Submitted to: Journal of Dairy Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/2/2009
Publication Date: 11/19/2009
Citation: Nonnecke, B.J., Foote, M.R., Miller, B.L., Fowler, M., Johnson, T.E., Horst, R.L. 2009. Effects of Chronic Environmental Cold on Growth, Health and Select Metabolic and Immunologic Responses of Preruminant Calves. Journal of Dairy Science. 92(12):6134-6143. Interpretive Summary: In the northern climates, calves born in late winter and early spring often experience sustained periods of cold during the first weeks of life. This study evaluated the effects of sustained exposure to cold on the growth, health, and select metabolic and immunologic responses of preruminant calves. Preruminant calves provided adequate nutrition exhibited a remarkable degree of adaptability to sustained cold. When compared to warm-environment calves, cold-environment calves had comparable growth rates likely maintained by their increased intake of starter grain. Immune response variables also were unaffected by cold. With the exception of a modest increase in respiratory scores, health of cold-stressed calves was comparable to that of warm-environment calves. These results support the contention that the successful adaptation of the dairy calf to sustained cold is linked to the availability of adequate nutrition.
Technical Abstract: The physiological response of the preruminant calf to sustained exposure to cold has not been studied extensively. Effects of cold on growth performance and health of preruminant calves as well as functional measures of energy metabolism, fat-soluble vitamin, and immune responsiveness were evaluated in the present study. Calves, 3 to 10 d of age, were assigned randomly to cold (n = 14) or warm environments (n = 15). Temperatures in the cold-environment calves were maintained as close to 2 deg C as possible. Frequent wetting of the environment and calves were used to augment effects of the cold environment. The warm environment was maintained at approximately 15 deg C with no attempt to increase the humidity. Preventative medications or vaccinations that might influence disease resistance were not administered. Non-medicated MR (20% CP and 20% fat fed at 0.45 kg/d) and a non-medicated starter grain fed ad libitum to all calves. During the 7-wk study, temperatures in the cold environment averaged 20 deg C lower than those in the warm environment. Relative humidity averaged almost 10% higher in the cold environment. Warm-environment calves were moderately healthier (i.e., lower respiratory scores) and required less antibiotics. Scour scores, days scouring, and electrolyte costs, however, were unaffected by environmental temperature. Growth rates were comparable in warm and cold environments; although cold-environment calves consumed more starter grain, had lower blood glucose, and higher blood NEFA concentrations suggesting sustained exposure to cold may induce a state of mild negative-energy balance. Fat-soluble vitamin, antibody, tumor-necrosis factor-alpha, and haptoglobin levels were unaffected by cold exposure. These results support the contention that the successful adaptation of the dairy calf to sustained cold is dependent upon the availability of adequate nutrition.