The Occurrence Of Heat Waves In Sao Paulo - Brazil Using Temperature Humidity Index (thi) And Milk Decline Index (mdec)

Climate is not simply defined by the average temperature and precipitation, but also by the type, frequency and intensity of weather events. The climatic changes have the potential to alter the prevalence and severity of extremes, such as, storms, droughts and heatwaves (IPCC, 2007). A heat wave is a period of abnormal intense heat generally followed by high relative humidity with the duration of at least one day; however, conventionally being extended by some days or even some weeks (AhiS, 1989). The occurrence of heat waves can cause heat stress that input a negative influence on animal production. Thus, this research had as its general objective to estimate milk production losses as function of heat wave incidence in Sao Paulo state based on the average temperature and humidity index (THI). A historical of heat wave occurrence was developed based on climatic data over an interval of two to ten years. The estimated average milk production loss in the major dairy regions was also quantified during the identified heat wave periods. The results showed that the counties within the Vale do Paraiba dairy region as well as Presidente Prudente - Sao Paulo presented the highest number of heat waves per year, and that not always the heat wave with longest period presented higher intensity of occurrence. The conclusion is that the study of heat wave occurrence shows in a more effective way the heat stress effect on dairy production, which is not practically identified when studying just the average THI occurrence.881888Aguiar, I.S.Baccari JR., F.Gottshalk, A.F. etal. 1996. Produção de leite de vacas Holandesas em função da temperatura do ar e do indice de temperatura e umidade. Proc. Reunia̧o Anual da Sociedade Brasileira de Zootecnia, 37., Fortaleza. p.617-619(1989) Glossary of Meteorology, , AMS, 5th Edition. Am. Meteorological Society. Boston, MABerry, I.L., Shanklin, M.D., Johnson, H.D., Dairy shelter design based on milk production decline as affected by temperature and humidity (1964) Trans. ASAE, 7, pp. 329-331Bouraoui, R., Lahmar, M., Majdoub, A., Djemali, M., Belyea, R., The relationship of temperature-humidity index with milk production of dairy cows in a Mediterranean climate (2002) Anim.Res, 51, pp. 479-491Campos. A. T.Pires. M. F. A.Silva Junior. J. L.C.Costa. L.C. 2005. Zoneamento bioclimatológico da regia̧o Sudeste do Brasil para prognostico na produção de leite e na taxa de concepçã o de vacas Holandesas em função do Indice de Temperatura e Umidade. Embrapa Gado de Leite. Available al http://wwvv.cnpgl.eiTibrapa.br Accessed 16 March 2005Hubbard, K.G., Stocksbury, D.E., Hahn, G.L., A climatological perspective on feedlot cattle performance and mortality related to the THI (1997) Reprints Tenth Conference on Applied Climatology, pp. 349-353. , American Meteorological Society. Boston, MAHuhnke, R. L.McCowan, L. CMeraz, G. M.Harp, S. L.Payton, M. E. 2003. Using evaporative cooling to reduce the frequency and duration of elevated temperature-humidity indices in Oklahoma. American Society of Agriculture Engineering. ASAE Paper 014111. v. 2 0, p.95-99Huhnke, R.L., McCowan, L.C., Meraz, G.M., Harp, S.L., Payton, M.E., Determining the frequency and duration of elevated Temperature-Humidity Index (2001) American Society of Agriculture Engineering. ASAE, , Paper 01 -4 111. 12p(2001) Climate Change 2001: Impacts Adaptation and Vulnerability, , IPPCC, Intergovernmental Panel in Climate Changes, Genebra, SuiçaLaloni, L.A., Naas, I.A., Macari, M., Pereira, D.F., Pinheiro, M.G., (2003) Model for predicting milk production in jersey cows in hot weather, pp. 320-324. , ASAE paper 701P0203 pMeehl, G.A., Tebaldi, C., More intense, more frequent, and longer lasting heat waves in the 21 st century (2004) Science, 305 (5686), pp. 994-997Moura, F., Degradação Ambiental Muda Clima do Vale. Vale Verde (Associação de Defesa do Meio-Ambiente) Available at: Htip, , www.valeverde.org.br/html/midia2.phn?id=l7, Accessed 21 July 2006Nienaber, J. A.Hahn, G. L. 2004. Engineering and management practices to ameliorate livestock heat stress. In: Proc, International Symposium of The Cigr. New Trends In Farm Buildings, Lecture 6, 1-18. May 2-6, 2004, Evora, Portugal. CdromNienaber, J.A., Hahn, G.L., Brown-Brandl, T.M., Eigenberg, R.A., Heat Stress Climatic Conditions and physiological Responses of Cattle (2003) Proc. International Dairy Housing Conference, 5. , Fort Worth, Fort Worth: ASAEOliver, J.C.H.M., Hellman, S.E., Bishop, C.L., Bennett, P.L.F., Heat stress survey (1979) Calif. Agric, 33, pp. 6-8Ravagnolo, O., Misztal, I., Studies on genetics of heat tolerance in dairy cattle with reduced weather information via cluster analysis (2002) Journal of Dairy1 Science, 85, pp. 1586-158