Potential Nutritional Strategies for Intensively Managed Cattle during Thermal Stress

Beede, D.K.; Collier, Robert J.

doi:10.2527/jas1986.622543x

Cited by 384 publications

(315 citation statements)

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“…De acordo com Beede & Collier (1986), temperatura ambiente elevada, acima da zona de conforto, reduz o consumo de alimento, principalmente para aqueles com alto teor de fibra, como é o caso das pastagens de clima tropical, além de elevar a temperatura retal dos animais.…”

Section: Methodsunclassified

Avaliação do comportamento de ovinos Santa Inês em sistema silvipastoril no norte fluminense

et al. 2011

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RESUMOUm estudo foi desenvolvido em Quissamã, RJ utilizando-se 20 ovelhas da raça Santa Inês com idade média de dois anos objetivando-se avaliar o comportamento dos animais em dois sistemas de criação. Os animais foram mantidos em piquetes com pastagem de capim-quicuio, sendo dez ovelhas alojadas em piquete sem sombreamento e outras 10 alojadas em piquete, com consórcio de pastagem e o cultivo de coco (Cocus nucifera). Durante o período de 10 dias consecutivos, os animais tiveram seus respectivos comportamentos observados de acordo com o tempo despendido com as atividades de alimentação, ruminação e ócio, aferidos de dez em dez minutos das 9:00 às 17:00 horas, período em que permaneciam a pasto. Os animais expostos ao sol despenderam menor tempo diário pastejando, aumentando atividade de ruminação e ócio, mantendo essas atividades menos constantes quando comparadas aos animais mantidos à sombra. O consórcio da cultura de coco com a pastagem influenciou positivamente o comportamento dos animais. Termos para indexação:Bem estar, comportamento, sistema de criação. ABSTRACTA study was developed in Quissamã, RJ, Brazil, with twenty two-year-old sheep of the Santa Inês with the objective of evaluating the animals' behavior in two raising system. The animals were maintained in two pickets with "capim-quicuio" pasture. The animals were separated in two groups, ten of which without shade and the other ten in a picket with a consortium of pasture and a coconut cultivation (Cocus nucifera). During a period of ten consecutive days, the animals had their behavior evaluated according to the time spent on feeding, rumination and resting time, checked every ten minutes, from 9 a.m. to 5 p.m. The animals exposed to sunlight spent less time grazing, increased rumination time and resting time, and these activities were less stable when compared to the sheep under shade. Coconut cultivation, therefore, had a positive impact on the behavior of the animals.

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Section: Methodsunclassified

Avaliação do comportamento de ovinos Santa Inês em sistema silvipastoril no norte fluminense

et al. 2011

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“…A direct (independent of reduced feed intake) effect of heat stress on serum prolactin levels has been shown (Ronchi et al, 2001). Increased prolactin initially seems contradictory (especially in lactating dairy cows), given prolactin's well-known role in maintaining galactopoiesis in some species and lactogenesis in ruminants, but prolactin may play an important role in acclimation through improved insensible heat loss and sweat gland function (Beede and Collier, 1986). Bromocryptine (a prolactin secretion inhibitor) treatment during heat acclimation affects sweat gland function by preventing increased sweat gland discharge (Kaufman et al, 1988).…”

Section: Metabolic and Hormonal Acclimation To Hot Environmentmentioning

confidence: 99%

“…The hypothalamic-pituitary-adrenal axis is also a key component of the acclimatory response to thermal stress (Beede and Collier, 1986;Collier et al, 2005). Corticotropinreleasing hormone stimulates somatostatin; possibly a key mechanism by which heat-stressed animals have reduced GH and thyroid levels (Riedel et al, 1998).…”

Section: Metabolic and Hormonal Acclimation To Hot Environmentmentioning

confidence: 99%

“…Prolactin levels also differ with season and it appears to be involved in acclimating to seasonal/weather changes (Leining et al, 1979). Whether increased prolactin levels affect the ability of animals to metabolically adapt during a heat load is currently unknown but is of interest, given its importance as a homeorhetic hormone.The hypothalamic-pituitary-adrenal axis is also a key component of the acclimatory response to thermal stress (Beede and Collier, 1986;Collier et al, 2005). Corticotropinreleasing hormone stimulates somatostatin; possibly a key mechanism by which heat-stressed animals have reduced GH and thyroid levels (Riedel et al, 1998).…”

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Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Bernabucci

