Effect of Season and Age on Thermophysiological and Hematological Variables of Crossbred Dairy Calves in Tropical Environment


  • Fernanda Gatti de Oliveira Nascimento Programa de Pós-graduação em Ciências Veterinárias, Faculdade de Medicina Veterinária, UFU. Uberlândia, MG, Brazil.
  • Amanda Bizare Programa de Pós-graduação em Ciências Veterinárias, Faculdade de Medicina Veterinária, UFU. Uberlândia, MG, Brazil.
  • Ednaldo Carvalho Guimarães Programa de Pós-graduação em Ciências Veterinárias, Faculdade de Medicina Veterinária, UFU. Uberlândia, MG, Brazil.
  • Antonio Vicente Mundim Programa de Pós-graduação em Ciências Veterinárias, Faculdade de Medicina Veterinária, UFU. Uberlândia, MG, Brazil.
  • Mara Regina Bueno de Mattos Nascimento Programa de Pós-graduação em Ciências Veterinárias, Faculdade de Medicina Veterinária, UFU. Uberlândia, MG, Brazil.




Background: The wellbeing and performance of calves may be impaired if raised in high temperature environments. Physiological and hematological variables serve as a tool to assess the welfare of cattle; therefore, the influence of seasons and age on physiological and hematological variables was evaluated of crossbred dairy calves in a tropical environment.

Materials, Methods & Results: Forty-two male and female calves were evaluated from July 2016 to July 2017, when the calves were of 2, 15, 30, and 60 days of age. Respiratory (RR) and heart rates (HR) and rectal (RT) and body surface (BST) temperatures were quantified in the morning. Additionally, in the morning, dry bulb (Tdb) and wet bulb (Twb) temperatures were measured, and then, relative humidity (RH) and a temperature-humidity index (THI) were calculated. Blood was collected to perform hemogram. The day before the calves were evaluated, thermal environment data were collected to verify whether there were cyclic periods of heat stress. The mean air temperature ranged from 19°C to 22.1°C, and the highest THI value of 68 occurred in the summer mornings. In the afternoon, the maximum air temperature ranged from 27.5°C to 29.7°C. In autumn, respiratory and heart rates and body surface temperature were higher in 2-day-old calves than in other ages. The body surface temperature of 60-day-old calves was higher in spring and summer than in autumn. Rectal temperature remained in the normal range throughout the study period. Season did not influence the erythrogram and plaquetogram. The values for red blood cells, MCV, MCHC, RDW, platelets, and MPV varied among the calf ages. Season did not influence the values of leukocytes, monocytes, lymphocytes, or N/L ratio; however, band neutrophils and eosinophils varied among seasons. Band neutrophils and monocytes were not altered by age, whereas leukocyte, segmented neutrophils, eosinophils, lymphocytes, and N/L ratio values varied with age among the calves.

Discussion: The air temperature and THI remained within the thermoneutral zone of crossbred dairy calves in the morning; however, in the afternoon the air temperature and THI increased, which indicates cyclic periods of critical heat stress. Higher RR and HR values observed in 2-day-old calves may be due to the physiological changes that accompany adapting to extrauterine life. The RT remained within the reference range for species during all seasons and at all ages, and therefore, the calves were able to maintain normothermia. The air temperature remained lower than the BST and was within the thermoneutral zone; thus, the loss of sensible heat was predominant in relation to evaporation dissipation. Age, breed, time of day, and meteorological variables may influence hematological constituents. Red blood cells of newborn calves are large, of fetal origin, and are replaced by smaller cells with advancing age, which results in a smaller MCV value. The higher neutrophil concentrations in 2-day-old calves resulted in a higher N/L ratio following the trend of plasma cortisol concentration, which is high at birth and decreases with age. The highest values of band neutrophils are because these cells are responsible for phagocytosis of microorganisms and other foreign materials. Since new-born calves are in contact with microorganisms in the environment and are highly susceptible to infections, it is justifiable to observe an increased number of band neutrophils. The differences observed in lymphocyte numbers in calves aged 30 and 60 days during autumn, winter, and spring is likely due to the production of B lymphocytes as an exposure response to agents present in the environment. We conclude that seasons interfere with BST and neutrophil and eosinophil counts, while age affects thermophysiological variables, erythrogram, plaquetogram, and leukogram.


