Influence of thermal comfort in housing facilities on the increase in live weight of guinea pigs (Cavia porcellus) in the high Andean region of Puno, Peru

Abstract

The high-altitude region of Puno is characterized by a pronounced daily thermal oscillation, which poses a challenge for the production of guinea pigs (Cavia porcellus), a species that is highly sensitive to microclimatic variability. This study analyzed the association between the thermal conditions of the houses and the weight gain of guinea pigs, considering both the mean level of the Temperature-Humidity Index (THI) and its intraday stability, measured by the thermal amplitude THI. The research followed a quantitative, non-experimental and longitudinal design, using productive and environmental data from INIA's Illpa Experimental Center. A total of 36 Peru breed guinea pigs housed in three pre-existing and independent facilities were evaluated, with weight records collected every 14 days between November 2023 and February 2024 (216 observations). The climatic variables were monitored by digital sensors that recorded measurements every 15 minutes. The results show that a higher intraday thermal amplitude of the Temperature and Humidity Index (THI) is negatively and statistically significantly associated with weight gain. On the other hand, no statistically significant association was detected between the mean level of the THI and weight gain under the observed conditions. This result does not imply the absence of a possible biological effect of the average THI, but rather that this effect could not be statistically identified within the thermal range and the period analyzed. Likewise, males showed greater weight gains than females, while the estimated coefficient for age was negative, although it did not reach statistical significance in the linear mixed model. Overall, the results suggest that intraday thermal stability may be related to productive performance; however, they do not allow us to conclude that it is more important than the average level of the THI or that it constitutes the only determining factor of weight gain (p<0.001).