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Held, S., Mendl, M., Devereux, C., & Byrne, R. W. (2001). Studies in Social Cognition: From Primates to Pigs. Animal Welfare, 10, 209–217.
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Evans, C. S., & Evans, L. (2007). Representational signalling in birds. Biology Letters, 3(1), 8–11.
Abstract: Some animals give specific calls when they discover food or detect a particular type of predator. Companions respond with food-searching behaviour or by adopting appropriate escape responses. These signals thus seem to denote objects in the environment, but this specific mechanism has only been demonstrated for monkey alarm calls. We manipulated whether fowl (Gallus gallus) had recently found a small quantity of preferred food and then tested for a specific interaction between this event and their subsequent response to playback of food calls. In one treatment, food calls thus potentially provided information about the immediate environment, while in the other the putative message was redundant with individual experience. Food calls evoked substrate searching, but only if the hens had not recently discovered food. An identical manipulation had no effect on responses to an acoustically matched control call. These results show that chicken food calls are representational signals: they stimulate retrieval of information about a class of external events. This is the first such demonstration for any non-primate species. Representational signalling is hence more taxonomically widespread than has previously been thought, suggesting that it may be the product of common social factors, rather than an attribute of a particular phylogenetic lineage.
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Rescorla, R. A., & Holland, P. C. (1982). Behavioral Studies of Associative Learning in Animals. Annual Review of Psychology, 33(1), 265–308.
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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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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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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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Koenen, E. P. C., van Veldhuizen, A. E., & Brascamp, E. W. (1995). Genetic parameters of linear scored conformation traits and their relation to dressage and show-jumping performance in the Dutch Warmblood Riding Horse population. Livestock Production Science, 43(1), 85–94.
Abstract: In this study genetic parameters of linear scored conformation traits of the Dutch Warmblood Riding Horse were estimated in relation to performance in competition. Observations on 10 665 mares were analyzed with an animal model including the fixed effects age, classifier, location and percentage of thoroughbred. Using restricted maximum likelihood algorithms, heritabilities of 26 linear scored conformation traits were estimated in the range 0.09-0.28. Several conformation traits had high up to very high mutual genetic correlations. Competition results of 3476 horses with performance in dressage and 3220 horses with performance in show-jumping were linked to the conformation data to estimate the genetic relationship between conformation and performance in competition. The model for the evaluation of the competition results included the fixed effects riding club, age and sex. Estimated heritabilities for dressage and show-jumping were 0.17 +/- 0.05 and 0.19 +/- 0.04, respectively. Genetic correlations between conformation and performance were low to moderate. The length of the neck, length and position of the shoulders, shape and length of croup and muscularity of the haunches had a significant moderate genetic correlation with dressage. Muscularity of the neck, shape of the croup and muscularity of the haunches had a significant genetic correlation with show-jumping. The results indicate that, due to the low genetic correlations with performance traits, indirect selection for performance using conformation results is of limited value.
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Cho, K. C., & Chan, K. K. (1984). Kinetics of cold-induced denaturation of metmyoglobin. Biochimica et Biophysica Acta (BBA) – Protein Structure and Molecular Enzymology, 786(1-2), 103–108.
Abstract: Using a slow temperature-jump spectrophotometer, we have studied the kinetics of cold-induced denaturation of metmyoglobin between 0[degree sign]C and 20[degree sign]C at acidic pH. The time-scale of the transition is slow and is of the order of minutes. The results are consistent with the transition's involving a total of three states, native (N), transient intermediate (I) and denatured (D), which are converted from one to the other in that order.
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