Effect of solar radiation on dairy cattle behaviour, use of shade and body temperature in a pasture-based system

A large fraction of the world grasslands and savannas are undergoing a rapid shift from herbaceous to woody-plant dominance. This land-cover change is expected to lead to a loss in livestock production (LP), but the impacts of woody-plant encroachment on this crucial ecosystem service have not been assessed. We evaluate how tree cover (TC) has affected LP at large spatial scales in rangelands of contrasting social-economic characteristics in the United States and Argentina. Our models indicate that in areas of high productivity, a 1% increase in TC results in a reduction in LP ranging from 0.6 to 1.6 reproductive cows (Rc) per km 2 . Mean LP in the United States is 27 Rc per km 2 , so a 1% increase in TC results in a 2.5% decrease in mean LP. This effect is large considering that woody-plant cover has been described as increasing at 0.5% to 2% per y. On the contrary, in areas of low productivity, increased TC had a positive effect on LP. Our results also show that ecological factors account for a larger fraction of LP variability in Argentinean than in US rangelands. Differences in the relative importance of ecological versus nonecological drivers of LP in Argentina and the United States suggest that the valuation of ecosystem services between these two rangelands might be different. Current management strategies in Argentina are likely designed to maximize LP for various reasons we are unable to explore in this effort, whereas land managers in the United States may be optimizing multiple ecosystem services, including conservation or recreation, alongside LP.global change | food production | social-ecological systems G rasslands, shrublands, and savannas, collectively termed "rangelands," constitute about 50% of the Earth's land surface (1). Although characterized by low yet highly variable annual rainfall, these areas provide 30-35% of terrestrial net primary productivity (NPP) (2), contain >30% of the world's human population, and support the majority of the world's livestock production (LP) (3, 4). Besides LP, rangelands also provide a variety of other ecosystem services, including fiber production, carbon sequestration, maintenance of the genetic library (conservation), and recreation (5).One of the most striking land-cover changes in rangelands worldwide over the past 150 y has been the proliferation of trees and shrubs at the expense of perennial grasses (6). In the United States, nonforest lands undergoing woody-plant encroachment are now estimated to cover up to 335 million ha (40% of the coterminous United States) (7) and the increase in woody cover ranges from 0.5% to 2% per y (8). The causes of this vegetation change are debated and the main potential drivers include intensification of livestock grazing, changes in climate and fire regimes, the introduction of nonnative woody species, and declines (natural and human induced) in the abundance of browsing animals (9-12). Historical increases in atmospheric nitrogen deposition and atmospheric carbon dioxide concentration have also been suggested to play ...

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“…1). In these areas, TC might provide shelter and shade, decreasing overall near-ground temperatures and animal respiration costs (35).…”

Section: Resultsmentioning

confidence: 99%

Effect of woody-plant encroachment on livestock production in North and South America

Anadón

Sala

Turner

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

172

123

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“…A summary of the major behavioural responses includes changes on feeding, defecating and urinating frequency, water intake, lying time, standing time, shade seeking behaviour (Ratnakaran et al 2017). In addition, body temperature as well behaviour has been affected by heat stress (Jara et al 2016, Tucker et al 2008.…”

Section: Introductionmentioning

confidence: 99%

Physiological and behavioural response of two dairy cows’ genotypes during summertime in the central region of Chile

Árias

Herrera

Larraín

et al. 2018

Austral j. vet. sci.

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ABSTRACT. Heat stress has been recognised as a serious problem in dairy farms. The study goal was to assess the effects of climatic conditions on physiological and behavioural responses of dairy cows in Central Chile. Data of tympanic temperature (TT), panting score, respiration rate (RR), and shade utilization of cows from two genotypes, Holstein (H) and Holstein x Montbeliarde (HM), were collected twice per day (AM/PM) during three periods of the summer season in Central Chile. Moreover, three thermal comfort indices: Comprehensive climate index (CCI), temperature humidity-index (THI), and adjusted THI were estimated using meteorological data. The hour of each day was classified as "Normal" or "Stressful" based on CCI threshold of 25 °C. Statistical analysis included ANOVA, repeated measures analysis and Chi square test (α=0.05). There was an interaction of genotype x CCI condition x period (P=0.0026) with the highest TT of both genotypes under a stressful condition within each period. In addition, interactions of genotype x hour (P<0.0001) and genotype x CCI condition (P<0.0002) were also observed. The HM cows showed greater TT than H cows in both CCI conditions. The RR was higher during the afternoon and a greater proportion of cows used shade at "Mild" and "Moderate" CCI categories (P<0.001). Both genotypes showed some degree of heat stress, but cool nights and shade seem to be enough to allow to cows' cope with the challenging diurnal conditions observed in the summer season. A study of these effects on milk production is necessary to confirm or discard the previous.

