Most Appropriate Heat Stress Index for Half-blood Dairy Heifers

Patrícia Kelly de Moraes Brettas, Mara Regina Bueno de Mattos Nascimento, Ednaldo Carvalo Guimarães, Gabriella Pereira Souza

Abstract


Background: Heat stress indexes integrate several variables of the thermal environment in a single figure and predict their impact on animal welfare and performance. The correct interpretation of these indexes is of help in the choice of more adequate measures to attenuate the stress caused by the heat. Therefore, the aim of this research is to examine some of the heat stress indexes mentioned in the literature and to decide which ones best reflect the potential impact of meteorological conditions on the thermal homeostasis of half-blood dairy heifers bred in Uberlândia, Triângulo Mineiro area, Minas Gerais, Brazil.

Materials, Methods & Results: Eight half-blood dairy heifers were exposed to direct sunlight from 9 h to 13 h in the months of November and December of 2016, and also January and February of 2017, 5 days per month on average, in Uberlândia, MG, Brazil. After this challenge, the respiratory rate and the rectal temperature were measured. Simultaneously to the collection of physiological variables, the temperatures of dry bulb and wet bulb, as well as that of black globe, were quantified, as was the wind speed. Afterwards, the solar radiation, the relative humidity, the mean radiant temperature and some heat stress indexes were calculated, the latter being Temperature-Humidity Index, Black Globe-Humidity Index, Equivalent Temperature Index, Environmental Stress Index, Respiratory Rate Index, Thermal Load Index, Environmental Specification Index, Thermal Comfort Index for Dairy Cattle, Comprehensive Climate Index and Cattle Heat Stress Index. These indexes were, then, correlated with the physiological variables. The averages of room temperature, black globe temperature, solar radiation, wind speed, radiant temperature and relative humidity were, respectively, 29.96°C, 41.73°C, 831.02 W/m2, 0.11 m/s-1, 318.14 K and 50.51%. Rectal temperature averaged 38.8ºC while respiratory rate averaged 41.97 breaths per minute-1. Correlating the 10 heat stress indexes with these two physiological variables, it was verified that the highest values, with a confidence of 95%, were demonstrated by the Equivalent Temperature Index (0.200 and 0.317, respectively), followed by the Cattle Heat Stress Index (0.186 and 0.314, respectively).

Discussion: Room temperature was within the thermoneutral zone for half-blood dairy cattle. Nevertheless, the mean radiant temperature and the black globe temperature were higher, due to intense solar radiation. Wind speed was not very expressive and relative humidity was close to what was required. The average values of rectal temperature and respiratory rate were normal, which indicated the heifers are adapted to the thermal environment. Regarding the heat stress indexes, the Equivalent Temperature Index was recommended, as it presented the highest amount of meaningful correlations with the physiological variables, followed by the Cattle Heat Stress Index and the Environmental Stress Index. The average value of the Equivalent Temperature Index remained in the “caution” category, according to the literature’s two existing scales for interpretation of said index’s results, indicating the occurrence of stress by heat, albeit not severe. In conclusion, the Equivalent Temperature Index is considered the most appropriate heat stress index for evaluating a heat stress situation in half-blood dairy heifers bred in Uberlândia, Triângulo Mineiro, followed by the Cattle Heat Stress Index and the Environmental Stress Index.


Keywords


heat stress; respiratory rate; dairy cattle; rectal temperature.

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References


Almeida Neto L.A., Pandorfi H., Almeida G.L. & Guiselini C. 2014. Climatização na pré-ordenha de vacas Girolando no inverno do semiárido. Revista Brasileira de Engenharia Agrícola Ambiental. 18: 1072-1078.

Baeta F.C., Meador N.F., Shanklin M.D. & Johnson H.D. 1987. Equivalent temperature index at temperatures above the thermoneutral for lactating cows. In: Proceedings of the Meeting of the American Society of Agricultural Engineers (Baltimore, U.S.A.). p.21.

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: 1453-1462.

Buffington D.E., Collasso-Arocho A., Canton G.H., Pitt D., Thatcher W.W. & Collier R.J. 1981. Black globehumidity index (BGHI) as comfort equation for dairy cows. Transactions of the ASAE. 24: 711-714.

Costa A.N.L., Feitosa J.V., Montezuma 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: 1647-1653.

Costa M.D., Ruas J.R.M., Rodriguez M.A.P., Nogueira T.M. & Venturini R.P. 2016. Análise da relação benefíciocusto em sistema de produção de leite com animais mestiços no Norte de Minas Gerais. Boletim de Indústria Animal. 73: 244-251.

Eigenberg R.A., Brown-Brandl T.M., Nienaber J.A. & Hahn G.L. 2002. Dynamic response of feedlot cattle to shade and no-shade. In: Proceedings of the Meeting of The American Society of Agricultural Engineers (Baltimore, U.S.A.). Paper no. 024050.

