Submitted to: European Association of Animal Production Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 31, 2003
Publication Date: September 8, 2003
Citation: BROWN BRANDL, T.M., EIGENBERG, R.A., NIENABER, J.A., HAHN, G.L. SHADE EFFECTS ON PHYSIOLOGICAL RESPONSES OF FEEDER CATTLE. EUROPEAN ASSOCIATION OF ANIMAL PRODUCTION PROCEEDINGS. 2003. pg. 107. Technical Abstract: Heat stress in cattle causes decreases in feed intake and growth, and in extreme cases can cause death. Shade has been shown to reduce direct and indirect losses in some areas of the country. The objective of this study was to further evaluate the physiological responses of feedlot cattle to shade during summer conditions. Eight crossbred steers (initially weighing 294.7+/-10.8) were randomly assigned to one of eight individual pens where one of two treatments was applied; shade, or no shade. Data were collected during seven, 5-day periods. Respiration rate (RR), feed intake (FI), and core body temperature (tcore) were collected using automated systems. Shade preference data were evaluated using video recordings. The data were categorized by daily maximum temperature (Hot days tmax>34.5C [7 days]; Cool days tmax<28.4C [5 days]). Hourly data for hot and cool days were analyzed using the general linear model procedure in SAS (SAS, 2000) for effects of animal (A), treatment (TRT), period (P), hr, and the interaction of TRT and hr (TRT*hr). On cool days, RR and tcore were significantly affected by A, P, hr, TRT*hr, where on hot days TRT had a significant influence also. Shade was found to be beneficial on cool as well as hot days; as expected, the beneficial effects were much greater on hot days. Between the hours of 1000- 1900 on the hot days, shade reduced RR by over 25 bpm and tcore by 0.5C. Feed intake was 1.86 kg greater in the shade.