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Author Hausberger, M.; Fureix, C.
Title On the significance of puzzling behaviours: what do yawning and adult play tell us about horse (Equus caballus) welfare? Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue (up) Pages
Keywords welfare indicators, yawning, adult play, altered welfare, horse
Abstract Some behaviours remain a mystery and their determinants are still uncertain. Here we propose a critical interpretation of two puzzling behaviours, i.e. yawning and adult play, recorded in large samples of domestic horses kept in sub-optimal conditions (e.g. time-restricted feeding practices, social isolation). Yawning is involved in behavioural state changes, especially in quiet contexts of motor relaxation, but seems also to be triggered by stress and emotional contexts. Thus, we investigated specific correlates of yawning and stereotypic behaviours in two large samples of working horses (n1 = 87, n2 = 59). A clear co-occurrences of yawning and stereotypic behaviours appeared: stereotypic horses yawned more than the non-stereotypic horses (Fisher test, p < 0.02), yawning increased at the same time periods as stereotypic behaviours did (Wilcoxon tests, p < 0.05 to 0.001) and yawning frequency was even sometimes positively correlated with stereotypic behaviour frequencies (Spearman correlations, p < 0.005). Play, more typical of young stages in healthy individuals, occurs rarely at adult stages but then more often in captive/domestic animals (which can be challenging to welfare) than in animals living in natural conditions. Thus, we tested the hypothesis that adult play may reflect altered welfare states in horses, where, as in several species, play rarely occurs at adult stages in natural conditions. We observed the behaviour (in particular social play) of 29 adult riding school horses during occasional outings in a paddock and measured several stress indicators (health-related, behavioural and physiological) when these horses were in their home individual boxes. Results revealed that the number of horses and rates of adult play appeared very high compared to field report data and that most stress indicators measured differed between “players” and “non-players”, revealing that most “playful” animals were more prone to suffer from chronic stress contrarily to “non-playful” horses (Fisher, Chi-square, Mann-Whitney and Spearman correlation tests, p < 0.05 to 0.001). Altogether, these results show that yawning and adult play can both reflect altered welfare states in horses, highlighting that these puzzling behaviours should not be considered, as currently thought, as reliable indicators of good welfare states and / or expression of positive emotions.
Address
Corporate Author Hausberger, M. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5516
Permanent link to this record
 

 
Author Russell, M.A.; Aldridge, B.E.
Title Solving Current Domestic Horse Nutrition Challenges Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue (up) Pages
Keywords horse nutrition, clinical diseases, digestion, feeding, management
Abstract Solving horse nutrition challenges require contributions from Psychology, Biology, Agriculture, and Veterinary Medicine because these are biological challenges of an anthropological nature. The domesticated horse has shifted from an animal of war, transportation, and farmwork, to a companion enjoyed for sport, leisure and recreation. The first realization and responsibility must lie in the fact that it is the owners and managers which are the source of many of the horses’ challenges. Nutritional challenges include: defining requirements and absorption of nutrients, improving feed efficiencies for performance, improving feeding management and eating behaviors, and preventing or treating clinical problems. These challenges can be addressed through science, horse management, and education. Many of today’s challenges in horse nutrition can be related to the equine genome and genetics. Those that can be addressed with nutritional consequences include Polysaccharide Storage Myopathy, Equine Metabolic Syndrome, Recurrent Exertional Rhabdomyolysis, Glycogen Branching Enzyme Deficiency, Hyperkalemic Periodic Paralysis, and Development Orthopedic Disorders. It is the scientific understanding of cellular processes in relation to nutrients which address the symptoms associated with these diseases. Consequently, feeding management can be changed to actually treat the disease. The most recent advances in equine nutrition implement the use of molecular and cellular based techniques to understand how nutrients are needed during times of stress, feed withdrawal and to maintain gut health. For example, the absorptive capacity and transporter gene expression and localization, are now being quantified. We are also now assessing the impact of the loss of reproductive endocrines on calcium and phosphorus homeostasis in the horse. Additionally, bioluminescent pathogenic bacteria have been utilized to view attachment rates in the gastrointestinal tract of the horse. These are merely examples of the approaches of science to these nutritional challenges. Science is of little use unless it is incorporated into improved management of horses. Every type of horse requires different management and good husbandry. In our country, 70+% of the horses are kept in small herds, on limited acreage, and used for recreation and sport. Since we have taken the horse out of its natural environment and subjected it to these roles, we now seek to determine ways to feed the horse in our environments; i.e. obesity, inconsistent exercise, confinement, surgery, competition, diseases. Private horse feed agribusinesses have aggressively positioned excellent products with claims to improve health, reproduction, performance, and even horse happiness. Owners and managers seek unbiased science upon which they ultimately make their own decisions. General challenge categories seem to be feeding geriatric horses, active performance horses, and idle horses with secondary metabolic problems. Thus, feeding recommendations include the determination of specific horse nutrient requirements, maximization of available forages, providing other nutrients, and exercise to manage horses more as horses. Private and public companies and Extension systems exist to provide online and other sources of information. As more and more people own horses as a hobby and for recreation, they share responsibility to inform themselves on how to best feed and care for their horses.
