Determination of piglets’ rectal temperature and respiratory rate through skin surface temperature under climatic chamber conditions

Abstract

ABSTRACT:In animal farming, an automatic and precise control of environmental conditions needs information from variables derived from the animals themselves, i.e. they act as biosensors. Rectal temperature (RT) and respiratory rate (RR) are good indicators of thermoregulation in pigs. Since there is a growing concern on animal welfare, the search for alternatives to measure RT has become even more necessary. This research aimed to identify the most adequate body surface areas, on nursery-phase pigs, to take temperature measurements that best represent the correlation of RT and RR. The main experiment was carried out in a climate chamber with five 30-day-old littermate female Landrace x Large White piglets. Temperature conditions inside chamber were varied from 14 °C up to 35.5 °C. The measurements were taken each 30 minutes, over six different skin regions, using a temperature data logger Thermochron iButton ® -DS1921G (Tb) and an infrared thermometer (Ti). As shown by the results, the tympanic region is the best one for RT and RR monitoring using an infrared thermometer (TiF). In contrast, when using temperature sensors, the ear (TbE) is preferred to be used for RT predictions and the loin region (TbC) for RR. KEYWORDS RESUMO:O controle automático e preciso do ambiente para animais de produção carece de informações e variáveis originadas dos próprios animais, tendo-os como biossensores. A temperatura retal (TR) e a frequência respiratória (FR) são bons indicadores da termorregulação de suínos. Porém, com a crescente preocupação em relação ao bem-estar animal, torna-se necessária a busca por alternativas à mensuração da TR. Com a presente pesquisa, objetivou-se identificar a região mais adequada para a aferição da temperatura da superfície corporal dos suínos, em fase de creche, e que apresentasse a melhor correlação com a TR e a FR. O experimento principal foi conduzido em câmara climática, com cinco leitões da raça Landrace x Large White, com 30 dias de idade, provenientes de uma mesma ninhada e do mesmo sexo (fêmea). As temperaturas ambientes utilizadas variaram de 14 °C a 35,5 °C. Realizaram-se medidas de temperatura repetidas em intervalos de 30 minutos, em seis diferentes regiões corporais, utilizando-se de dois métodos: via data logger de temperatura Thermochron iButton ® -DS1921G (Tb) e via termômetro de infravermelho (Ti). Por meio dos resultados, foi possível observar que a região timpânica mostrou--se como a melhor opção para acompanhamento tanto da TR quanto da FR via termômetro de infravermelho (TiF), enquanto que ao utilizar sensores de temperatura da superfície corporal, a melhor opção foi a orelha (TbE) para predição de TR, e a região do lombo (TbC) para predição de FR.

Machine learning algorithms to predict core, skin, and hair-coat temperatures of piglets

“…These errors are lower than those previously reported from either statistical or mechanistic models. Mostaço et al (2015) predicted rectal temperatures of pigs with 2.5% error using multiple linear regression for air enthalpy and tympanic temperature (known to be correlated with internal body temperature; Korthals et al, 1995). Costa et al (2010) predicted surface temperature of piglets with 5.5% error using a linear regression model.…”

“…Empirical models are data-based and usually assume a linear relationship between predictor variables (e.g., air temperature) and the response variable (e.g., internal-body temperature). These relationships are chosen by the researcher and has a considerable impact on the accuracy of the model (Mostaço et al, 2015;Pathak et al, 2009;Ramirez, 2017;Soerensen and Pedersen, 2015).…”

Non-Contact Evaluation of Pigs’ Body Temperature Incorporating Environmental Factors

“…Therefore, in order to apply IRT to fever diagnosis, modeling the correlation between skin temperature and internal temperature becomes inevitable. Previous research has shown that the "thermal windows" of pigs, such as the sulcus auriculae posterior [15], eye [16], and vulva [11,12], are highly correlated with the surface temperature and internal temperature of swine. Such regions are usually referred to as regions of interest (ROI).…”

Large-Scale Phenotyping of Livestock Welfare in Commercial Production Systems: A New Frontier in Animal Breeding

“…Infrared cameras are more software intensive than infrared thermometers and can be used for monitoring large areas (Sellier et al, 2014), which allow for a greater representation of the T S of the entire animal or at specific sites as desired by the researcher. An alternative to infrared technology that may be more invasive are contact sensors affixed to the skin (Teunissen et al, 2011;Mostaço et al, 2015). Contact sensors are more accurate than infrared technology and provide continuous automated measurements, but potential issues precluding their use may include battery life and long-term adhesion to the skin (Mostaço et al, 2015), and destruction or loss of the devices in group-housed animals.…”

“…An alternative to infrared technology that may be more invasive are contact sensors affixed to the skin (Teunissen et al, 2011;Mostaço et al, 2015). Contact sensors are more accurate than infrared technology and provide continuous automated measurements, but potential issues precluding their use may include battery life and long-term adhesion to the skin (Mostaço et al, 2015), and destruction or loss of the devices in group-housed animals. Therefore, researchers should assess both types of technology and determine which one best fits their requirements in a particular environment or research setting.…”