Eugenio Losada’s research while affiliated with Xunta de Galicia and other places

Postweaning is one of the most sensitive and energy-demanding phases of swine production. The objective of this research was to assess the energy, production and environmental characteristics of a conventional farm with temperature-based environmental control. The selected energy, environmental and production variables were measured on farm, in a high livestock density area of NW Spain, for seven production cycles. The quantification of variables was aimed at obtaining the maximum performance with the lowest possible use of resources, focusing on animal welfare and production efficiency. The Brown–Forsythe, Welch and Games-Howell tests revealed significant differences in terms of temperature, relative humidity and CO2 concentrations among production cycles, and among the critical, postcritical and final periods. Improved humidity management resulted in a 17% reduction of climate control energy, which involved energy savings in the range of 33% to 47% per kg produced at the end of the postweaning cycle. Accordingly, adding humidity as a control variable could result in higher ventilation rates, thereby improving animal welfare, reducing heating energy use and increasing weight gain per unit climate control energy. In addition, the strong correlations found between heating energy and relative humidity (R2 = 0.73) and ventilation energy and CO2 (R2 = 0.99) suggest that these variables could be readily estimated without additional sensor costs.

Ammonia (NH 3) concentration has seldom been used for environmental control of weaner buildings despite its impact on environment, animal welfare, and workers' health. This paper aims to determine the effects of setpoint temperature (ST) on the daily evolution of NH 3 concentration in the animal-occupied zone. An experimental test was conducted on a conventional farm, with ST between 23 • C and 26 • C. NH 3 concentrations in the animal-occupied zone were dependent on ST insofar as ST controlled the operation of the ventilation system, which effectively removed NH 3 from the building. The highest NH 3 concentrations occurred at night and the lowest concentrations occurred during the daytime. Data were fitted to a sinusoidal model using the least squares setting (LSS) and fast Fourier transform (FFT), which provided R 2 values between 0.71 and 0.93. FFT provided a better fit than LSS, with root mean square errors (RMSEs) between 0.09 ppm for an ST of 23 • C and 0.55 ppm for an ST of 25 • C. A decrease in ST caused a delay in the wave and a decrease in wave amplitude. The proposed equations can be used for modeling NH 3 concentrations and implemented in conventional controllers for real-time environmental control of livestock buildings to improve animal welfare and productivity.