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Dewsbury, D. A. (1989). Comparative Psychology, Ethology, and Animal Behavior. Annual Review of Psychology, 40(1), 581–602.
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Kamil, A. C., & Roitblat, H. L. (1985). The Ecology of Foraging Behavior: Implications for Animal Learning and Memory. Annual Review of Psychology, 36(1), 141–169.
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Maple,, M. L. W., Meredith J. Bashaw, Kimberly Fountain, Sarah Kieschnick, & Terry L. (2006). Nocturnal behavior in a group of female African elephants. Zoo Biology, 25(3), 173–186.
Abstract: The nocturnal behavior of a stable group of female, African elephants (Loxodonta africana africana) was studied to: (1) examine their behavior as a function of hour of night; (2) qualitatively compare the elephants' activity budgets to those reported in a previous study; and (3) document the presence of aggressive and stereotypic behaviors that might necessitate a change in their management. The elephants were systematically observed at least five times per week for 10 weeks between 17:00 and 08:00. Instantaneous focal samples of behavior, location, and proximity were taken every minute on a rotating basis, and all observed occurrences of social behavior were recorded. The hour of night affected elephant activity: significant relationships were found between hour of night and percent of time they spent feeding, lying, and standing. The overall activity budgets of the elephants were similar to the activity budgets reported in a previous study, although differences were evident in lying, stereotypic, and social behaviors. These differences might be a function of age. Affiliative behaviors accounted for 57% of the elephants' social behaviors, and agonistic behaviors among the elephants occurred infrequently and caused no injuries. Additionally, the elephants used all areas to which they had access. These findings provide compelling evidence that unrestricted social access during the night is the appropriate management strategy for these elephants. The results from the present study also highlight the importance of replicating existing studies and using multiple behavioral measures to make decisions regarding the welfare and management of stable groups of captive elephants. Zoo Biol 25:173-186, 2006. 2006 Wiley-Liss, Inc.
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Savage,, A. O., Kirsten Leong, Laura Graham, & Anne. (2005). Behavioral indices of estrus in a group of captive African elephants (Loxodonta africana). Zoo Biology, 24(4), 311–329.
Abstract: This study investigated behavioral signals of estrus by systematically monitoring the interactions of one male with four female African elephants housed in a naturalistic outdoor enclosure at Disney's Animal Kingdom over a period of 11 months. We measured changes in five spatial behaviors and 22 tactile-contact behaviors, as well as changes in serum progestagen and LH concentrations, across three ovarian cycles for each female. Two females did not cycle during the study. Three different phases of the ovarian cycle were identified: mid luteal, anovulatory follicular, ovulatory follicular. The male followed more and carried out more genital inspections, flehmen, and trunk-to-mouth behaviors toward cycling females during their ovulatory phase. Genital inspections by the male peaked above baseline levels on the day of an LH surge, and up to 9 days before, in both cycling females and, thus, might be a useful behavioral index of estrus. The male also carried out more genital inspections, flehmen, and trunk touches to the back leg toward ovulatory cycling than noncycling females. Overall, our results indicated that: 1) a single subadult African elephant male could discriminate two females in the ovulatory phase of their cycle (i.e., during the 3 weeks preceding ovulation) from the mid luteal phase; 2) the male also discriminated two cycling females in the ovulatory and anovulatory follicular phases from two noncycling females; 3) two females in the ovulatory phase of the cycle displayed a greater variety of tactile-contact behavior toward the male compared to the other cycle phases. Zoo Biol 0:1-19, 2005. – 2005 Wiley-Liss, Inc.
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Snycerski, S., Laraway, S., & Poling, A. (2005). Response acquisition with immediate and delayed conditioned reinforcement. Behav. Process., 68(1), 1–11.
Abstract: Groups comprising eight rats initially were exposed to response-independent water deliveries, then to conditions under which a lever-press response raised an empty dipper immediately or after a resetting delay of 15, 30, or 45 s. When their performance was compared to that of control animals using a 90% confidence level, six rats in the immediate-reinforcement group met the primary criterion for response acquisition during a single 6-h session; 4, 4, and 3 did so in the 15, 30, and 45 s delay groups, respectively. Similar evidence of acquisition was obtained when a 95% confidence level was used. With a 99% confidence level, however, evidence of acquisition was not compelling. Although these data appear to provide the first demonstration of response acquisition in the absence of handshaping or autoshaping under conditions where the putative reinforcer is both conditioned and delayed, they also demonstrate that whether response acquisition occurs depends, in part, on how it is defined.
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Ducro, B. J., Koenen, E. P. C., van Tartwijk, J. M. F. M., & Bovenhuis, H. (2007). Genetic relations of movement and free-jumping traits with dressage and show-jumping performance in competition of Dutch Warmblood horses. Livestock Science, 107(2-3), 227–234.
Abstract: Genetic parameters for traits evaluated at the studbook entry inspection and genetic correlations with dressage and show-jumping performance in competition were estimated. Data comprised 36,649 Warmblood horses that entered the studbook between 1992 and 2002. The genetic analyses were performed using univariate and bivariate animal models. Heritabilities of the studbook entry traits were estimated in the range 0.15-0.40. The movement traits showed moderate to strong mutual genetic correlations, whereas the genetic correlations of movement traits with free-jumping traits were weak to moderate. The free-jumping traits showed strong to very strong mutual genetic correlations. Competition results of 33,459 horses with performance in dressage and 30,474 horse with performance in show-jumping were linked to the studbook entry data to estimate the genetic relationship with performance in competition. Heritability estimates for dressage and show jumping were 0.14. Genetic correlations of the movement traits with dressage were moderate to strong, and with show-jumping weak to moderate. Genetic correlations of the free-jumping traits with dressage were weak to moderate and unfavourable. The free-jumping traits were genetically strong to very strong correlated to show-jumping. It was concluded that a selection of the traits evaluated at the studbook entry inspection will favourably contribute to estimation of breeding values for sport performance.
