Effects of diet type and metabolizable energy intake on tympanic temperature of steers fed during summer and winter seasons
Effects of diet type and metabolizable energy intake on tympanic temperature of steers fed during summer and winter seasons
Authors
Arias Inostroza, Rodrigo
Mader, Terry
Parkhurst, A.M.
Mader, Terry
Parkhurst, A.M.
Authors
Date
2012-03-07
Datos de publicación:
10.2527/jas.2010-2975
Keywords
Ganado - Producción animal - Stress
Collections
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.