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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.
Keywords: Breeding objective; Sport horse; Sport performance; Conformation; Specialisation
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Huizinga, H. A., Boukamp, M., & Smolders, G. (1990). Estimated parameters of field performance testing of mares from the Dutch Warmblood riding horse population. Livestock Production Science, 26(4), 291–299.
Abstract: The field performance testing (FPT) of mares of the Dutch Warmblood riding horse population is evaluated. Phenotypic and genetic parameters of scored traits are estimated and the genetic relationship with performance of half-sibs in dressage and jumping competition are estimated. Data from 1984 to 1987 are used, covering scores from 2023 at least 3-year-old mares. Seven subjectively scored traits are considered, walk, trot, canter, riding ability, character, jumping ability and total score. Analysis of data is according to a sire model. Variance and covariance components are estimated by Restricted Maximum Likelihood (REML) procedures. Estimates of heritability are moderately low for gaits (average 0.19), jumping ability (0.15) and total score (0.17) and extremely low for riding ability (0.03) and character (0.06). Dressage in competition is most correlated with riding ability (0.83) and is moderately correlated with total score (0.41) from FPT of mares. Jumping competition is most correlated with jumping ability (0.48) and not correlated with total score (0.05) from field test of mares. Some possible bias owing to previous knowledge and preselection is discussed. It is concluded that efficiency of present FPT of mares is limited for selection of broodmares for dressage and jumping ability in competition.
Keywords: competition; genetic parameters; horse breeding; mares; performance test
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Drent, P. J., van Oers, K., & van Noordwijk, A. J. (2003). Realized heritability of personalities in the great tit (Parus major). Proc Biol Sci, 270(1510), 45–51.
Abstract: Behaviour under conditions of mild stress shows consistent patterns in all vertebrates: exploratory behaviour, boldness, aggressiveness covary in the same way. The existence of highly consistent individual variation in these behavioural strategies, also referred to as personalities or coping styles, allows us to measure the behaviour under standardized conditions on birds bred in captivity, link the standardized measurements to the behaviour under natural conditions and measure natural selection in the field. We have bred the great tit (Parus major), a classical model species for the study of behaviour under natural conditions, in captivity. Here, we report a realized heritability of 54 +/- 5% for early exploratory behaviour, based on four generations of bi-directional artificial selection. In addition to this, we measured hand-reared juveniles and their wild-caught parents in the laboratory. The heritability found in the mid-offspring-mid-parent regression was significantly different from zero. We have thus established the presence of considerable amounts of genetic variation for personality types in a wild bird.
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Hamilton, W. D. (1971). Geometry for the selfish herd. J. Theor. Biol., 31(2), 295–311.
Abstract: This paper presents an antithesis to the view that gregarious behaviour is evolved through benefits to the population or species. Following Galton (1871) and Williams (1964) gregarious behaviour is considered as a form of cover-seeking in which each animal tries to reduce its chance of being caught by a predator.
It is easy to see how pruning of marginal individuals can maintain centripetal instincts in already gregarious species; some evidence that marginal pruning actually occurs is summarized. Besides this, simply defined models are used to show that even in non-gregarious species selection is likely to favour individuals who stay close to others. Although not universal or unipotent, cover-seeking is a widespread and important element in animal aggregation, as the literature shows. Neglect of the idea has probably followed from a general disbelief that evolution can be dysgenic for a species. Nevertheless, selection theory provides no support for such disbelief in the case of species with outbreeding or unsubdivided populations. The model for two dimensions involves a complex problem in geometrical probability which has relevance also in metallurgy and communication science. Some empirical data on this, gathered from random number plots, is presented as of possible heuristic value. Keywords: Animals; Anura; *Behavior, Animal; Breeding; Communication; Evolution; Fear; Metallurgy; *Models, Biological; Probability; Snakes; *Spatial Behavior
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Haring, H. (2005). Development, level and prospects of the german horse breeding. Zuechtungskunde, 77(6), 490–495.
Abstract: The economic impact of the horses of the Federal Republic of Germany has gone up, the statistic numerals verify obviously that Germany took pride of place in Europe in terms of numbers of riders as well as numbers of horses. Successes of German branded horses let their breeders reach the summit worldwide. The carefully agreed breeding programme connects practical cognitions with those of science and permits the leading breeding areas unobstructed space to set their own priorities. Globalisation and rised demand of customers forces breeding associations towards a far-reaching reorganisation because just large powerful institutions can meet these requirements. An end of this process, which scarcely has just begun, cannot yet be conceivable seen. – Eugen Ulmer KG, Stuttgart.
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Dubois, C., Manfredi, E., & Ricard, A. (2008). Optimization of breeding schemes for sport horses. Livestock Science, 118(1-2), 99–112.
