The live export of cattle is an important industry for Australia. Concerns have arisen about animal welfare and in particular heat stress which may cause production losses and death. Cattle shipped live to the Middle East from a southern Australian winter can face continuous and prolonged periods of high heat and humidity as they cross the equator and arrive into a northern hemisphere summer, leading to heat stress and excessive heat load. Some live animal exporters treat heat stressed cattle with electrolyte supplements, but no scientific data exists as to whether this is beneficial to cattle in these unique environmental conditions. In response to industry’s concerns, the experiments described here monitored the physiological responses of Bos taurus and Bos indicus to conditions similar to those experienced by cattle being shipped from southern Australian to the Middle East. Initial experiments were conducted in climate controlled rooms at Murdoch University where intensive monitoring was possible. In the Bos taurus, increases in core body temperature, reductions in feed intake, and increased water intake were measured. There were also changes in blood gas variables consistent with the observed panting causing a compensated respiratory alkalosis. Following the heating period, there were decreases in blood and urinary pH. Bos indicus showed similar responses to the heat, but the changes were less pronounced at the temperatures tested. A pair feeding experiment was conducted to separate the effects of heat from the reductions in feed intake, and this indicated that the major measured effects were due to the responses to heat. On the basis of the measured responses, an electrolyte supplement was formulated and tested on Bos taurus, in the climate controlled rooms, and then on a commercial live export vessel. Results from these experiments indicated improved buffering capacity and a weight advantage for supplemented cattle, even in the absence of extreme heat stress. A final experiment investigated the effects of amount and quality of roughage in a pelleted feed on core and rumen temperature and feed intakes in Bos taurus subjected to hot environmental conditions in climate controlled rooms at Murdoch University. Both pelleted feeds had approximately the same metabolisable energy and crude protein but differed in content and type of roughage. There were no differences in feed intake, core temperature or rumen temperature between diets. This work has led to a greater understanding of the physiological responses of cattle to prolonged and continuous high heat and humidity, the requirements and effects of supplemental electrolytes in these conditions, and the effect of manipulating export diets. The demonstration of advantages in weight and buffering capacity with the electrolyte supplement highlights future areas of research to investigate electrolyte doses, route and types of supplementation, and dietary manipulation.

Orientador: Elisabete Maniglia / Resumo: A pecuária representa uma das indústrias mais ambientalmente degradantes que existem. No entanto, possuidora de forte poder político enraizado na herança agrária brasileira, a atividade resiste a mudanças e busca constante expansão, com apoio do Poder Público, que não procura implementar políticas públicas mitigadoras de danos. Neste ínterim, o movimento pela consideração dos animais como sujeitos de direitos apenas cresce, e as denúncias de crueldade para com os animais se multiplicam. Em face de denúncias preocupantes por parte de agências internacionais quanto à crise ambiental, o presente trabalho busca investigar se a pecuária efetivamente atinge os objetivos de desenvolvimento sustentável, respeitando a vedação constitucional da crueldade para com animais. Para ilustrar o debate, foram realizados dois estudos de caso: o primeiro referente à exportação de animais vivos por via marítima e o segundo relativo à Operação Carne Fraca, que expôs uma organização criminosa em torno da adulteração de alimentos e fraudes no processo de segurança sanitária. Para tal, este trabalho se valeu dos métodos de abordagem indutivo e dedutivo, e elegeu como principal método de procedimento o histórico-evolutivo, acompanhando a evolução da moral e da legislação quanto ao meio ambiente, à agropecuária e aos animais. Foram realizadas pesquisas bibliográficas e documentais, com base em material nacional e internacional, e na legislação brasileira correlata. Quanto aos estudos de caso, foram ana... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Livestock represents one of the most environmentally degrading industries in the world. However, with its political power deriving from Brazil’s agrarian heritage, the industry resists change and seeks constant expansion, with support from Government, which doesn’t seek to implement mitigating public policies. Meanwhile, the movement for the consideration of animals as rights holders grows, and reports of animal cruelty in the sector only increase. In light of worrisome data released by international agencies, this dissertation seeks to investigate wether the livestock industry really contibutes to sustainable development, respecting the prohibition of animal cruelty. In order to illustrate the debate, two case studies were done: the first one regarding live export ships and the second one in relation to Operation “Carne Fraca”, which exposed a criminal organization around the adulteration of foods and fraud in the process of health security. In order to achieve those goals, this paper has utilized inductive and deductive methods, and elected as main procedural method the historic-evolutionary analysis, following moral and legislative evolution in regards to the environment and animals. Bibliographic and documentary research took place, based on national and international material, and brazilian legislation. As for the case studies, inquiries and lawsuits were analyzies, in order to illustrate the theoretical debate. It was concluded that livestock has mainly negative effects... (Complete abstract click electronic access below) / Mestre