Infrared thermography as a method for evaluating the heat tolerance in dairy cows

Abstract

-The objective of this study was to determine whether infrared thermography is a useful tool for the recognition of dairy cows in a state of thermal heat stress, as well as to identify the best region of the animal to be evaluated for this recognition. Physiological variables, including rectal temperature, respiratory frequency, cardiac frequency, and panting score were recorded in 38 lactating cows. For the assessment of environmental parameters, a digital black globe thermometer (TGD-200 model) was used. Thermographic photographs of different regions of the body of cows were taken using an infrared camera (FLIR ® System T300) and indicated respective superficial temperature. Physiological variables and superficial body temperature in different regions varied between genetic groups (Girolando: ½ Holstein × ½ Gir and ¾ Holstein × ¼ Gir; purebred Holstein). The environmental temperature ranged from 20.7 to 37.9 °C with a relative humidity reaching 95%. The mean rectal temperature (40.84 °C), respiratory frequency (111.36 breaths/min), and cardiac frequency (99.22 beats/min) were higher for pure Holstein than for Girolando cows. Positive correlations were found between the physiological parameters and thermographic measures. The highest positive correlation (0.74) was found between the temperature in the lateral region of the udder and rectal temperature. Thermography is a good indicator of thermal comfort. The best region to identify heat stress in cows using thermography is the lateral region of the udder.

Multivariate analysis of the behavior and physiology of Girolando heifers in pasture

“…This association was also found by Barbosa et al (2014), who employed multivariate analysis to assess heat tolerance in cattle and observed that during the times of greater availability of solar radiation, and consequent increase of air temperature, the physiological variables of the animals tended to increase. Daltro et al (2017), using principal component analysis to examine the resistance to heat of dairy cows through infrared technology, found that in the periods in which the animals were under higher heat stress, there were more evident responses in the intensification of the physiological mechanisms of energy dissipation to the environment, in order to maintain homeothermy.…”

“…Given this scenario, livestock farming is the preponderant activity in the region, but penalized by the thermal stress faced by dairy cattle (Daltro et al, 2017). Thus, two strategies can be used to ensure animal performance; the first one would be the use of less demanding races, genetically more adapted to the climate of the region, and the second one would be the modification of the production environment, in order to reduce thermal stress and facilitate homeothermy (Almeida et al, 2013).…”

“…With emphasis on the criteria of thermal evaluation and behavioral responses, the use of multivariate analysis to determine the degree of association of the principal components allows to simultaneously explore various correlated experimental factors (Massari et al, 2015). The utilization of the technique in studies on dairy cattle raising environment includes research on the evaluation of heat tolerance (Daltro et al, 2017) and impacts on milk production due to meteorological variables (Gabbi et al, 2017).…”

Correlations between Environmental Factors and Milk Production of Holstein Cows

“…Indices that take into account the mobility of air, the intensity of insolation, and other factors besides temperature and humidity were also proposed not so long ago [8][9][10]. As a rule, they are all built taking into account the close connection (correlation) between environmental factors and individual indicators of the functional state of cows, which act as specific predictors [11,12]. Milk yield and milk components can also be indicators of animal comfort, since they are affected by the physiological state of the organism subject to high temperature [13].…”

<b>Adjuvantes nas vacinas reprodutivas:</b> efeitos adversos, temperatura no sítio da injeção, resposta inflamatória e produção de anticorpos neutralizantes para BVDV e BoHV-1

“…Esta técnica envolve a medição precisa da radiação infravermelha emitida por um objeto, o que permite que a temperatura da superfície seja determinada (SPEAKMAN; WARD, 1998). A termografia infravermelha permite a observação de diferentes aspectos da fisiologia térmica, lesão e doença; sua grande vantagem é que pode ser utilizada como uma avaliação não invasiva com animais e podem ser aplicado para a verificação do bem-estar animal (STEWART et al, 2008;DALTRO et al, 2017;McMANUS et al, 2015). Cook et al, (2017) O desconforto animal após a vacinação está diretamente relacionado ao estresse e dor, resultando em redução na ingestão de alimentos, apatia e queda na produção de leite.…”