Address
Corporate Author Russell, M.A. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5523
Permanent link to this record
 

 
Author Posta, J.; Mezei, A.; Mihók, S.
Title Genetic evaluation of competition years, as a kind of measurement of durability in Hungarian show-jumping horses Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue (up) Pages
Keywords Sport horse, show-jumping, genetic evaluation, durability
Abstract The aim of the study was to investigate the possibilities to use “number of years in competition” as a measure of durability in the genetic evaluation of Hungarian show-jumping horses. Competition results recorder between 1996 and 2009 in show-jumping competitions were used to estimate genetic parameters for number of years in competition. The results were collected by the Show-jumping Group of the Hungarian Horse Breeder’s Society. For estimation of genetic parameters for number of years in competition different linear mixed models were tested. In the first model, sex and birth year were taken into account as fixed effects. In the second model, an adjustment was made for age at first result in competition. The model fit was compared based on their determination coefficient. Variance components were estimated with VCE-6 software package. The determination coefficients of the models were 0.09 and 0.20, while the estimated heritability for number of years in competition was 0.27 and 0.23, respectively.
Address
Corporate Author Posta, J. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5524
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Author Spasskaya, N.N.
Title Results of investigations of an island population of the feral horse (Rostov Region, Russia) Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue (up) Pages
Keywords feral horse, island population, social population structure, demography
Abstract A feral horse population inhabiting the Vodnyi Isl, Manych-Ghudilo Lake, on the territory of Rostov Region, S Russia, has been established in 1950s according to questionnaire data (Paklina, Klimov, 1990). It is a sole permanent grouping of feral horse known to exist in European Russia (Spasskaya, Spasskyi, 2007; Spasskaya, 2008). Range of this group is part of Federal Reserve “Rostovsky” established in 1995, and its monitoring has being been conducted since 2006. The principal aim of monitoring includes gathering data on demographic, spatial, and ethological structure of the island horse population, along with investigation of its phenotypic and ethological patterns. Analysis of previously published (Paklina, Klimov, 1990) and recently obtained data on the color patterns of the island horse indicate that they have become isolated supposedly about 18–20 years ago. Some trends in variation of several phenotypic traits indicate slight rising of inbreeding level in this population, including decrease in the horse withers height, changes in body proportions, increase of heterogeneity in body color patterns (size and number of head and leg spots), and increase of frequency of dental malformations, especially of false polydonty of P1 (Spasskaya et al., 2010). Principal demographic parameters of this population are similar in general to those known for other feral horse studied by now. However, several peculiar features of this population were revealed: its age structure appeared to be of steadily fading type judging by high proportion of mature individuals (64–72 %); high mortality rate of individuals of the first year of life (16–25 %); predominance of males among newborns with increase of population size. Ethological structure of the population included standard harem bands and bachelor groups, with few solitary animals (usually old or sick stallion). The most of individuals (58.2–84.3 %) were the part of harem bands, which appeared to be the most stable groupings. The harems were small in their numbers with predominatingly 3–8 individuals. The bachelor groups were inconstant in composition, their portion in population being not high (7.7–15.4 % of the total number). A lot of “mixed” groupings of various composition were recorded in the population during its high number phase: harem bands with several mature stallions; associations consisting of several harem bands; youth groupings consisting of approximately coeval stallions and mares. These “mixed” groupings appeared to be rather stable, with their total number reaching up to 25.8 % of the population. They however used to disappear with population number decrease. The Rostov population is characterized by absence of conspicuous home range of social groupings (Spasskaya, Shcherbakova, 2007; Spasskaya, 2009), so the latter form a united herd with minimal intergroup distances. This phenomenon is probably not related to population density or to the island size, but is rather caused by some other factors to be revealed.
Address
Corporate Author Spasskaya, N.N. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5526
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Author De Giorgio, F.; Schoorl, J.M.
