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

Data distribution and regression equation between infrared temperatures points (rump and flank) and black globe temperature under shade (BGTsd).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4541933&req=5

sensors-15-17258-f001: Data distribution and regression equation between infrared temperatures points (rump and flank) and black globe temperature under shade (BGTsd).

Mentions: The infrared temperatures had significant correlations with environmental factors. The AT had high and positive correlations with all surface temperatures (0.54 < r < 0.82). The BGT under sun and shade had high and positive correlations with all surface temperatures (0.58 < r < 0.88). In both, the axilla had the lowest correlation and the rump and the flank had the highest. The regression equations (Table 6 and Figure 1) show the relation between environmental factors, such as air temperature (AT), air relative humidity (RH), wind speed (WS) and BGT under sun (BGTsun) and shade (BGTsd), and the infrared temperatures. The regressions showed the BGTsd explaining a high proportion of variation in infrared temperatures, mainly the flank and rump points (Figure 1).


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)

Data distribution and regression equation between infrared temperatures points (rump and flank) and black globe temperature under shade (BGTsd).
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-17258-f001: Data distribution and regression equation between infrared temperatures points (rump and flank) and black globe temperature under shade (BGTsd).
Mentions: The infrared temperatures had significant correlations with environmental factors. The AT had high and positive correlations with all surface temperatures (0.54 < r < 0.82). The BGT under sun and shade had high and positive correlations with all surface temperatures (0.58 < r < 0.88). In both, the axilla had the lowest correlation and the rump and the flank had the highest. The regression equations (Table 6 and Figure 1) show the relation between environmental factors, such as air temperature (AT), air relative humidity (RH), wind speed (WS) and BGT under sun (BGTsun) and shade (BGTsd), and the infrared temperatures. The regressions showed the BGTsd explaining a high proportion of variation in infrared temperatures, mainly the flank and rump points (Figure 1).

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