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“…An alternative to decrease solar radiation and minimize heat stress is to use natural or artificial shade, which aids thermal comfort and favors homeothermy (TUCKER; ROGERS; SCHÜTZ, 2008).…”

Section: Introductionmentioning

confidence: 99%

Efeitos da disponibilidade de sombra a campo sobre características reprodutivas de touros da raça Nelore (Bos indicus) criados na região Sudeste do Brasil

Tarragó

Rodrigues

Zaffalon

et al. 2013

Braz. J. Vet. Res. Anim. Sci.

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Solar radiation is responsible for bull body temperature elevation. An alternative to minimize heat stress is to use artificial shade. Thus, this study aimed to evaluate the effect of thermal stress reduction, through shade availability, on reproductive characteristics of Nellore bulls (Bos indicus). For this, ten bulls were divided in: Available artificial shade (AS, n = 5) and Unavailable shade (US, n = 5). Each group was kept in two hectare paddocks, in which shade availability for group AS was artificially created. Animals were submitted to a clinical-reproductive evaluation and seminal analyses. No interaction was observed between treatments (AS and US) and time (8 collections) for all analyzed variables (P>0.05). No significant effect (P > 0.05) of treatment was observed for all parameters analyzed. So, it can be concluded that the absence of shaded areas during summer does not negatively affect reproductive characteristics such as: scrotal circumference, testicular consistency, progressive motility, percentage of rapidly moving cells (Computer Assisted Semen Analysis -CASA), morphology or sperm viability in Nellore bulls raised in southeastern Brazil, considering that results could be different in other regions of the country where average temperature is higher. Keywords:Semen. Artificial shade. Nellore. Bull. ResumoA radiação solar é responsável pelo aumento da temperatura corpórea em touros. Uma alternativa para minimizar o estresse térmico é usar sombreamento artificial. Assim, este estudo teve como objetivo avaliar o efeito da redução do estresse térmico através da disponibilização de sombra artificial, sobre características reprodutivas de touros da raça Nelore (Bos indicus). Para isso, dez touros foram divididos em: Disponibilidade de sombra artificial (AS, n = 5) e Não-disponibilidade de sombra artificial (US, n=5). Cada grupo foi mantido em piquete de dois hectares cada, no qual a sombra para o grupo AS foi criada artificialmente. Os animais foram submetidos a avaliações clínicas-reprodutivas e análise seminal. Nenhuma interação foi observada entre os tratamentos (AS e US) e o tempo (8 coletas), para todas as variáveis analisadas (P > 0.05). Nenhum efeito significativo (P>0.05) de tratamento foi observado para os parâmetros analisados. Dessa forma, concluiu-se que a ausência de áreas sombreadas, durante o verão, não afetou negativamente as características reprodutivas como: circunferência escrotal, consistência testicular, motilidade progressiva, percentagem de células com movimentos rápidos (Computer Assisted Semen Analisys -CASA), morfologia e viabilidade espermática em touros da raça Nelore criados na região sudeste do Brasil, considerando que esse resultado pode ser diferente em outras regiões do país, onde as temperaturas ambientais são mais elevadas.Palavras-chave: Sêmen. Sombreamento artificial. Nelore. Touro.

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Effect of solar radiation on dairy cattle behaviour, use of shade and body temperature in a pasture-based system

Cited by 302 publications

References 22 publications

Effect of woody-plant encroachment on livestock production in North and South America

Effect of woody-plant encroachment on livestock production in North and South America

Physiological and behavioural response of two dairy cows’ genotypes during summertime in the central region of Chile

Efeitos da disponibilidade de sombra a campo sobre características reprodutivas de touros da raça Nelore (Bos indicus) criados na região Sudeste do Brasil

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Effect of solar radiation on dairy cattle behaviour, use of shade and body temperature in a pasture-based system

Cited by 302 publications

References 22 publications

Effect of woody-plant encroachment on livestock production in North and South America

Effect of woody-plant encroachment on livestock production in North and South America

Physiological and behavioural response of two dairy cows&#8217; genotypes during summertime in the central region of Chile

Efeitos da disponibilidade de sombra a campo sobre características reprodutivas de touros da raça Nelore (Bos indicus) criados na região Sudeste do Brasil

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Physiological and behavioural response of two dairy cows’ genotypes during summertime in the central region of Chile