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Author Edouard, N.; Fleurance, G.; Dumont, B.; Baumont, R.; Duncan, P. url  doi
openurl 
  Title Does sward height affect feeding patch choice and voluntary intake in horses? Type Journal Article
  Year 2009 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.  
  Volume 119 Issue 3-4 Pages 219-228  
  Keywords Patch selection; Intake; Sward height; Horse; Pasture  
  Abstract The numbers of horses grazing at pasture are increasing in developed countries, so a proper understanding of their feeding selectivity and of the tactics they use for extracting nutrients from swards is essential for the management of horses and grasslands. Resource acquisition in herbivores can be optimised through the modulation of their intake and patch selection, both being strongly dependent on the characteristics of swards. However, the principles by which horses adjust their grazing behaviour in response to variations in sward features are not completely understood. The aim of this study was to determine whether the behaviour of horses conforms to optimal foraging models. We hypothesized that, faced with binary choices between vegetative swards of a good and similar quality at three different heights, horses would select the taller sward, i.e. that allowing a higher reward in terms of dry matter intake rate. Three groups of three 2-year-old saddle horses were grazed on a semi-natural pasture that was managed to produce three contrasting sward heights at 6, 11 and 17 cm, in a Latin-square design. The instantaneous intake rate was determined from bite rate measured at pasture on the three sward heights, and bite mass estimated from measurements using swards offered indoors in experimental trays. Daily dry matter intake was estimated individually by total faecal collection and an estimation of digestibility from faecal nitrogen. Short-term (first 30 min) and daily preferences were assessed from the time spent grazing each sward offered in pair-wise tests at pasture. The results show that daily voluntary intake (an average of 21 g DM kg LW-1 day-1) and total grazing time (an average of 14 h day-1) were independent of sward height and of the choice of patches offered. In choice situations, the animals spent more time grazing on the taller sward, both during the first 30 min and at the daily scale. These results show that horses choose between vegetative patches of a good and similar quality according to the predictions from optimal foraging models, and select the one that they can ingest faster. Further research will now have to explore how the horses will adapt their feeding behaviour when they face a trade-off between sward height and quality.  
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  ISSN 0168-1591 ISBN Medium  
  Area Expedition Conference  
  Notes Approved (up) no  
  Call Number Equine Behaviour @ team @ Serial 5094  
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Author Duncan, P. url  doi
openurl 
  Title Foal killing by stallions Type Journal Article
  Year 1982 Publication Applied Animal Ethology Abbreviated Journal Appl. Animal. Ethol.  
  Volume 8 Issue 6 Pages 567-570  
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  Abstract Feral horses live in social systems similar to those of some species in which infant killing has been reported (e.g. lions), but such behaviour has been reported neither in horses nor in any other ungulate. The results of interviews with owners of free-ranging horses (Camargue breed) are given which show that, though rare, infant killing occurs in this breed, and that it seems to be confined to male foals. It is argued that the observed behaviour cannot simply be considered as pathological, and that close attention should be paid to the possibility that it occurs in wild and feral equids.  
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  ISSN 0304-3762 ISBN Medium  
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  Notes Approved (up) no  
  Call Number Equine Behaviour @ team @ Serial 5260  
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Author Duncan, P.; Foose, T. J.; Gordon, I. J.; Gakahu,C. G.; Lloyd, M. doi  openurl
  Title Comparative nutrient extraction from forages by grazing bovids and equids: a test of the nutritional model of equid/bovid competition and coexistence Type Journal Article
  Year 1990 Publication Oecologia Abbreviated Journal Oecologia  
  Volume 84 Issue 3 Pages 411-418  
  Keywords Ruminant – Hind-gut fermenter – Intake – Digestion – Competition  
  Abstract Ruminants are unevenly distributed across the range of body sizes observed in herbivorous mammals; among extant East African species they predominate, in numbers and species richness, in the medium body sizes (10-600 kg). The small and the large species are all hind-gut fermenters. Some medium-sized hind-gut fermenters, equid perissodactyls, coexist with the grazing ruminants, principally bovid artiodactyls, in grassland ecosystems. These patterns have been explained by two complementary models based on differences between the digestive physiology of ruminants and hind-gut fermenters. The Demment and Van Soest (1985) model accounts for the absence of ruminants among the small and large species, while the Bell/Janis/Foose model accounts both for the predominance of ruminants, and their co-existence with equids among the medium-sized species (Bell 1971; Janis 1976; Foose 1982). The latter model assumes that the rumen is competitively superior to the hind-gut system on medium quality forages, and that hind-gut fermenters persist because of their ability to eat more, and thus to extract more nutrients per day from high fibre, low quality forages. Data presented here demonstrate that compared to similarly sized grazing ruminants (bovids), hind-gut fermenters (equids) have higher rates of food intake which more than compensate for their lesser ability to digest plant material. As a consequence equids extract more nutrients per day than bovids not only from low quality foods, but from the whole range of forages eaten by animals of this size. Neither of the current nutritional models, nor refinements of them satisfactorily explain the preponderance of the bovids among medium-sized ungulates; alternative hypotheses are presented.  
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  Notes from Professor Hans Klingels Equine Reference List Approved (up) yes  
  Call Number Serial 1035  
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