Download data is not yet available.


Alves J.R.A., Andrade T.A.A., Assis D.M., Gurjão T.A., Melo L.R.B. & Souza B.B. 2017. Productive and reproductive performance, behavior and physiology of cattle under heat stress conditions. Journal of Animal Behavior and biometeorology. 5(3): 91-96.

Araújo J.I.M., Araújo A.C., Rodrigues H.T.M., Oliveira L.G., Júnior C.P.B., Fonseca W.J.L., Luz C.S.M. & Souza Júnior S.C. 2016. Efeito de diferentes ambiente climáticos sobre características fisiológicas de bezerros mestiços (Holandês x Gir). Revista de Ciências Agroveterinárias. 15(3): 259-265.

Berman A., Horovitz T., Kaim M. & Gacitua H. 2016. A comparison of THI indices leads to a sensible heat-based heat stress index for shaded cattle that aligns temperature and humidity stress. International Journal of Biometeorology. 60(10): 1453-1462.

Birgel Júnior E.H., D’Angelino J.L. & Benesi F.J. 2001. Valores de referência do eritrograma de bovinos da raça Jersey criados no Estado de São Paulo. Arquivo Brasileiro de Medicina Veterinária e Zootecnia. 53(2): 164-171.

Brettas P.K.M., Nascimento M.R.B.M., Guimarães E.C. & Souza G.P. 2017. Melhor índice de estresse térmico para novilhas leiteiras mestiças. Acta Scientiae Veterinariae. 45(1486): 1-8.

Broucek J., Kisac P. & Uhrincat M. 2009. Effect of hot temperatures on the hematological parameters, health and performance of calves. International Journal of Biometeorology. 53(2): 201-208.

Costa A.N.L., Feitosa J.V., Montezuma Jr P.A., Souza P.T. & Araújo A.A. 2015. Rectal temperatures, respiratory rates, production, and reproduction performances of crossbred Girolando cows under heat stress in northeastern Brazil. International Journal of Biometeorology. 59(11): 1647-1653.

Da Silva R.G. & Campos Maia A.S. 2013. Principles of Animal Biometeorology. v2. New York: Springer, 283p.

Davis C.L. & Drackley J.K. 1998. The development, nutrition, and management of the young calf. Ames: Iowa State University Press, 339p.

Ebehart R.J. & Patt J.A. 1971. Plasma cortisol concentrations in newborn calves. American Journal of Veterinary Research. 32(12): 1921- 1927.

Feitosa F.L.F. 2008. Semiologia Veterinária. A arte do diagnóstico. 2.ed. São Paulo: Rocca, 792p.

Ferreira Neto J.M., Viana E.S. & Magalhaes L.M. 1982. Patologia Clínica Veterinária. 2.ed. Belo Horizonte: Editora Rabelo, 293p.

Finch V.A. 1986. Body temperature in beef cattle: its control and relevance to production in the tropics. Journal of Animal Science. 62(2): 531-542.

Hahn G.L., Parkhurrst A.M. & Gaughan J.B. 1997. Cattle respiration rate as a function of ambient temperature. Transactions of American Society of Agricultural Engineering. 40(6): 97-121.

Indu S. & Pareek A. 2015. A Review: Growth and Physiological Adaptability of Sheep to Heat Stress under Semi–Arid Environment. International Journal of Emerging Trends in Science and Technology. 2(9): 3188-3198.

Jain N.C. 1993. Comparative hematology of common domestic animals. In: Essentials of Veterinary Hematology. Philadelphia: Lea & Febiger, pp.19-53.

Lee D.H.K. 1965. Climatic stress indices for domestic animals. International Journal of Biometeorology. 9(1): 29-35.

Maywald P.G. & Marçal Júnior O. 2013. Estrutura de Áreas protegidas dos assentamentos de reforma agrária no município de Uberlândia-MG, Brasil: um estudo de ecologia de paisagem. Revista Sociedade & Natureza. 25(1): 75-90.

