Effects of forage species or concentrate finishing on animal performance, carcass and meat quality1,2

Abstract

Angus-cross steers (n = 128; initial BW = 270 ± 3.8 kg) were used in a 3-yr study to assess effects of forage species grazed before slaughter versus concentrate finishing on carcass and meat quality. At the completion of the stockering phase, steers were randomly allotted to mixed pasture (MP; n = 36/yr) or corn-silage concentrate (CON; n = 12/yr) finishing treatments. At 40 d before harvest, MP steers were randomly divided into 3 forage species treatments: alfalfa (AL), pearl millet (PM), or mixed pasture (MP). Average daily BW gain was greater (P = 0.001) for CON than for forage-finished (FOR) steers during the early and overall finishing phase. During the late finishing phase when FOR steers were grazing difference forage species, ADG was greater (P = 0.03) for PM than MP or AL. Harvest weight and HCW were greater (P < 0.001) for CON than FOR due to the differences in animal performance. Total fat percentage of the 9th to 11th rib section was 46% less(P = 0.028) for FOR than CON due to reductions (P < 0.001) in the percentage of subcutaneous fat. Warner-Bratzler shear force (WBS) values at 14 d and 28 d of aging did not differ (P > 0.78) between CON and FOR and were not altered (P > 0.40) by forage species. Trained sensory panel juiciness, initial tenderness, and overall tenderness scores did not differ (P > 0.17) by finishing treatment or forage species. Beef flavor intensity was greater (P < 0.001) for CON than FOR. Beef flavor intensity was greater (P < 0.02) for AL and PM than MP. Off-flavor intensity was greater (P < 0.001) for all forage-fed steaks, regardless of forage species, than CON. Finishing on forages reduced (P = 0.003) total lipid content by 61% for the LM compared with CON finished cattle. Forage species grazed before harvest did not alter (P > 0.05) total lipid content of the LM. Oleic acid concentration and total MUFA of the LM were 21% and 22% less (P = 0.001) for FOR than CON. Concentrations of all individual [linolenic acid, eicosapentaenoic (EPA), docosapentaenoic (DPA), and docosadexaenoic (DHA) acids] and total n-3 fatty acids were greater (P < 0.001) for FOR than CON. Finishing on AL increased (P = 0.017) the concentration of linolenic acid compared with MP or PM. The ratio of n-6 to n-3 fatty acids was greater (P = 0.001) for CON than FOR and did not differ (P = 0.88) by forage species. Concentrate finishing increases carcass weight with same time endpoints and accelerates deposition of MUFA in comparison with FOR, which reduces carcass weight and fat deposition but maintains high concentrations of n-3 and CLA fatty acids. Finishing system or forage species grazed 40 d before slaughter did not alter beef tenderness but FOR had greater off-flavors according to both trained and descriptive sensory panelists.

Diet and Genotype Effects on n-3 Polyunsaturated Fatty Acids of Beef Lipids

“…In our study beef PUFAs content was higher than the values reported by others (Scollan et al, 2006) LA is the primary PUFAs in both grass/forage-fed and grain-finished beef providing 60-85% of total PUFAs (Duckett et al, 2013). Usually the percentage of PUFAs in beef is increased by as much as 25% in response to grass-feeding due to the lower intramuscular total fat of most grass-fed beef.…”

“…However, the total www.scholink.org/ojs/index.php/ra estimated amount of PUFAs in steaks from U.S. grass/forage-fed cattle may be up to 75mg lower per 100g of beef, primarily as LA (Daley et al, 2010). Only 16 to 26 mg ALA have been reported in various lean cuts for grass/forage cattle versus 4-13 mg ALA from U.S. grain-finished beef, whereas but only traces of n-3 LC-PUFAs are noted in meat from U.S. grass/forage-fed cattle (Duckett et al, 2013).…”

Honduran and U.S. Consumer Assessment of Beef from Various Production Systems with or Without Marinating

“…Although biological type can certainly influence carcass fat deposition (Ito et al, 2012), the grainbased diet of HCF had a positive effect on flavor liking despite the Bos indicus influence of those cattle. Grass fed beef has been reported by U.S. consumers to have less acceptance for beef flavor due to off-flavors (Duckett et al, 2013). Despite previous evidence of a reduction of "grassy" off-flavor from including grain in the animal diet (Larick et al, 1987), in our study no differences in flavor liking scores were observed between HSC and HDP, whereas HCF was more liked than either.…”

“…However, differences in beef production systems, such as those in the U.S. compared to those in Central America, can affect flavor (Smith et al, 1985;Savell et al, 1987). Beef from animals raised on a finishing diet with grains tend to deposit more fat (Duckett et al, 2007;Duckett et al, 2013), positively affecting flavor (Umberger et al, 2000). The grain finishing diet of HCF may have been responsible for similar scores between HCF and U.S. treatments.…”

Quantitative carcass traits of Holstein calves, finished in different systems and slaughter weights

“…REZENDE et al (2012) evaluating Holstein cattle slaughtered at 395 kg, also found no difference in eating plans in growing and finishing for the loin eye area, obtaining average values of 51.46cm². DUCKETT, et al, (2013), found superiority for all quantitative carcass traits who compared finishing systems (feedlot x pasture). However, the amount of the concentrate used was 82% of the diet.…”