Title Why isolate during training? Social learning and social cognition applied as training approach for young horses (Equus caballus) Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue (up) Pages
Keywords Cognitive approach; Horse training; Horse-Human relationship; Social environment; Social learning
Abstract In the last decade an increasing number of studies has been oriented towards equine social learning and their social behavior within the herd (Kruger‚ 2006-2008). In social species, social learning is important to learn and gain useful skills to move and live in their own social and environmental context. Group housing has been recognized as an important element to fulfill the physical and behavioral needs of horses, especially their need for social contact (Søndergaard‚ 2011). Still‚ when it comes to horse training, the social aspect and‚ in general‚ cognitive abilities of the horse are rarely taken into account. Although it is widely accepted that social isolation is stressful for horse (Mal et al, 1991a and 1991b) still isolating a young horse is the first step when it comes to training methods. Due to tradition and culture and our performance-oriented society it is both difficult to accept and apply a different social/cognitive training approach. Training sessions are focused on immediate results whereas in cognitive learning part of the process is latent and will not be visible immediately‚ but taking the cognitive skills into account plays an important role in avoiding tension both in the horse as in the human-horse interaction (Baragli and De Giorgio, 2011). In this study we tested the possibility to apply social learning by creating a social environment‚ favoring a cognitive learning approach‚ for the training of six young horses. The group existed in three males and three females, between two and three years old. All six showed initial difficulties and defense to human interaction. They were housed in two groups in adjacent spacious paddocks where they had ample opportunity to move and express their individual and social behavioral repertoire. Each horse had one training session per week without isolating it from the others. The training sessions were held following a cognitive-relational model defined as the equine-zooanthropologic approach (De Giorgio, 2010 – Marchesini, 2011). The learning objectives were to be able to handle each horse‚ conduct it‚ saddle and ride it within a maximum time-frame of two years. Every time a defensive or alert behavior would occur the training activity was re-arranged to not over-pressure the horse. Therefore the persons working with the horses carried out the activities without tight expectations focusing on the horses’ positive attention. After eighteen months all six horses were used to the saddle and to riding. None of the horses ever fled or showed defense behavior and in the case of unexpected events they showed no emotional reactivity/reactive behavior. Today the horses show the same calm behavior whenever worked individually. This preliminary study highlights how social learning applied to equestrian activity can be fundamental for safety and welfare and the establishment of a more problem-free relationship between horse and human. Safety as the defensive behavior seems to have been reduced and welfare as the horses have been trained in a social context without being isolated and thus without being stressed during the training experience.
Address
Corporate Author De Giorgio, F. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5528
Permanent link to this record
 

 
Author Pokorná, M.; Bartošová, J.
Title Social learning in horses Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue (up) Pages
Keywords horse, human demonstrator, interspecific observational learning
Abstract Social observational learning is one of learning abilities expected in domestic horses (Equus caballus) because of their ecological and evolutional history. However, a few studies on this type of learning in horses failed to provide clear evidence of observational learning and/or could not distinguished it from other types of learning. We tested interspecific observational learning abilities using the spatial task and a human demonstrator. We hypothesised that 1) horses with possibility of observing a human demonstrator will complete the task in shorter time than control horses without any demonstrator, and 2) horses observing a familiar demonstrator will carry out the task in shorter time than horses with an unfamiliar demonstrator due to established positive human-horse relationship. We randomly allocated 24 riding horses of mixed age and breed to three groups per 8 and started the task either with observing a familiar demonstrator, unfamiliar demonstrator or without demonstrator (control group). Each horse was released individually at the starting point in the experimental paddock and the latency to pass the task was recorded. A horse completed the task once it walked 25 m from the starting point to the squared area (4x4 m) fenced by a tape, went into it through the entrance on the opposite side and touched the bucket with food. Eight people served as demonstrators, each for one familiar and one unfamiliar horse. Horses from groups with a demonstrator, either familiar or unfamiliar, reached the food bucket significantly faster than control horses during the first trial (mean±SE: 29.1±3.13 s with familiar, 28.9±3.13 s unfamiliar and 41.5 ± 3.13 s without demonstrator, P<0.02, GLMM, PROC MIXED, SAS). Horses did not differ in time needed to reach the fence of the squared area, but in “solving time”, i.e. time from reaching the fence of the squared area and touching the bucket (14.6±2.34, 14.3±2.34 and 27.6±2.34 s in horses with familiar, unfamiliar or without demonstrator, P<0.001). Despite our presumption, the horses observing a familiar demonstrator finished the task in comparable time as horses with an unfamiliar demonstrator (P=0.85) which indicated little effect of long lasting positive relationship between a horse and a particular human. We found, however, large individual variability in performance of individual demonstrators. Further, horses did not differ in time needed to pass the same task without a demonstrator repeated either shortly or 7 days after the first test which supported that interspecific observational learning rather than social facilitation occurred. In conclusion, horses with a human demonstrator, regardless familiar or unfamiliar, were able to solve the task in shorter time compared to control horses but they did not differ in performing repeated task if they learned it by individual or social learning process. This indicates that interspecific observational learning does occur in horses. Supported by AWIN, EU FP7 project No. 266213.
