Decision three to predict respiratory rate of piglets submitted to cold conditions

P.F.P. Ferraz¹*, V.G. Cadavid², G.A.S. Ferraz¹, J.A.O. Saraz², G. Rossi³ and M. Barbari³

¹Federal University of Lavras, Agricultural Engineering Department, Campus
Universitário, PO Box 3037, CEP 37200-000 Lavras, Minas Gerais, Brazil
²Universidad Nacional de Colombia Sede Medellin, Facultad de Cuencias Agrarias, Departamento de Ingenieria Agricola y de Alimentos, PO Box 050034 Medellín, Colombia
³University of Florence, Department of Agriculture, Food, Environment and Forestry, 13 Via San Bonaventura, IT50145 Firenze, Italy
*Correspondence: paricia.ponciano@ufla.br

Abstract:

Pigs subjected to thermal conditions outside their comfort zones may show altered physiological and behavioural responses, which may consequently cause productive losses. For these reasons, the aim of this paper is to develop a decision tree for the prediction of respiratory rate (RR, mov min-1) of piglets exposed to different thermal situations. The experiment was carried out in an experimental pig farm of the Universidad Nacional de Colombia Campus Medellin, located at the San Pablo Agraria Experimental Station located in the eastern sector of the department of Antioquia, during August 2019. A database containing the raw data for dry bulb temperature – tdb (°C), and relative humidity – RH (%) as input variables, and RR (mov min^-1) of six piglets were assessed every two hours as output variable for piglets was generated. The experimental database was composed of 78 observed data. The decision trees were developed to conditions of tdb between 19.2 to 29.5 °C and RH between 50.2 to 88.4%. In the experimental period, RR of piglets submitted to tdb higher than 27.1 °C the RR was around 60 mov min^-1, tdb smaller than 27.1 °C the RR varied from 36 to 46 mov min^-1. These low values of physiological responses may indicate that the piglets are not in a comfortable situation, so their development, welfare and production can be affected. The decision tree developed can be useful to provide a quick understanding of the piglet’s welfare condition based on the environmental variables and physiological responses.

Key words:

Spatial variability of litter temperature, relative air humidity and skin temperature of chicks in a commercial broiler house

P.F.P. Ferraz¹*, G.A.S. Ferraz¹, L. Schiassi¹, V.H.B. Nogueira¹, M. Barbari² and F.A. Damasceno¹

¹Federal University of Lavras, Agricultural Engineering Departament, Campus Universitário, PO Box 3037, Lavras, Minas Gerais, Brazil
²University of Firenze, Department of Agriculture, Food, Environment and Forestry, Via San Bonaventura, 13, IT50145 Firenze, Italy
*Correspondence: patricia.ponciano@ufla.br

Abstract:

The thermal environment inside a broiler house has a great influence on animal welfare and productivity during the production phase. Among the importance of the chicken litter is the function of absorbing moisture, provide thermal insulation and provide a soft surface for broilers. The skin temperature is an important physiological parameter to quantify the thermal comfort of animals, its variations may occur as a function of thermal variables. So, the aim of this work was to analyse the magnitude and spatial variability of chicken litter temperature and relative humidity of the air and to correlate them with the spatial distribution of chicks’ skin surface temperature throughout the broiler house during the 7th, 14th and 21st days of the chicks’ life, using geostatistical techniques. The experiment was performed in a commercial broiler house located in the western mesoregion of Minas Gerais, Brazil, where 28,000 male Cobb chicks were housed. The heating system consisted of an industrial indirect-fired biomass furnace. The heated air was inflated by an AC motor, 2,206 W of power, 1,725 RPM. Geostatistical techniques were used through semivariogram analysis and isochore maps were generated through data interpolation by kriging. The semivariogram was fitted by the restricted maximum likelihood method. The used mathematical model was the spherical one. After fitting the semivariograms, the data were interpolated by ordinary kriging. The semivariograms along with the isochore maps allowed identifying the non-uniformity of spatial distribution of the broiler litter temperature throughout the broiler house for 3 days of chicks’ life. It was observed that skin surface presented a positive correlation with the litter temperature and a negative correlation with the air humidity. The semivariograms along with the isochore maps allowed identifying the non-uniformity of spatial distribution of the litter temperature, air humidity and skin temperature of chicks throughout the broiler aviary for the three days. In addition, the use of geostatistics and distribution maps made possible to identify different environmental conditions in regions inside the broiler house that may harm the development of chicks.

Key words:

environment, geostatistics, physiological responses, thermal comfort