Thermal comfort of Nelore (Bos indicus) and Canchim (Bos taurus x Bos indicus) bulls kept in an integrated crop-livestock-forestry system in a tropical climate

https://doi.org/10.1016/j.agsy.2023.103687Get rights and content

Highlights

  • Afforested systems have been singled out as a possible solution for mitigating animal thermal stress.

  • We assessed the thermoregulation of beef bulls over 13 months.

  • The air temperature, the BGHI, and the thermal load were lower in the crop-livestock-forestry system.

  • Bulls in the crop-livestock-forestry system showed greater thermal comfort and lower heat stress biomarkers.

  • The Crop-livestock-forestry system may be a suitable option for increasing animal welfare in tropical climates.

Abstract

CONTEXT

Climate change presents challenges for livestock productivity and animal health. Thus, management strategies to mitigate the effects of the global temperature increase on livestock production have become progressively relevant. However, the use of integrated crop-livestock-forestry systems to optimize the beef cattle thermal balance has not been examined more deeply.

OBJECTIVE

The study aimed to evaluate the microclimate in a non-shaded pasture system (NS) and in an integrated crop-livestock-forestry system (ICLF) and its influence on thermoregulatory and endocrine responses of zebu and composite bulls, during different climatic seasons.

METHODS

The experiment was carried out in a tropical region, São Carlos-SP, Brazil (21°57′42″S, 47°50′28″W). Nelore (Bos indicus) and Canchim (5/8 Bos taurus x 3/8 Bos indicus) bulls were equally allocated in a non-shaded system (NS; n = 32) or in an integrated crop-livestock-forestry system (ICLF; n = 32). The animals were monthly evaluated and the data were analyzed using a GLM Model. Means were compared using Tukey test (P < 0.05).

RESULTS AND CONCLUSIONS

The ICLF system reduced the air temperature (−0.6 °C; P = 0.0010), the Black Globe Temperature and Humidity Index-BGHI (−3.8; P < 0.0001), and the Radiant Thermal Load (−104 W/m2; P < 0.0001) compared to the NS system. The infrared thermograms of NS bulls were characterized by higher temperatures on the surface of the back and in the trunk, during Autumn and Winter (P < 0.05). In addition, NS bulls presented higher respiratory rate (RR: 35.85 ± 0.88 vs 31.97 ± 0.88 breaths/min; P = 0.0210) and internal body temperature (BT: 39.54 ± 0.05 vs 39.35 ± 0.05 °C; P = 0.0057) during Autumn. There was a significant reduction in cortisol concentration (−12.13 ng/mL; P < 0.05) in both systems throughout the experiment. Nelore bulls had lower RR and BT, lower mean concentration of cortisol, and higher secretion of triiodothyronine than Canchim bulls. The ICLF system was effective in mitigating the microclimate of pastures due to the action of natural shading, providing greater thermal comfort, especially for composite animals, and favored the maintenance of homeothermy in the bulls.

SIGNIFICANCE

This thesis has provided a deeper insight into the physiological mechanisms involved in the thermoregulation of cattle raised in integrated crop-livestock-forestry systems. The insights gained from this study may be of assistance to indicate ICLF as a suitable option for increasing animal welfare in tropical climates.

Introduction

Several countries have been suffering from the effects of climate change, which has led to direct losses in the agri-food sector (Bayssa et al., 2021). According to the IPCC (2021), the temperature of Earth's surface could increase by 2.1 to 3.5 °C by the year 2100 in an intermediate scenario of greenhouse gas emission. It is estimated that there will be an increase in the frequency, intensity, and duration of extreme bioclimate events (Howden et al., 2008). Among livestock species, beef cattle are one of the most susceptible to suffer from water and food stress due to recent climate change (Ali et al., 2020).

