Heat tolerance and the effects of shade on the behavior of Simmental bulls on pasture

Abstract

The objectives were to assess the degree of thermolysis capacity as a characteristic of heat tolerance of the Simmental beef cattle and evaluate the effects of shade and shade type (artificial: AS, trees: TS, or no shade: NS) on daily behavior patterns during summer. Black globe temperature (BGT) was different under the two types of shade (P < 0.05) and was lower under the TS (P < 0.01) and under AS (P > 0.01) than average BGT in the sun. Animals when in AS used more intensely the shade (P = 0.002) mostly lying down under it (10.00-14.00 hours), while time standing was similar (P = 0.107) between TS and NS. Bulls without shade (NS) spent significantly more time at the water trough and most part of the day standing idle (72.4%, 10.1 h/14 h). TS bulls spent more time grazing/standing (P < 0.001). The Simmental bulls that were in TS and AS spent more time ruminating than bulls that stay without shade (NS). The availability of shade changes grazing, rumination and idling behavior of cattle in response to environmental conditions. Shade provided by trees can be more efficient than artificial shading as cattle spent more time grazing when tree shade was available. Thermolysis capacity can be used to select heat-tolerant animals.

Effect of Heat Stress on Buck’s Adaptability and Semen Characteristics

“…Thus bucks with low TC values are more heat-tolerant than higher TC valued animals. The present findings in agreement with the findings of animal with low TC value are more heat-tolerant than higher TC valued animals (Aguilar et al, 2010;Titto et al, 2011). The thermolysis capacity found during a heat tolerance test is a valuable tool that should be used on a routine basis to guide decisions about animals to be selected for selective breeding or crossbreeding programs …”

“…The test used to evaluate the heat tolerance is a measure of the capacity of heat loss by recovery of the rectal temperature. The thermolysis capacity (TC) can be used to evaluate the heat tolerance in ruminants (Aguilar et al, 2010;Titto et al, 2011). To find out the TC, animals are exposed to a heat challenge by sun exposure.…”

“…To find out the TC, animals are exposed to a heat challenge by sun exposure. Animal with low TC value are more heattolerant than higher TC valued animals (Titto et al, 2011). The TC found during a heat tolerance test is a valuable tool that should be used on a routine basis to guide decisions about animals to be selected for selective breeding or crossbreeding programs.…”

Thermoregulatory response in hair sheep and shorn wool sheep

“…From 1100 to 1500 h the animals were deprived of food and water. The heat challenge was adapted from Titto et al (2011), which is usually used for cattle. The Thermotolerance Index (TCI) was calculated using the rectal temperatures by the following formula: 10-(RTa − RT2).…”

Estrutura do dossel forrageiro e comportamento ingestivo de novilhas em <i>Brachiaria brizantha</i> cv. Piatã sob regimes de sombra em área de integração lavoura-pecuária-floresta

“…O calor intenso, por exemplo, influencia de maneira direta o comportamento alimentar (ROSSELLE et al, 2012), com impactos potenciais negativos sobre o desempenho animal. Em climas quentes o comportamento animal pode ser influenciado pela disponibilidade de sombra, uma vez que esta promove melhoria do conforto térmico e pode favorecer maior atividade de pastejo (TITTO et al, 2011;LOPES et al, 2016). Por outro lado, a redução da radiação fotossinteticamente ativa que chega ao sub-bosque altera as características de crescimento da planta forrageira, promovendo modificações morfológicas e estruturais tais como:…”