Records |
Author |
Young, L.E.; Rogers, K.; Wood, J.L.N. |
Title |
Left ventricular size and systolic function in Thoroughbred racehorses and their relationships to race performance |
Type |
Journal Article |
Year |
2005 |
Publication |
Journal of Applied Physiology (Bethesda, Md. : 1985) |
Abbreviated Journal |
J Appl Physiol |
Volume |
99 |
Issue |
4 |
Pages |
1278-1285 |
Keywords |
*Adaptation, Physiological; Aging/physiology; Animal Husbandry; Animals; *Echocardiography; Female; Heart/*physiology; Heart Ventricles; Horses/*physiology; Male; *Physical Conditioning, Animal; Running/*physiology; Stroke Volume; Systole; Task Performance and Analysis |
Abstract |
Cardiac morphology in human athletes is known to differ, depending on the sports-specific endurance component of their events, whereas anecdotes abound about superlative athletes with large hearts. As the heart determines stroke volume and maximum O(2) uptake in mammals, we undertook a study to test the hypothesis that the morphology of the equine heart would differ between trained horses, depending on race type, and that left ventricular size would be greatest in elite performers. Echocardiography was performed in 482 race-fit Thoroughbreds engaged in either flat (1,000-2,500 m) or jump racing (3,200-6,400 m). Body weight and sex-adjusted measures of left ventricular size were largest in horses engaged in jump racing over fixed fences, compared with horses running shorter distances on the flat (range 8-16%). The observed differences in cardiac morphologies suggest that subtle differences in training and competition result in cardiac adaptations that are appropriate to the endurance component of the horses' event. Derived left ventricular mass was strongly associated with published rating (quality) in horses racing over longer distances in jump races (P < or = 0.001), but less so for horses in flat races. Rather, left ventricular ejection fraction and left ventricular mass combined were positively associated with race rating in older flat racehorses running over sprint (<1,408 m) and longer distances (>1,408 m), explaining 25-35% of overall variation in performance, as well as being closely associated with performance in longer races over jumps (23%). These data provide the first direct evidence that cardiac size influences athletic performance in a group of mammalian running athletes. |
Address |
Centre for Equine Studies, Animal Health Trust, Newmarket, Suffolk, UK. lesley.young@aht.org.uk |
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ISSN |
8750-7587 |
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Notes |
PMID:15920096 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3768 |
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Author |
Johnstone, R.A. |
Title |
Eavesdropping and animal conflict |
Type |
Journal Article |
Year |
2001 |
Publication |
Proceedings of the National Academy of Sciences of the United States of America |
Abbreviated Journal |
Proc. Natl. Acad. Sci. U.S.A. |
Volume |
98 |
Issue |
16 |
Pages |
9177-9180 |
Keywords |
*Aggression; Animals; *Behavior, Animal; *Conflict (Psychology); Models, Theoretical |
Abstract |
Fights between pairs of animals frequently take place within a wider social context. The displays exchanged during conflict, and the outcome of an encounter, are often detectable by individuals who are not immediately involved. In at least some species, such bystanders are known to eavesdrop on contests between others, and to modify their behavior toward the contestants in response to the observed interaction. Here, I extend Maynard Smith's well known model of animal aggression, the Hawk-Dove game, to incorporate the possibility of eavesdroppers. I show that some eavesdropping is favored whenever the cost of losing an escalated fight exceeds the value of the contested resource, and that its equilibrium frequency is greatest when costs are relatively high. Eavesdropping reduces the risk of escalated conflict relative to that expected by chance, given the level of aggression in the population. However, it also promotes increased aggression, because it enhances the value of victory. The net result is that escalated conflicts are predicted to occur more frequently when eavesdropping is possible. |
Address |
Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, United Kingdom. raj1003@hermes.cam.ac.uk |
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0027-8424 |
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Notes |
PMID:11459936 |
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no |
Call Number |
refbase @ user @ |
Serial |
497 |
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Author |
Reiss, D.; Marino, L. |
Title |
Mirror self-recognition in the bottlenose dolphin: a case of cognitive convergence |
