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- Title
Physiological and productive response of feedlot steers with an open space cooling system in an arid, dry climate.
- Authors
Calderón, Abelardo Correa; Cantabrana, Víctor M. Yañez; Zárate, Francisco J. Verdugo; Reyes, Leonel Avendaño; Almora, Enrique Alvarez; Flores, Carlos F. Árechiga; Acuña, Fernando Rivera
- Abstract
Evaluation of the effects of an open space cooling system on weight gain, respiration rate and serum thyroid hormone (T3 and T4) levels in feedlot steers was done using 60 Holstein steers (344 kg) allotted randomly in two treatments: a control with only shade in the corral (n = 30); and a cooling with an open space cooling system (n = 30). Daily maximum temperature-humidity index (THI) ranged from 82 to 88 during the 12-week study period. The open space cooling system consisted of a fan with 2.4 m diameter blade that displaced 1,416 m³ of air per minute and had a 90° oscillation range, and sprinklers. The fan was installed at 8 m distance on the south side of the shade. Water discharge was 12 L per minute over a 7 h period. Body weight and thyroid hormone levels were measured every two weeks and respiration rate twice a week (1400). Data were analyzed by repeated measures, including initial weight as a covariate. Daily weight gain was different (P<0.05) between the cooling treatment (1.43±0.091 kg/d) and the control treatment (1.25±0.091 kg/d). Respiration rate was lower (P<0.05) in steers in the cooling treatment (94±0.74 breaths per minute) than in those in the control treatment (111±0.74 breaths per minute). Levels of T3 were higher (P<0.05) in the cooling treatment (1.7±0.042) than in the control (1.5±0.042). Levels of T4 were similar between the cooling (79.3±1.82 ng/ml) and control (78.2±1.82 ng/ml) treatments. Use of this cooling system improved production performance and comfort in feedlot Holstein steers in a hot, dry climate.
- Subjects
FEEDLOTS; OPEN spaces; WEIGHT gain; RESPIRATION; THYROID hormones; TEMPERATURE; HUMIDITY
- Publication
Técnica Pecuaria en México, 2007, Vol 45, Issue 3, p345
- ISSN
0040-1889
- Publication type
Article