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This Article Full Text (PDF) All Versions of this Article: jas.2008-1196v1 87/4/1314    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ametaj, B. N. Articles by Beauchemin, K. A. Search for Related Content PubMed PubMed Citation Articles by Ametaj, B. N. Articles by Beauchemin, K. A.

Backgrounding and finishing diets are associated with inflammatory responses in feedlot steers

B. N. Ametaj^*, K. M. Koenig, S. M. Dunn^*, W. Z. Yang, Q. Zebeli^* and K. A. Beauchemin

^* Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5 Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada T1J 4B1

burim.ametaj{at}ualberta.ca

Abstract

The objective of this investigation was to study the effects of feeding backgrounding and finishing diets on selected acute phase proteins in the plasma of feedlot steers. Two groups of 12 steers each, at the backgrounding and finishing stages, were offered either a backgrounding (45% barley grain-based concentrate and 55% barley silage on DM basis) or a finishing (91% barley grain-based concentrate and 9% barley silage) diet for 12 and 15 wk, respectively. Steers at the backgrounding and finishing stages had initial BW of about 250 and 380 kg, respectively, at the start of experiment. Blood samples were obtained from the jugular vein at 3-wk intervals during the experimental period starting at wk 3 or 0 for backgrounding and finishing periods, respectively. Plasma samples were analyzed for serum amyloid A (SAA), lipopolysaccharide binding protein (LBP), haptoglobin, and alpha₁-acid glycoprotein (₁-AGP). Steers fed the finishing diet showed peak plasma SAA, LBP, and haptoglobin within 3 wk from the initiation of the diet (20, 23, and 1,940 µg/mL for SAA, LPB, and haptoglobin, respectively). Although plasma ₁-AGP reached a peak concentration (449 µg/mL) at the beginning of the finishing phase; no diet effect was obtained for this variable. Steers fed the backgrounding diet showed less variation in the concentrations of plasma acute phase proteins measured; plasma haptoglobin reached a peak concentration (1,720 µg/mL) 9 wk after the start of this diet. In conclusion, feeding feedlot steers the backgrounding or finishing diet was associated with increased peak concentrations of acute phase proteins in the plasma. More research is warranted to elucidate the mechanisms behind the inflammatory responses observed in feedlot steers and their implications on health issues and production efficiency of feedlot operations.

Key Words: acute phase proteins • barley grain • feedlot • cattle