Suchergebnisse

O estresse calórico em bovinos de leite pode comprometer diversas funções fisiológicas, incluindo produção de leite, reprodução e função imunológica. Os objetivos deste estudo foram correlacionar a temperatura da superfície corporal (TSC) e a temperatura retal (TR) de vacas leiteiras usando um termômetro digital a laser infravermelho, bem como determinar a emissividade ideal. Dez vacas leiteiras foram mantidas em área coberta por três dias consecutivos. As medidas de TSC e TR foram realizadas às 8h, 13h e 16h, todos os dias. As leituras térmicas foram feitas em quatro localizações anatômicas distintas: face, caixa torácica, garupa e glândula mamária nas emissividades de 0,95 e 0,50. As temperaturas e localizações anatômicas das medidas térmicas foram avaliadas por ANOVA e as médias foram comparadas usando o Teste Tukey a 5%. Emissividade em 0,50 não estabeleceu correlação significativa (P>0,05) entre TSC e TR, enquanto uma correlação significativa (P<0,05) foi obtida na emissividade 0,95. Portanto, a emissividade de 0,95 foi utilizada para avaliar as variáveis. Foi estabelecida a seguinte equação: RT = 0,143 x BST + 33,534, que se mostrou significativa com coeficiente de determinação de 82%. Os resultados deste estudo sugerem que a utilização de termômetro digital a laser infravermelho com emissividade de 0,95 direcionada para a região média da caixa torácica pode ser eficiente para estimar a temperatura retal de vacas leiteiras.

Palavras-chave: Bem-Estar Animal. Emissividade. Estresse Calórico. Termorregulação.

Abstract
Heat stress in dairy cattle can jeopardize several physiological functions, including milk production, reproduction and immune function. The objectives of this study were to correlate body surface temperature (BST) and rectal temperature (RT) of dairy cows by using an infrared digital laser thermometer as well as to determine the ideal emissivity. Ten dairy cows were maintained under a covered area for three consecutive days. BST and RT measurements were taken at 8 am, 01 pm and 04 pm every day. Thermal readings were carried out at four distinct anatomic locations: the face, ribcage, rump, and mammary gland at 0.95 and 0.50 emissivity. The temperatures and anatomic locations of thermal measurements were evaluated by ANOVA and the means were compared using the Tukey Test at 5%. Emissivity at 0.50 did not establish a significant (P>0.05) correlation between BST and RT, while a significant correlation (P<0.05) was obtained at 0.95 emissivity. Therefore, emissivity at 0.95 was used to assess the variables. The following equation was established: RT = 0.143 x BST + 33.534, which was found to be significant with a determination coefficient of 82%. The results of this study suggest that the utilization of infrared digital laser thermometer with emissivity of 0.95 directed at the middle region of the ribcage can be efficient to estimate the rectal temperature of dairy cows.

Keywords: Animal Well-Fare. Emissivity. Heat Stress. Thermoregulation.

Mycobacterium bovis is a bacterium belonging to the Mycobacterium tuberculosis complex that causes tuberculosis in cattle and in other domestic and wild animals, as well as in humans. Disease control measures are carried out by slaughtering animals tested positive in the intradermal tuberculinization test and sanitation of their original living spaces, in addition to epidemiological surveillance carried out through the sanitary inspection of bovine carcasses in slaughterhouses. In the latter, official inspection services collect samples from macroscopic lesions suspected of bovine tuberculosis, which are then sent for laboratory analysis. Knowledge concerning the variables associated with the occurrence of M. bovis can aid in decision-making regarding control and disease eradication efforts. In this context, the aim of this study was to identify the risk factors for a positive M. bovis diagnosis in suspected bovine tuberculosis lesions obtained during epidemiological surveillance activities in the state of Mato Grosso, Brazil. A total of 105 suspicious lesions were analyzed using the Nested Polymerase Chain Reaction (nested q-PCR) method, of which 14 (13.33%) tested positive for M. bovis. Univariate and bivariate statistical analyses indicated that the variable "animal slaughter" was the only risk factor presenting statistical significance associated with the diagnosis of M. bovis (p < 0.05), demonstrating that macroscopic lesions suspected as being caused by bovine tuberculosis from animals with an in vivo diagnosis were 2.82 - fold more likely to result in a positive M. bovis diagnosis by molecular tests.