Exploratory data inference for detecting mastitis in dairy cattle

Rodes Angelo Batista Da Silva,Héliton Pandorfi,Gledson Luiz Pontes De Almeida,Marcos Vinícius Da Silva

doi:10.4025/actascianimsci.v42i1.46394

Rodes Angelo Batista Da Silva, Héliton Pandorfi + Show 2 more

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https://doi.org/10.4025/actascianimsci.v42i1.46394

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Abstract

The aim of this study was to employ the principal component technique to physiological data and environmental thermohygrometric variables correlated with detection of clinical and subclinical mastitis in dairy cattle. A total of 24 lactating Girolando cows with different clinical conditions were selected (healthy, and with clinical or subclinical mastitis). The following physiological variables were recorded: udder surface temperature, ST (°C); eyeball temperature, ET (°C); rectum temperature, RT (°C); respiratory frequency, RF (mov. min-1). Thermohygrometric variables included air temperature, AirT (°C), and relative humidity, RU (%). ST was determined by means of thermal images, with four images per animal, on these quarters: front left side (FL), front right side (FR), rear right side (RR) and rear left side (RL), totaling 96 images. Exploratory data analysis was run through multivariate statistical technique with the employment of principal components, comprehending nine variables: ST on the FL, FR, RL and RR quarters; ET, RT; RF, AirT and RU. The representative quarters of the animals with clinical and subclinical mastitis showed udder temperatures 8.55 and 2.46° C higher than those of healthy animals, respectively. The ETs of the animals with subclinical and clinical mastitis were, respectively, 7.9 and 8.0% higher than those of healthy animals. Rectum temperatures were 2.9% (subclinical mastitis) and 5.5% (clinical mastitis) higher compared to those of healthy animals. Respiratory frequencies were 40.3% (subclinical mastitis) and 61.6% (clinical mastitis) higher compared to those of healthy animals. The first component explained 91% of the total variance for the variables analyzed. The principal component technique allowed verifying the variables correlated with the animals' clinical condition and the degree of dependence between the study variables.

Highlights

Dairy husbandry is a relevant activity in Brazilian agribusiness and responsible for the availability of a product high in nutritional value for the population
The amount of samples was determined according to selection criteria and totaled 24 animals – eight healthy animals, eight with subclinical mastitis and eight with clinical mastitis, totaling 96 quarters analyzed
Temperature differences were found between healthy quarters and quarters with clinical mastitis, estimated at 8.55°C (Table 1)

Summary

Introduction

Dairy husbandry is a relevant activity in Brazilian agribusiness and responsible for the availability of a product high in nutritional value for the population. Mastitis is a multi-etiological disease characterized by an inflammatory process of the mammary glands, as a result of a bacterial infection that presents itself in subclinical and clinical forms (Langoni et al, 2017; Vliegher, Fox, Piepers, McDougall, & Barkema, 2012) The application of this technique, with an emphasis on detecting early inflammatory cases, has been reported in some studies, such as Polat et al (2010), Pezeshki et al (2011) and Digiovani et al (2016), which investigated thermal images as a diagnosis tool for detecting subclinical mastitis and verified that thermography allowed identifying temperature changes on the animals' udder skin surface. The principal component technique in animal researches has been applied to assess production characteristics concerning laying birds (Paiva, Teixeira, & Yamaki, 2010)

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