Shade-seeking behavior and grazing activity of Pantaneira and Girolando heifers
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Shade-seeking behavior and grazing activity of Pantaneira and Girolando heifers Pedro Gustavo Loesia Lima 1
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& Kheyciane Viana da Silva & Robson Marcelo Rossi & Marcus Vinicius Morais de Oliveira
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Received: 14 May 2020 / Accepted: 21 July 2020 # Springer Nature B.V. 2020
Abstract This study aimed to model and compare the shade-seeking behavior and grazing activity of Pantaneira and Girolando heifers by time of day. Eight heifers were used, four Pantaneira and four Girolando (3/4 Holstein × 1/4 Gir). The animals were about 18 months old and weighed 328 ± 14 kg (Pantaneira) and 430 ± 28 kg (Girolando). Shade-seeking behavior and grazing activity were recorded during the summer from 06:00 to 18:00 h in 10-min intervals, totaling 288 observations for each breed. A binary regression model was developed by means of a Bayesian approach considering logit, probit, cloglog, and Cauchy link functions. The most parsimonious model was constructed using the Cauchy function. The variables varied according to the time of day. Heifers of both breeds were more likely to graze toward the end of the day, when ambient temperatures were lower. Girolando heifers were more likely to seek shade between 06:00 and 14:00 h. From 12:00 to 13:00, the probability of seeking shade between breeds differed 22 percentage points. Pantaneira heifers were more likely to graze from 06:00 to 13:00 h, and their probability of grazing at 11:00 h was 21 percentage points higher than that of Girolando heifers. The results suggest that Pantaneira heifers are more heat-tolerant. Keywords Animal behavior . Bayesian approach . Pantaneiro bovine . Probability
Introduction Livestock in the upper Pantanal region in Mato Grosso do Sul, Brazil, must endure high temperatures during the summer. Temperatures above 38 °C are common in the upper Pantanal region of Mato Grosso do Sul, Brazil (INPE 2018). According National Institute of Meteorology (INMET) in summer the index of bovine thermal comfort remain ranges between 74 and 76 indicating attention for pasture production (INMET 2016). Ruminant animals regulate their body temperature by exchanging heat with the environment through the skin surface. When the ambient temperature is high, this thermoregulatory mechanism may be compromised, leading to heat stress. Under this condition, less heat-tolerant animals seek shade and graze less (Vizzotto et al. 2015; Rashamol * Pedro Gustavo Loesia Lima [email protected] 1
Department of Animal Sciences, State University of Maringá, Avenida Colombo, 5790, Maringá, PR 87020-900, Brazil
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Department of Animal Sciences, State University of Mato Grosso do Sul, Aquidauana, MS, Brazil
et al. 2018; Saizi et al. 2019). Natural shading provides a favorable microclimate for pastured cattle, as it reduces ambient temperature and the incidence of solar radiation (Baliscei et al. 2013). Heat tolerance varies among cattle breeds. Higher heat tolerance can help cows carry out daily activities that are essential for reproductive and productive performance, such
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