McManus C., Prescott E., Paludo G.R, Bianchini E., Louvandini H. & Mariante A.S. 2009. Heat tolerance in naturalized Brazilian cattle breeds. Livestock Science. 120(3): 256-264.

Nascimento G.V.D., Cardoso E.D.A., Batista N.L., Souza B.B.D. & Cambuí G.B. 2013. Indicadores produtivos, fisiológicos e comportamentais de vacas de leite. Agropecuária Científica no Semiárido. 9(4): 28-36.

National Research Council - NRC. 1971. A guide to environmental research on animals. Washington DC: National Academy of Sciences, 374p.

Rocha T.G., Nociti R.P., Sampaio A.A.M. & Fagliari J.J. 2013. Hemograma e proteínas de fase aguda de bezerros sadios do nascimento aos 30 dias de idade. Pesquisa Veterinária Brasileira. 33(Supl 1): 25-31.

Roland L., Drillich M., Klein-Jöbstl D. & Iwersen M. 2016. Invited review: Influence of climatic conditions on the development, performance, and health of calves. Journal of Dairy Science. 99(4): 2438-2452.

Silanikove N. 2000. Effects of heat stress on the welfare of extensively managed domestic ruminants. Livestock Production Science. 67(1): 1-18.

Silva E.M. & Assunção W.L. 2004. O clima na cidade de Uberlândia – MG. Sociedade & Natureza. 16(30): 91-107.

Silva R.M.N., Souza B.B., Souza A.P., Marinho M.L., Tavares G.P. & Silva E.M.N. 2005. Efeito do sexo e da idade sobre os parâmetros fisiológicos e hematológicos de bovinos da raça Sindi no semi-árido. Ciência e Agrotecnologia. 29(1): 193-199.

Silva R.G., Morais D.A.E.F. & Guilhermino M.M. 2007. Evaluation of termal stress indexes for dairy cows in tropical regions. Revista Brasileira de Zootecnia. 36(4): 1192-1198.

Silva R.G. 2008. Biofísica ambiental: os animais e o seu ambiente. Jaboticabal: FUNEP, 393p.

Silva J.A.R., Araújo A.A., Lourenço Júnior J.B., Santos N.F.A., Garcia A.R. & Oliveira R.P. 2015. Thermal comfort índices of female Murrah buffaloes reared in the Eastern Amazon. International Journal of Biometeological. 59(9): 1261-1267.

Singh S.P. & Newton W.M. 1978. Acclimation of young calves to high temperatures: physiologic responses. American Journal of Veterinary Research. 39(5): 795-797.

Starling J.M.C., Silva R.G., Cerón-Muñoz M., Barbosa G.S.S.C. & Costa M.J.R.P. 2002. Análise de algumas variáveis fisiológicas para avaliação do grau de adaptação de ovinos submetidos ao estresse por calor. Revista Brasileira de Zootecnia. 31(5): 2070-2077.

Thrall M.A., Weiser G., Allison R.W. & Campbell T.W. 2015. Hematologia e Bioquímica Clínica Veterinária. 2.ed. Rio de Janeiro: Guanabara Koogan, 678p.

Thom E.C. 1959. The discomfort index. Weatherwise. 12(2): 57-61.

Wood D. & Quiroz-Rocha G.F. 2010. Normal hematology of cattle. In: Weiss D.J. & Wardrop K.J. (Eds). Schalm’s Veterinary Hematology. 6th edn. Ames: Blackwell Publishing, pp.829-835.

Yousef M.K. 1985. Stress physiology in livestock. Basic principles. v.1. Boca Raton: CRC Press, 217p.



How to Cite

de Oliveira Nascimento, F. G., Bizare, A., Guimarães, E. C., Mundim, A. V., & de Mattos Nascimento, M. R. B. (2019). Effect of Season and Age on Thermophysiological and Hematological Variables of Crossbred Dairy Calves in Tropical Environment. Acta Scientiae Veterinariae, 47(1). https://doi.org/10.22456/1679-9216.89413




Most read articles by the same author(s)