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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 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 (down) 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
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Author Stahlbaum, C.C.; Houpt, K.A.
Title The role of the Flehmen response in the behavioral repertoire of the stallion Type Journal Article
Year 1989 Publication Physiology & behavior Abbreviated Journal Physiol. Behav.
Volume 45 Issue 6 Pages 1207-1214
Keywords Animals; Behavior, Animal/*physiology; Circadian Rhythm; Discrimination (Psychology)/physiology; Estrus; Feces; Female; Horses/*physiology; Male; Sexual Behavior, Animal/*physiology; Smell/*physiology; Taste/physiology; Urine
Abstract The role of the Flehmen response in equine behavior was investigated under field and laboratory conditions. In Experiment 1, a field study made of five stallions on pasture with between three and eighteen mares each during the season indicated the following: 1) The Flehmen response was most frequently preceded by nasal, rather than oral, investigation of substances; 2) The stallions' rate of Flehmen varied with the estrous cycles of the mares; 3) The rate of Flehmen response did not show a variation with time of day; and 4) The Flehmen response was most frequently followed by marking behaviors rather than courtship behaviors. The results suggest that the Flehmen response is not an immediate component of sexual behavior, e.g., courtship of the stallion but may be involved in the overall monitoring of the mare's estrous cycle. Therefore the Flehmen response may contribute to the chemosensory priming of the stallion for reproduction. In Experiment 2 stallions were presented with urine or feces of mares in various stages of the reproductive cycle as well as with their own or other males' urine or feces. The occurrence of sniffing and Flehmen was used to determine the discriminatory ability of the stallions. Stallions can differentiate the sex of a horse on the basis of its feces alone, but cannot differentiate on the basis of urine. This ability may explain the function of fecal marking behavior of stallions.
Address New York State College of Veterinary Medicine, Cornell University, Ithaca 14853
Corporate Author Thesis
Publisher Place of Publication Editor (down)
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9384 ISBN Medium
Area Expedition Conference
Notes PMID:2813545 Approved no
Call Number refbase @ user @ Serial 44
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Author Heitor, F.; do Mar Oom, M.; Vicente, L.
Title Social relationships in a herd of Sorraia horses Part I. Correlates of social dominance and contexts of aggression Type Journal Article
Year 2006 Publication Behavioural Processes Abbreviated Journal Behav. Process.
Volume 73 Issue 2 Pages 170-177
Keywords Age Factors; *Aggression; Animals; Female; *Hierarchy, Social; Horses/*psychology; Male; Sex Factors; *Social Dominance; *Social Environment; Statistics, Nonparametric
Abstract Factors related to dominance rank and the functions of aggression were studied in a herd of Sorraia horses, Equus caballus, under extensive management. Subjects were 10 adult mares 5-18 years old and a stallion introduced into the group for breeding. Dominance relationships among mares were clear, irrespective of rank difference, and remained stable after introduction of the stallion. The dominance hierarchy was significantly linear and rank was positively correlated with age and total aggressiveness. Higher-ranking mares received lower frequency and intensity of agonistic interactions. Nevertheless, higher-ranking dominants were not more likely to elicit submission from their subordinates than lower-ranking dominants. Neither close-ranking mares nor mares with less clear dominance relationships were more aggressive towards each other. Agonistic interactions seemed to be used more importantly in regulation of space than to obtain access to food or to reassert dominance relationships. Contexts of aggression were related to mare rank. The results suggest that dominance relationships based on age as a conventional criterion were established to reduce aggressiveness in a herd where the costs of aggression are likely to outweigh the benefits.
Address Centro de Biologia Ambiental, Faculdade de Ciencias da Universidade de Lisboa, Campo Grande, Edificio C2, 1749-016 Lisboa, Portugal
Corporate Author Thesis
Publisher Place of Publication Editor (down)
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0376-6357 ISBN Medium
Area Expedition Conference
Notes PMID:16815645 Approved no
Call Number refbase @ user @ Serial 292
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Author Cameron, E.Z.
Title Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism Type Journal Article
Year 2004 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume 271 Issue 1549 Pages 1723-1728
Keywords Age Factors; Animals; Body Constitution; *Evolution; Female; Glucose/metabolism/physiology; Litter Size; Male; Mammals/*physiology; *Models, Biological; Reproduction/physiology; Seasons; Sex Factors; *Sex Ratio; Time Factors
Abstract Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios.
