Valadez-Noriega, M., Méndez-Gómez-Humarán, M. C., Rayas-Amor, A. A. et al. 2020. Effects of greenhouse roofs on thermal comfort, behavior, health, and finishing performance of commercial zebu steers in cold arid environments. Journal of Veterinary Behavior 35, 54-61.
The aim of this study was to determine the effects of two housing systems (thermal plastic greenhouse roofs—PGR—vs. without roof—PWR) on health, welfare, and finishing performance of zebu steers in cold arid environments. A total of 880 animals were included in the study; these were divided into two independent studies. For the first study, 260 steers were used (effect on steers' welfare), and for the second study, 620 steers were used (effect on steers' performance). Steers in the PWR treatment showed a trend of standing during 12:00 to 14:59 h, which was considered the hottest period of the day and the steers that were standing showed a trend for feed intake. On the other hand, the steers in the PGR treatment showed a trend of lying down (P < 0.001) and ruminating (P = 0.031) during the same period of the day; in addition, more steers were drinking in PGR than in PWR treatment. Survival analysis of physical health indicated that the number of healthy steers decreased as the number of days increased; more sick steers were observed in PWR treatment (P < 0.05). Finally, steers in PGR achieved different (P < 0.001) final body weight (599.7 ± 46.4 kg) compared with steers in PWR treatment (569.0 ± 31.6 kg). The steers in PWR showed higher feed intake (P < 0.001); nonetheless, the steers in PGR treatment showed higher average daily gain (P < 0.001) and higher feed conversion efficiency (P < 0.001). Under the winter conditions where the temperatures fluctuated from a high of 33.9°C to a low of −2.7°C, the use of thermal plastic greenhouse roofs demonstrated an improvement of steers’ welfare, health, the average daily gain and feed conversion efficiency.