Sire variation in fatty acid composition of crossbred Wagyu steers and heifers

Effects of sires on lipid composition of subcutaneous adipose tissue and lo ngissimus dorsi muscle were studied using 113 F-1 heifer and steer calves s ired by eight Wagyu bulls out of three different cow herds. Wagyu sires wer e used and grouped as Old (n = 6) and New (n = 2) sires, respectively, base d on the chronological order in which they were imported into the US. Anima ls were fed a backgrounding diet for 112 days consisting of an 80:20 ratio of roughage:concentrate, then grazed on orchard grass and bluegrass for 84 days, and finished on a 10:90 ratio of roughage:concentrate diet for 231 da ys in a feedlot. For longissimus dorsi muscle, progeny from Old sires had h igher (P<0.05) monounsaturated to saturated fatty acid ratios (MUFA:SFA) th an progeny of New sires. There were also differences (P<0.05) among individ ual sires for polyunsaturated to saturated fatty acid ratio (PUFA:SFA) (0.0 5-0.08) and MUFA:SFA (1.03-1.21). Progeny of Angus cows at Washington Stale University (WSU) had lower (P<0.05) MUFA:SFA and lower SFA than progeny of WSU crossbred and commercial cows. Steers had lower (P<0.05) MUFA:SFA and higher (P<0.05) SFA than heifers. For subcutaneous fat, heifers had higher levels (P<0.05) of linoleic acid (C18:2) and PUFA:SFA than the steers. Mean s for ether extractable fat in longissimus dorsi muscle differed among sire s (P<0.05) and ranged from 7.58 to 13.13%. Progeny from WSU Angus cows had higher (P<0.05) ether extractable Eat than WSU crossbred and commercial cow s. Cholesterol content of longissimus dorsi muscle was not influenced by si re, cowherd or sex (P>0.05). (C) 2000 Elsevier Science Ltd. All rights rese rved.