Lacetera

Baumgard

et al. 2010

Animal

679

492

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Environmentally induced periods of heat stress decrease productivity with devastating economic consequences to global animal agriculture. Heat stress can be defined as a physiological condition when the core body temperature of a given species exceeds its range specified for normal activity, which results from a total heat load (internal production and environment) exceeding the capacity for heat dissipation and this prompts physiological and behavioral responses to reduce the strain. The ability of ruminants to regulate body temperature is species-and breed-dependent. Dairy breeds are typically more sensitive to heat stress than meat breeds, and higher-producing animals are more susceptible to heat stress because they generate more metabolic heat. During heat stress, ruminants, like other homeothermic animals, increase avenues of heat loss and reduce heat production in an attempt to maintain euthermia. The immediate responses to heat load are increased respiration rates, decreased feed intake and increased water intake. Acclimatization is a process by which animals adapt to environmental conditions and engage behavioral, hormonal and metabolic changes that are characteristics of either acclimatory homeostasis or homeorhetic mechanisms used by the animals to survive in a new 'physiological state'. For example, alterations in the hormonal profile are mainly characterized by a decline and increase in anabolic and catabolic hormones, respectively. The response to heat load and the heat-induced change in homeorhetic modifiers alters post-absorptive energy, lipid and protein metabolism, impairs liver function, causes oxidative stress, jeopardizes the immune response and decreases reproductive performance. These physiological modifications alter nutrient partitioning and may prevent heat-stressed lactating cows from recruiting glucose-sparing mechanisms (despite the reduced nutrient intake). This might explain, in large part, why decreased feed intake only accounts for a minor portion of the reduced milk yield from environmentally induced hyperthermic cows. How these metabolic changes are initiated and regulated is not known. It also remains unclear how these changes differ between short-term v. long-term heat acclimation to impact animal productivity and well-being. A better understanding of the adaptations enlisted by ruminants during heat stress is necessary to enhance the likelihood of developing strategies to simultaneously improve heat tolerance and increase productivity.Keywords: ruminants, heat stress, metabolism, acclimation, adaptation ImplicationsHeat stress is a significant financial burden to animal agriculture in most areas of the world. Acclimation to heat stress imposes behavioral, physiological and metabolic adjustments to reduce the strain and enhances the likelihood of surviving the stress, and it also frequently reduces ruminant performance and compromises health. Improving our knowledge of physiological and metabolic mechanisms of acclimation may contribute to the development and adoption of proce...

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“…A redução observada na AAL ao sol a partir das 10 h (Figura 3A) é normal para alguns autores, visto que, a partir do ITGU observado, provavelmente submeteram os animais a temperaturas elevadas, estando fora da zona de conforto (ZC) que, para Cezar et al (2004), fica situada entre 25 e 30 °C, tendo como limite crítico superior a temperatura de 34 °C e, para Beede & Collier (1986) essas temperaturas acima da ZC, reduzem a AAL, ainda mais em se tratando de pastagens tropicais que geralmente dispõem de um teor maior de fibra.…”

Section: éPocaunclassified

Comportamento de ovinos da raça Santa Inês em ambientes com e sem disponibilidade de sombra

Oliveira¹,

Turco

Aaraújo

et al. 2013

Rev. bras. eng. agríc. ambient.

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RESUMOCom o objetivo de observar os efeitos do sombreamento propiciado pela tela de polipropileno sobre o comportamento de ovinos da raça Santa Inês em diferentes épocas do ano, montou-se um experimento em Petrolina, PE, no período de junho a novembro de 2010. Utilizaram-se 40 animais distribuídos em igual quantidade em dois tratamentos (Sombreado e Não sombreado) com oferta de pastagem (Tiffton 85) irrigada. Foram feitas aferições dos dados meteorológicos em todas as épocas, com a montagem de termômetros de globo negro e psicrômetros nas duas áreas e de uma mini-estação meteorológica na área sombreada. Nessas épocas foram realizados ensaios de comportamento tendo-se feito observações visuais pelo método da varredura instantânea em intervalos de 10 min no período diurno, verificando-se o percentual de animais quanto à alimentação, ruminação e ócio, a partir da metodologia proposta por Johnson & Combs (1991) adaptada para o tempo de 12 h. O sombreamento não influenciou no número de animais em referência às atividades avaliadas nos diferentes tratamentos. A procura por sombra foi intensa nos períodos mais quentes do dia para a atividade de ócio.Palavras-chave: enriquecimento ambiental, fisiologia, ócio, pastejo, ruminação Behavior of sheep breed Santa Inês in environments with and without shade availability ABSTRACT With the goal of observing the effects of shade provided by polypropylene screen on the behaviour of Santa Inês sheep, in different times of year, an experiment was set up in Petrolina, PE, in the period from June to November 2010. Forty animals divided into equal quantity in two treatments (shaded and nonshaded) were used with supply of irrigated pastures (Tiffton 85). Measurements of meteorological data were made at all times, with the assembly of black globe thermometers and psychrometers in the two areas, and a mini-weather station, at the shaded area. Under these conditions a trials was carried out on behavior of animals, being made visual observations by the method of instantaneous scan at intervals of 10 min during the daytime period, checking the percentage of animals under food, rumination and leisure using the methodology proposed by Johnson & Combs (1991), adapted for a period of 12 h. The shading did not influence the number of animals under the activities evaluated in different treatments. The search for shade was intense in the hottest periods of the day for leisure activity.

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Potential Nutritional Strategies for Intensively Managed Cattle during Thermal Stress

Cited by 384 publications

References 0 publications

Avaliação do comportamento de ovinos Santa Inês em sistema silvipastoril no norte fluminense

Avaliação do comportamento de ovinos Santa Inês em sistema silvipastoril no norte fluminense

Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Comportamento de ovinos da raça Santa Inês em ambientes com e sem disponibilidade de sombra

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