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:

Productive performance of broilers at the final stage of breeding submitted to different levels of metabolizable energy in different thermal environments

K.P. Oliveira¹, C.F.S. Ferreira¹, I.F.F. Tinoco¹, R.R. Andrade¹, M. Barbari²*, V.M.F. Cruz³, F.J.F. Baptista³, M.F.A. Vieira⁴, L. Conti² and G. Rossi²

¹University of Viçosa, Department of Agricultural Engineering of Federal, Av. Peter Henry Rolfs, s/n Campus University of Viçosa, CEP: BR36570-900, Viçosa, Brazil
²University of Firenze, Department of Agricultural, Food and Forestry Systems, Via San Bonaventura, 13, IT50145 Firenze, Italy
³University of Évora, Department of Rural Engineering, Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Núcleo da Mitra, Évora, Portugal
⁴Federal Rural University of Amazonia – UFRAPA-256, s/n – Nova Conquista, Paragominas – PA, 68627-451
*Correspondence: matteo.barbari@unifi.it; kelle.oliveira@ufv.br

Abstract:

The Brazilian poultry industry is an activity in constant development due to the high indices of productive efficiency. The accelerated evolution of poultry production has allowed to obtain early and very efficient broilers able to convert different foods into animal protein. However, due to this intensive breeding system, a series of metabolic and management problems appeared, with emphasis on thermal stress. The objective of this work was to evaluate the physiological responses of broiler chickens in the final stage of breeding (21 to 42 days of life), submitted to two thermal conditions, one representative of the thermoneutrality situation (T1) and one giving a situation of cyclic stress by heat (T2). For each experimental thermal condition, the birds were submitted to different levels of metabolizable energy of 3,050, 3,125, 3,200, 3,275 kcal kg^-1. At 28, 35 and 42 days, the birds and the feed leftovers were weighed to measure the performance variables: CR (feed intake), GP (weight gain) and CA (feed conversion), viability of the rearing (Vb), productive efficiency index (PEI).
As conclusions, the GP was 13.6% higher for the birds maintained at the thermoneutrality situation T1. The PEI was 32.5% higher for the birds maintained in T1 condition, when compared to those kept in T2. However, both in thermoneutral and in heat stress conditions, the increase in the level of metabolizable energy in the diet did not influence the performance and the productive efficiency index of broiler chickens aged between 21 and 42 days of age.

Key words:

broilers, feed, metabolizable energy, productivity, thermal stress