Location: Livestock Issues ResearchTitle: Temperament alters the metabolic response to glucose and insulin challenges and feed restriction in steers Author
|Carroll, Jeffery - Jeff Carroll|
|Hughes, Heather - West Texas A & M University|
|Roberts, Shelby - West Texas A & M University|
|Richeson, John - West Texas A & M University|
|Schmidt, Ty - University Of Nebraska|
|Vann, Rhonda - Mississippi State University|
Submitted to: Experiment Station Bulletins
Publication Type: Experiment Station
Publication Acceptance Date: 11/15/2014
Publication Date: 1/1/2015
Citation: Sanchez, N.C., Carroll, J.A., Hughes, H.D., Roberts, S.L., Richeson, J.T., Schmidt, T.B., Vann, R.C. 2015. Temperament alters the metabolic response to glucose and insulin challenges and feed restriction in steers. Experiment Station Bulletins. PAGES: 32-39.
Interpretive Summary: A collaborative study was conducted with researchers from the USDA-ARS-LIRU, Mississippi State University, West Texas A&M University, and the University of Nebraska-Lincoln in order to further study the metabolic differences observed between Temperamental and Calm beef calves. Temperamental cattle are behaviorally, physiologically, and immunologically different than Calm cattle. For example, Temperamental cattle display limited or no sickness behaviors to an endotoxin challenge and have greater basal body temperature than Calm cattle. Additionally, Temperamental cattle have greater basal stress hormone concentrations yet have diminished responses to stress and endotoxin challenges. Recently, the dramatic metabolic differences between Temperamental and Calm cattle have been elucidated. Temperamental cattle maintain greater circulating concentrations of non-esterified fatty acids (NEFA) while on full feed, yet do not produce an increase in glucose concentrations in response to an endotoxin challenge. Therefore, this study examined whether temperament influences the metabolic responses of cattle to a glucose tolerance test, an insulin sensitivity test, and a feed restriction challenge. Data from this study confirmed that Temperamental steers had greater NEFA concentrations, decreased blood urea nitrogen concentrations, altered glucose and insulin kinetics, and reduced insulin sensitivity. These differences are due to a complex, yet undefined paradigm involving stress, immune, and metabolic parameters ultimately resulting in greater NEFA concentrations and insulin insensitivity. The data further implicate metabolic differences as the primary factor associated with the differences observed in immune function and performance traits between Calm and Temperamental cattle, and accentuate the need for different management strategies for feeding Temperamental cattle. These data will be of interest to scientists in the areas of animal behavior, health, nutrition, and well-being as well as beef cattle producers.
Technical Abstract: Recently the dramatic metabolic differences between Temperamental and Calm cattle have been elucidated; Temperamental cattle maintain greater circulating concentrations of non-esterified fatty acids (NEFA) when compared to Calm cattle, which may influence other metabolic parameters including glucose and insulin. The objective of this study was to determine whether temperament influences cattle’s metabolic responses to a glucose tolerance test (GTT), insulin sensitivity test (IST) and feed restriction (FR). Angus-cross steers (16 Calm and 15 Temperamental; 216 +/- 6 kilograms body weight) were selected based on weaning temperament score. On day 1 steers were moved into indoor individual stanchions to allow measurement of individual feed intake. On day 6 steers were fitted with jugular catheters and were returned to individual stanchions. At 9am on day 7 steers received the GTT (0.5 mililiters/kilogram body weight of a 50% dextrose solution) and at 2pm steers received the IST (2.5 international units bovine insulin/kilogram body weight). Feed was removed for 72 hours beginning at 8am on day 8, and was provided at 25%, 50%, 75%, and 100% of ad libitum on day 11, 12, 13, and 14, respectively. Blood samples were collected and serum isolated and stored until analyzed for glucose, insulin, NEFA, and blood urea nitrogen (BUN). All variables changed over time (P<0.01). For the duration of the study, Temperamental steers maintained greater (P<0.01) NEFA and decreased (P=0.01) BUN and insulin sensitivity (measured using RQUICKI) compared to Calm steers. During the GTT Temperamental steers had greater (P<0.01) glucose, decreased (P=0.03) insulin. During the IST, Temperamental steers had decreased (P=0.04) glucose and greater (P<0.01) insulin. For the duration of the FR challenge, Temperamental steers maintained greater (P=0.001) glucose and decreased (P=0.001) insulin than Calm steers. These data demonstrate that differences exist in the manner that Temperamental steers respond to glucose, insulin, and feed restriction.