Title page for ETD etd-11142012-150127


Type of Document Master's Thesis
Author Rodriguez, Jose M
Author's Email Address jrodr57@lsu.edu
URN etd-11142012-150127
Title Forage Systems for Finishing Steers in South Louisiana
Degree Master of Science (M.S.)
Department Animal Science (Animal, Dairy, & Poultry Sciences)
Advisory Committee
Advisor Name Title
Gentry, Glen T. Committee Chair
McMillin, Kenneth W. Committee Member
Scaglia, Guillermo Committee Member
Keywords
  • carcass evaluation
  • ADG
  • Forage
  • fatty acids
Date of Defense 2012-07-09
Availability unrestricted
Abstract
Research has found conflicting results on animal performance and carcass traits associated with the use of forage as the primary feed source for finishing cattle. Consumer interest in forage-fed products has grown and little research has been done comparing performance of forage-fed animals and beef finished on different forages. Spring weaned calves (n=54; 257 2.5 kg; 3/8 Gelbvieh, 3/8 Red Angus, and 1/4 Brahman) were used in the evaluation of three forage systems (S1, S2, and S3) on a 100% forage diet in two consecutive years (June 2009 and 2010). Steers were divided into 9 groups based on initial body weight (d0) and randomly assigned to replicates within system (3 replicates per system). Pastures were rotationally stocked at 1.01 ha/steer. Steers in S1 grazed bermudagrass (45% of area) during summer, and ryegrass (35% of area) and ryegrass sod-seeded into bermudagrass paddocks (20% of area) in winter. Steers in S2 grazed bermudagrass (45% of area) during summer, dallisgrass/clover mix (20% of area) during fall and spring, and ryegrass/cereal rye/clover mix (35% of area) during winter. Those in S3 had access to bermudagrass (20% of area) and sorghum-sudan hybrid/forage soybean during summer (7.5% of area each), dallisgrass/clover mix (20% of area) during fall and spring, and ryegrass/cereal rye/clover mix (45% of area) during winter. Excess forage was cut for hay and fed within system when necessary. Average daily gain (ADG) for summer, winter and for the whole study were not different (P > 0.05) between systems. Animals in Y2 (0.5 kg/d) gained more (P > 0.05) than those in Y1 during summer (0.21 kg/d), but ADG in Y1 (1.5 kg/d) was greater (P > 0.05) than in Y2 (1.3 kg/d) during winter. No significant differences (P > 0.05, Table 3.12) were found in final weights, LM area, KPH, YG, lean color and marbling. Dressing percentage and hot carcass weight were greater (P < 0.05) for S3 than those for S1 and S2 was intermediate. Backfat and PYG was affected by YxS interaction (P < 0.05). Cooking loss and Warner-Bratzler shear force were greater (P < 0.01) for Y1 than for Y2.

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