Type |
Journal Article |
Year |
2001 |
Publication |
Proceedings of the National Academy of Sciences of the United States of America |
Abbreviated Journal |
Proc. Natl. Acad. Sci. U.S.A. |
Volume |
98 |
Issue |
10 |
Pages |
5937-5942 |
Keywords |
Animals; *Cognition; Dolphins/*physiology; *Visual Perception |
Abstract |
The ability to recognize oneself in a mirror is an exceedingly rare capacity in the animal kingdom. To date, only humans and great apes have shown convincing evidence of mirror self-recognition. Two dolphins were exposed to reflective surfaces, and both demonstrated responses consistent with the use of the mirror to investigate marked parts of the body. This ability to use a mirror to inspect parts of the body is a striking example of evolutionary convergence with great apes and humans. |
Address |
Osborn Laboratories of Marine Sciences, New York Aquarium, Wildlife Conservation Society, Brooklyn, NY 11224, USA. dlr28@columbia.edu |
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0027-8424 |
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Notes |
PMID:11331768 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
2822 |
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Author |
Griffin, D.R. |
Title |
Animals know more than we used to think |
Type |
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Year |
2001 |
Publication |
Proceedings of the National Academy of Sciences of the United States of America |
Abbreviated Journal |
Proc. Natl. Acad. Sci. U.S.A. |
Volume |
98 |
Issue |
9 |
Pages |
4833-4834 |
Keywords |
Animal Communication; Animals; Attention/physiology; Brain/physiology; Choice Behavior/physiology; Cognition/*physiology; Humans; Macaca mulatta/physiology/*psychology; Memory/*physiology; Optic Disk/physiology; Psychological Tests |
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0027-8424 |
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PMID:11320232 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
2823 |
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Author |
Hampton, R.R. |
Title |
Rhesus monkeys know when they remember |
Type |
Journal Article |
Year |
2001 |
Publication |
Proceedings of the National Academy of Sciences of the United States of America |
Abbreviated Journal |
Proc. Natl. Acad. Sci. U.S.A. |
Volume |
98 |
Issue |
9 |
Pages |
5359-5362 |
Keywords |
Animals; Choice Behavior/physiology; Cognition/*physiology; Cues; Food Preferences/psychology; Macaca mulatta/*physiology/*psychology; Male; Memory/*physiology; Probability; Psychological Tests; Reproducibility of Results; Sensitivity and Specificity |
Abstract |
Humans are consciously aware of some memories and can make verbal reports about these memories. Other memories cannot be brought to consciousness, even though they influence behavior. This conspicuous difference in access to memories is central in taxonomies of human memory systems but has been difficult to document in animal studies, suggesting that some forms of memory may be unique to humans. Here I show that rhesus macaque monkeys can report the presence or absence of memory. Although it is probably impossible to document subjective, conscious properties of memory in nonverbal animals, this result objectively demonstrates an important functional parallel with human conscious memory. Animals able to discern the presence and absence of memory should improve accuracy if allowed to decline memory tests when they have forgotten, and should decline tests most frequently when memory is attenuated experimentally. One of two monkeys examined unequivocally met these criteria under all test conditions, whereas the second monkey met them in all but one case. Probe tests were used to rule out “cueing” by a wide variety of environmental and behavioral stimuli, leaving detection of the absence of memory per se as the most likely mechanism underlying the monkeys' abilities to selectively decline memory tests when they had forgotten. |
Address |
Section on the Neurobiology of Learning and Memory, Laboratory of Neuropsychology, National Institute of Mental Health, Building 49, Room 1B-80, Bethesda, MD 20892, USA. robert@ln.nimh.nih.gov |
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ISSN |
0027-8424 |
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Notes |
PMID:11274360 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
2824 |
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Author |
Hogan, D.E.; Zentall, T.R.; Pace, G. |
Title |
Control of pigeons' matching-to-sample performance by differential sample response requirements |
Type |
Journal Article |
Year |
1983 |
Publication |
The American journal of psychology |
Abbreviated Journal |
Am J Psychol |
Volume |
96 |
Issue |
1 |
Pages |
37-49 |
Keywords |
