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Fetterman, J. G. (1996). Dimensions of stimulus complexity. J Exp Psychol Anim Behav Process, 22(1), 3–18.
Abstract: Animal learning research has increasingly used complex stimuli that approximate natural objects, events, and locations, a trend that has accompanied a resurgence of interest in the role of cognitive factors in learning. Accounts of complex stimulus control have focused mainly on cognitive mechanisms and largely ignored the contribution of stimulus information to perception and memory for complex events. It is argued here that research on animal learning stands to benefit from a more detailed consideration of the stimulus and that James Gibson's stimulus-centered theory of perception serves as a useful framework for analyses of complex stimuli. Several issues in the field of animal learning and cognition are considered from the Gibsonian perspective on stimuli, including the fundamental problem of defining the effective stimulus.
Keywords: Animals; *Behavior, Animal; Cognition; *Learning; Memory; Time Factors
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Sufit, E., Houpt, K. A., & Sweeting, M. (1985). Physiological stimuli of thirst and drinking patterns in ponies. Equine Vet J, 17(1), 12–16.
Abstract: The stimuli that elicit thirst were studied in four ponies. Nineteen hours of water deprivation produced an increase in plasma protein from 67 +/- 0.1 g/litre to 72 +/- 2 g/litre, a mean (+/- se) increase in plasma sodium from 139 +/- 3 to 145 +/- 2 mmol/litre and an increase in plasma osmolality from 297 +/- 1 to 306 +/- 2 mosmol/litre. Undeprived ponies drank 1.5 +/- 0.9 kg/30 mins; 19 h deprived ponies drank 10.2 +/- 2.5 kg/30 mins and corrected the deficits in plasma protein, plasma sodium and plasma osmolality as well as compensating for the water they would have drunk during the deprivation period. In order to determine if an increase in plasma osmolality would stimulate thirst, 250 ml of 15 per cent sodium chloride was infused intravenously. The ponies drank when osmolality increased 3 per cent and when plasma sodium rose from 136 +/- 3 mmol/litre to 143 +/- 3 mmol/litre. Ponies infused with 15 per cent sodium chloride drank 2.9 +/- 0.7 kg; those infused with 0.9 per cent sodium chloride drank 0.7 +/- 0.5 kg. In order to determine if a decrease in plasma volume would stimulate thirst, ponies were injected with 1 or 2 mg/kg bodyweight (bwt) frusemide. Plasma protein rose from 68 +/- 2 g/litre pre-injection to 75 +/- 2 g/litre 1 h after 1 mg/kg bwt frusemide and to 81 +/- 1 g/litre 1 h after 2 mg/kg bwt frusemide.(ABSTRACT TRUNCATED AT 250 WORDS)
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Bell, R. J. W., Kingston, J. K., Mogg, T. D., & Perkins, N. R. (2007). The prevalence of gastric ulceration in racehorses in New Zealand. N Z Vet J, 55(1), 13–18.
Abstract: AIM: To establish the prevalence and factors influencing the prevalence and severity of gastric ulceration in racehorses in New Zealand. METHODS: Horses (n=171) in active training for racing by trainers (n=24) located throughout New Zealand were examined using gastroscopy during 2003 and 2004. Images of the examination were recorded and reviewed, and an ordinal grade based on the severity of gastric ulceration present was assigned, using the grading system proposed by the Equine Gastric Ulcer Council (EGUC). Information about the horses such as age, breed, sex, stabling, time at pasture, pasture quality, and presence of clinical signs consistent with equine gastric ulcer syndrome (EGUS) was recorded. RESULTS: Of the 171 horses in the study, 133 (78%) were Thoroughbreds and 38 (22%) were Standardbreds. Evidence of gastric ulceration was present in 151 (88.3%) of these. Prevalence of ulceration was higher at the lesser curvature (LC) and greater curvature (GC) of the stomach than at the saccus caecus (SC; p<0.01), and ulceration was more severe at the LC than at either the GC (p=0.02) or the SC (p<0.001). The prevalence of ulceration did not differ between the two breeds (p=0.51) or between horses of differing ages (p=0.56). Gastric ulceration was evident in 125/141 (89%) horses kept at pasture for at least 4 h/day, in all 13 (100%) horses kept at pasture full time, and in 16/17 (94%) horses stabled full time. Prevalence and severity of ulceration did not differ between horses stabled full time, kept at pasture for part of the day or kept at pasture full time (p=0.33 and 0.13, respectively), and for horses grazed on pasture severity of ulceration did not vary significantly with the quality of the pasture (p=0.12). Neither prevalence (p=0.26) nor severity (p=0.49) of gastric ulceration varied significantly with duration of training. CONCLUSIONS: The prevalence of gastric ulceration in racehorses in New Zealand is similar to that reported elsewhere for horses in active training for racing. Access to pasture for some or all of the day did not appear to be protective.