Climate change presents challenges for livestock productivity and animal health. Heat stress causes deleterious effects in homeostasis, leading to nutritional and metabolic disorders that reduce growth rate, weight gain, and meat quality (Henry et al., 2012). Heat loads are capable of displacing cattle from their thermal comfort zone, leading to heat stress, which compromises reproduction and reduces fertility (Lees et al., 2019), decreasing the efficiency of production systems. In addition, extreme environmental events can determine adverse effects on the immunological condition of cattle, making them more susceptible to diseases and not able to live in an expected condition of welfare (Caminade et al., 2019).

Considering this, studies to develop strategies to mitigate the heat stress of pasture-based herds have been gaining importance, especially in tropical (Domiciano et al., 2016; Giro et al., 2019a; Santos et al., 2021) and subtropical regions (Davison et al., 2016; Deniz et al., 2021). In this regard, the implementation of integrated production systems, such as the crop-livestock-forestry (ICLF) (Telles et al., 2021), has been changing paradigms of pasture cattle production with the development of more sustainable, specialized, and technified systems (Garrett et al., 2017; Kruchelski et al., 2023). The adoption of the ICLF system presents benefits like the rationalization and intensification of land use, besides the diversification of productive components, providing the producer with the option of including trees, grains, and forage in the system (Figueiredo et al., 2017). Furthermore, the ICLF system has a potential of contributing to the reduction of greenhouse gas emissions, especially carbon dioxide and methane (Sá et al., 2017).

ICLF can benefit animals from the increased quality of forage (Assmann et al., 2014) if grasses adapted to shaded conditions are used (Abraham et al., 2014). The introduction of trees into the system may also promote positive microclimate changes by providing natural shading, a milder ambient temperature, and better indices of thermal comfort (Oliveira et al., 2018), which gives the animals fewer hours of exposure to heat stress (Pezzopane et al., 2019). However, despite the importance and growing interest in the adoption of integrated systems, and some previous reports about possible ICLF's benefits to thermal comfort of water buffaloes (Garcia et al., 2011; Joele et al., 2017), dairy heifers (Silva et al., 2008) and beef cows (Lemes et al., 2021), there are gaps in the scientific literature regarding the positive effects on beef bulls.

One of the intriguing points is how the homeothermy maintenance mechanisms in zebu and composite breeds respond when animals are kept in the ICLF system. In this context, the objective of the study was to evaluate the production systems in a non-shaded pastures and in a crop-livestock-forestry pastures on microclimatic conditions and their effects on the thermoregulatory and endocrine responses of Nelore and Canchim bulls during different seasons in a tropical environment.

Section snippets

Location and period

The experiment was conducted at the Embrapa-Brazilian Agricultural Research Corporation in São Carlos, Brazil (21°57′42″ S, 47°50′28″ W, 854 a.m.s.l.). The local climatic type is Cwa, altitude tropical, according to the Köppen-Geiger classification (Kottek et al., 2006) with four distinct seasons: winter, spring, summer, and autumn. Throughout the year, the daily minimal air temperature varies from 6.6 to 23.8 °C, the average of maximum air temperature varies from 29.0 to 34.6 °C with peaks up

Biometeorological variables and thermal comfort indexes

The presence of trees reduced the radiant heat load on pastures from 656 to 551 W/m2 (Table 1) and significantly decreased the mean air temperature by 0.6 °C and the black globe temperature by 3.7 °C. In consequence, the BGHI was 3.8 points higher in non-shaded areas, where wind speed was higher than 0.6 m/s. Relative humidity did not differ between treatments.

Body surface temperature

MibT, MebT, and TTr were higher in NS bulls in Autumn and Winter, with no difference between treatments in the other stations (Fig. 5).

