Data/hora: 21/06/2024 09:58:28

Biblioteca(s): | Embrapa Pantanal.
Data corrente: | 07/10/1996
Data da última atualização: | 03/04/2017
Autoria: | DUNCAN, P.; FOOSE, T. J.; GORDON, I. J.; GAKAHU, C. G.; LLOYD, M.
Título: | Comparative nutrient extraction from forages by grazing bovids and equids: a test of the nutritional model of equid/bovid competition and coexistence.
Ano de publicação: | 1990
Fonte/Imprenta: | Oecologia, v.84, p.411-418, 1990.
Idioma: | Inglês
Conteúdo: | Ruminants are unevently 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 hall hind-gut fermenters. Some medium-sized hind-gut fermeters, equid perissodactyls, coexist with the grazing ruminants, principally bovid artiodactyls, in grassland ecosystems. These patterns have been explained two complementary models based on differences between the digestive physiology of ruminants and hindu-gut fermeters. 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 tyo 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-gur 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 forage eaten by animals of this size. Neither of the current nutritional models, nor refinements of them satisfactorily explain the preponderance of the bovids medium-sized ungulates; alternative hypotheses are presented.
Palavras-Chave: | Competicao; Competition; Hind-gut fermenter; Intake; Ruminant.
Thesagro: | Digestão; Ruminante.
Thesaurus Nal: | digestion.
Categoria do assunto: | --
Registro original: | Embrapa Pantanal (CPAP)
Exemplares: | CPAP - (33133-1) - ADD - SP - PP - SP15008 -  - 15008 - DIS