Keywords: Age Factors; *Animal Feed; Animal Husbandry/methods; Animals; Female; Horse Diseases/*epidemiology/pathology/prevention & control; Horses; Male; New Zealand/epidemiology; Physical Conditioning, Animal/*adverse effects/physiology; Poaceae; Prevalence; Risk Factors; Severity of Illness Index; Sex Factors; Stomach Ulcer/epidemiology/pathology/prevention & control/*veterinary; Time Factors
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Palagi, E., Paoli, T., & Tarli, S. B. (2004). Reconciliation and consolation in captive bonobos (Pan paniscus). Am. J. Primatol., 62(1), 15–30.
Abstract: Although reconciliation in bonobos (Pan paniscus) has previously been described, it has not been analyzed heretofore by the postconflict (PC) match-control (MC) method. Furthermore, although reconciliation has been investigated before in this species, consolation has not. In this study we analyzed agonistic and affiliative contacts in all sex-class combinations to clarify and reevaluate the occurrence of reconciliation in bonobos via the PC-MC method. We also investigated the occurrence of consolation by analyzing the victims' triadic contact tendency (TCT), the influence of the sex of victims, and the relative occurrence of consolation and reconciliation. We collected 167 pairs of PC-MC observations in a captive group of bonobos (in Apeldoorn, The Netherlands). The conciliatory tendency (CCT) we obtained was tendentially lower than the mean value previously found for Yerkes captive chimpanzees. Close relationships, which were present in all female-female (FF) and some male-female (MF) dyads, positively affected reconciliation rates. When only adult PC-MC pairs (157) were considered, the mean TCTs and CCTs did not differ significantly. When we focused on types of PC affiliative contact, in the case of consolation we found a striking preference for sociosexual patterns. As to the relative occurrence of consolation and reconciliation, the highest level of the former was found in the absence of the latter. When reconciliation took place, consolation generally preceded it, suggesting that consolation may be a substitutive behavior. Our findings suggest that even if reconciliation remains the best option, consolation may be an alternative substitute for reconciliation that is used to buffer the tension originating from an unresolved conflict. Reconciliation and consolation are complex phenomena that are probably related to the life history of a group. Given that few studies have been conducted on this subject, we can not at this time make any generalizations regarding conflict resolution in certain species by comparing results among studies.
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Crowell-Davis, S. L., & Houpt, K. A. (1985). Coprophagy by foals: effect of age and possible functions. Equine Vet J, 17(1), 17–19.
Abstract: In colts and fillies observed from birth to 24 weeks old, coprophagy occurred from Weeks 1 to 19. Its frequency was greatest during the first two months. Coprophagy was rarely observed in mares and stallions. Foals usually ate the faeces of their mother but were observed to eat their own and those of a stallion and another unrelated mare. Urination by the foal occurred before, during or after 26 per cent of the coprophagy incidents. It is hypothesised that foals may consume faeces in response to a maternal pheromone which signals the presence of deoxycholic acid or other acids which the foal may be deficient in and which it may require for gut immuno-competence myelination of the nervous system. Such a pheromone may also serve to accelerate growth and sexual maturation. Coprophagy may also provide nutrients and introduce normal bacterial flora to the gut.
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Domjan, M. (1976). Determinants of the enhancement of flavored-water intake by prior exposure. J Exp Psychol Anim Behav Process, 2(1), 17–27.
Abstract: The intake of a 2.0% sodium saccharin solution in rats was observed to increase as a function of both the number (Experiment 1) and the duration (Experiment 3) of prior periods of access to the saccharin flavor, but did not increase when subjects were maintained on a fluid deprivation procedure in the absence of saccharin exposure (Experiment 2). The enhancement of intake was further influenced by the schedule of saccharin preexposures in the absence of variations in the amount of solution tasted (Experiment 4). The effect was not a function of the opportunity for subjects to determine their own pattern of contact with the saccharin flavor, the opportunity for association of the flavor with hunger and thirst reduction, or the amount of saccharin swallowed during preexposure (Experiment 5). These results suggest that mere exposure to a flavored solution is sufficient to increase subsequent intakes. The phenomenon is discussed in terms of the attenuation of neophobia elicited by the novelty of flavored solutions.
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Hogan, D. E., Zentall, T. R., & Pace, G. (1983). Control of pigeons' matching-to-sample performance by differential sample response requirements. Am J Psychol, 96(1), 37–49.
