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Sullivan, K. A., Hill, A. E., & Haussler, K. K. (2008). The effects of chiropractic, massage and phenylbutazone on spinal mechanical nociceptive thresholds in horses without clinical signs. Equine Vet J, 40(1), 14–20.
Abstract: REASON FOR PERFORMING STUDY: Common methods used to treat back problems in horses need to be assessed objectively. OBJECTIVES: To measure spinal mechanical nociceptive thresholds (MNTs) and evaluate the effects of chiropractic, massage and phenylbutazone, compared with active and inactive control groups. METHODS: Baseline MNTs at 7 sites within the thoracolumbar and sacral regions were measured in 38 healthy mature horses exhibiting no clinical signs of lumbar pain. Horses were assigned to one of 3 treatment groups: instrument-assisted chiropractic treatment, therapeutic massage and phenylbutazone; or 2 control groups: ridden exercise (active control) or routine paddock turnout with no ridden exercise (inactive control). MNT measurements were repeated at 1, 3 and 7 days post treatment. The percentage change from baseline MNT values was calculated within groups. RESULTS: On Day 7, the median MNT had increased by 27, 12 and 8% in the chiropractic, massage and phenylbutazone groups, respectively. MNT changes of <1% were seen within the active and inactive control groups. CONCLUSIONS: Chiropractic treatment and massage therapy increased spinal MNTs within horses not exhibiting signs of lumbar pain. POTENTIAL RELEVANCE: Pressure algometry provides an objective tool to evaluate the effects of commonly used, but currently unproven treatment modalities on spinal MNTs. Future studies need to evaluate combined treatment effects and longer-term MNT changes in horses with documented back pain.
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O'Grady, S. E. (2008). Basic farriery for the performance horse. Vet Clin North Am Equine Pract, 24(1), 203–218.
Abstract: Proper farriery promotes a healthy functional foot and biomechanical efficiency and prevents lameness. Because the equine veterinarian is responsible for the soundness of the horse, a working knowledge of farriery becomes essential. A thorough knowledge of traditional horseshoeing enables the veterinarian to interact with the farrier at the farrier's level; this ultimately enhances and promotes quality hoof care. This article focuses on fundamental farriery and recognizing subtle changes in hoof conformation that can be used to preserve the integrity of the hoof capsule, along with the structures enclosed within, and thus prevent lameness in the performance horse.
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Weishaupt, M. A. (2008). Adaptation strategies of horses with lameness. Vet Clin North Am Equine Pract, 24(1), 79–100.
Abstract: The skill to diagnose lameness in horses is paramount for every equine practitioner. Early recognition of locomotor deficiencies plays a central role in sports medicine management, preventing deterioration of the disease or catastrophic injuries. Horses use characteristic compensatory movements of specific body parts to decrease loading of the affected limb. This article describes the underlying changes in intra- and interlimb coordination and the resulting load redistribution between the limbs. This enables the practitioner to better understand the changes in movement associated with lameness.
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Charif, R. A., Waack, A. M., & Strickman, L. M. (2008). Raven Pro 1.3 User's Manual. Ithaca, New York: Cornell Laboratory of Ornithology.
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Christensen, J. W., Malmkvist, J., Nielsen, B. L., & Keeling, L. J. (2008). Effects of a calm companion on fear reactions in naive test horses. Equine Vet J, 40(1), 46–50.
Abstract: REASON FOR PERFORMING STUDY: In fear-eliciting situations, horses tend to show flight reactions that can be dangerous for both horse and man. Finding appropriate methods for reducing fearfulness in horses has important practical implications. OBJECTIVES: To investigate whether the presence of a calm companion horse influences fear reactions in naive subject horses. HYPOTHESES: The presence of a habituated (calm) companion horse in a fear-eliciting situation can reduce fear reactions in naive subject horses, compared to subject horses with a nonhabituated companion (control). METHODS: Minimally handled (n = 36), 2-year-old stallions were used, 18 as subjects and 18 as companions. Companion horses (n = 9) were habituated to an otherwise frightening, standardised test stimulus (calm companions), whereas the rest (n = 9) of the companion horses remained nonhabituated (control companions). During the test, unique pairs of companion and subject horses were exposed to the test stimulus while heart rate and behavioural responses were registered. Subsequently, subject horses were exposed to the stimulus on their own (post test). RESULTS: Subject horses, paired with a calm companion horse, showed less fear-related behaviour and lower heart rate responses compared to subject horses with control companions. Results from the post test suggest that the difference between treatment groups remained in the subsequent absence of companion horses. CONCLUSIONS AND POTENTIAL RELEVANCE: It appears possible to reduce fear reactions in young, naive horses by allowing them to interact with a calm companion horse in fear-eliciting situations.