Address
Corporate Author Pokorná, M. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5529
Permanent link to this record
 

 
Author Theodoropoulou, P.; Youlatos, D.
Title Prevalence of stereotypies amongst Thoroughbred race horses (Equus caballus) in Greece Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue (up) Pages
Keywords Thoroughbred, race horse, stereotypy, Greece
Abstract Thoroughbred horses are keen to develop stereotypies in higher rates compared to other breeds. In Greece, race horses are exclusively thoroughbreds, which are intensively kept under strict environments. Our study, the first of its kind in Greece, explores the prevalence of stereotypic behaviour in these horses and its interrelation to intrinsic and management factors. For these purposes, we recorded intrinsic (age, gender, indoors and outdoors temperament, playfulness, etc.) and management parameters (time spent out, number of horses per groom, etc.) in association with established stereotypic behaviours (box walking, weaving, head nodding, wind sucking, bed eating) in 209 horses in the Markopoulo Race Track, Attica, Greece. Our analysis showed an overall prevalence of 46.6 %, which is way too high compared to those reported for other race horses worldwide. Furthermore, box walking was strongly associated with indoors temperament (p=0.012), playfulness (p=0.03), and horses per groom (p<0.001). Bed eating with gender (p=0.009), outdoors temperament (p=0.018) and playfulness (p=0.004), while head nodding with indoors and outdoors temperament (p=0.001 and p=0.002, respectively). These results corroborate with previous investigations in other race horses, and indicate the importance of intrinsic factors in developing stereotypies in Thoroughbreds.
Address
Corporate Author Theodoropoulou, P. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5536
Permanent link to this record
 

 
Author Erber, R.; Wulf, M.; Aurich, J.; Becker-Birck, M.; Rose-Meierhöfer, S.; Möstl, E.; Hoffmann, G.; Aurich, C.
Title Physiological stress parameters in sport horse mares transferred from group housing to individual stabling Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue (up) Pages
Keywords horse, isolation, cortisol, heart rate, locomotion
Abstract Initial equestrian training and especially first mounting of a rider are stressful challenges for young horses (1). Most young horses are raised in groups but, in association with equestrian training, they are commonly transferred to individual stabling in loose boxes. Although, in most stables, visual contact with horses in adjacent boxes is possible, separation from the herd might be an additional stressor. We have studied physiological stress parameters, in 3-year-old sport horse mares (n=8), transferred from a group stable with access to a paddock to individual boxes without paddock. Once stabled in the individual boxes, mares underwent a standard training for young horses. Horses had been accustomed to lunging and tolerating a rider on their back several weeks before the study. Mares were studied from 5 days before to 5 days after changing the stable. Cortisol concentration in saliva, locomotion activity (ALT pedometers), heart rate (HR) and HR variability (RMSSD: root mean square of successive beat-to-beat intervals) were determined. We hypothesized that the change of the stable increases cortisol release and is associated with changes in HR and RMSSD and reduced locomotion. Before mares were moved to individual boxes, cortisol concentration showed a pronounced diurnal rhythm with values around 0.6 ng/ ml in the morning and a continuous decrease throughout the day. When the mares were moved to individual boxes, cortisol concentration increased to 1.8±0.2 ng/ml and did not return to baseline values within 6 h (p<0.05 over time). On subsequent days, a diurnal rhythm was re-established but shifted to a higher level than before. Locomotion activity determined by ALT pedometers was increased for some minutes only after mares has been placed in individual boxes but was only slightly higher than during the time mares spent with the group in a paddock. On days 2-5 in individual boxes, locomotion activity was reduced compared to the group stable. HR increased and the HRV variable RMSSD decreased when mares were separated. In conclusion, separating horses during initial training from their group is an additional stressor, although the stress is less pronounced than induced by other social challenges, e.g. weaning of foals (2). When stabled in individual boxes, mares move less than when kept as a group. Horses kept in a group thus appear to exercise themselves freely, such an effect is absent when the animals are kept individually.
