Limits...
Infrared Thermography to Evaluate Heat Tolerance in Different Genetic Groups of Lambs.

McManus C, Bianchini E, Paim Tdo P, de Lima FG, Neto JB, Castanheira M, Esteves GI, Cardoso CC, Dalcin VC - Sensors (Basel) (2015)

Bottom Line: Heat stress is considered a limiting factor for sheep production.Forty-eight four-month-old male lambs from eight genetic groups were used.Statistical analyses included variance, correlations, factor, discrimination and regression.

View Article: PubMed Central - PubMed

Affiliation: Faculdade de Agronomia e Medicina Veterinária, Universidade de Brasília, Brasília 70910-900, DF, Brasil. concepta.mcmanus@ufrgs.br.

ABSTRACT
Heat stress is considered a limiting factor for sheep production. We used information from physiological characteristics linked to heat tolerance to determine whether infrared thermography temperatures were able to separate groups of animals and determine the most important variables in this differentiation. Forty-eight four-month-old male lambs from eight genetic groups were used. Physiological (rectal temperature-RT, heart rate-HR, respiratory rate-RR) and blood traits, infrared thermography temperatures, heat tolerance indices, body measurements, weight and carcass traits were measured. Statistical analyses included variance, correlations, factor, discrimination and regression. Observing the correlations between physiological characteristics (RT, RR and HR) with temperatures measured by infrared thermography, regions for further studies should include the mean temperature of flank, nose and rump. Results show that there are strong relationships between thermograph measurements and RR, RT and HR in lambs, which are suggested to be directly correlated with heat tolerance capacity of the different genetic groups evaluated in this study. The assessment of body surface temperature measured by the thermograph could be used as a noninvasive tool to assess heat tolerance of the animals.

No MeSH data available.


Related in: MedlinePlus

First two eigenvectors for climatic and thermograph measures on lambs. RR–respiratory rate; RT–rectal temperature; RY–Rauschenbach Yerokhin index; AT–air temperature; RH–relative humidity; WS–windspeed; BGTsun–Black Globe temperature in the sun and shade (BGTsd).
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sensors-15-17258-f002: First two eigenvectors for climatic and thermograph measures on lambs. RR–respiratory rate; RT–rectal temperature; RY–Rauschenbach Yerokhin index; AT–air temperature; RH–relative humidity; WS–windspeed; BGTsun–Black Globe temperature in the sun and shade (BGTsd).

Mentions: The first two factors (Figure 2) showed that, as air temperature increases, all thermographic measurements increased and Iberia and Baccari indices decreased along with RH. In the second moment, higher AT was associated with increasing RT, RR as well as nose temperatures but this was not accompanied by increasing measurements from the other thermograph measurements. This may indicate a limit to the animal´s ability to lose heat from it surface area while continuing to produce heat internally.


Infrared Thermography to Evaluate Heat Tolerance in Different Genetic Groups of Lambs.

McManus C, Bianchini E, Paim Tdo P, de Lima FG, Neto JB, Castanheira M, Esteves GI, Cardoso CC, Dalcin VC - Sensors (Basel) (2015)

First two eigenvectors for climatic and thermograph measures on lambs. RR–respiratory rate; RT–rectal temperature; RY–Rauschenbach Yerokhin index; AT–air temperature; RH–relative humidity; WS–windspeed; BGTsun–Black Globe temperature in the sun and shade (BGTsd).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541933&req=5

sensors-15-17258-f002: First two eigenvectors for climatic and thermograph measures on lambs. RR–respiratory rate; RT–rectal temperature; RY–Rauschenbach Yerokhin index; AT–air temperature; RH–relative humidity; WS–windspeed; BGTsun–Black Globe temperature in the sun and shade (BGTsd).
Mentions: The first two factors (Figure 2) showed that, as air temperature increases, all thermographic measurements increased and Iberia and Baccari indices decreased along with RH. In the second moment, higher AT was associated with increasing RT, RR as well as nose temperatures but this was not accompanied by increasing measurements from the other thermograph measurements. This may indicate a limit to the animal´s ability to lose heat from it surface area while continuing to produce heat internally.

Bottom Line: Heat stress is considered a limiting factor for sheep production.Forty-eight four-month-old male lambs from eight genetic groups were used.Statistical analyses included variance, correlations, factor, discrimination and regression.

View Article: PubMed Central - PubMed

Affiliation: Faculdade de Agronomia e Medicina Veterinária, Universidade de Brasília, Brasília 70910-900, DF, Brasil. concepta.mcmanus@ufrgs.br.

ABSTRACT
Heat stress is considered a limiting factor for sheep production. We used information from physiological characteristics linked to heat tolerance to determine whether infrared thermography temperatures were able to separate groups of animals and determine the most important variables in this differentiation. Forty-eight four-month-old male lambs from eight genetic groups were used. Physiological (rectal temperature-RT, heart rate-HR, respiratory rate-RR) and blood traits, infrared thermography temperatures, heat tolerance indices, body measurements, weight and carcass traits were measured. Statistical analyses included variance, correlations, factor, discrimination and regression. Observing the correlations between physiological characteristics (RT, RR and HR) with temperatures measured by infrared thermography, regions for further studies should include the mean temperature of flank, nose and rump. Results show that there are strong relationships between thermograph measurements and RR, RT and HR in lambs, which are suggested to be directly correlated with heat tolerance capacity of the different genetic groups evaluated in this study. The assessment of body surface temperature measured by the thermograph could be used as a noninvasive tool to assess heat tolerance of the animals.

No MeSH data available.


Related in: MedlinePlus