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Title: EFFECTS OF WINTER STOCKER GROWTH RATE AND FINISHING DIET ON BEEF LONGISSIMUS FATTY ACID COMPOSITION

Author
item Sonon, R
item Duckettt, S
item Neel, James - Jim
item Realini, C
item Fontenot, J
item Clapham, William

Submitted to: American Society of Animal Science
Publication Type: Proceedings
Publication Acceptance Date: 6/30/2005
Publication Date: 7/24/2005
Citation: Sonon, R.N., Duckettt, S.K., Neel, J.P., Realini, C., Fontenot, J.P., Clapham, W.M. 2005. Effects of winter stocker growth rate and finishing diet on beef longissimus fatty acid composition. #260 J. Anim. Sci., Vol. 83, Suppl. 1, p. 204.

Interpretive Summary:

Technical Abstract: Longissimus muscle of Angus-cross steers (n=68, year 1; n=63, year 2; n=67, year 3) was assayed to determine the effects of winter stocker growth rate (LOW, MED, or HIGH) and finishing diet (corn silage-concentrate, CONC or pasture, PAST) on total lipid content and fatty acid composition of this tissue. Tissue lipid was extracted by chloroform-methanol solvent and fatty acid composition was determined by GLC. Total LM lipid content was greater (P < 0.01) for CONC than PAST (4.03% vs 2.34%) and was higher (P < 0.01) in years 1 and 3 than year 2. Regardless of year and growth rate, LM trans vaccenic acid (C18:1t11) concentration was higher (P < 0.01) for PAST than CONC except for steers grown at LOW in year 2. PAST LM CLAc9t11 concentration was higher by about 100% than in the LM of CONC. Total saturated fatty acids concentration in LM tended to be greater (P = 0.062) for steers on PAST than on CONC and was higher (P < 0.01) in year 1 than years 2 and 3. The sum of LM monounsaturated fatty acids (MUFA) concentration was higher (P < 0.01) in year 1 than year 2 but was similar to year 3. Between growth rates, LM MUFA of steers grown on HIGH rate was greater (P = 0.014) than those on LOW but was similar to those on MED. CONC steers had greater (P < 0.01) LM MUFA concentration than PAST. In years 1 and 2, LM total omega-6 fatty acids concentration did not differ between growth rates but was greater (P < 0.01) for steers at LOW than on HIGH in year 3. Furthermore, LM total omega-6 fatty acids concentration was higher (P = 0.042) for CONC than PAST when steers were grown at LOW but was unaffected by diet when grown at MED or HIGH. Total omega-3 fatty acids concentration was higher (P < 0.01) for PAST than CONC in all years. Omega-6 to omega-3 fatty acids concentration ratio was lower (P < 0.01) for PAST than CONC in all years indicating that pasture finishing system results in the production of a potentially healthier beef.