Animals; Association; *Color Perception; Columbidae; Cues; *Discrimination Learning; Reinforcement Schedule; Time Factors |
Abstract |
Pigeons were trained on a matching-to-sample task in which sample hue and required sample-specific observing behavior provided redundant, relevant cues for correct choices. On trials that involved red and yellow hues as comparison stimuli, a fixed-ratio 16 schedule (FR 16) was required to illuminate the comparisons when the sample was red, and a differential-reinforcement-of-low-rates 3-sec schedule (DRL 3-sec) was required when the sample was yellow. On trials involving blue and green hues as comparison stimuli, an FR 16 schedule was required when the sample was blue and a DRL 3-sec schedule was required when the sample was green. For some pigeons, a 0-sec delay intervened between sample offset and comparison onset, whereas other pigeons experienced a random mixture of 0-sec and 2-sec delay trials. Test trial performance at 0-sec delay indicated that sample-specific behavior controlled choice performance considerably more than sample hue did. Test performance was independent of whether original training involved all 0-sec delay trials or a mixture of 0-sec and 2-sec delays. Sample-specific observing response requirements appear to facilitate pigeons' matching-to-sample performance by strengthening associations between the observing response and correct choice. |
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ISSN |
0002-9556 |
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Notes |
PMID:6859346 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
265 |
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Author |
Nallan, G.B.; Pace, G.M.; McCoy, D.F.; Zentall, T.R. |
Title |
The role of elicited responding in the feature-positive effect |
Type |
Journal Article |
Year |
1983 |
Publication |
The American journal of psychology |
Abbreviated Journal |
Am J Psychol |
Volume |
96 |
Issue |
3 |
Pages |
377-390 |
Keywords |
Animals; Color Perception; Columbidae; *Discrimination (Psychology); Male; Practice (Psychology); Reinforcement (Psychology); Time Factors |
Abstract |
Hearst and Jenkins proposed in 1974 that elicited responding accounts for the feature-positive effect. To test this position, pigeons were exposed to a feature-positive or feature-negative discrimination between successively presented displays--one consisted of a red and a green response key and the other consisted of two green response keys. There were four main conditions: 5-5 (5-sec trials, 5-sec intertrial intervals), 5-30, 30-30, and 30-180. Conditions 5-30 and 30-180 should produce the largest amount of elicited responding, and therefore the largest feature-positive effects. A response-independent bird was yoked to each response-dependent bird to allow direct assessment of the amount of elicited responding generated by each condition. Contrary to the predictions by Hearst and Jenkins's theory, response-dependent birds showed large feature-positive effects in each condition. The largest feature-positive effect was obtained in condition 5-5. Response-independent birds produced similar results, but manifested low response rates. |
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0002-9556 |
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PMID:6650707 |
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no |
Call Number |
refbase @ user @ |
Serial |
266 |
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Author |
Barros, A.T. |
Title |
Seasonality and relative abundance of Tabanidae (Diptera) captured on horses in the Pantanal, Brazil |
Type |
Journal Article |
Year |
2001 |
Publication |
Memorias do Instituto Oswaldo Cruz |
Abbreviated Journal |
Mem Inst Oswaldo Cruz |
Volume |
96 |
Issue |
7 |
Pages |
917-923 |
Keywords |
Animals; Brazil; Climate; Diptera/classification/*physiology; Ecology; Horses/*parasitology; Population Dynamics; Seasons; Species Specificity |
Abstract |
Once a month, from June 1992 to May 1993, collections of tabanids on horse were conducted in the Nhecolandia, Pantanal State of Mato Grosso do Sul, Brazil. Tabanid catches using hand nets were conducted from sunrise to sunset at grassland and cerradao (dense savanna) habitats. A total of 3,442 tabanids from 21 species,12 genera, and 3 subfamilies were collected. Although species abundance varied seasonally depending on habitat, no habitat specificity was observed for the most abundant species. In the grassland, 1,625 (47.2%) tabanids belonging to 19 species were collected, while 1,817 (52.8%) tabanids from 17 species were caught in the cerradao. The number of tabanid species varied from 7 during winter (July/August) to 15 in the spring (October). Tabanus importunus (56%) was the most abundant species, followed by T. occidentalis (8.2%), and T. claripennis (8.1%). The tabanid peak, in October, coincided with the beginning of the rainy season. The population peak of most species, including those with higher vector potential, suggests that the rainy season can be considered as the period of potentially higher risk of mechanical transmission of pathogens by tabanids to horses in the region. |
