Wind protection effects and airflow patterns in outside feedlots.

Steers were finished in three different sets of outside lots: 1) pens with overhead shelter on the north side; 2) pens south and southeast of a shelterbelt; and 3) pens with no shelter or windbreak. In trials conducted over a 3-yr period with predominantly British and British x Continental crossbred yearlings, performance improvements due to providing shelter or wind protection in the winter were not detected; however, in the summer, providing wind protection or shelter resulted in decreased (P < .10) cattle gains. Cattle fed in the unprotected area had greater (P < .05) fat thickness in the winter and greater marbling scores in the winter (P < .05) and autumn (P < .10) than cattle fed in protected areas. When averaged across facilities, season effects were detected for DMI (autumn > summer > winter > spring; P < .05). Feed:gain ratios followed a similar trend among seasons (summer and autumn > winter > spring P < .05). As a percentage of BW, winter (2.21), spring (2.19), and summer (2.18) DMI were less (P < .05) than autumn (2.35) DMI. Wind velocity data indicated that greater air flows tends to be found on mounds and less at the feedbunk in pens protected by shelterbelts. In unprotected, unsheltered pens, the greater airflow tends to be at the highest point in the pen (bunks and mounds). In Nebraska, benefits realized from feeding cattle in sheltered or protected areas under average or slightly milder than average winter weather conditions may be offset by lower performance experienced by cattle fed in those same areas in the summer. In addition, fat deposition seems to be enhanced in cattle exposed to moderate cold stress.