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Scheiber, I. B. R., WeiB, B. M., Hirschenhauser, K., Wascher, C. A. F., Nedelcu, J. T., & Kotrschal, K. (2008). Does 'Relationship Intelligence' Make Big Brains in Birds? Open Biol J, 1, 6–8 (3).
Abstract: Lately, Emery et al. developed a bird-specific modification of the *social brain hypothesis*, termed *relationship intelligence hypothesis*. Although the idea may be valuable, we doubt that it is supported by sufficient evidence and critically discuss some of the arguments raised by the authors in favour of their new idea.
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Siniscalchi, M., Quaranta, A., & Rogers, L. J. (2008). Hemispheric specialization in dogs for processing different acoustic stimuli. PloS ONE, 3, e3349.
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Hemelrijk, C. K., Wantia, J.,, & Isler, K. (2008). Female Dominance over Males in Primates: Self-Organisation and Sexual Dimorphism. PLoS ONE, 3(7), e2678.
Abstract: The processes that underlie the formation of the dominance hierarchy in a group are since long under debate. Models of self-organisation suggest that dominance hierarchies develop by the self-reinforcing effects of winning and losing fights (the so-called winner-loser effect), but according to ‘the prior attribute hypothesis’, dominance hierarchies develop from pre-existing individual differences, such as in body mass. In the present paper, we investigate the relevance of each of these two theories for the degree of female dominance over males. We investigate this in a correlative study in which we compare female dominance between groups of 22 species throughout the primate order. In our study female dominance may range from 0 (no female dominance) to 1 (complete female dominance). As regards ‘the prior attribute hypothesis’, we expected a negative correlation between female dominance over males and species-specific sexual dimorphism in body mass. However, to our surprise we found none (we use the method of independent contrasts). Instead, we confirm the self-organisation hypothesis: our model based on the winner-loser effect predicts that female dominance over males increases with the percentage of males in the group. We confirm this pattern at several levels in empirical data (among groups of a single species and between species of the same genus and of different ones). Since the winner-loser effect has been shown to work in many taxa including humans, these results may have broad implications.3
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Roth II, T. C., Cox, J. G., & Lima, S. L. (2008). The Use and Transfer of Information About Predation Risk in Flocks of Wintering Finches. Ethology, 114(12), 1218–1226.
Abstract: ABSTRACT
Several studies in behavior have focused in some way on how groups of prey gather and use information about predation risk. Although asymmetries in information about risk exist among members of real groups, we know little about how such uneven information might affect individual or group antipredator decisions. Hence, we studied the use and transfer of information about the risk of predation in small flocks of wintering birds. House finches (Carpodacus mexicanus; 28 groups of three) were held in large enclosures divided into safe and risky patches. We controlled the information about risk available to each individual by conducting attacks with a model hawk that was visible to only a single (informed) bird. Repeated attacks on a single individual did not reduce the amount of feeding by other birds in that patch, although the time to resume feeding after observing a response to an attack event was somewhat longer than after a no attack event. These results suggest that informed individuals impart some information to naive (uninformed) birds, but this effect was not strong. In fact, the frequent return of informed individuals to feeders after observing uninformed individuals feed suggests that finches relied more on public information regarding safety than their own personal information in deciding when to feed. Group patch choice appeared to be based on a majority-rules decision, although an effect of dominance status was apparent. Our results suggest that subordinate flock members may exert a large influence over group decision-making by acting as spatial 'anchors'.
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Blumstein, D. T., Barrow, L., & Luterra, M. (2008). Olfactory Predator Discrimination in Yellow-Bellied Marmots. Ethology, 114(11), 1135–1143.
Abstract: The mechanism underlying olfactory predator identification may be relatively experience-independent, or it may rely on specific experience with predators. A mechanism by which prey might identify novel predators relies on the inevitable creation of sulfurous metabolites that are then excreted in the urine of carnivorous mammals. We tested whether free-living, yellow-bellied marmots (Marmota flaviventris) and mid-sized herbivores that fall prey to a variety of carnivorous mammals could discriminate herbivore (elk-Cervus elephas) urine from predator (red fox-Vulpes vulpes, coyote-Canis latrans, mountain lion-Felis concolor, wolf-Canis lupus) urine, a novel herbivore (moose-Alces alces), and a distilled water control. We further asked how specific this assessment was by testing whether marmots responded differently to predators representing different levels of risk and to familiar vs. unfamiliar predators. We found that marmots responded more to urine from coyotes (a familiar predator on adults), mountain lions (a potentially unfamiliar predator that could kill adults) and wolves (a locally extinct predator that could kill adults) than to elk urine (a non-predator). Red fox (a predator that poses a risk only to recently emerged marmot pups) urine elicited a less substantial (but not significantly so) response than coyote urine. Marmots can identify predators, even novel ones, using olfactory cues, suggesting that experience with a specific predator is not required to identify potential threats.
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