Eigenberg R.A., Nienaber J.A. & Brown-Brandl T.M. 2004. Development of a livestock safety monitor for cattle. In: Proceedings of the Meeting of The American Society of Agricultural Engineers (Baltimore, U.S.A.). Paper no. 032338.

Fonsêca V.D.F.C., Cândido E.P., Gonzaga Neto S., Saraiva E.P., Furtado D.A., Gama J.F.P., Nascimento G.V., Saraiva C.A.S. & Almeida G.H.O. 2016. Thermoregulatory responses of sindhi and guzerat heifers under shade in a tropical environment. Semina: Ciências Agrárias. 37: 4327-4338.

Gaughan J.B., Holt S.M., Hahn G.L., Mader T.L. & Eigenberg R. 2000. Respiration Rate – Is It a Good Measure of Heat Stress in Cattle? Asian-Australasian Journal of Animal Sciences. 13: 329- 332.

Gaughan J.B., Mader T.L., Holt S.M. & Lisle A. 2008. A new heat load index for feedlot cattle. Journal of Animal Science. 86: 226-234.

Hahn G.L. 1985. Management and housing of farm animals in hot environments. In: Stress physiology in livestock. Boca Raton: CRC Press, pp.151-174.

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: 97-121.

Mader T.L., Johson L.J. & Gaughan J.B. 2010. A comprehensive index for assessing environmental stress in animals. Journal of Animal Science. 88: 2153-2165.

Maia A.S.C., Silva R.G., Nascimento S.T., Nascimento C.C.N., Pedroza H.P. & Domingos H.G.T. 2015. Thermoregulatory responses of goats in hot environments. International Journal of Biometeorology. 59: 1025-1033.

Martello L.S., Savastano Júnior H., Silva S.L.D.A. & Titto E.A.L. 2004. Respostas fisiológicas e produtivas de vacas holandesas em lactação submetidas a diferentes ambientes. Revista Brasileira de Zootecnia. 33: 181-191.

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: 75-90.

Moran D.S., Pandolf K.B., Shapiro Y., Heled Y., Shani Y., Mathew W.T. & Gonzalez R.R. 2001. An environmental stress index (ESI) as a substitute for the wet bulb globe temperature (WBGT). Journal of Thermal Biology. 26: 427-431.

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: 28-36.

Nienaber J.A., Hahn G.L. & Eigenberg R.A. 2004. Engineering and management practices to ameliorate livestock heat stress. In: Proceedings, International Symposium of The CIGR (Evora, Portugal). pp.1-18.

Pires M.F.A. & Campos A.T. 2004. Modificações ambientais para reduzir o estresse calórico em gado de leite. Embrapa Gado de Leite-Comunicado Técnico. 42:1-6.

Silva E.M. & Aassunção W.L. 2004. O Clima na cidade de Uberlândia. Revista Sociedade e Natureza. 16: 91-107.

Silva R. G. 2000. Introdução à bioclimatologia animal. São Paulo: Nobel, 286p.

Silva R.G., Maia A.S.C. & Costa L.L.M. 2015. Index of thermal stress for cows (ITSC) under high solar radiation in tropical environments. International Journal of Biometeorology. 59: 551-559.

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

Silva R.G., Morais D.A.E.F., Guilhermino M.M., LaScala Junior N. & Maia A.S.C. 2010. Índices de Estresse Térmico para Vacas Leiteiras em Regiões Equatoriais Secas. Revista Científica de Produção Animal. 12: 125-128.

Souza B.D., Silva I.J.O., Mellace E.M., Santos R.F.S., Zotti C.A. & Garcia P.R. 2010. Avaliação do ambiente físico promovido pelo sombreamento sobre o processo termorregulatório em novilhas leiteiras. Agropecuária Científica no Semiárido. 6: 59-65.

Takahashi L.S., Biller J.D., Takahashi K.M. 2009. Bioclimatologia zootécnica. 2.ed. Jaboticabal: Funep, 91p.

Tonello C.L. 2011. Validação de Índice de Conforto Térmico e Zoneamento Bioclimático da Bovinocultura de Leite. 140f. Maringá, PR. Tese (Doutorado em Zootecnia) - Programa de Pós-graduação em Zootecnia - Área de Concentração Produção Animal, Universidade Estadual de Maringá.

Thom E.C. 1959. The discomfort index. Weatherwise. 12: 57- 59.

West J.W. 2003. Effects of Heat-Stress on Production in Dairy Cattle. Journal of Dairy Science. 86: 2131-2134.




DOI: https://doi.org/10.22456/1679-9216.80577

Copyright (c) 2018 Patrícia Kelly de Moraes Brettas, Mara Regina Bueno de Mattos Nascimento, Ednaldo Carvalo Guimarães, Gabriella Pereira Souza

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