Angus-cross steers (n = 60) were used to assess the effect of forage species [alfalfa (AL; Medicago sativa L.), bermudagrass (BG; Cynodon dactylon), chicory (CH; Cichorium intybus L.), cowpea (CO; Vigna unguiculata L.), and pearl millet (PM; Pennisetum glaucum (L. R Br.)] in replicated 2-ha paddocks for finishing on cattle performance, carcass quality, and meat quality in a 2-yr study. Steers were blocked by BW and assigned randomly to finishing-forage treatments before the start of the experiment. Steers grazing AL and CH had greater (P < 0.05) ADG than those grazing for BG, CO, and PM, whereas AL produced more (P < 0.05) gain/ha than CH, CO, and PM. Days steers spent grazing were longest (P < 0.05) for PM and shortest (P < 0.05) for CO. Steers grazing BG and CO produced heavier (P < 0.05) HCW than steers grazing BG and PM. Dressing percentage was greatest (P < 0.05) in steers grazing CO, and grazing AL resulted in greater (P < 0.05) dressing percentages than grazing BG, CH, and PM. Grazing AL and CH produced carcasses with more (P < 0.05) fat at the 12th rib than steers grazing warm-season grasses (BG and PM). Marbling scores tended to be greater (P = 0.06) for CO, but carcasses from steers grazing CO received greater (P < 0.05) quality grades than AL and CH. Trans-11 vaccenic (C18:1 trans-11; TVA) acid concentration in the LM was greater (P < 0.05) for BG than CH, CO, and AL. Conjugated linoleic acid, cis-9 trans-11 isomer, concentration was greatest (P < 0.05) for BG and PM than AL, CH, and CO. Grazing CH and PM increased (P < 0.05) the ratio of omega-6 to omega-3 fatty acids in the LM compared with AL, BG, and CO. Grazing legumes (AL and CO) resulted in lower (P < 0.05) Warner-Bratzler shear force values than other forage species. Consumers rated steaks from steers finished on AL and CO pastures greatest (P < 0.05) and steaks from steers finished on BG and CH least (P < 0.05) for overall palatability. Consumer preference was greatest (P < 0.05) for steaks from steers finished on AL and least (P < 0.05) for steaks from steers finished on BG and CH. Finishing steers on AL and CH during summer increased steer performance (> 1 kg/d). Finishing on legumes (AL and CO) increased dressing percentage, reduced Warner-Bratzler shear force values, and increased consumers preference, whereas finishing on grasses (BG and PM) enhanced anticarcinogenic fatty acid concentrations.

Palmitelaidic (C16:1 trans-9) acid has been suggested to have beneficial effects on human health, including reduced adiposity. Objectives of this research were to quantify the amounts of palmitelaidic acid in beef samples and determine the effect of palmitelaidic acid supplementation on lipogenesis in bovine preadipocytes and adipocytes in vitro. For the first objective, palmitelaidic acid content of LM samples from steers finished on forage or concentrate systems was determined. Palmitelaidic acid in LM samples from forage-finished beef ranged from 10 to 17 mg/100 g of muscle corresponding to 0.52% to 0.65% of total fatty acids. Forage species grazed during finishing, and animal age at harvest also altered palmitelaidic acid concentrations and contents in the LM of forage-finished beef. Palmitelaidic acid concentration of concentrate-finished beef was lower (P < 0.05; 0.25% vs. 0.56%); however, because of increased (P < 0.05) total fatty acid content with concentrate finishing, amount of palmitelaidic acid was similar (P > 0.05) to beef from steers finished on pearl millet and greater (P < 0.05) than those finished on alfalfa. For the second objective, undifferentiated preadipocytes and differentiated adipocytes were supplemented with 0 to 300 μM of palmitelaidic acid. Palmitelaidic acid supplementation reduced (P < 0.05) cell viability of undifferentiated preadipocytes at greater levels (150 and 300 μM) but did not affect (P > 0.05) the viability of differentiated adipocytes. In preadipocytes, palmitelaidic acid increased (P < 0.05) palmitelaidic and trans-11 vaccenic (C18:1 trans-11) acids at high levels of supplementation (300 μM). In adipocytes, palmitelaidic acid supplementation increased (P < 0.05) palmitelaidic acid, trans-11 vaccenic acid, and total fatty acid content. In addition, cis-9, trans-11 CLA also increased (P < 0.05) with palmitelaidic acid supplementation in adipocytes. These results indicate that palmitelaidic acid can be elongated in both preadipocytes and adipocytes and desaturated in adipocytes to generate trans-11 vaccenic acid and cis-9, trans-11 CLA, respectively. Beef products are a source of palmitelaidic acid in the human diet, which can be elongated and desaturated to produce trans-11 vaccenic acid and cis-9, trans-11 CLA.

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Thirty-two steers were used to examine forage type (legumes [ and ] vs. grasses [ and ]) with or without individual corn grain supplementation (0 vs. 0.75% of live weight [LW]/d) on beef fatty acid composition and palatability. In each year, steers ( = 16/yr) were randomly assigned to forage type ( = 8/forage type per yr) and to supplementation treatments within forage type ( = 4/supplementation treatment/forage type per yr). Forage types (grasses vs. legumes) were replicated in 2 paddocks of perennial and annual forage type pastures. A mixed model was developed with forage type, corn grain supplementation, and the 2-way interaction as fixed effects and 2 different error terms, one for testing forage and another for testing grain supplement and grain supplement × forage interaction. Corn grain supplementation increased ( = 0.01) ADG by 0.29 kg/d and final LW by 13 kg. Hot carcass weight, dressing percentage (DP), and KPH were greater ( < 0.05) for steers supplemented with corn grain. Carcasses from steers grazing legumes had greater ( = 0.04) DP compared with carcasses from steers grazing grasses. Alpha-linolenic acid concentration was higher ( < 0.05) in LM of steers grazing legumes than in LM of steers grazing grasses, both without supplementation. Supplementation decreased ( < 0.05) linolenic acid levels for both forage types; however, the magnitude of this reduction was greater for legumes than for grasses. The ratio of -6 to -3 PUFA was greater ( = 0.03) in the LM of corn grain-supplemented steers than in the LM of nonsupplemented steers. Supplementation of corn grain decreased ( < 0.05) the percentage of odd-chain fatty acids and increased ( < 0.05) the percentage of MUFA in the LM. Warner-Bratzler shear force values were not altered ( > 0.05) by forage type, supplementation, or the 2-way interaction. Beef finished on legumes had greater concentrations of -3 PUFA, whereas beef supplemented with corn grain had a greater ratio of -6 to -3 fatty acids. On a gravimetric basis (mg/100 g LM), -3 PUFA and CLA contents were not altered with supplementation, indicating that corn grain can be supplemented at this level in a forage-finishing beef system without negative consequences on perceived beneficial fatty acids.