Relationship between blood serum insulin-like growth factor I concentration and postweaning feed efficiency of crossbred cattle at three levels of dietary intake

Blood serum concentration of IGF-I was analyzed to determine its relationship with individual postweaning feed efficiency (gain/feed) of 36 crossbred steer calves fed at three levels of feed intake (n = 12 at each level). Diets consisted of a corn silage-based growing diet for 84 d followed by a 91%...

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Bibliographic Details
Published in:Journal of animal science 1998-02, Vol.76 (2), p.498-505
Main Authors: Stick, D.A. (Ohio State University, Columbus.), Davis, M.E, Loerch, S.C, Simmen, R.C.M
Format: Article
Language:English
Subjects:
Animal Feed
Animal productions
Animals
BEEF CATTLE
Biological and medical sciences
Biomarkers - blood
BLOOD SERUM
BULLOCKS
Cattle
Crosses, Genetic
Diet
ENERGY INTAKE
Energy Metabolism
FEED CONVERSION EFFICIENCY
FEEDING LEVEL
Fundamental and applied biological sciences. Psychology
INSULIN-LIKE GROWTH FACTOR
Insulin-Like Growth Factor I - analysis
Insulin-Like Growth Factor I - metabolism
LIVEWEIGHT GAIN
Male
NUTRIENT INTAKE
Orchiectomy
Physical growth
PLANE OF NUTRITION
Regression Analysis
STEERS
Terrestrial animal productions
Vertebrates
WEIGHT GAIN
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Summary:Blood serum concentration of IGF-I was analyzed to determine its relationship with individual postweaning feed efficiency (gain/feed) of 36 crossbred steer calves fed at three levels of feed intake (n = 12 at each level). Diets consisted of a corn silage-based growing diet for 84 d followed by a 91% concentrate finishing diet for 56 d. Dietary intake levels were at 80, 90, or 100% of ad libitum. Diets were formulated to ensure equal daily intake of protein, vitamins, and minerals across intake treatment levels. Intake was measured daily; ADG, DMI, and feed efficiency were calculated at 28-d intervals, through d 140. Individual weights and serum samples were collected at the beginning of the study and at 28-d intervals thereafter. The IGF-I concentrations were determined with a RIA. Data were analyzed as a multivariate split-plot in time. Imposed dietary intake restrictions did not affect serum IGF-I concentration (P = .90) or individual feed efficiency (P = .36), even though the least squares means for IGF-I concentration tended to decrease and the feed efficiency means tended to increase under the restricted intake levels. Serum IGF-I concentration, ADG, and feed efficiency were affected (P .001) by collection date. Residual correlations between IGF-I concentrations at adjacent 28-d sampling times averaged .72. Diet intake level x sampling time interactions existed for ADG (P
ISSN:0021-8812
1525-3163
0021-8812
DOI:10.2527/1998.762498x