Abstract
With demand for grass-fed beef continuing to increase, there is an immediate need to determine animal performance and product quality from varying grass-fed systems. Therefore, using a whole systems approach, we investigated the performance and carcass quality of multiple grass-fed beef systems in California. The treatments included: 1) steers stocked on pasture, then feedyard finished for 140 days (CON); 2) steers grass-fed for 20 months (20GF); 3) steers grass-fed for 20 months with a 45-day grain finish (GR45); and 4) steers grass-fed for 25 months (25GF). The data were analyzed using a mixed model procedure in R. Final body weight (FBW) varied significantly between treatments (P < 0.05) with the CON cattle finishing at 626 kg and GF20 finishing with the lowest FBW of 478 kg. There were no significant differences in FBW between GF45 and GF25 treatments (P > 0.05), with FBW equaling 551 kg and 570 kg, respectively. Dressing percentage (DP) differed significantly between all treatments (P < 0.05), with CON DP at 61.8%, followed by GR45 at 57.5%, GF25 at 53.4%, and GF20 at 50.3%. Marbling scores and quality grades were significantly higher for CON compared to all other treatments (P < 0.05), with a marbling score of 421; 14% of CON animals graded select and 85% graded choice or upper choice. Cattle in the GR20 had the lowest marbling score of 285 (P < 0.05); 59% of the GR20 cattle graded select and 41% graded standard. There was no difference in marbling when comparing the GF25 and GR45 (P > 0.5). In addition, carcasses graded similarly between the two treatments with GF25 grading 13% standard 82% select, and 6% choice, GR45 graded 85% select and 15% choice. The findings from this study indicate that varying CA grass-fed beef production systems results in significant differences in both animal performance and meat quality.
DEVELOPMENT OF A TECHNOLOGICAL INDEX FOR THE ASSESSMENT OF THE BEEF PRODUCTION SYSTEMS OF THE VERMELHO RIVER BASIN IN GOIÁS, BRAZIL
