Hereford yearling steers (N= 144) were alloted to one of three pasture systems: tall fescue, smooth bromegrass-red clover or orchardgrassred clover. After the grazing period, steers were finished in drylot and then serially slaughtered at 0, 56, 84 and 112 days. Carcass quality grades and yield grade numbers increased when steers were fed grain up to 112 days. Tenderness of loin steaks increased up to 84 days, after which no improvements were observed. Sensory panel scores for grassy flavor of steaks and ground beef decreased up to 112 days. Fifty-three compounds were identified in the volatiles of melted subcutaneous fat by direct sampling-gas chromatography/mass spectrometry. The major differences between volatiles from fat of forage-fed compared to grain-fed steers were the higher concentrations of 2,3-octanedione and various diterpenoids present in the samples of the forage-fed animals.

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To evaluate effects of previous forage systems on feedlot performance, yearling Hereford steers (average initial weight of 249 kg) were grazed on tall fescue (TF), smooth bromegrass-red clover (BG-RC) or orchardgrass-red clover (OG-RC) pastures before finishing. Serial slaughter was utilized during the first 2 yr of this study to determine changes in carcass characteristics throughout finishing, while steers were slaughtered at approximately 29% body fat during the third year. Steers grazing TF entered the feedlot at lighter weights and maintained lighter weights throughout finishing (P less than .05) even though dry matter intakes and feed conversions were similar (P greater than .05) among treatments. Steers that previously grazed TF had less (P less than .05) body fat, body protein, fat thickness and marbling, smaller (P less than .05) ribeye areas and lower (P less than .05) USDA yield and quality grades than than those that grazed BG-RC and OG-RC. However, linear contrasts indicated that steers grazing TF were compensating in ribeye area, marbling and quality grade as days in feedlot increased. This was confirmed in the third-year study, since carcass characteristics were similar among all steers. During the third year, linear and quadratic contrasts indicated that steers that grazed TF partially compensated in body protein. As days in feedlot increased, live and hot carcass weights, body fat, fat thickness, kidney, pelvic and heart fat, marbling, and USDA yield and quality grades increased (P less than .05), while ribeye area and body protein plateaued. Although carcass characteristics were similar among treatments, steers backgrounded on TF entered the feedlot at lighter weights, and partially compensated in weight after 134 d of finishing.

The objective of this paper is to review alternative methods of increasing the use of forage in beef finishing systems. Most finishing systems based on an all‐forage diet have not been particularly successful. Without grain finishing, the final product can have an inconsistent quality grade and a grassy flavor. The greatest sensory difference between forage‐fed and grain‐fed steers appears to be the flavor of the fat. Diterpenoids seem to be the off‐flavor's source. These are derived from the action of ruminal microorganisms as they break down chlorophyll. Phyt‐2‐ene has been identified as the most discriminating compound for off‐flavor. It was also found to be the strongest indicator that a steer had been forage‐finished. As time on grain lengthened, the levels of ‐ tetradecalactone and ‐hexadecalactone increased, indicating their correlation with desirable flavor characteristics of grain‐finished beef. Other investigators have correlated the off‐flavor to C 18:3 unsaturated fatty acids. The two methods that show the most promise and increase the use of forage in beef finishing systems are (i) supplemental feeding of cattle on pastures to reduce length of time required for feedlot finishing and (ii) finishing cattle in a pasture with supplemented energy. Efforts to reduce feedlot time have lessened the total concentrate fed and have been economically successful. When finishing cattle in a pasture with supplemental energy, those studies that limited grain intake the last 60 to 80 d before slaughter had mixed results. However, when proper forage management was used in order to ensure adequate supply of high quality forage, carcasses with acceptable quality were produced. Researchers who provided limited supplementation or energy for at least 112 d and fed free choice grain the last 60 to 80 d before slaughter reported that USDA Choice beef was produced. However, USDA quality grade is not necessarily an adequate means to determine the effectiveness of a pasture‐based finishing system. Researchers have to determine when meat flavor changes from “grass” to “grain” and the possibility of achieving this transfer on pasture with energy supplementation. Research Question Cattle are typically finished in a confinement feedlot. Lately, these feedlots have come under close scrutiny. Two of the major concerns are: (i) animal waste with its potential impact on water quality and (ii) economic implications of feeding large amounts of grain to fatten cattle. To respond to these concerns, there is a growing interest in using more pasture in the finishing phase of cattle production. Three of the major reasons for this interest are: (i) an increasing pressure to use practices that are environmentally friendly, (ii) a search for alternative methods of finishing that are profitable, and (iii) a desire to reduce the amount of grain fed to livestock. The beef industry needs to seriously consider all alternative production systems for finishing beef. This study reviews methods of increasing the use of forage when finishing beef, while m...