Address Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za
Corporate Author Thesis
Publisher Place of Publication Editor (down)
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0962-8452 ISBN Medium
Area Expedition Conference
Notes PMID:15306293 Approved no
Call Number refbase @ user @ Serial 413
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Author Hemelrijk, C.K.; Wantia, J.
Title Individual variation by self-organisation Type Journal Article
Year 2005 Publication Neuroscience and biobehavioral reviews Abbreviated Journal Neurosci Biobehav Rev
Volume 29 Issue 1 Pages 125-136
Keywords Aggression; Animals; Behavior, Animal/*physiology; Competitive Behavior/*physiology; Female; Humans; *Individuality; Male; Models, Psychological; Sex Characteristics; *Social Dominance; Time Factors
Abstract In this paper, we show that differences in dominance and spatial centrality of individuals in a group may arise through self-organisation. Our instrument is a model, called DomWorld, that represents two traits that are often found in animals, namely grouping and competing. In this model individual differences grow under the following conditions: (1) when the intensity of aggression increases and grouping becomes denser, (2) when the degree of sexual dimorphism in fighting power increases. In this case the differences among females compared to males grow too, (3) when, upon encountering another individual, the tendency to attack is 'obligate' and not conditional, namely 'sensitive to risks'. Results resemble phenomena described for societies of primates, mice, birds and pigs.
Address Theoretical Biology, University of Groningen, NN Haren, The Netherlands. hemelrij@ifi.unizh.ch
Corporate Author Thesis
Publisher Place of Publication Editor (down)
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0149-7634 ISBN Medium
Area Expedition Conference
Notes PMID:15652260 Approved no
Call Number refbase @ user @ Serial 443
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Author Boyd, L.
Title Behavior problems of equids in zoos Type Journal Article
Year 1986 Publication The Veterinary clinics of North America. Equine practice Abbreviated Journal Vet Clin North Am Equine Pract
Volume 2 Issue 3 Pages 653-664
Keywords Aerophagy/veterinary; Aggression/psychology; Animals; *Animals, Zoo; *Behavior, Animal; Coprophagia/psychology; Female; *Horses; Impotence/veterinary; Male; Mastication; Motor Activity; *Perissodactyla; Pregnancy; Sexual Behavior, Animal; Social Environment
Abstract Behavior problems in zoo equids commonly result from a failure to provide for needs basic to equine nature. Equids are gregarious, and failure to provide companions may result in pacing. Wild equids spend 60 to 70 per cent of their time grazing, and failure to provide ad libitum roughage contributes to the problems of pacing, cribbing, wood chewing, and coprophagia. Mimicking the normal processes of juvenile dispersal, bachelor-herd formation, and mate acquisition reduces the likelihood of agonistic and reproductive behavior problems. Infanticide can be avoided by introducing new stallions to herds containing only nonpregnant mares and older foals.
Address
Corporate Author Thesis
Publisher Place of Publication Editor (down)
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0749-0739 ISBN Medium
Area Expedition Conference
Notes PMID:3492252 Approved no
Call Number refbase @ user @ Serial 660
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Author Keiper, R.; Houpt, K.
Title Reproduction in feral horses: an eight-year study Type Journal Article
Year 1984 Publication American journal of veterinary research Abbreviated Journal Am J Vet Res
Volume 45 Issue 5 Pages 991-995
Keywords Abortion, Veterinary/epidemiology; Anestrus; Animal Population Groups/*physiology; Animals; Animals, Wild/*physiology; Birth Rate; Female; Fertility; Horse Diseases/epidemiology; Horses/*physiology; Lactation; Male; Maryland; Pregnancy; *Reproduction; Seasons; Sex Ratio; Virginia
Abstract The reproductive rate and foal survival of the free-ranging ponies on Assateague Island National Seashore were studied for 8 years, 1975 to 1982. Most (52%) of the 86 foals were born in May, 13% were born in April, 22.6% in June, 10.4% in July, and less than 1% in August and September. The mean foaling rate was 57.1 +/- 3.9% and the survival rate was 88.3 +/- 3.6%. Forty-eight colts and 55 fillies were born (sex ratio 53% female). Mares less than 3 years old did not foal and the foaling rate of 3-year-old mares was only 23%, that of 4-year-old mares was 46%, that of 5-year-old mares was 53%, and 6-year-old mares was 69%. The relatively poor reproduction rate was believed to be a consequence of the stress of lactating while carrying a foal when forage quality on the island was low. The hypothesis was supported by the higher reproductive rate (74.4 +/- 2.4%) of the ponies in the Chincoteague National Wildlife Refuge on the southern part of the island. Their foals are weaned and sold in July each year. Despite the low reproductive rate on Assateague Island National Seashore , the number of ponies increased from 43 to 80, a 90% increase in the 8-year period or greater than 10%/yr. There were 24 deaths and 8 dispersals from the study area.