Discussion

One of the purposes of inserting a tree component in a cattle production system is to reduce the exposure of the animals to solar radiation and high temperatures of the environment, providing a microclimate that favors thermal comfort (Castro-Pérez et al., 2020). This effect was efficiently achieved, with the observation of a change in the set of biometeorological variables that led to a milder environmental condition in the ICLF system. This occurred regardless of 2018 being one of the four

Conclusions

The integrated crop-livestock-forestry system was effective in mitigating the microclimate of the pastures, since the provided natural shade reduced the negative effects of high air temperature and direct solar radiation on the animals in a tropical environment. By providing a better thermal comfort condition to the bulls, the ICLF system positively impacted the physiological characteristics related to the thermodynamic balance of the animals and the maintenance of their homeothermy. In regard

CRediT authorship contribution statement

Narian Romanello: Conceptualization, Methodology, Investigation, Data curation, Writing – original draft. Andréa do Nascimento Barreto: Methodology, Investigation. Marco Antonio Paula de Sousa: Investigation. Júlio Cesar de Carvalho Balieiro: Data curation, Formal analysis. Felipe Zandonadi Brandão: Methodology, Investigation. Felipe Tonato: Methodology, Investigation. Alberto Carlos de Campos Bernardi: Conceptualization, Methodology, Investigation, Funding acquisition. José Ricardo Macedo

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Alexandre Rossetto Garcia reports financial support was provided by National Council for Scientific and Technological Development. Julio Cesar de Carvalho Balieiro reports financial support was provided by National Council for Scientific and Technological Development. Alexandre Rossetto Garcia reports financial support was

Acknowledgments

The authors thank the Embrapa (Precision Agriculture Network, grant# 11.14.09.001.03.03), Instituto Brasileiro de Desenvolvimento e Sustentabilidade (Sustainable Rural Project-Cerrado), IABS, ILPF Network, and FAPESP for the financial support (Process 2015/26627-5, Process 2019/04528-6). This study was also financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. ARG, JCCB, FZB, ACCB and JRMP are CNPq - National Council for Scientific and

References (90)

  • J.R.M. Pezzopane et al.

    Animal thermal comfort indexes in silvopastoral systems with different tree arrangements

    J. Therm. Biol.

    (2019)
  • M.A. Rahman et al.

    Vertical air temperature gradients under the shade of two contrasting urban tree species during different types of summer days

    Sci. Total Environ.

    (2018)
  • D. Renaudeau et al.

    Adaptation to hot climate and strategies to alleviate heat stress in livestock production

    Animal

    (2012)
  • J.C. et al.

    Low-carbon agriculture in South America to mitigate global climate change and advance food security

    Environ. Int.

    (2017)
  • M. Sathiyabarathi et al.

    Infrared thermal imaging of udder skin surface temperature variations to monitor udder health status in Bos indicus (Deoni) cows

    Infrared Phys. Technol.

    (2018)
  • N. Silanikove

    Effects of heat stress on the welfare of extensively managed domestic ruminants

    Livest. Prod. Sci.

    (2000)
  • F. Sosa et al.

    Effects of the SLICK1 mutation in PRLR on regulation of core body temperature and global gene expression in liver in cattle

    Animal

    (2022)
  • E. Van Laer et al.

    Importance of outdoor shelter for cattle in temperate climates

    Livest. Sci.

    (2014)
  • E.F. Vizzotto et al.

    Access to shade changes behavioral and physiological attributes of dairy cows during the hot season in the subtropics

    Animal

    (2015)
  • E.M. Abraham et al.

    Growth, dry matter production, phenotypic plasticity, and nutritive value of three natural populations of Dactylis glomerata L. under various shading treatments

    Agrofor. Syst.

    (2014)
  • H. Akaike

    Information theory and an extension of the maximum likelihood principle

  • M.Z. Ali et al.

    Impact of global climate change on livestock health: Bangladesh perspective

    Open Vet. J.

    (2020)
  • F.C. Baêta et al.

    Ambiência em edificações rurais: conforto animal

    (2010)
  • D.V. Barros et al.

    Evaluation of thermal comfort, physiological, hematological, and seminal features of buffalo bulls in an artificial insemination station in a tropical environment

    Trop. Anim. Health Prod.

