ORIGINAL RESEARCH Use of multivariate analyses for determining heat tolerance in Brazilian cattle Concepta McManus & Marlos Castanheira & Samuel Rezende Paiva & Helder Louvandini & Maria Clorinda Soares Fioravanti & Giane Regina Paludo & Eliandra Bianchini & Patricia Spoto Corrêa Published online: 23 December 2010 # Springer Science+Business Media B.V. 2010 Abstract Adaptability can be evaluated by the ability of an animal to adjust to environmental conditions and is especially important in extreme weather conditions such as that found in tropical Brazil. A multivariate analysis using physical and physiological traits in exotic (Nellore and Holstein) and naturalized (Junqueira, Curraleira, Mocho Nacional, Crioula Lageana, and Pantaneira) cattle breeds was carried out in the Federal District of Brazil to test and determine which traits are important in the adaptation of animal to heat stress as well as the ability of these traits and statistical techniques to separate the breeds studied. Both physical and physiological traits were measured on three occasions and included body measure- ments, skin and hair thickness, hair number and length, pigmentation, sweat gland area as well as heart and breathing rates, rectal temperature, sweating rate, and blood parameters. The data underwent multivariate statistical analyses, including cluster, discriminate, and canonical procedures. The tree diagram showed clear distances between the groups studied, and canonical analysis was able to separate individuals in groups. Coat traits explained little variation in physiological parameters. The traits which had higher discriminatory power included packed cell volume, shoulder height, mean corpuscular volume, body length, and heart girth. Morphological and physiological traits were able to discriminate between the breeds tested, with blood and size traits being the most important. More than 80% of animals of all breeds were correctly classified in their genetic group. Keywords Adaptation . Bovidae . Naturalized breeds . Temperature . Thermolysis Introduction Animal production systems have been undergoing radical transformations in recent years due to the need to increase productivity and incorporate new technologies for the improvement of the efficiency, profit, animal welfare, and product quality. This trend involves not only animal breeding and nutrition but also animal comfort based on its relationship with the environment as well as costs and facilities for the farmer in terms of animal management, installation cleaning, and labor usage (Perissinotto et al. 2007). C. McManus (*) : H. Louvandini : G. R. Paludo : E. Bianchini Faculdade de Agronomia e Medicina Veterinária, Universidade de Brasília, Brasília, Federal District, Brazil e-mail: concepta@unb.br H. Louvandini e-mail: hlouvand@unb.br G. R. Paludo e-mail: giane@unb.br M. Castanheira : M. C. S. Fioravanti Escola de Veterinária, Universidade Federal de Goiás, Goiânia, Goiás, Brazil M. Castanheira e-mail: castanheira_m@hotmail.com M. C. S. Fioravanti e-mail: clorinda@vet.ufg.br S. R. Paiva EMBRAPA Recursos Genéticos e Biotecnologia, Brasília, Federal District, Brazil e-mail: samuel@cenargen.embrapa.br P. S. Corrêa Secretaria de Vigilância em Saúde, Ministério da Saúde, Brasília, Federal District, Brazil e-mail: Patricia.Louvandini@saude.gov.br Trop Anim Health Prod (2011) 43:623–630 DOI 10.1007/s11250-010-9742-8