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Corporate Author Thesis
Publisher Place of Publication Editor (down)
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-9645 ISBN Medium
Area Expedition Conference
Notes PMID:6732036 Approved no
Call Number refbase @ user @ Serial 665
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Author Weeks, J.W.; Crowell-Davis, S.L.; Caudle, A.B.; Heusner, G.L.
Title Aggression and social spacing in light horse (Equus caballus) mares and foals Type Journal Article
Year 2000 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 68 Issue 4 Pages 319-337
Keywords Dominance relationships; Horse; Sex differences; Social ontogeny; aggregation; parent-offspring interaction; social behavior
Abstract Aggression and social spacing were studied in 14 light horse mares and their foals living at pasture. Focal samples were collected on each mare-foal dyad for 6 to 10.5 h from 2 months of foal age until weaning at approximately 4 months of age. Observations on foals continued until approximately 6 months of age for 7.5 to 10.5 h per foal. Every 2 min the identities of all individuals within 5 m were recorded. All occurrences of agonistic behavior, and the participants, were recorded during the focal samples. In addition, during feeding of supplemental grain, all occurrences of agonistic behavior by all subjects were recorded. Significant correlations were found between mare rank and the rank of foals both prior to and after weaning. Before weaning, the rank of the foal was significantly correlated with birth order. No significant correlation between birth order and foal rank was found for the post-weaning hierarchy. An animal's gender had no significant effect on foal rank or the choice of preferred associate. Both prior to and after weaning, foals associated preferentially with the foal of their dam's most preferred associate. In addition, significant positive correlations were found between rank of mares and foals and the rate at which they directed aggression to other herd members. (C) 2000 Elsevier Science B.V.
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Notes Cited By (since 1996): 7; Export Date: 21 April 2007; Source: Scopus Approved no
Call Number refbase @ user @ Serial 788
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Author Klingel, H.
Title Social organization and reproduction in equids Type Journal Article
Year 1975 Publication Journal of Reproduction and Fertility. Supplement Abbreviated Journal J Reprod Fertil Suppl
Volume Issue 23 Pages 7-11
Keywords Animals; Behavior, Animal; Female; Male; Perissodactyla/*physiology; Reproduction; *Sexual Behavior, Animal; Social Behavior; Territoriality
Abstract There are two distinct types of social organization and, accordingly, two types of mating systems in equids. In the horse, Plains zebra and Mountain zebra, the adults live in non-territorial and cohesive one-male groups and in stallion groups. The family stallions have exclusive mating rights which are respected by all others. In Grevy's zebra and in the African and Asiatic wild asses, the stallions are permanently territorial and have exclusive mating rights within their territories. Ecological and evolutionary aspects are discussed.
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Publisher Place of Publication Editor (down)
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0449-3087 ISBN Medium
Area Expedition Conference
Notes PMID:1060868 Approved no
Call Number Equine Behaviour @ team @ Serial 2303
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Author McDonnell, S.M.; Henry,M. Bristol, F.
Title Spontaneous erection and masturbation in equids Proc 35th Type Journal Article
Year 1991 Publication Abbreviated Journal J. Reprod. Fert. Suppl
Volume 44 Issue Pages 664-665
Keywords Horse; Masturbation; Erection; Aversive conditioning; Sexual behavior; Ejaculation; Semen
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Notes This paper is part of the special issue entitled “Proceedings of the 4th International Symposium on Stallion Reproduction”, Guest Edited by Dr. Edward Squires. Approved no
Call Number Serial 1378
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