouettes and somersaults, had an important role in triggering social play.
|
|
Jonart, L. M., Hill, G. E., & Badyaev, A. V. (2007). Fighting ability and motivation: determinants of dominance and contest strategies in females of a passerine bird. Anim. Behav., 74(6), 1675–1681.
Abstract: The communication of aggressive motivation or fighting ability has important fitness consequences for competing animals. Selection should favour rapid and honest communication between opponents to settle dominance relationships while avoiding prolonged and intense fighting. We investigated factors that influence fighting strategies and contest outcomes in female house finches, Carpodacus mexicanus, specifically focusing on the following questions. (1) What social contexts trigger an aggressive response? (2) Does body size and condition contribute to female fighting ability? (3) Do contextual factors, such as mate presence, nest status, nest proximity, and site experience contribute to fighting motivation? (4) Does contest intensity and duration increase as the differences in fighting ability between opponents decrease? (5) What is the relative contribution of fighting ability and aggressive motivation to the outcome of a contest? We found that aggression was triggered most frequently by female intrusions in the vicinity of nest and by extrapair female intrusions on an established pair. Female fighting and contest outcomes were strongly influenced by body condition and body size, and females were more motivated to initiate fights and won more contests when their mates were present. Females at the later breeding stages and those fighting closer to their nests were dominant and won more fights compared to females at earlier breeding stages or further from their nests. Females initiated a greater proportion of contests against opponents with similar local familiarity and breeding history. Escalated and prolonged contests, while rare, occurred exclusively between females of the most similar body size and condition. When differences in body condition between opponents are not easily perceived, contestants might escalate contests for more reliable assessments of relative fighting ability. Finally, body condition was not a strong determinant of contest outcome in the contexts with easily assessed differences in the resource value (e.g. mate presence), but without these motivational differences, body condition was the ultimate determinant of contest outcomes.
|
|
Scordato, E. S., & Drea, C. M. (2007). Scents and sensibility: information content of olfactory signals in the ringtailed lemur, Lemur catta. Anim. Behav., 73(2), 301–314.
Abstract: The function of olfactory signalling in social species is less well understood than in asocial species. Consequently, we examined olfactory communication in the ringtailed lemur, a socially complex primate that retains a functional vomeronasal organ, has well-developed scent glands and shows a suite of scent-marking behaviour. To assess the information content of different types of scent gland secretions, we decoupled olfactory cues from the visual and behavioural modalities with which scent marking is normally associated. We presented male and female subjects (signal receivers) with a series of choice tests between odours derived from conspecific donors (signal senders) varying by sex, age, social status and reproductive condition. We additionally examined the influence of the receivers' reproductive state and familiarity with the signaller. The reproductive condition, social status and familiarity of senders and receivers affected signal transmission; specifically, male receivers attended most to the odours of conspecifics in breeding condition and to the odours of familiar, dominant animals. By contrast, females varied their responses according to both their own reproductive state and that of the sender. Based on male and female patterns of countermarking, we suggest that scent marking serves a function in intergroup spacing and intrasexual competition for both sexes, as might be expected in a female-dominant species. By contrast, minimal female interest in male odours counters a female mate choice function for scent marking in this species. Nevertheless, scent marks are critical to male-male competition and, therefore, may be subject to sexual selection.
|
|
Udell, M. A. R., Dorey, N. R., & Wynne, C. D. L. (2008). Wolves outperform dogs in following human social cues. Anim. Behav., 76(6), 1767–1773.
Abstract: Domestic dogs, Canis familiaris, have been shown capable of finding hidden food by following pointing gestures made with different parts of the human body. However, previous studies have reported that hand-reared wolves, C. lupus, fail to locate hidden food in response to similar points in the absence of extensive training. The failure of wolves to perform this task has led to the proposal that the ability to understand others' intentions is a derived character in dogs, not present in the ancestral population (wolves). Here we show that wolves, given the right rearing environment and daily interaction with humans, can use momentary distal human pointing cues to find food without training, whereas dogs tested outdoors and dogs at an animal shelter do not follow the same human points. In line with past studies, pet dogs tested indoors were successful in following these points. We also show that the reported failure of wolves in some past studies may be due to differences in the testing environment. Our findings indicate that domestication is not a prerequisite for human-like social cognition in canids, and show the need for additional research on the role of rearing conditions and environmental factors in the development of higher-level cognitive abilities.
|