Effects of diet type and metabolizable energy intake on tympanic temperature of steers fed during summer and winter seasons

• Published in: Journal of animal science 2011-05, Vol.89 (5), p.1574-1580
• Main Authors: Arias, R. A., Mader, T. L., Parkhurst, A. M.
• Format: Article
• Language: English
• Subjects: Animal productions; Animals; Biological and medical sciences; Body Temperature - physiology; Cattle; Cattle - metabolism; Cattle - physiology; Diet; Dietary Fiber - metabolism; Dietary supplements; Energy Intake - physiology; Fundamental and applied biological sciences. Psychology; Male; Random Allocation; Seasons; Temperature; Terrestrial animal productions; Vertebrates
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jas.2010-2975

ABSTRACT A summer study and a winter study were conducted using an incomplete factorial structure in a complete randomized design. Within season, the factors studied were 1) type of diet, which included 2 levels of ME, classified as either concentrate (3.04 Mcal of ME/kg) or roughage (2.63 Mcal of ME/kg) diets, and 2) daily ME intakes (MEI) of 11, 18, and 25 Mcal of ME/d for the roughage diets and 18, 25, and 32 Mcal of ME/d for the concentrate diets. In Exp. 1 (summer study), 30 steers (5 steers/treatment combination) were used to collect tympanic temperatures (TT). In Exp. 2 (winter study), 24 steers (4 steers/treatment combination) were used to collect TT. Mean TT was 0.3°C greater for summer than winter (38.9 vs. 38.6°C, respectively; P < 0.05). Steers fed diets based on concentrate tended to display greater TT than steers fed diets based on roughage. Season × diet × hour interactions were found for TT (P = 0.01). In the winter, greater TT (P < 0.05) were found from 0900 to 1400 h when an equal amount of MEI was derived from a concentrate-based vs. roughage-based diet. In cattle fed roughage-based diets during the summer, TT = 38.63 + 0.0114∙MEI, whereas for cattle fed concentrate-based diets, TT = 38.69 + 0.0114∙MEI. During the winter, for cattle fed a roughage-based diet, TT = 37.65 + 0.0856∙MEI − 0.0018∙MEI2, whereas for cattle fed a concentrate-based diet, TT = 35.37 + 0.2635∙MEI − 0.0051∙MEI2. In summary, results demonstrate that increases in the energy of the diet resulted in increases in TT. However, the response was dependent on season of the year, with a linear response in TT for summer and a quadratic response during winter.