    (2015)
  • D.V. Barros et al.

    Assessment of surface temperatures of buffalo bulls (Bubalus bubalis) raised under tropical conditions using infrared thermography

    Arq. Bras. Med. Vet. Zoot.

    (2016)
  • M. Bayssa et al.

    Production, reproduction and some adaptation characteristics of Boran cattle breed under changing climate: a systematic review and meta-analysis

    PLoS One

    (2021)
  • W. Bianca

    Reviews of the progress of dairy physiology cattle in a hot environment

    J. Dairy Sci.

    (1965)
  • C. Bosi et al.

    Silvopastoral system with Eucalyptus as a strategy for mitigating the effects of climate change on Brazilian pasturelands

    An. Acad. Bras. Cienc.

    (2020)
  • Brasil-Conselho Nacional de Controle de Experimentação Animal

    Diretriz Brasileira para o Cuidado e a Utilização de Animais em Atividades de Ensino ou de Pesquisa Científica

  • H.B. Brunetti et al.

    Productive and nutritive traits of Piatã palisadegrass after thinning the forest component of a silvopastoral system in southeastern Brazil

    J. Agric. Sci.

    (2022)
  • D.E. Buffington et al.

    Black globe-humidity index (BGHI) as comfort equation for dairy cows

    Trans. ASAE

    (1981)
  • C. Caminade et al.

    Impact of recent and future climate change on vector-borne diseases

    Ann. N. Y. Acad. Sci.

    (2019)
  • B.I. Castro-Pérez et al.

    The influence of shade allocation or total shade plus overhead fan on growth performance, efficiency of dietary energy utilization, and carcass characteristics of feedlot cattle under tropical ambient conditions

    Asian-Austral. J. Anim. Sci.

    (2020)
  • R.F. Cooke et al.

    Effects of acclimation to human interaction on performance, temperament, physiological responses, and pregnancy rates of Brahman - crossbred cows

    J. Anim. Sci.

    (2009)
  • A. Correa-Calderon et al.

    Thermoregulatory responses of Holstein and Brown Swiss heat-stressed dairy cows to two different cooling systems

    Int. J. Biometeorol.

    (2004)
  • K.M.S. Davila et al.

    Genetic parameters for hair characteristics and core body temperature in a multibreed Brahman-Angus herd

    J. Anim. Sci.

    (2019)
  • T.M. Davison et al.

    Comparison of the impact of six heat-load management strategies on thermal responses and milk production of feed-pad and pasture fed dairy cows in a subtropical environment

    Int. J. Biometeorol.

    (2016)
  • F.L.G.B. Deak et al.

    Effects of physiological stage and season on infrared thermograms of different body areas of dairy cows raised under tropical conditions

    Anim. Reprod.

    (2019)
  • M. Deniz et al.

    Social hierarchy influences dairy cows’ use of shade in a silvopastoral system under intensive rotational grazing

    Appl. Anim. Behav. Sci.

    (2021)
  • L.F. Domiciano et al.

    Performance and behaviour of Nellore steers on integrated systems

    Anim. Prod. Sci.

    (2016)
  • EMBRAPA-Empresa Brasileira de pesquisa Agropecuária

    Condições meteorológicas da estação da Embrapa Pecuária Sudeste

  • M.L. Esmay

    Principles of Animal Environment

    (1978)
  • P.G. Eusebi et al.

    Gene expression profiles underlying aggressive behavior in the prefrontal cortex of cattle

    BMC Genomics

    (2021)
  • E. Fazio et al.

    Effect of long-distance road transport on thyroid and adrenal function and haematocrit values in Limousin cattle: influence of body weight decrease

    Vet. Res. Commun.

    (2005)
  • E.B. Figueiredo et al.

    Greenhouse gas balance and carbon footprint of beef cattle in three contrasting pasture-management systems in Brazil

    J. Clean. Prod.

    (2017)
  • Cited by (3)

    View full text