|
|
Thoren Hellsten, E., Viklund, A., Koenen, E. P. C., Ricard, A., Bruns, E., & Philipsson, J. (2006). Review of genetic parameters estimated at stallion and young horse performance tests and their correlations with later results in dressage and show-jumping competition. Livestock Science, 103(1-2), 1–12.
Abstract: Results from performance tests and competitions of young horses are used by major European warmblood horse breeding associations for genetic evaluations. The aim of this review was to compare genetic parameters for various tests of young horses to assess their efficiency in selection for dressage and show-jumping. Improved understanding of genetic information across countries is also necessary, as foreign trade with semen is rapidly increasing. The review is based on inquiries to European breed associations and on (17) scientific publications available, which have analysed genetic parameters of young horse data and/or relationships between young and mature horse results in sport. Despite differences in testing methods of young horses, results for major horse populations were in good agreement. Specially designed young horse performance tests, including stallion tests, showed high heritabilities and high genetic correlations with later competition results. We recommend that test results are encouraged to be used across countries for genetic evaluation of imported stallions and semen. Short station tests are generally preferred when selecting stallions for both dressage and jumping traits, whereas competition data may be used when selecting for only one discipline. We also recommend that extensive field testing of young horses is encouraged and should include both genders.
|
|
|
|
Bryson, J., & Leong, J. (2007). Primate errors in transitive inference: a two-tier learning model. Anim. Cogn., 10(1), 1–15.
Abstract: Abstract Transitive performance (TP) is a learning-based behaviour exhibited by a wide range of species, where if a subject has been taught to prefer A when presented with the pair AB but to prefer B when presented with the pair BC, then the subject will also prefer A when presented with the novel pair AC. Most explanations of TP assume that subjects recognize and learn an underlying sequence from observing the training pairs. However, data from squirrel monkeys (Saimiri sciureus) and young children contradict this, showing that when three different items (a triad) are drawn from the sequence, subjects`` performance degrades systematically (McGonigle and Chalmers, Nature 267:694-696, 1977; Chalmers and McGonigle, Journal of Experimental Child Psychology 37:355-377, 1984; Harris and McGonigle, The Quarterly Journal of Experimental Psychology 47B:319-348, 1994). We present here the two-tier model, the first learning model of TP which accounts for this systematic performance degradation. Our model assumes primate TP is based on a general-purpose task learning system rather than a special-purpose sequence-learning system. It supports the hypothesis of Heckers et al. (Hippocampus 14:153-162, 2004) that TP is an expression of two separate general learning elements: one for associating actions and contexts, another for prioritising associations when more than one context is present. The two-tier model also provides explanations for why phased training is important for helping subjects learn the initial training pairs and why some subjects fail to do so. It also supports the Harris and McGonigle (The Quarterly Journal of Experimental Psychology 47B:319-348, 1994) explanation of why, once the training pairs have been acquired, subjects perform transitive choice automatically on two-item diads, but not when exposed to triads from the same sequence.
|
|
|
|
Górecka-Bruzda, A., Chruszczewski, M. H., Jezierski, T., & Murphy, J. (). Behaviour-related traits of Polish sport horse stallions participating in 100-day performance tests. Livest Sci, In Press, Corrected Proof.
Abstract: Sport horse studbooks frequently use performance tests to identify, evaluate and approve stallions for future breeding programmes. The aim of this study was to analyse behaviour-related traits of Polish Warmblood stallions participating in studbook 100-day performance tests. Both relatedness and differences of traits and their contribution to overall variability were analysed. Three-year-old stallions (n = 374) participated in 100-day performance test programmes at two Polish training stations from 2004 to 2008. Traits including character, temperament and trainability (trainer rated), free-jumping, jumping under the rider, walk, trot and canter (independently rated by both trainer and the selection jury) and jumping ability, dressage-ability and rideability (rated by the independent test rider) were subjected to Factor Analysis (FA) with varimax rotation. The FA produced three factors [Cooperation (Cp), Jumping Potential (JP) and Dressage Potential (DP)] with eigenvalues > 1, which accounted for 64.6% of the total variance of the traits examined. After rotation, the factors represented Cp: 23.2.0%, JP: 21.5% and DP: 19.8% of variance respectively. The traits of character, temperament, trainability, jumping under the rider, rideability, dressage and jumping abilities had high loadings on the second factor (Cp) and thereafter, the assessment of all behaviour-related traits contributed to the general evaluation with approximately one-fifth of total variability. The findings may indicate that successful sport careers for any horse may be much more closely associated with willingness to cooperate with the rider and riding and handling behaviour, than to the horse's actual physical performance potential. It would appear that only so-called sport-suitable performance of the horse is being selected for in performance tests (during jumping and dressage suitability testing). This approach may be short-sighted and inadequate with serious implications for horse under-performance in leisure activities notwithstanding general horse welfare within the disciplines of equitation.
|
|