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Ducro, B. J., Koenen, E. P. C., van Tartwijk, J. M. F. M., & van Arendonk, J. A. M. (2007). Genetic relations of First Stallion Inspection traits with dressage and show-jumping performance in competition of Dutch Warmblood horses. Livestock Science, 107(1), 81–85.
Abstract: Genetic parameters for traits evaluated at the First Stallion Inspection (FSI) and genetic correlations with dressage and show-jumping performance in competition were estimated. Data comprised 2361 stallions with FSI-observations from 1994 through 1999. Genetic analyses were performed using univariate and bivariate animal models. Heritability estimates of the FSI-traits ranged from 0.25 to 0.61. FSI-traits related to gaits showed strong genetic correlations (above 0.70) and FSI-traits related to free jumping had correlations close to unity. Competition results of 23,897 horses with performance in dressage and 22,811 horses with performance in show-jumping were linked to the FSI data to estimate the genetic relationship with performance in competition. Heritability estimates for dressage and show-jumping were 0.14. Genetic correlation between FSI-gaits and dressage in competition were positive, ranging from 0.37 to 0.72. Genetic correlation between FSI-jumping traits and show-jumping were all above 0.80. FSI-jumping traits showed negative correlations with dressage (about – 0.48). FSI-gait traits showed negative correlations with show-jumping, except for canter. It is concluded that selection at First Stallion Inspection comprises an important component of the stallion selection program, because FSI-traits have good genetic relationships with performance in competition and, due to the number of animals involved, relative high selection intensities can be achieved.
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Stock, K. F., & Distl, O. (2005). Prediction of breeding values for osseous fragments in fetlock and hock joints, deforming arthropathy in hock joints, and pathologic changes in the navicular bones of Hanoverian Warmblood horses. Livestock Production Science, 92(1), 77–94.
Abstract: The results of a standardised radiological examination of 5928 Hanoverian Warmblood horses selected for sale at auction were used to predict relative breeding values (RBV) in the 23,662 horses included in the last four generations of the probands' pedigrees. The distribution of the RBV was investigated in the whole four-generation pedigree, in the probands and in those stallions that contributed at least three offspring to the probands. The RBV of the probands' sires were further compared with the officially published performance-based relative breeding values, i.e., total indices dressage (TID) and jumping (TIJ). The sires' level of dressage indices was considerably higher (mean TID=110) than of the jumping indices (mean TIJ=98). Total indices radiographic findings (TIR) were calculated for the sires with varying weighting given to the individual RBV. In each case, this resulted in a mean TIR of 99. Finally, total indices were derived from TIR and TID and/or TIJ in order to develop different selection schemes for all-purpose breeding and for breeding focused on dressage and show jumping. All breeding values under consideration increased by between 1% and 19% when radiographic findings were weighted with between 30% and 60% complementary to the corresponding performance parameters, and when only sires were selected with above average total indices. At the same time, the prevalences of the radiographic findings investigated here were lowered by up to 10% each. When only one radiographic finding was considered at a time, the maximum attainable response to selection was a 16-23% increase in the relative breeding values and a relative decrease in prevalences of radiographic findings of between 31% and 52%. The results of this study indicate that it is possible in horse breeding to consider simultaneously health and performance traits. Medical data should be included in the prediction of breeding values in order to improve the radiological status of today's riding horses.
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Koenen, E. P. C., Aldridge, L. I., & Philipsson, J. (2004). An overview of breeding objectives for warmblood sport horses. Livestock Production Science, 88(1-2), 77–84.
Abstract: The aim of this paper is to review the current breeding objectives of organisations that run a selection programme for warmblood riding horses in the light of an increasing trend in trade of semen across countries. In a questionnaire, 19 horse breeding organisations provided information on breeding objective traits. Variation both in length and amount of details used to define individual breeding objectives was large, reflecting that many traits in sport horse breeding are not easy to measure, and therefore, have to be defined in a subjective way. The majority of the breeding objectives included conformation, gaits and performance in show jumping and dressage. Some breeding objectives also included behaviour, soundness, health and fertility. However, several organisations did not specify the sport discipline and the level of competition (amateur, national or international level) in the breeding objective. In general, relative weightings of the traits within the verbally presented breeding objectives were not given, but were assessed by the organisations in response to this study. The relevance of more information on expected future production circumstances and on the genetic parameters of the traits of interest are discussed. A further review of the consistency, completeness and the number of traits of the present breeding objectives for sport horses is recommended to optimise the efficiency of selection decisions.
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Murray, J. K., Singer, E. R., Morgan, K. L., Proudman, C. J., & French, N. P. (2004). Memory decay and performance-related information bias in the reporting of scores by event riders. Preventive Veterinary Medicine, 63(3-4), 173–182.
Abstract: We used data from a case-control study investigating risk factors for horse falls in the cross-country phase of eventing in Great Britain (GB) to examine evidence for memory decay and information bias. Responses to two questions obtained by telephone for 173 cases and 521 controls were examined for evidence of differential reporting according to the respondent's case-control status and performance in the dressage and cross-country phases of competitions. Information bias was found in the accuracy of reporting dressage penalty scores when analysed as a function of performance level (good/poor). Poor dressage performers were less likely to report accurate dressage scores than good performers. The accuracy of reporting dressage scores decreased as the time between the event and questionnaire completion increased, with no case-control interaction. Competitors who incurred cross-country jumping penalties at the event preceding the selected event reported their cross-country scores with less accuracy when compared with competitors who incurred no penalties. No information bias was found when the reporting of dressage and cross-country scores were analysed as a function of respondent category (case/control).
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