Morpho-physiological responses of Bos indicus, Bos taurus and crossbred weaned heifers to seasonal variations

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DOI:

https://doi.org/10.18188/sap.v20i2.27040

Resumo


Beef cattle kept in extensive systems are constantly exposed to the effects of the climate. In tropical and intertropical regions, the reproductive management of Bos taurus animals with B. indicus animals is an alternative for zootechnical improvement. The objective was to evaluate morphophysiological characteristics of heat adaptation of beef heifers on pasture. For this, fifty-four animals from four distinct genetic groups: (1) Nellore, (2) Senepol, (3) Angus x Nellore and (4) ¼ Brahman x ¼ Nellore x ½ Senepol (Tri-cross), with six months-old, were evaluated during the summer and autumn seasons of 2016. The morphological characteristics of the coat (length, diameter, thickness, density and number of hairs and coat color) and physiological (skin, hair and rectal temperature; sweat rate; respiratory and heart rate) were evaluated. The environment was evaluated using the temperature and humidity index, black globe temperature, humidity index and radiation thermal load. We observed that the production environment presented thermal discomfort for the animals. Thus, the animals’ rectal temperature differed between seasons. All groups studied showed some adaptive characteristic to the tropical environment. Angus x Nellore heifers had the highest values for the morphological measures in the months evaluated, coinciding with thermal comfort indexes above those considered comfortable for cattle and the lowest value of respiratory rate when compared between the crossing. In conclusion, all genetic groups have at least three adaptive characteristics to the tropical environment when analyzing the physiological responses.

Biografia do Autor

Ariadne Pegoraro Mastelaro

Médica Veterinária e doutora em Zootecnia

Eliane Sayuri Miyagi, Teacher at Federal University of Goiás - UFG

Department of Animal Production

Nivaldo Karvatte Junior, Phd student at Federal University of Goiás - UFG

Department of Animal Production

Gilberto Romeiro de Oliveira Menezes, Research, Brazilian Agricultural Research Corporation - Embrapa Beef Cattle

Embrapa Beef Cattle

Paulo Gustavo Macedo de Almeida Martins, Teacher of Federal University of Jequitinhonha and Mucuri Valleys - UFVJM

Department of Animal Science

Fabiana Villa Alves, Research, Brazilian Agricultural Research Corporation - Embrapa Beef Cattle

Embrapa Beef Cattle

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Publicado

30-06-2021

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PEGORARO MASTELARO, A.; SAYURI MIYAGI, E.; KARVATTE JUNIOR, N.; ROMEIRO DE OLIVEIRA MENEZES, G.; GUSTAVO MACEDO DE ALMEIDA MARTINS, P.; VILLA ALVES, F. Morpho-physiological responses of Bos indicus, Bos taurus and crossbred weaned heifers to seasonal variations. Scientia Agraria Paranaensis, [S. l.], v. 20, n. 2, p. 186–192, 2021. DOI: 10.18188/sap.v20i2.27040. Disponível em: https://saber.unioeste.br/index.php/scientiaagraria/article/view/27040. Acesso em: 26 maio. 2022.

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Artigos Científicos