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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Elhay, M., Newbold, A., Britton, A., Turley, P., Dowsett, K., & Walker, J. (2007). Suppression of behavioural and physiological oestrus in the mare by vaccination against GnRH. Aust Vet J, 85(1-2), 39–45.
Abstract: OBJECTIVE: To examine the immunogenicity of an equine immunocontraceptive vaccine and its efficacy in controlling hormone-related behaviour. DESIGN: A total of 24 mares at two sites in Australia were vaccinated with an immunocontraceptive vaccine comprising gonadotrophin releasing hormone (GnRH) conjugated to a carrier protein in immunostimulating complex as an adjuvant. Twelve animals at each site received a placebo of adjuvant alone and served as controls for seasonal oestrus, hormonal and behaviour patterns. Animals were observed for injection site reactions, ovarian and follicular activity, and serum levels of antibody, 17beta-oestradiol and progesterone in the weeks following vaccination. Mares were also examined for oestrous behaviour by teasing with a stallion. RESULTS: All mares responded to vaccination. Two weeks following the second vaccination there was a peak in antibody response to GnRH that declined gradually over the following weeks. Commensurate with the elevated anti-GnRH antibody there was a marked effect on ovarian activity with a reduction in 17beta-oestradiol and progesterone levels in the 24 vaccinated mares. There was also a reduction of oestrus-related behaviour as determined by a teaser stallion. This effect lasted a minimum of 3 months and correlated with the initial level of antibody response. CONCLUSION: Following a conventional two-dose immunisation regime this commercially available equine immunocontraceptive vaccine was effective at inhibiting oestrous behaviour for at least 3 months. This vaccine has a high level of safety since there were no significant local reactions nor were there any adverse systemic responses to vaccination.
Keywords: Animals; Antibodies/blood; Estradiol/blood; *Estrus/drug effects/physiology; Female; Gonadotropin-Releasing Hormone/*immunology/*pharmacology; Horses/*physiology; Luteinizing Hormone/blood; Ovulation/*drug effects/physiology; Progesterone/blood; Safety; Sexual Behavior, Animal/drug effects/physiology; Time Factors; Vaccination/veterinary
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Barrey, E., & Galloux, P. (1997). Analysis of the equine jumping technique by accelerometry. Equine Vet J Suppl, (23), 45–49.
Abstract: The purpose of this study was to demonstrate the relationships between jumping technique and dorsoventral acceleration measured at the sternum. Eight saddle horses of various jumping abilities competed on a selective experimental show jumping course including 14 obstacles. An accelerometric belt fastened onto the thorax continuously measured the dorsoventral acceleration during the course. At each jump, 11 locomotor parameters (acceleration peaks, durations and stride frequency) were obtained from the dorsoventral acceleration-time curves. The type of obstacle significantly influenced the hindlimb acceleration peak at take-off and the landing acceleration peak (P<0.01). The poor jumpers exhibited a higher mean forelimb acceleration peak at take-off, a higher forelimb/hindlimb ratio between peaks of acceleration (F/H), and a lower approach stride frequency than good jumpers. Knocking over an obstacle was significantly associated with a low hindlimb acceleration peak at take-off and a high F/H ratio (P<0.01). In order to observe the continuous changes in the frequency domain of the dorsoventral acceleration during the approach and take-off phase, a Morlet's wavelet analysis was computed for each horse jumping over a series of 3 vertical obstacles. Different patterns of time-frequency images obtained by wavelet analysis were found when the horse either knocked over a vertical obstacle or cleared it. In the latter case, the image pattern showed an instantaneous increase in stride frequency at the end of the approach phase, and a marked energy content in the middle frequency range at take-off.
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Mitchell, D., Kirschbaum, E. H., & Perry, R. L. (1975). Effects of neophobia and habituation on the poison-induced avoidance of exteroceptive stimuli in the rat. J Exp Psychol Anim Behav Process, 1(1), 47–55.
Abstract: Two experiments on the role of neophobia in poison-induced aversions to exteroceptive stimuli are reported. In Experiment 1, rats were given either 10 or 25 days of habituation to the test situation prior to conditioning. Those animals with the longer habituation period avoided a complex of novel exteroceptive stimuli while those with the shorter habituation period did not. In Experiment 2 rats initially avoided the more novel of two containers, but gradually came to eat equal amounts from both. A single pairing of toxicosis with consumption from either the novel or the familiar container reinstated the avoidance of the novel container in both cases. The results were discussed in terms of an interaction between habituation and conditioning procedures. It was suggested that previously reported differences between interoceptive and exteroceptive conditioning effects may have been influenced by the differential novelty of the two classes of stimuli in the test situation. It was further suggested that non-contingently poisoned control groups should routinely be included in poison avoidance conditioning studies.
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