Journal of Animal Science, Vol 71, Issue 8 2079-2088, Copyright © 1993 by American Society of Animal Science

JOURNAL ARTICLE

Effects of time on feed on beef nutrient composition

S. K. Duckett, D. G. Wagner, L. D. Yates, H. G. Dolezal and S. G. May
Department of Animal Science, Oklahoma State University, Stillwater 74078-0425.

Forty-eight Angus x Hereford yearling steers were used to assess the effect of time on feed (TOF) on the nutrient composition of beef longissimus muscle (LM). Steers were fed a high-concentrate diet with the exception of the d-0 group, which served as a grass-fed control, and then were serially slaughtered at 28-d intervals during the 196-d feeding period. Steaks were removed from the 10th rib and trimmed of exterior fat and epimysial connective tissue before nutrient analysis. Intramuscular fat content doubled (P < .05) between d 84 and 112 but did not differ (P > .05) from d 0 to 84 or from d 112 to 196. This increase in fat content resulted in decreased (P < .05) concentrations of moisture, protein, and ash in the LM. Concentrations of Mg, K, and Fe in the LM increased (P < .10) with advanced TOF. The increase in the total lipid (TL) content of the LM stemmed from a proportional increase (P < .05) in neutral lipid (NL). Polar lipid (PL) remained constant (P = .33) throughout TOF. The NL and TL became more unsaturated as TOF increased, primarily due to a linear (P < .01) increase in oleic (C18:1) acid concentration. In contrast, the polyunsaturated fatty acid (PUFA) concentration in the PL exhibited a linear (P < .01) decrease across TOF. As a result, advanced TOF increased the monounsaturated fatty acid (MUFA) content by 22% and decreased the PUFA content by 72% in the LM. The ratio of hypercholesterolemic (C14 + C16):hypocholesterolemic (MUFA+PUFA) fatty acids was unaffected by increasing TOF from d 28 to 196; however, this ratio was lower (P < .05) for grass-fed controls (d 0) than for d 28 to 84 and d 196. Cholesterol content (milligrams/100 grams) changed cubically (P = .06) across TOF. Ultimately, by limiting TOF to 112 d, the beef industry could provide consumers a palatable beef product that easily fits into a healthy diet and at the same time diminishes the costs associated with external fat trim.

This article has been cited by other articles:

				E. Pavan and S. K. Duckett Corn oil supplementation to steers grazing endophyte-free tall fescue. II. Effects on longissimus muscle and subcutaneous adipose fatty acid composition and stearoyl-CoA desaturase activity and expression J Anim Sci, July 1, 2007; 85(7): 1731 - 1740. [Abstract] [Full Text] [PDF]

				M. H. Gillis, S. K. Duckett, and J. R. Sackmann Effects of supplemental rumen-protected conjugated linoleic acid or corn oil on lipid content and palatability in beef cattle J Anim Sci, June 1, 2007; 85(6): 1504 - 1510. [Abstract] [Full Text] [PDF]

				E. Pavan, S. K. Duckett, and J. G. Andrae Corn oil supplementation to steers grazing endophyte-free tall fescue. I. Effects on in vivo digestibility, performance, and carcass traits J Anim Sci, May 1, 2007; 85(5): 1330 - 1339. [Abstract] [Full Text] [PDF]

				F. Noci, P. French, F. J. Monahan, and A. P. Moloney The fatty acid composition of muscle fat and subcutaneous adipose tissue of grazing heifers supplemented with plant oil-enriched concentrates J Anim Sci, April 1, 2007; 85(4): 1062 - 1073. [Abstract] [Full Text] [PDF]

				R. L. Larson Effect of cattle disease on carcass traits J Anim Sci, June 1, 2005; 83(13_suppl): E37 - 43. [Abstract] [Full Text] [PDF]

				F. Noci, F. J. Monahan, P. French, and A. P. Moloney The fatty acid composition of muscle fat and subcutaneous adipose tissue of pasture-fed beef heifers: Influence of the duration of grazing J Anim Sci, May 1, 2005; 83(5): 1167 - 1178. [Abstract] [Full Text] [PDF]

				K. W. Bruns, R. H. Pritchard, and D. L. Boggs The relationships among body weight, body composition, and intramuscular fat content in steers J Anim Sci, May 1, 2004; 82(5): 1315 - 1322. [Abstract] [Full Text] [PDF]

				M. H. Gillis, S. K. Duckett, and J. R. Sackmann Effects of supplemental rumen-protected conjugated linoleic acid or corn oil on fatty acid composition of adipose tissues in beef cattle J Anim Sci, May 1, 2004; 82(5): 1419 - 1427. [Abstract] [Full Text] [PDF]

				Z. C. T. R. Daniel, R. J. Wynn, A. M. Salter, and P. J. Buttery Differing effects of forage and concentrate diets on the oleic acid and conjugated linoleic acid content of sheep tissues: The role of stearoyl-CoA desaturase J Anim Sci, March 1, 2004; 82(3): 747 - 758. [Abstract] [Full Text] [PDF]

				M. H. Gillis, S. K. Duckett, J. R. Sackmann, C. E. Realini, D. H. Keisler, and T. D. Pringle Effects of supplemental rumen-protected conjugated linoleic acid or linoleic acid on feedlot performance, carcass quality, and leptin concentrations in beef cattle J Anim Sci, March 1, 2004; 82(3): 851 - 859. [Abstract] [Full Text] [PDF]

				M. J. Azain Role of fatty acids in adipocyte growth and development J Anim Sci, March 1, 2004; 82(3): 916 - 924. [Abstract] [Full Text] [PDF]

				K. E. Griswold, G. A. Apgar, R. A. Robinson, B. N. Jacobson, D. Johnson, and H. D. Woody Effectiveness of short-term feeding strategies for altering conjugated linoleic acid content of beef J Anim Sci, July 1, 2003; 81(7): 1862 - 1871. [Abstract] [Full Text] [PDF]