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Fifty-four Holstein bulls were blocked by initial BW (301 [+ or -] 7.4 kg) and randomly assigned to 6 treatments following a 3 x 2 factorial arrangement, with 3 concentrate lipid levels (5, 8, and 11% of DM) and 2 lipid sources (whole canola seed and whole linseed), with the objective of evaluating the possibility of increasing the content of n-3 fatty acids in meat. Concentrates (mostly corn meal) were isonitrogenous and isocaloric. Concentrate and straw were both fed ad libitum. Animal BW was recorded every 2 wk, and feed consumption was recorded weekly. Ruminal pH and VFA concentrations were determined monthly. Bulls were transported to the slaughterhouse when they achieved the target slaughter weight of 443 kg (after 105 [+ or -] 4 d of fattening). After slaughter, a sample of LM from the sixth to the eighth ribs was dissected and analyzed for intramuscular fat content and fatty acid profile. Dietary lipid source did not affect overall animal performance, rumen fermentation, or carcass quality. Rumen pH was >6.0 despite consumption by the bulls of large amounts of concentrate. In bulls fed linseed, the percentage of n-3 fatty acids in LM increased linearly with lipid level, whereas in bulls fed canola seed it remained constant. The ratio of n-6:n-3 fatty acids was lower (P < 0.01) in the LM of bulls fed linseed (10.0) than in those fed canola seed (26.0). The content of cis9, trans-11-CLA in the LM tended (P = 0.06) to be greater in the bulls fed linseed than in those fed canola seed (62.9 vs. 49.2 mg/kg of LM, respectively). Concentration of n-3 fatty acids in meat of bulls fed high-concentrate diets can be enhanced by whole linseed supplementation without affecting animal performance, ruminal fermentation, or carcass quality. Key words: beef, conjugated linoleic acid, omega-3, linseed, rumen

Using recent geologic mapping combined with digital elevation data, aerial photo interpretation, and cross section balancing, we describe the three-dimensional (3-D) geometry and kinematics of the Nuncios Fold Complex in the Monterrey Salient of northeastern Mexico. This map-scale, evaporite-cored detachment fold structure involves Upper Jurassic through Cretaceous rocks deformed during the Laramide orogeny and comprises two westward plunging anticlines and an intervening, eastward plunging syncline. Seven balanced cross sections and a 3-D model of this north vergent structure document substantial along-strike variations in both fold geometry and detachment depth, suggesting that 3-D flow of the detachment layer may have occurred during folding. Comparison of folds in the Monterrey Salient with those in the neighboring Parras Basin suggests that the latter south vergent folds root to a shallower detachment. We suggest that northward transport of the Monterrey Salient folds on the lower evaporite detachment may have been inhibited by a thick sequence of foreland basin rocks in the northeastern Parras and southern La Popa basins and that the smaller, south verging folds formed where the lower detachment was abandoned and slip was transferred to the shallower detachment, forming a triangle zone at the front of the Sierra Madre orogenic wedge. doi: 10.1029/2003TC001615.