Validação de um protótipo de balança automática utilizando o sistema walk-over-weighning em ovinos

Abstract

Given the importance of accurate and daily monitoring of individual body weight (BW), new investments have been made in research to find alternatives to static weighing (SW) based weighing systems. A key among these alternatives is the Walk-Over-Weighing (WoW) technology, where animals freely and spontaneously pass through an equipment that is strategically positioned to be attractive for spontaneous passages of animals without human assistance. The objective of this work is to analyze the performance of a prototype automatic scale that uses the WoW weighing concept. The prototype used in this research was designed by the researcher Eliel Gonzalez-Garcia (Institut National de la Recherche Agronomique - INRA) the scale is aimed at small ruminants and equipped with tag readers that use radiofrequency technology for accurate storage of BW data. This experiment was divided into two distinct parts that complement each other. The first part was performed during the spring period with 42 Lacaune ewes of different ages and physiological states that were weighed in a SW to obtain BW as reference body weight (RBW), all animals were spontaneously directed to WoW in an indoor system where each animal went through the automatic weighing scale three times, where the WoW body weight value (WBW) was obtained. This first phase was characterized as the calibration phase of the equipment and training of all the team involved and lasted for two hours. The second phase consisted of the use of 237 Romane sheep of different ages and physiological states. In the first experiment the prototype was exposed to the transition period between spring/summer and a larger number of animals, since in previous experiments (GONZÁLEZ-GARCÍA et al., 2018a) the maximum number of individuals used was 98 sheep. The animals remained for a period of 29 days in the pasture, exposed to WoW and with limited access to water and salt stones within the area of attraction. The Bland and Altman concordance analysis method and the Lin concordance correlation coefficient (CCC) were used to establish agreement, correlation and reproducibility between RBW and WBW records, with the objective of validating the use of prototype of the WoW automatic scale for accurate and reliable data collection of animals during the spring/summer transition period in southern France (LIN, 1989; ALTMAN; BLAND, 1986). The CCC was used to establish agreement between PCW and PCR records. The results show that after respecting the period of adaptation to the equipment, the animals show a decrease in unwanted behaviors and together with the treatment of the database aiming at eliminating discrepant data caused by unwanted behavior and/or external factors that may harm the data, the correlation, reproducibility and CCC presented values between 0.95 and 0.99, demonstrating a high correlation between the two methods.