Address |
Embrapa Pantanal, 79320-900 Corumba, MS, Brasil. thadeu@cpap.embrapa.br |
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ISSN |
0074-0276 |
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PMID:11685255 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
2644 |
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Author |
Bergstrom, C.T.; Lachmann, M. |
Title |
Signaling among relatives. III. Talk is cheap |
Type |
Journal Article |
Year |
1998 |
Publication |
Proceedings of the National Academy of Sciences of the United States of America |
Abbreviated Journal |
Proc. Natl. Acad. Sci. U.S.A. |
Volume |
95 |
Issue |
9 |
Pages |
5100-5105 |
Keywords |
Animal Communication; Animals; Costs and Cost Analysis; *Evolution; Interpersonal Relations; Models, Biological |
Abstract |
The Sir Philip Sidney game has been used by numerous authors to show how signal cost can facilitate honest signaling among relatives. Here, we demonstrate that, in this game, honest cost-free signals are possible as well, under very general conditions. Moreover, these cost-free signals are better for all participants than the previously explored alternatives. Recent empirical evidence suggests that begging is energetically inexpensive for nestling birds; this finding led some researchers to question the applicability of the costly signaling framework to nestling begging. Our results show that cost-free or inexpensive signals, as observed empirically, fall within the framework of signaling theory. |
Address |
Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA. carl@charles.stanford.edu |
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0027-8424 |
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PMID:9560235 |
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no |
Call Number |
refbase @ user @ |
Serial |
561 |
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Author |
Kirkpatrick, J.F.; Liu, I.M.; Turner, J.W.J.; Naugle, R.; Keiper, R. |
Title |
Long-term effects of porcine zonae pellucidae immunocontraception on ovarian function in feral horses (Equus caballus) |
Type |
Journal Article |
Year |
1992 |
Publication |
Journal of reproduction and fertility |
Abbreviated Journal |
J Reprod Fertil |
Volume |
94 |
Issue |
2 |
Pages |
437-444 |
Keywords |
Animals; Contraception, Immunologic/*veterinary; *Egg Proteins; Estrogens, Conjugated (USP)/urine; Female; Glycoproteins/*pharmacology; Horses/immunology/*physiology; *Membrane Glycoproteins; Ovary/drug effects/*physiology; Progesterone/metabolism; *Receptors, Cell Surface; Swine/immunology; Time Factors; Zona Pellucida/*immunology |
Abstract |
Ten feral mares free-roaming in Maryland, USA, were inoculated with porcine zonae pellucidae (PZP) protein before the breeding season for three consecutive years (1988-90). Ovarian function was monitored for 51 days during the peak of the breeding season after the third annual PZP inoculation, in seven of these mares and in four untreated control mares, by means of urinary oestrone conjugates and nonspecific progesterone metabolites. None of the ten inoculated mares became pregnant in 1990, compared with 55% of 20 control mares, which included two of the four monitored for ovarian function. Three of the untreated mares demonstrated apparent normal ovarian activity, characterized by preovulatory oestrogen peaks, concurrent progesterone nadirs at ovulation, breeding activity, and luteal-phase progesterone increases after ovulation. Two of the seven monitored PZP-treated mares demonstrated ovulatory cycles that did not result in conception. One was pregnant as a result of conception in 1989 and demonstrated a normal, late-gestation, endocrine profile. The remaining four PZP-treated mares revealed no evidence of ovulation, and urinary oestrogen concentrations were significantly depressed. The experiments indicated that (i) a third consecutive annual PZP booster inoculation is greater than 90% effective in preventing pregnancies in mares and (ii) three consecutive years of PZP treatment may interfere with normal ovarian function as shown by markedly depressed oestrogen secretion. |
Address |
Deaconess Research Institute, Billings, MT 59102 |
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0022-4251 |
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PMID:1317449 |
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no |
Call Number |
refbase @ user @ |
Serial |
145 |
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