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Do newborn lambs with black and white hair-coats in an equatorial semi-arid environment maintain homeothermy?
Fonsêca, V F C; Dos Santos, J D C; Saraiva, E P; Xavier Neta, G C; Morais, L K C; Bícego, K C; Pereira, W E; Pimenta Filho, E C; Moura, G A B; Sejian, V; Fuller, A.
Afiliação
  • Fonsêca VFC; Laboratory of Animal Biometeorology, São Paulo State University, Jaboticabal, Brazil. vinicius_fonseca86@hotmail.com.
  • Dos Santos JDC; Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa. vinicius_fonseca86@hotmail.com.
  • Saraiva EP; Animal Biometeorology and Ethology Group, Department of Animal Science, Federal University of Paraiba, Areia, Brazil.
  • Xavier Neta GC; Animal Biometeorology and Ethology Group, Department of Animal Science, Federal University of Paraiba, Areia, Brazil.
  • Morais LKC; Department of Animal Morphology and Physiology, São Paulo State University, Jaboticabal, SP, Brazil.
  • Bícego KC; Animal Biometeorology and Ethology Group, Department of Animal Science, Federal University of Paraiba, Areia, Brazil.
  • Pereira WE; Department of Animal Morphology and Physiology, São Paulo State University, Jaboticabal, SP, Brazil.
  • Pimenta Filho EC; Department of Fundamental and Social Sciences, Federal University of Paraíba, Areia, Paraíba, Brazil.
  • Moura GAB; Department of Fundamental and Social Sciences, Federal University of Paraíba, Areia, Paraíba, Brazil.
  • Sejian V; Laboratory of Animal Biometeorology, São Paulo State University, Jaboticabal, Brazil.
  • Fuller A; Rajiv Gandhi Institute of Veterinary Education and Research Puducherry, Puducherry, India.
Int J Biometeorol ; 2024 Jun 17.
Article em En | MEDLINE | ID: mdl-38884796
ABSTRACT
We assessed newborn lambs from two hair-coat sheep breeds, the black Santa Ines (n = 29) and white Dorper (n = 26), to determine how they behaviourally and physiologically respond to the prevailing thermal conditions in an equatorial semi-arid environment. Measurements of hair-coat surface temperature, rectal temperature and the lambs' exposure to sun were recorded across the first 24 h of life every hour, after the lambs had received colostrum. Lambs and ewes were kept in a lambing pen and could freely move between a shaded area or be exposed to sun. During the study period, the air temperature ranged between 20 ºC and 34 ºC. When exposed to sun, lambs and ewes could experience as much as 1200 W m-2 of solar irradiance. Santa Ines lambs exhibited higher (highest density interval at 95%, HDI) hair-coat surface temperatures than did Dorper lambs. Overall, both Santa Ines and Dorper lambs sustained homeothermy, with a mean rectal temperature ranging from 38.7 ºC to 39.1 ºC between night and daytime phase, and a mean amplitude of ~ 0.8 ºC. Nevertheless, from 1000 to 1500, some lambs were found to be moderately hyperthermic. Five Santa Ines and three Dorper lambs had rectal temperatures above 40 ºC, and one Santa Ines lamb, while exposed to sun, had a rectal temperature of 41.3 ºC. Over this time period, lambs were more likely to move to shade (HDI at 95%). From 0000 to 0600, despite the air temperature being lower than the hair-coat surface, favouring high rates of sensible heat loss to the environment, no lamb exhibited signs of hypothermia (rectal temperature < 37.5 ºC). In conclusion, haired newborn lambs coped well with high levels of radiant heat during the daytime and lower temperatures at night. However, providing access to shade during the daytime is important to improve the welfare of newborn lambs delivered in equatorial semi-arid regions.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: Int J Biometeorol Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Brasil País de publicação: Estados Unidos
Texto completo
Adicionar na Minha BVS
Imprimir
XML
PubMed Links
Buscar no Google

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: Int J Biometeorol Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Brasil País de publicação: Estados Unidos