Abstract: A selection scheme for jumping sport horses is modelled with four stages of selection for males and one stage for females. The selection objective included three traits: conformation and gaits (CG, weighted 20%), competition jumping (CJ, weighted 60%) and a third trait (TT, weighted 20%) such as sperm quality or orthopaedic status. The first selection stage is based on knowledge of the pedigree with the aim of selecting horses suitable for CG test (at 3Â years old) and CJ test (at 5Â years old). The second stage includes the horse's own performance with respect to CG and CJ with the aim of selecting horses suitable for the TT test. The third stage is the selection of a limited number of males who are allowed to reproduce. The fourth stage (at 12Â years old) takes into account the results of the horse's progeny. Females are selected in one step, whatever the number of performances measured at 5Â years old. The annual genetic response was 9.4% genetic standard deviation of the objective, 2.6% for CG, 9.0% for CJ and 1.5% for TT. Results showed that selection by progeny testing did not contribute much to genetic response (12% of progeny issued from proven sires), the female pathway represented 26% of genetic response, TT was difficult to improve when the genetic correlation was unfavourable (-Â 0.6% genetic standard deviation for -Â 0.20 genetic correlation), and should consequently be directed towards the use of molecular markers. When compared with a selection scheme involving a station test, genetic response was the same if the breeding values used for selection before entering the station test took into account the results of the relatives for CJ and CG. This revealed the importance of an extensive performance test (like for competition performance) when designing breeding schemes for sport horses.
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Creel, S. (2001). Social dominance and stress hormones. Trends. Ecol. Evol, 16(9), 491–497.
Abstract: In most cooperatively breeding birds and mammals, reproductive rates are lower for social subordinates than for dominants, and it is common for reproduction in subordinates to be completely suppressed. Early research conducted in captivity showed that losing fights can increase glucocorticoid (GC) secretion, a general response to stress. Because GCs can suppress reproduction, it has been widely argued that chronic stress might underlie reproductive suppression of social subordinates in cooperative breeders. Contradicting this hypothesis, recent studies of cooperative breeders in the wild show that dominant individuals have elevated GCs more often than do subordinates. The findings that elevated GCs can be a consequence of subordination or a cost of dominance complicate the conventional view of social stress, with broad ramifications for the evolution of dominance and reproductive suppression.
Keywords: Dominance; rank; stress; glucocorticoids; cooperative breeding; sociality; behavioural endocrinology; mammals
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Valone, Thomas J., & Templeton, J. J. (2002). Public information for the assessment of quality: a widespread social phenomenon. Phil. Trans. Biol. Sci., 357(1427), 1549–1557.
Abstract: We propose that the use of public information about the quality of environmental resources, obtained by monitoring the sampling behaviour of others, may be a widespread social phenomenon allowing individuals to make faster, more accurate assessments of their environment. To demonstrate this (i) we define public information and distinguish it from other kinds of social information; (ii) we review empirical work demonstrating the benefits and costs of using public information to estimate food patch quality; (iii) we examine recent work showing that individuals may also be using public information to improve their estimates of the quality of such disparate environmental parameters as breeding patches, opponents and mates; and finally (iv) we suggest avenues of future work to better understand the nature of public information use and when it might be used or ignored. Such work should lead to a more complete understanding of the behaviour of individuals in social aggregations.
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Mech L.D. (2000). Leadership in Wolf, Canis lupus, Packs. Can Field Nat, 114(2), 259–263.
Abstract: I examine leadership in Wolf (Canis lupus) packs based on published observations and data gathered during summers from 1986 to 1998 studying a free-ranging pack of Wolves on Ellesmere Island that were habituated to my presence. The breeding male tended to initiate activities associated with foraging and travel, and the breeding female to initiate, and predominate in, pup care and protection. However, there was considerable overlap and interaction during these activities such that leadership could be considered a joint function. In packs with multiple breeders, quantitative information about leadership is needed.
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Benhajali, H., Richard-Yris, M. - A., Ezzaouia, M., Charfi, F., & Hausberger, M. (2010). Reproductive status and stereotypies in breeding mares: A brief report. Appl. Anim. Behav. Sci., 128(1-4), 64–68.
Abstract: The aim of this study was to investigate the relationship between age, reproductive status and sire of the mare and the tendency to perform stereotypies. One hundred and fourteen purebred Arab mares, offspring of 39 sires ( offspring per sire) and aged 4-21 years () were observed from the 30th March to the 15th of May 2005 using instantaneous scan sampling. We used a multivariate logistic regression in order to study the relationship between age, reproductive status and sire of the mare and the tendency to perform stereotypies. 28% of the observed mares showed stereotypic behaviour, mostly weaving (22%). Neither age (χ2 Wald = 9.36, p = 0.89) nor sire (χ2 Wald = 4.34, p = 1.0) affected the occurrence of stereotypies whilst the reproductive status of the mare influenced significantly the occurrence (χ2 Wald = 10.75, p = 0.001) but also the type (χ2 = 12.1, p < 0.001) of stereotypic behaviour. Weaving was more frequent in non foaling mares (41.4%) than in foaling mares (1.8%) that performed mostly stall-walking.
Keywords: Stereotypies; Breeding mare; Sire; Reproductive-status
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