Address
Corporate Author Erber, R. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5542
Permanent link to this record
 

 
Author Dubcová, J.; Bartošová, J.; Komárková, M.
Title Impact of weaning method on weanlings’ weight gain in domestic horses Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue (up) Pages
Keywords Horse, Equus caballus, weaning, weight gain
Abstract Artificial weaning is associated with various stresses for the foal, such as loss of the mother, feeding changes, new and unfamiliar environment, etc. We investigated the impact of two different methods of abrupt weaning on weight gain in group housed Kladruby horses born 2009 (National Stud Kladruby nad Labem, CZ). Two groups of the foals were weaned abruptly at age from 5,5 to 8 months and transported to the other facility but the first group (G1, N=14) spent one week in their home environment after their mothers were led away. The other foals (G2, N=15) were moved away immediately after separation from the mothers (i.e. they lost the mother and known environment at one time). Foals were weighed: at the weaning day, weekly within the first month and then monthly up to 6 months after weaning. Neither birth nor weaning weight differed significantly between the two groups kept under similar nutrition. We hypothesised that a week spent in the home environment should reduce foal’s weight loss usually following the loss of the mother and moving to the unknown environment. The weaning type significantly influenced weight gain the foals reached one week after weaning (p < 0.001, GLM, PROC GLM, SAS). Contrary to our expectations, G1 foals lost their weight whereas G2 ones gained weight during the same period (-4.9 vs. +3.2 kg). G1 foals reached back their weaning weight within 3 weeks after weaning. The weight of the foals at 6 months after weaning was still marginally higher in G2 than G1foals (388.2 vs. 365.7 kg, p < 0.07). We found lower detrimental effect on weight gain in G2 foals (i.e. weaned and immediately moved) compared to G1 foals (weaned and stayed before moved). Thus, our results indicate lower stress induced to the foals in more radical type of weaning. Supported by AWIN, EU FP7 project No. 266213.
Address
Corporate Author Dubcová, J. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5543
Permanent link to this record
 

 
Author Bartos, L..; Bartosova, J.; Pluhacek, J.; Sindelarova, J.
Title Promiscuous behaviour disrupts pregnancy block in domestic horse (Equus caballus) mares: A counterstrategy against possible male infanticide Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue (up) Pages
Keywords foetal loss, domestic horse, Bruce effect, sexual behaviour
Abstract It is a common practice that the domestic horse mare is removed from her home environment and transported elsewhere for mating. After conceiving she is returned back into her home environment and social group, containing often familiar stallions and geldings. If we presume that the behavioural adaptation for infanticide relevant for wild, or free-ranging horses has not be lost in domestication (and it is clear that it remains at least within feral populations), then we may expect that, unless prevented by fencing or other management measures, the dominant males in the home social group may subsequently attempt infanticide. Foetal loss is a common phenomenon in domestic horses, being usually substantially higher than that in other domestic ungulates reaching up to 40%. One adaptive response to infanticide risk in polygynous populations is the Bruce effect. Pregnant females terminate their pregnancies when exposed to a dominant strange male. Our previous studies on plain zebra suggested the possibility of the Bruce effect also in equids. In this study we therefore tested the presumption that the Bruce effect could explain foetal loss in domestic horses. Based on reproduction records from horse breeders, we have recently published that bringing a pregnant mare which had been mated away from home into a vicinity of a familiar male who was not the father of her foetus increased probability of pregnancy disruption (Behav Ecol Sociobiol DOI: 10.1007/s00265-011-1166-6). These mares aborted in 31% of cases, while none of those mated within the home stable aborted. Repeated sexual activity either by a stallion or dominant gelding from the normal home group was observed shortly after the mare came from away-mating. Pregnant mares isolated from home males by a fence were even seen soliciting them over the fence. Therefore, there is probably some other mechanism than the Bruce effect leading to pregnancy block in the mare. We speculate that, once returned to the home “herd”, and introduced to familiar males, mares were more likely to terminate their pregnancy to save energy and avoid likely future infanticidal loss of their progeny by dominant male(s) of the home social group. Additional data has now showed that if a mare was mated away from home and was brought into an environment containing mares only, she was less likely to abort than a mare returning to an environment containing familiar male or males. This further supports our above hypothesis. Supported by AWIN, EU FP7 project No. 266213.
Address
Corporate Author Bartos, L. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5544
Permanent link to this record