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Holmstrom, M., Magnusson, L. E., & Philipsson, J. (1990). Variation in conformation of Swedish warmblood horses and conformational characteristics of elite sport horses. Equine Vet J, 22(3), 186–193.
Abstract: The variation in conformation of 356 Swedish Warmblood horses is described, using a quantitative method of measuring horses. Thirty-three of the horses were elite dressage horses, 28 were elite showjumpers, 100 were riding school horses and 195 were unselected four-year-olds. Most horses had a long body form. The average height at the withers was 163.4 cm. Sixty per cent of the horses had a bench knee conformation, 50 per cent had a toe-in conformation of the forelimbs and 80 per cent had outwardly rotated hind limbs. The majority of these deviations were mild or moderate. Conformation was influenced by sex and age. Mares were smaller and had longer bodies and shorter limbs. The elite dressage horses and showjumpers had larger hock angles and more sloping scapulas than other horses. The showjumpers also had smaller fetlock angles in the front limbs. It is suggested that the larger hock angles among the elite horses may be because hocks with small angles are more prone to injury, and because small hock angles may negatively influence the ability to attain the degree of collection necessary for good performance in advanced classes.
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Jablonska, E. M., Ziolkowska, S. M., Gill, J., Szykula, R., & Faff, J. (1991). Changes in some haematological and metabolic indices in young horses during the first year of jump-training. Equine Vet J, 23(4), 309–311.
Abstract: Effects of an 18 min exercise test, on three separate occasions during a one year jump-training programme, was studied in seven horses. Determinations were carried out on venous blood for packed cell volume, haemoglobin, total protein, lactate and pyruvate, glucose, free fatty acids, insulin, glucagon, blood gases, bicarbonate, pH, aldolase, aspartate aminotransferase and alanine amino-transferase. Exercise caused a slight increase in lactate and pyruvate, total protein, aldolase, alanine aminotransferase, pO2, bicarbonate and pH. Glucose, free fatty acids and pCO2 levels decreased. Training caused no significant difference in these changes. However, during the year, increases in lactate and decreases in pH (resting levels) were observed.
Keywords: Alanine Transaminase/blood; Animals; Bicarbonates/blood; Blood Glucose/analysis; Blood Proteins/analysis; Breeding; Carbon Dioxide/blood; Exercise Test/veterinary; Fatty Acids, Nonesterified/blood; Female; Fructose-Bisphosphate Aldolase/blood; Hematocrit/veterinary; Hemoglobins/analysis; Horses/*blood/metabolism; Hydrogen-Ion Concentration; Lactates/blood; Male; Oxygen/blood; *Physical Conditioning, Animal; Pyruvates/blood
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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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Seghrouchni, M., Elkasraoui, H., Piro, M., Alyakine, H., Bouayad, H., Chakir, J., et al. (2019). Osteoarticular radiographic findings of the distal forelimbs in Tbourida Horses. Heliyon, 5(9), e02514.
Abstract: Tbourida is a traditional Moroccan equestrian sport in which 15 horses gallop 200 m in a line while riders fire into the sky with muskets. The stop is the finale and representative demands of this equestrian event. Such particular sudden stop after a fast gallop requires a hyperextension of the metacarpophalangeal joint. Indeed, it is well known that Tbourida show predisposes horses to different injuries of the hard and soft tissues of the distal forelimbs. Yet, there is a paucity of research that examined such lesions. The aim of the present study was to investigate for the first time the type and the prevalence of osteoarticular findings in the distal forelimbs of Tbourida horses using radiographic images. The study was conducted on 127 Tbourida horses aged between 2.5 and 15 years old with 6-year-old horses being the most affected. Data analysis showed that 93,7% of horses exhibit degenerative joint lesions of the fetlock, 86,6% showed ossification of the ungual cartilage, 78,7% had enthesophytes associated with the deep digital flexor tendons, 81,1% had enthesophytes associated with the suspensory ligament branches, and 19,6% showed a particular exostosis on the first phalanx. This large number of lesions reflects how this sport is difficult for horses and also argues that animals are suffering from a lack of welfare and care in their husbandry management.
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Albentosa, M. J., Kjaer, J. B., & Nicol, C. J. (2003). Strain and age differences in behaviour, fear response and pecking tendency in laying hens. Br Poult Sci, 44(3), 333–344.
Abstract: 1. Behaviours associated with a high or low tendency to feather peck could be used as predictors of feather pecking behaviour in selective breeding programmes. This study investigated how strain and age at testing influenced responses in behavioural tests. 2. Four layer-type strains (ISA Brown, Columbian Blacktail, Ixworth and a high feather pecking (HP) and a low feather pecking (LP) line of White Leghorn) were reared in 6 same-strain/line pens of 8 birds from one day old. Birds in half the pens were given an open field test, a novel object test and a test with loose feather bundles between 4 and 12 weeks of age and a tonic immobility (TI) test at 13 weeks of age. All pens were tested with fixed feather bundles at 26 weeks, and undisturbed behaviour in the home pens was videoed at 1 and 27 weeks of age. Daily records of plumage damage were used as an indicator of feather pecking activity in the home pens. 3. Strain did not influence novel object test, open field test or loose feather test behaviour, although age effects in all three tests indicated a reduction in fearfulness and/or an increase in exploratory behaviour with increasing age. 4. White Leghorns showed longer TI durations than the other strains but less pecking at fixed feather bundles than ISA Browns and Columbian Blacktails. 5. There were few associations between behaviour in the 5 different tests, indicating that birds did not have overall behavioural traits that were consistent across different contexts. This suggests hens cannot easily be categorised into different behavioural 'types', based on their test responses and casts doubt on the usefulness of tests as predictors of feather pecking.
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Clutton-Brock, T. H., Russell, A. F., Sharpe, L. L., Brotherton, P. N., McIlrath, G. M., White, S., et al. (2001). Effects of helpers on juvenile development and survival in meerkats. Science, 293(5539), 2446–2449.
Abstract: Although breeding success is known to increase with group size in several cooperative mammals, the mechanisms underlying these relationships are uncertain. We show that in wild groups of cooperative meerkats, Suricata suricatta, reductions in the ratio of helpers to pups depress the daily weight gain and growth of pups and the daily weight gain of helpers. Increases in the daily weight gain of pups are associated with heavier weights at independence and at 1 year of age, as well as with improved foraging success as juveniles and higher survival rates through the first year of life. These results suggest that the effects of helpers on the fitness of pups extend beyond weaning and that helpers may gain direct as well as indirect benefits by feeding pups.
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