Tympanic Temperature of Steers Fed Different Levels of Metabolic Energy Intake During Summer and Winter

Tympanic temperatures (TT) of steers were recorded during July (8 days) and January (6 days). In each experiment, steers were fed 11, 18, or 25 Mcal/day ME in a roughage-based diet, or 18, 25, or 32 Mcal/day ME in a concentrate-based diet. Tympanic temperatures were greater during summer than during winter. Also, steers fed a concentrate diet had greater TT than those fed a roughage diet. Linear equations were obtained to estimate TT of cattle for summer and winter seasons. During the winter, TT response to MEI was dependent on the type of diet. Resultsdemonstrate that increases in the energy level of the diet result in increases in TT. However, the response appears to be dependent on season of year