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Cameron, E. Z., & du Toit, J. T. (2007). Winning by a neck: tall giraffes avoid competing with shorter browsers. Am Nat, 169(1), 130–135.
Abstract: With their vertically elongated body form, giraffes generally feed above the level of other browsers within the savanna browsing guild, despite having access to foliage at lower levels. They ingest more leaf mass per bite when foraging high in the tree, perhaps because smaller, more selective browsers deplete shoots at lower levels or because trees differentially allocate resources to promote shoot growth in the upper canopy. We erected exclosures around individual Acacia nigrescens trees in the greater Kruger ecosystem, South Africa. After a complete growing season, we found no differences in leaf biomass per shoot across height zones in excluded trees but significant differences in control trees. We conclude that giraffes preferentially browse at high levels in the canopy to avoid competition with smaller browsers. Our findings are analogous with those from studies of grazing guilds and demonstrate that resource partitioning can be driven by competition when smaller foragers displace larger foragers from shared resources. This provides the first experimental support for the classic evolutionary hypothesis that vertical elongation of the giraffe body is an outcome of competition within the browsing ungulate guild.
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Chilton, N. B. (2004). The use of nuclear ribosomal DNA markers for the identification of bursate nematodes (order Strongylida) and for the diagnosis of infections. Anim Health Res Rev, 5(2), 173–187.
Abstract: Many bursate nematodes are of major importance to animal health. Animals are often parasitized by multiple species that differ in their prevalence, relative abundance and/or pathogenicity. Implementation of effective management strategies for these parasites requires reliable methods for their detection in hosts, identification to the species level and measurement of intensity of infection. One major problem is the difficulty of accurately identifying and distinguishing many species of bursate nematode because of the remarkable morphological similarity of their eggs and larvae. The inability to identify, with confidence, individual nematodes (irrespective of their life-cycle stage) to the species level by morphological methods has often led to a search for species-specific genetic markers. Studies over the past 15 years have shown that sequences of the internal transcribed spacers of ribosomal DNA provide useful genetic markers, providing the basis for the development of PCR-based diagnostic tools. Such molecular methods represent powerful tools for studying the systematics, epidemiology and ecology of bursate nematodes and, importantly, for the specific diagnosis of infections in animals and humans, thus contributing to improved control and prevention strategies for these parasites.
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Grandin, T. (1999). Safe handling of large animals. Occup Med, 14(2), 195–212.
Abstract: The major causes of accidents with cattle, horses, and other grazing animals are: panic due to fear, male dominance aggression, or the maternal aggression of a mother protecting her newborn. Danger is inherent when handling large animals. Understanding their behavior patterns improves safety, but working with animals will never be completely safe. Calm, quiet handling and non-slip flooring are beneficial. Rough handling and excessive use of electric prods increase chances of injury to both people and animals, because fearful animals may jump, kick, or rear. Training animals to voluntarily cooperate with veterinary procedures reduces stress and improves safety. Grazing animals have a herd instinct, and a lone, isolated animal can become agitated. Providing a companion animal helps keep an animal calm.
Keywords: Accidents, Occupational/*prevention & control/statistics & numerical data; Aggression/physiology/psychology; Animal Husbandry/*methods; Animals; *Behavior, Animal/physiology; Cattle; Conditioning, Operant/physiology; Crowding/psychology; Fear/physiology/psychology; Female; *Horses/physiology/psychology; Humans; Male; Movement/physiology; *Occupational Health; Risk Factors; *Ruminants/physiology/psychology
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